Nano_Vaders

Space Invaders for the Nano Every using a 2.7" OLED Display

Nov 19, 2022

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games

Devices & Components

Arduino Nano Every

2.7 Inch 128x64 White OLED display

Audio Transducer

Vero Board (Strip Board)

Push Buttons

Hardware & Tools

Soldering iron (generic)

Solder Wire, Lead Free

Software & Tools

Arduino IDE

Project description

Code

Nano Vaders

arduino

Sketch for my Nano Vaders game.

1// Space Invaders game based on the work of
2// http://www.xtronical.com/projects/space-invaders/
3//  and Ricardo Moreno (check out youtube video)
4//
5// Uses SSD1325 SPI OLED display  128x64
6//
7// MEGA/LEONARDO/NANO EVERY Only. Needs the Extra Ram
8
9
10#include  <SPI.h>
11#include <U8g2lib.h>
12#include <EEPROM.h>
13 
14// DISPLAY SETTINGS
15#define  SCREEN_WIDTH 128
16#define SCREEN_HEIGHT 64
17
18#define OLED_CLK 13
19#define  OLED_MOSI 11
20#define OLED_CS 3
21#define OLED_DC 2
22#define OLED_RST 8
23
24
25U8G2_SSD1325_NHD_128X64_F_4W_HW_SPI  display(U8G2_R0, OLED_CS, OLED_DC, OLED_RST);  // 2.7 inch White/Black
26  
27
28  
29// Input settings
30#define FIRE_BUT 6
31#define RIGHT_BUT 5
32#define  LEFT_BUT 4
33 
34// Mothership
35#define MOTHERSHIP_HEIGHT 3
36#define MOTHERSHIP_WIDTH  7
37#define MOTHERSHIP_SPEED 1
38#define MOTHERSHIP_SPAWN_CHANCE 150                //  Was 150
39#define DISPLAY_MOTHERSHIP_BONUS_TIME 20           // how long bonus  stays on screen for displaying mothership
40 
41// Alien Settings
42#define ALIEN_HEIGHT  3                             // Was 8
43#define NUM_ALIEN_COLUMNS 11                       //  Was 7
44#define NUM_ALIEN_ROWS 5
45#define X_START_OFFSET 26
46#define SPACE_BETWEEN_ALIEN_COLUMNS  2
47#define LARGEST_ALIEN_WIDTH 5
48#define SPACE_BETWEEN_ROWS 6
49#define INVADERS_DROP_BY  2                          // Was 4
50#define INVADERS_SPEED 10                           //  Was 6
51#define INVADER_HEIGHT 3                            // Was 8 
52#define  EXPLOSION_GFX_TIME 10                       // Was 7
53#define AMOUNT_TO_DROP_BY_PER_LEVEL  4               // NEW How much farther down aliens start per new level
54#define  LEVEL_TO_RESET_TO_START_HEIGHT 4            // EVERY MULTIPLE OF THIS LEVEL THE  ALIEN y START POSITION WILL RESET TO TOP
55#define ALIEN_X_MOVE_AMOUNT 1                       //  Was 1
56#define CHANCEOFBOMBDROPPING 40                     // Was 40
57#define  BOMB_HEIGHT 4
58#define BOMB_WIDTH 2
59#define MAXBOMBS 3                                  //  Was 3
60#define CHANCE_OF_BOMB_DAMAGE_TO_LEFT_OR_RIGHT 20   // higher more chance
61#define  CHANCE_OF_BOMB_PENETRATING_DOWN 1           // higher more chance
62 
63// Player  settingsc
64#define TANKGFX_WIDTH 5
65#define TANKGFX_HEIGHT 3
66#define PLAYER_X_MOVE_AMOUNT  2                       // Was 5
67#define LIVES 3                                      //  NEW
68#define PLAYER_EXPLOSION_TIME 10                     // How long an ExplosionGfx  remains on screen before dissapearing
69#define PLAYER_Y_START 61
70#define PLAYER_X_START  20
71#define BASE_WIDTH 8               
72#define BASE_HEIGHT 6
73#define BASE_Y  53
74#define NUM_BASES 4
75 
76#define MISSILE_HEIGHT 4
77#define MISSILE_WIDTH  1
78#define MISSILE_SPEED 3                              // Was 5
79 
80// Status  of a game object constants
81#define ACTIVE 0
82#define EXPLODING 1
83#define  DESTROYED 2
84
85unsigned long lastMillis;
86unsigned long frameCount;
87unsigned  int framesPerSecond;
88
89
90// background dah dah dah sound setting
91#define  NOTELENGTH 1                                 // larger means play note longer
92  
93
94 
95// graphics
96// aliens
97 
98 const unsigned char MotherShipGfx  [] PROGMEM = {
99  B01111100,
100  B10111010,
101  B11101110
102};
103 
104const  unsigned char InvaderTopGfx [] PROGMEM = {
105  B00000010,
106  B00000111,
107  B00000101,
108};
109  
110const unsigned char InvaderTopGfx2 [] PROGMEM = {
111  B00000101,
112  B00000111,
113  B00000010,
114};
115 
116const unsigned char PROGMEM InvaderMiddleGfx []=
117{
118  B00001010,
119  B00011111,
120  B00010101,
121};
122 
123const unsigned char PROGMEM  InvaderMiddleGfx2 [] = {
124  B00010101,
125  B00011111,
126  B00001010,
127};
128  
129const unsigned char PROGMEM InvaderBottomGfx [] = {
130  B00001010,
131  B00010101,
132  B00011011,
133};
134 
135const unsigned char PROGMEM InvaderBottomGfx2 [] = {
136  B00011011,
137  B00010101,
138  B00001110,
139};
140 
141static const unsigned  char PROGMEM ExplosionGfx [] = {
142  B00010101,
143  B00001010,
144  B00010101,
145};
146  
147// Player grafix
148const unsigned char PROGMEM TankGfx [] = {
149  B00000100,
150  B00011111,
151  B00011111,
152};
153 
154static const unsigned char PROGMEM MissileGfx  [] = {
155  B00000001,
156  B00000001,
157  B00000001,
158  B00000001,
159};
160  
161static const unsigned char PROGMEM AlienBombGfx [] = {
162  B00000010,
163  B00000001,
164  B00000010,
165  B00000001,
166};
167 
168static const unsigned char PROGMEM BaseGfx  [] = {
169  B00111100,
170  B01111110,
171  B11111111,
172  B11111111,
173  B11100111,
174  B11000011,
175};
176 
177 
178// Game structures
179 
180struct GameObjectStruct  {
181  // base object which most other objects will include
182    signed int  X;
183    signed int Y;  
184    unsigned char Status;  //0 active, 1 exploding,  2 destroyed
185};
186 
187 
188struct BaseStruct {
189    GameObjectStruct Ord;
190    unsigned char Gfx[6];
191};
192 
193 
194struct AlienStruct  {
195  GameObjectStruct  Ord;
196  unsigned char ExplosionGfxCounter;           // how long we want the ExplosionGfx  to last
197};
198 
199struct PlayerStruct  {
200    GameObjectStruct Ord;
201    unsigned  int Score;
202    unsigned char Lives;
203    unsigned char Level;
204    unsigned  char AliensDestroyed;              // count of how many killed so far
205    unsigned  char AlienSpeed;                   // higher the number slower they go, calculated  when ever alien destroyed
206    unsigned char ExplosionGfxCounter;          //  how long we want the ExplosionGfx to last
207};
208 
209 
210// general global variables
211  
212 
213//alien global vars
214//The array of aliens across the screen
215
216AlienStruct  Alien[NUM_ALIEN_COLUMNS][NUM_ALIEN_ROWS];
217AlienStruct MotherShip;
218GameObjectStruct  AlienBomb[MAXBOMBS];
219BaseStruct Base[NUM_BASES];
220 
221static const int TOTAL_ALIENS=NUM_ALIEN_COLUMNS*NUM_ALIEN_ROWS;  //NEW
222 
223 
224// widths of aliens
225// as aliens are the same type per row  we do not need to store their graphic width per alien in the structure above
226//  that would take a byte per alien rather than just three entries here, 1 per row,  saving significnt memory
227byte AlienWidth[]={5,5,5,5,5};  // top, middle ,bottom  widths
228 
229 
230char AlienXMoveAmount=2;  
231signed char InvadersMoveCounter;            // counts down, when 0 move invaders, set according to how many aliens  on screen
232bool AnimationFrame=false;                  // two frames of animation,  if true show one if false show the other
233 
234// Mothership
235signed char MotherShipSpeed;
236unsigned  int MotherShipBonus;
237signed int MotherShipBonusXPos;            // pos to display  bonus at
238unsigned char MotherShipBonusCounter;         // how long bonus amount  left on screen
239 
240 
241// Player global variables
242PlayerStruct Player;
243GameObjectStruct  Missile;
244 
245// game variables
246unsigned int HiScore;
247bool GameInPlay=false;
248  
249// Sound settings and variables
250 
251// music (dah dah dah sound) control,  these are the "pitch" of the four basic notes
252const unsigned char Music[] =  {
253  160,100,80,62
254};
255 
256unsigned char MusicIndex;                     //  index pointer to next note to play
257unsigned MusicCounter;                        //  how long note plays for countdown timer, is set to
258                                              //  NOTELENGTH define above
259bool ShootCompleted=true;                     // stops  music when this is false, so we can here shoot sound
260 
261 
262void setup() 
263{
264  display.begin();
265  display.clear();
266  display.setBitmapMode(1);
267  
268  InitAliens(0); 
269  InitPlayer();
270  
271  pinMode(RIGHT_BUT, INPUT_PULLUP);
272  pinMode(LEFT_BUT, INPUT_PULLUP);
273  pinMode(FIRE_BUT, INPUT_PULLUP);
274 
275  display.setFont(u8g2_font_t0_11b_tf);
276  display.setDrawColor(1);                    //set  the color
277  
278  EEPROM.get(0,HiScore);
279  if(HiScore==65535)                                             //  new unit never written to
280  { 
281    HiScore=0;
282    EEPROM.put(0,HiScore);
283  }
284}
285 
286void loop()  
287{  
288  if(GameInPlay)                                                 //NEW
289  {
290    Physics();
291    UpdateDisplay();
292  }
293  else  
294    AttractScreen();
295}
296
297
298//  3x5 pixel 7 Seg font
299const uint8_t digit[10][5] PROGMEM = {
300   B00000111,    B00000101,    B00000101,    B00000101,    B00000111,
301   B00000100,    B00000100,    B00000100,    B00000100,    B00000100,
302   B00000111,    B00000100,    B00000111,    B00000001,    B00000111,
303   B00000111,    B00000100,    B00000111,    B00000100,    B00000111,
304   B00000101,    B00000101,    B00000111,    B00000100,    B00000100,
305   B00000111,    B00000001,    B00000111,    B00000100,    B00000111,
306   B00000111,    B00000001,    B00000111,    B00000101,    B00000111,
307   B00000111,    B00000100,    B00000100,    B00000100,    B00000100,
308   B00000111,    B00000101,    B00000111,    B00000101,    B00000111,   
309   B00000111,    B00000101,    B00000111,    B00000100,    B00000111,
310  };
311
312 
313void draw_digit(int16_t x, int16_t y, uint8_t  n) {
314display.drawXBMP(x, y, 3, 5, digit[n % 10] );
315}
316
317void print_int(int16_t  x, int16_t y, uint16_t s, uint8_t digit) {
318  x += 4 * (digit - 1);
319  for (;  digit > 0; digit--) {
320    draw_digit(x, y, s % 10);
321    x -= 4;
322    s /=  10;
323  }
324}
325
326
327void AttractScreen()
328{
329  display.clearBuffer();
330
331  CentreText("Play",8); 
332  CentreText("Space Invaders",20); 
333  CentreText("Press  Fire to start",32); 
334  CentreText("Hi Score     ",44);   
335  display.setCursor(80,44);
336  display.print(HiScore);
337
338  display.sendBuffer();
339  
340  if(digitalRead(FIRE_BUT)==0){
341    GameInPlay=true;
342    NewGame();
343  }
344 
345  // CHECK FOR HIGH SCORE  RESET, PLAYER MUST HOLD LEFT AND RIGHT TOGETHER 
346  if((digitalRead(LEFT_BUT)==0)&(digitalRead(RIGHT_BUT)==0))
347  {
348    // Reset high score, don't need to worry about debounce as will ony write  to EEPROM if changed, so writes a 0 then won't write again
349    // if hiscore  still 0 which it will be
350    HiScore=0;
351    EEPROM.put(0,HiScore);
352  }
353}
354  
355void Physics()  {  
356  if(Player.Ord.Status==ACTIVE) {
357    AlienControl();  
358    MotherShipPhysics();
359    PlayerControl(); 
360    MissileControl();
361    CheckCollisions();
362  }
363}
364 
365unsigned char GetScoreForAlien(int RowNumber)
366{
367   // returns value for killing an alien at the row indicated
368   switch (RowNumber)
369   {
370     case 0:return 30;
371     case 1:return 20;
372     case 2:return 10;
373     case 3:return  5;
374     case 4:return  2;
375
376   }
377}
378 
379void MotherShipPhysics()  {
380  if(MotherShip.Ord.Status==ACTIVE)  {                   // spawned, move  it
381    tone(10, ( MotherShip.Ord.X % 8)*500,200);
382    MotherShip.Ord.X+=MotherShipSpeed;
383    if(MotherShipSpeed>0)                                // going left to right  , check if off right hand side
384    {
385      if(MotherShip.Ord.X>=(SCREEN_WIDTH-26))  
386      {
387        MotherShip.Ord.Status=DESTROYED;
388        noTone(10);
389      }
390    }
391    else                                                 //  going right to left , check if off left hand side
392    {
393      if(MotherShip.Ord.X+MOTHERSHIP_WIDTH<28)  
394      {
395        MotherShip.Ord.Status=DESTROYED;
396        noTone(10);
397      }
398    }
399    
400  }
401  else  {
402    // try to spawn mothership
403    if(random(MOTHERSHIP_SPAWN_CHANCE)==1)
404    {
405      MotherShip.Ord.Status=ACTIVE;                // Spawn a mother ship, starts just off screen at top
406      if(random(2)==1)                             // need to set direction
407      {
408        MotherShip.Ord.X=(SCREEN_WIDTH-20-MOTHERSHIP_WIDTH);
409        MotherShipSpeed=-MOTHERSHIP_SPEED;         // if we go in here swaps to  right to left 
410      }
411      else
412      {
413        MotherShip.Ord.X=20;                       // -MOTHERSHIP_WIDTH;
414        MotherShipSpeed=MOTHERSHIP_SPEED;          // set to go left ot right      
415      }
416    }
417  }
418}
419 
420void  PlayerControl()  {
421  // user input checks
422  if((digitalRead(RIGHT_BUT)==0)&(Player.Ord.X+TANKGFX_WIDTH<(SCREEN_WIDTH-20)))
423    Player.Ord.X+=PLAYER_X_MOVE_AMOUNT;
424  if((digitalRead(LEFT_BUT)==0)&(Player.Ord.X>PLAYER_X_START))
425    Player.Ord.X-=PLAYER_X_MOVE_AMOUNT;
426  if((digitalRead(FIRE_BUT)==0)&(Missile.Status!=ACTIVE))  
427  {
428    tone(10, 1000,100);
429    Missile.X=Player.Ord.X+(TANKGFX_WIDTH/2);
430    Missile.Y=PLAYER_Y_START;
431    Missile.Status=ACTIVE;
432  }
433}
434 
435void  MissileControl()
436{ 
437  if(Missile.Status==ACTIVE)  
438  {
439    Missile.Y-=MISSILE_SPEED;
440    if(Missile.Y+MISSILE_HEIGHT<0)       // If off top of screen destroy so can  be used again
441      Missile.Status=DESTROYED;
442  }
443}
444 
445 
446void AlienControl()
447{
448  if((InvadersMoveCounter--)<0)
449  {
450    bool Dropped=false;
451    if((RightMostPos()+AlienXMoveAmount>=(SCREEN_WIDTH-18))  |(LeftMostPos()+AlienXMoveAmount<21)) // at edge of screen
452    {
453      AlienXMoveAmount=-AlienXMoveAmount;               // reverse direction
454      Dropped=true;                                     //  and indicate we are dropping
455    }
456 
457    // play background music note  if other higher priority sounds not playing
458    if((ShootCompleted)&(MotherShip.Ord.Status!=ACTIVE))  {
459      tone(10, Music[MusicIndex],100);
460      MusicIndex++;
461      if(MusicIndex==sizeof(Music))
462        MusicIndex=0;
463      MusicCounter=NOTELENGTH;
464    }
465    // update  the alien postions
466    for(int Across=0;Across<NUM_ALIEN_COLUMNS;Across++) 
467    {
468      for(int Down=0;Down<NUM_ALIEN_ROWS;Down++)
469      {
470        if(Alien[Across][Down].Ord.Status==ACTIVE)
471        {
472          if(Dropped==false)
473            Alien[Across][Down].Ord.X+=AlienXMoveAmount;
474          else
475            Alien[Across][Down].Ord.Y+=INVADERS_DROP_BY;
476        }
477      }
478    }  
479    InvadersMoveCounter=Player.AlienSpeed;
480    AnimationFrame=!AnimationFrame;                      //swap to other frame
481  }
482  // should the alien drop  a bomb
483  if(random(CHANCEOFBOMBDROPPING)==1)  
484    DropBomb();
485  MoveBombs();
486}
487  
488 
489void MoveBombs(){
490  for(int i=0;i<MAXBOMBS;i++){
491    if(AlienBomb[i].Status==ACTIVE)
492      AlienBomb[i].Y+=1;
493  }
494}
495 
496 
497void DropBomb()  {
498  // if  there is a free bomb slot then drop a bomb else nothing happens
499  bool Free=false;
500  unsigned char ActiveCols[NUM_ALIEN_COLUMNS];  
501  unsigned char BombIdx=0;
502  // find a free bomb slot
503  while((Free==false)&(BombIdx<MAXBOMBS)){
504    if(AlienBomb[BombIdx].Status==DESTROYED)
505      Free=true;
506    else
507      BombIdx++;
508  }
509  if(Free)  {
510    unsigned  char Columns=0;
511    // now pick and alien at random to drop the bomb
512    //  we first pick a column, obviously some columns may not exist, so we count number  of remaining cols 
513    // first, this adds time but then also picking columns  randomly that don't exist may take time also
514    unsigned char ActiveColCount=0;
515    signed char Row;
516    unsigned char ChosenColumn;
517    
518    while(Columns<NUM_ALIEN_COLUMNS){
519      Row=(NUM_ALIEN_ROWS-1);
520      while(Row>=0)  {
521        if(Alien[Columns][Row].Ord.Status==ACTIVE)
522        {
523          ActiveCols[ActiveColCount]=Columns;
524          ActiveColCount++;
525          break;
526        }
527        Row--;
528      }
529      Columns++;
530    }
531    // we have ActiveCols array filled with the column numbers of the active  cols and we have how many
532    // in ActiveColCount, now choose a column at random
533    ChosenColumn=random(ActiveColCount);  // random number between 0 and the amount  of columns
534    // we now find the first available alien in this column to drop  the bomb from
535    Row=(NUM_ALIEN_ROWS-1);
536    while(Row>=0)  {
537      if(Alien[ActiveCols[ChosenColumn]][Row].Ord.Status==ACTIVE)  {
538        // Set the bomb from this alien
539        AlienBomb[BombIdx].Status=ACTIVE;
540        AlienBomb[BombIdx].X=Alien[ActiveCols[ChosenColumn]][Row].Ord.X+int(AlienWidth[Row]/2);
541        // above sets bomb to drop around invaders centre, here we add a litrle  randomness around this pos
542        AlienBomb[BombIdx].X=(AlienBomb[BombIdx].X-2)+random(0,4);
543        AlienBomb[BombIdx].Y=Alien[ActiveCols[ChosenColumn]][Row].Ord.Y+4;        
544        break;
545      }
546      Row--;
547    }
548  }
549}
550 
551 
552 
553void  BombCollisions()
554{
555  //check bombs collisions
556  for(int i=0;i<MAXBOMBS;i++)
557  {
558    if(AlienBomb[i].Status==ACTIVE)
559    {
560      if(AlienBomb[i].Y>64)                            // gone off bottom of screen
561        AlienBomb[i].Status=DESTROYED;
562      else  
563      {
564        // HAS IT HIT PLAYERS missile
565          if(Collision(AlienBomb[i],BOMB_WIDTH,BOMB_HEIGHT,Missile,MISSILE_WIDTH,MISSILE_HEIGHT))
566          {
567              // destroy missile and bomb
568              AlienBomb[i].Status=EXPLODING;
569              Missile.Status=DESTROYED;
570          }
571          else
572          {      
573             // has it hit players ship          
574            if(Collision(AlienBomb[i],BOMB_WIDTH,BOMB_HEIGHT,Player.Ord,TANKGFX_WIDTH,TANKGFX_HEIGHT))
575            {
576               PlayerHit();
577               AlienBomb[i].Status=DESTROYED;
578            }
579            else  
580              BombAndBasesCollision(&AlienBomb[i]);
581          }
582       }
583    }
584  }  
585}
586 
587void BombAndBasesCollision(GameObjectStruct  *Bomb)  {            // check and handle any bomb and base collision
588
589  for(int  i=0;i<NUM_BASES;i++)
590  {
591      if(Collision(*Bomb,BOMB_WIDTH,BOMB_HEIGHT,Base[i].Ord,BASE_WIDTH,BASE_HEIGHT))  
592      {
593        unsigned char X=Bomb->X-Base[i].Ord.X;
594        signed  char Bomb_Y=(Bomb->Y+BOMB_HEIGHT)-Base[i].Ord.Y;
595        unsigned char Base_Y=0;
596  
597        while((Base_Y <= Bomb_Y) & (Base_Y<BASE_HEIGHT) & (Bomb->Status==ACTIVE))
598        {
599          unsigned char Idx=(Base_Y);                             //  this gets the index for the byte in question from the gfx array
600          unsigned  char TheByte=Base[i].Gfx[Idx];                 // we now have the byte to inspect,  but need to only look at the 2 bits where the bomb is colliding
601          unsigned  char Mask=B00000011;
602          if (X>6) {X=6; };
603          Mask=(Mask<<(X));
604          TheByte=TheByte & Mask;
605          
606          if(TheByte>0) 
607          { 
608            Mask=~Mask; 
609            Base[i].Gfx[Idx]=Base[i].Gfx[Idx]  & Mask;
610            if (random(CHANCE_OF_BOMB_PENETRATING_DOWN) == false) //  if false BOMB EXPLODES else carries on destroying more
611            Bomb->Status  = EXPLODING;
612          }
613        else
614          Base_Y++;
615         }
616        }
617      }
618    }
619 
620void MissileAndBasesCollisions()  {
621  for(int  i=0;i<NUM_BASES;i++)
622  { 
623      if(Collision(Missile,MISSILE_WIDTH,MISSILE_HEIGHT,Base[i].Ord,BASE_WIDTH,BASE_HEIGHT))  
624      {
625        unsigned char X=Missile.X-Base[i].Ord.X;
626        signed  char Missile_Y=Missile.Y-Base[i].Ord.Y;
627        signed char Base_Y=BASE_HEIGHT-1;
628        while((Base_Y>=Missile_Y)&(Base_Y>=0)&(Missile.Status==ACTIVE))
629        {
630          unsigned char Idx=(Base_Y);
631          unsigned char TheByte=Base[i].Gfx[Idx];
632          unsigned char Mask = B00000011;
633          if (X>6) {X=6; }
634          Mask=(Mask<<(X));
635          TheByte=TheByte & Mask;
636          
637          if(TheByte>0) 
638          { 
639            Mask=~Mask; 
640            Base[i].Gfx[Idx]=Base[i].Gfx[Idx]  & Mask;
641           if(random(CHANCE_OF_BOMB_PENETRATING_DOWN)==false)   // if  false BOMB EXPLODES else carries on destroying more
642              Missile.Status=EXPLODING;
643          }
644          else
645            Base_Y--;
646        }
647      }
648  }
649}
650 
651void PlayerHit()  {
652  Player.Ord.Status=EXPLODING;
653  Player.ExplosionGfxCounter=PLAYER_EXPLOSION_TIME;
654  Missile.Status=DESTROYED;
655}
656 
657void CheckCollisions()
658{
659  MissileAndAlienCollisions();
660  MotherShipCollisions();
661  MissileAndBasesCollisions();
662  BombCollisions();  
663  AlienAndBaseCollisions();
664}
665 
666char GetAlienBaseCollisionMask(int  AlienX, int AlienWidth,int BaseX)
667{
668  signed int DamageWidth;
669  unsigned  char LeftMask,RightMask,FullMask;
670  
671 
672  // this routine uses a 1 to mean  remove bit and 0 to preserve, this is kind of opposite of what we would 
673  //  normally think of, but it's done this way as when we perform bit shifting to show  which bits are preserved
674  // it will shift in 0's in (as that's just was the  C shift operater ">>" and "<<" does
675  // at the end we will flip all the  bits 0 becomes 1, 1 becomes 0 etc. so that the mask then works correctly
676  //  with the calling code
677  
678  LeftMask=B11111111;     // initially set to remove  all
679  RightMask=B11111111;    // unless change in code below                
680  // if Alien X more than base x then some start bits are unaffected
681  if(AlienX>BaseX)  
682  {                    
683    // we shift the bits above to the right by  the amount unaffected, thus putting 0's into the bits
684    // not to delete
685    DamageWidth=AlienX-BaseX;
686    LeftMask>>=DamageWidth;          
687  }
688  
689  // now work out how much of remaining byte is affected
690  
691  // if  right hand side of alien is less than BaseX right hand side then some preserved  at the right hand end
692  if(AlienX+AlienWidth<BaseX+(BASE_WIDTH/2))
693  {
694    DamageWidth=(BaseX+(BASE_WIDTH/2))-(AlienX+AlienWidth);
695    RightMask<<=DamageWidth;      
696    
697  }
698  // we now have two masks, one showing which bits to preserve  on left of the byte, the other the right hand side, 
699  // we need to combine  them to one mask, the code in the brackets does this combining
700 
701  // at the  moment a 0 means keep, 1 destroy, but this is actually makes it difficult to implement  later on, so we flip
702  // the bits to be a more logical 1= keep bit and 0 remove  bit (pixel) and then return the mask
703  // the tilde (~) flips the bits that resulted  from combining the two masks
704  
705  return ~(LeftMask & RightMask);
706}
707  
708void DestroyBase(GameObjectStruct *Alien,BaseStruct *Base,char Mask,int BaseByteOffset)
709{
710  signed char Y;
711  // go down "removing" bits to the depth that the alien is  down into the base
712  Y=(Alien->Y+ALIEN_HEIGHT)-Base->Ord.Y;
713  if(Y>BASE_HEIGHT-1)  Y=BASE_HEIGHT-1;
714  for(;Y>=0;Y--){
715    Base->Gfx[(Y)+BaseByteOffset]=Base->Gfx[(Y)+BaseByteOffset]  & Mask;
716  }
717}
718 
719void AlienAndBaseCollisions()  
720{
721  unsigned char  Mask;
722  // checks if aliens are in collision with the tank
723  // start at bottom  row as they are most likely to be in contact or not and if not then none further  up are either
724  for(int row=(NUM_ALIEN_ROWS-1);row>=0;row--)
725  {
726    for(int  column=0;column<NUM_ALIEN_COLUMNS;column++)
727    {
728      if(Alien[column][row].Ord.Status==ACTIVE)
729      {
730        // now scan for a collision with each base in turn
731        for(int  BaseIdx=0;BaseIdx<NUM_BASES;BaseIdx++)
732        {          
733          if(Collision(Alien[column][row].Ord,AlienWidth[row],ALIEN_HEIGHT,Base[BaseIdx].Ord,BASE_WIDTH,BASE_HEIGHT))
734          {
735            // WE HAVE A COLLSISION, REMOVE BITS OF BUILDING
736            // process left half (first byte) of base first
737            Mask=GetAlienBaseCollisionMask(Alien[column][row].Ord.X,AlienWidth[row],Base[BaseIdx].Ord.X);
738            DestroyBase(&Alien[column][row].Ord,&Base[BaseIdx],Mask,0);
739          }
740        }
741      }
742    }
743  }
744}
745 
746void MotherShipCollisions()
747{
748  if((Missile.Status==ACTIVE)&(MotherShip.Ord.Status==ACTIVE))
749  {
750    if(Collision(Missile,MISSILE_WIDTH,MISSILE_HEIGHT,MotherShip.Ord,MOTHERSHIP_WIDTH,MOTHERSHIP_HEIGHT))
751    {
752      MotherShip.Ord.Status=EXPLODING;
753      MotherShip.ExplosionGfxCounter=EXPLOSION_GFX_TIME;
754      Missile.Status=DESTROYED;
755      // generate the score for the mothership  hit, note in the real arcade space invaders the score was not random but 
756      //  just appeared so, a player could infulence its value with clever play, but we'll  keep it a little simpler
757      MotherShipBonus=random(4); // a random number  between 0 and 3
758      switch(MotherShipBonus)
759      {
760        case 0:MotherShipBonus=50;break;
761        case 1:MotherShipBonus=100;break;
762        case 2:MotherShipBonus=150;break;
763        case 3:MotherShipBonus=300;break;
764      }
765      Player.Score+=MotherShipBonus;
766      MotherShipBonusXPos=MotherShip.Ord.X;    
767      if(MotherShipBonusXPos>100)                   // to ensure isn't half off right hand side of screen
768        MotherShipBonusXPos=100;       
769      if(MotherShipBonusXPos<0)                   // to ensure isn't  half off right hand side of screen
770        MotherShipBonusXPos=0;       
771      MotherShipBonusCounter=DISPLAY_MOTHERSHIP_BONUS_TIME;        
772    }
773  }
774}
775 
776 
777void MissileAndAlienCollisions()
778{
779   for(int across=0;across<NUM_ALIEN_COLUMNS;across++)
780  {
781    for(int down=0;down<NUM_ALIEN_ROWS;down++)
782    {
783      if(Alien[across][down].Ord.Status==ACTIVE)
784      {
785        if(Missile.Status==ACTIVE)
786        {
787          if(Collision(Missile,MISSILE_WIDTH,MISSILE_HEIGHT,Alien[across][down].Ord,AlienWidth[down],INVADER_HEIGHT))
788          {
789              // missile hit
790              Alien[across][down].Ord.Status=EXPLODING;
791             tone(10, 700,100);
792              Missile.Status=DESTROYED;
793              Player.Score+=GetScoreForAlien(down);
794              Player.AliensDestroyed++;
795              // calc new speed of aliens,  note (float) must be before TOTAL_ALIENS to force float calc else
796              //  you will get an incorrect result
797              Player.AlienSpeed=((1-(Player.AliensDestroyed/(float)TOTAL_ALIENS))*INVADERS_SPEED);              
798              // for very last alien make to  fast!
799              if(Player.AliensDestroyed==TOTAL_ALIENS-2)
800                if(AlienXMoveAmount>0)
801                  AlienXMoveAmount=ALIEN_X_MOVE_AMOUNT*2;
802                else
803                  AlienXMoveAmount=-(ALIEN_X_MOVE_AMOUNT*2);
804              // for very last alien make to super fast!
805              if(Player.AliensDestroyed==TOTAL_ALIENS-1)
806                if(AlienXMoveAmount>0)
807                  AlienXMoveAmount=ALIEN_X_MOVE_AMOUNT*4;
808                else
809                  AlienXMoveAmount=-(ALIEN_X_MOVE_AMOUNT*4);
810                  
811              if(Player.AliensDestroyed==TOTAL_ALIENS)
812                NextLevel(&Player);            
813          }
814        }
815          if(Alien[across][down].Ord.Status==ACTIVE)      // double check still  active afer above code
816        {
817          // check if this alien is in contact  with TankGfx
818          if(Collision(Player.Ord,TANKGFX_WIDTH,TANKGFX_HEIGHT,Alien[across][down].Ord,AlienWidth[down],ALIEN_HEIGHT))
819             PlayerHit();  
820          else 
821          {
822            //  check if alien is below bottom of screen
823             if(Alien[across][down].Ord.Y+8>SCREEN_HEIGHT)
824                 PlayerHit();                   
825          }
826        }
827      }
828    }
829  }
830}
831 
832bool Collision(GameObjectStruct Obj1,unsigned  char Width1,unsigned char Height1,GameObjectStruct Obj2,unsigned char Width2,unsigned  char Height2)
833{
834  return ((Obj1.X+Width1>Obj2.X)&(Obj1.X<Obj2.X+Width2)&(Obj1.Y+Height1>Obj2.Y)&(Obj1.Y<Obj2.Y+Height2));
835}
836  
837int RightMostPos()  {
838  //returns x pos of right most alien
839  int Across=NUM_ALIEN_COLUMNS-1;
840  int Down;
841  int Largest=0;
842  int RightPos;
843  while(Across>=0){
844    Down=0;
845    while(Down<NUM_ALIEN_ROWS){
846      if(Alien[Across][Down].Ord.Status==ACTIVE)
847      {
848        // different aliens have different widths, add to x pos to get  rightpos
849        RightPos= Alien[Across][Down].Ord.X+AlienWidth[Down];
850        if(RightPos>Largest)
851          Largest=RightPos;
852      }
853      Down++;
854    }
855    if(Largest>0)  // we have found largest for this coloum
856      return Largest;
857    Across--;
858  }
859  return 0;  // should never get this far
860}
861 
862int LeftMostPos()  {
863  //returns x pos of left most alien
864  int Across=0;
865  int Down;
866  int Smallest=SCREEN_WIDTH*2;
867  while(Across<NUM_ALIEN_COLUMNS){
868    Down=0;
869    while(Down<NUM_ALIEN_ROWS){
870      if(Alien[Across][Down].Ord.Status==ACTIVE)
871        if(Alien[Across][Down].Ord.X<Smallest)
872          Smallest=Alien[Across][Down].Ord.X;
873      Down++;
874    }
875    if(Smallest<SCREEN_WIDTH*2)  // we have found smalest  for this coloum
876      return Smallest;
877    Across++;
878  }
879  return 0;  // should nevr get this far
880}
881 
882void UpdateDisplay()  
883{
884  int  i;
885  
886  display.clearBuffer();
887  
888  // Mothership bonus display if required
889  if(MotherShipBonusCounter>0)
890  {
891    print_int(MotherShipBonusXPos, 0, MotherShipBonus,  3);
892    MotherShipBonusCounter--;   
893  }
894
895    print_int(0, 0, Player.Score,  5);                          // draw score and lives, anything else can go above  them
896    print_int(0, 20, HiScore, 5);
897    print_int(125, 0, Player.Lives,  1);
898    display.drawXBMP(115, 2, TANKGFX_WIDTH, TANKGFX_HEIGHT, TankGfx );
899    display.drawVLine(20,0,64 );
900    display.drawVLine(109,0,64 );
901
902    print_int(0,  59, framesPerSecond, 3);
903
904    frameCount ++;
905    if ((millis() - lastMillis)  > (1000)) {
906      framesPerSecond = (frameCount );
907      frameCount = 0;
908      lastMillis = millis();
909    }
910 
911  //BOMBS
912  // draw bombs next  as aliens have priority of overlapping them
913  for(i=0;i<MAXBOMBS;i++)  {
914      if(AlienBomb[i].Status==ACTIVE)
915        display.drawXBMP(AlienBomb[i].X,  AlienBomb[i].Y, 2, 4 , AlienBombGfx);
916      else  {// must be destroyed
917        if(AlienBomb[i].Status==EXPLODING)
918         display.drawXBMP(AlienBomb[i].X-4, AlienBomb[i].Y, 5, 3, ExplosionGfx );
919        // Ensure on next draw that ExplosionGfx dissapears
920        AlienBomb[i].Status=DESTROYED;
921      }
922  }
923  
924  //Invaders
925  for(int across=0;across<NUM_ALIEN_COLUMNS;across++)
926  {
927    for(int down=0;down<NUM_ALIEN_ROWS;down++)
928    {
929      if(Alien[across][down].Ord.Status==ACTIVE){
930
931        switch(down)  {
932          case 0: 
933            if(AnimationFrame)
934              display.drawXBMP(Alien[across][down].Ord.X, Alien[across][down].Ord.Y,  AlienWidth[down],INVADER_HEIGHT, InvaderTopGfx );
935            else
936              display.drawXBMP(Alien[across][down].Ord.X,  Alien[across][down].Ord.Y, AlienWidth[down],INVADER_HEIGHT, InvaderTopGfx2 );
937            break;
938          case 1: 
939            if(AnimationFrame)
940              display.drawXBMP(Alien[across][down].Ord.X,  Alien[across][down].Ord.Y, AlienWidth[down],INVADER_HEIGHT,  InvaderMiddleGfx );
941            else
942              display.drawXBMP(Alien[across][down].Ord.X, Alien[across][down].Ord.Y,  AlienWidth[down],INVADER_HEIGHT,  InvaderMiddleGfx2 );
943            break;
944          case 2: 
945            if(AnimationFrame)
946              display.drawXBMP(Alien[across][down].Ord.X,  Alien[across][down].Ord.Y, AlienWidth[down],INVADER_HEIGHT, InvaderMiddleGfx );
947            else
948              display.drawXBMP(Alien[across][down].Ord.X, Alien[across][down].Ord.Y,  AlienWidth[down],INVADER_HEIGHT, InvaderMiddleGfx2);
949            break;
950          case  3: 
951            if(AnimationFrame)
952              display.drawXBMP(Alien[across][down].Ord.X,  Alien[across][down].Ord.Y, AlienWidth[down],INVADER_HEIGHT, InvaderBottomGfx );
953            else
954              display.drawXBMP(Alien[across][down].Ord.X, Alien[across][down].Ord.Y,  AlienWidth[down],INVADER_HEIGHT, InvaderBottomGfx2 );
955          case 4: 
956            if(AnimationFrame)
957              display.drawXBMP(Alien[across][down].Ord.X,  Alien[across][down].Ord.Y, AlienWidth[down],INVADER_HEIGHT, InvaderBottomGfx );
958            else
959              display.drawXBMP(Alien[across][down].Ord.X, Alien[across][down].Ord.Y,  AlienWidth[down],INVADER_HEIGHT, InvaderBottomGfx2 );
960        }
961      }
962      else  {
963        if(Alien[across][down].Ord.Status==EXPLODING){
964          Alien[across][down].ExplosionGfxCounter--;
965          if(Alien[across][down].ExplosionGfxCounter>0)  {
966            tone(10,  Alien[across][down].ExplosionGfxCounter*100,100);
967            display.drawXBMP(Alien[across][down].Ord.X,  Alien[across][down].Ord.Y, 5, 3,  ExplosionGfx );
968          }
969          else
970            Alien[across][down].Ord.Status=DESTROYED;
971        }
972      }
973    }
974  }  
975  
976  // player
977  if(Player.Ord.Status==ACTIVE)
978    display.drawXBMP(Player.Ord.X,  Player.Ord.Y, TANKGFX_WIDTH, TANKGFX_HEIGHT,  TankGfx );
979  else {    
980    if(Player.Ord.Status==EXPLODING)  {
981        display.drawXBMP(Player.Ord.X, Player.Ord.Y, 5, 3,  ExplosionGfx  );
982        tone(10, Player.ExplosionGfxCounter*250,50);
983      Player.ExplosionGfxCounter--;
984      if(Player.ExplosionGfxCounter==0)  {
985        Player.Ord.Status=DESTROYED;
986        LoseLife();
987      }
988    }
989  }
990  //missile  
991  if(Missile.Status==ACTIVE)
992    display.drawXBMP(Missile.X, Missile.Y, MISSILE_WIDTH, MISSILE_HEIGHT , MissileGfx);
993  
994  // mothership (not bonus if hit)
995  if(MotherShip.Ord.Status==ACTIVE)
996    display.drawXBMP(MotherShip.Ord.X, MotherShip.Ord.Y, MOTHERSHIP_WIDTH, MOTHERSHIP_HEIGHT,  MotherShipGfx );
997  else
998  {
999    if(MotherShip.Ord.Status==EXPLODING)  
1000    {
1001      tone(10, MotherShip.ExplosionGfxCounter*250,50);
1002      MotherShip.ExplosionGfxCounter--;
1003      if(MotherShip.ExplosionGfxCounter==0)  {
1004        MotherShip.Ord.Status=DESTROYED;
1005      }
1006    }
1007  }
1008 
1009  // plot bases
1010  
1011  for(i=0; i <NUM_BASES;  i++)  {    
1012    if (Base[i].Ord.Status == ACTIVE)
1013      display.drawXBM(Base[i].Ord.X,  Base[i].Ord.Y, BASE_WIDTH, BASE_HEIGHT, Base[i].Gfx );
1014  }
1015  display.sendBuffer();
1016}
1017  
1018void LoseLife()  {
1019  Player.Lives--;
1020  if(Player.Lives>0)  {
1021    DisplayPlayerAndLives(&Player);
1022    // clear alien missiles
1023    for(int i=0;i<MAXBOMBS;i++)  {
1024      AlienBomb[i].Status=DESTROYED;
1025      AlienBomb[i].Y=0;
1026    }
1027    // ENABLE PLAYER
1028    Player.Ord.Status=ACTIVE;
1029    Player.Ord.X=PLAYER_X_START;
1030  }
1031  else  {
1032    GameOver();
1033  }
1034}
1035  
1036 
1037void GameOver()  {  
1038  GameInPlay=false;
1039  display.clearBuffer();
1040  CentreText("Player 1",8); 
1041  CentreText("Game Over",20);   
1042  CentreText("Score     ",32);   
1043  display.setCursor(72,32);
1044  display.print(Player.Score);
1045  if(Player.Score>HiScore)
1046  {
1047    CentreText("NEW HIGH SCORE!!!",44);
1048    CentreText("**CONGRATULATIONS**",56);    
1049  }
1050  display.sendBuffer();
1051  if(Player.Score>HiScore){    
1052    HiScore=Player.Score;
1053    EEPROM.put(0,HiScore);
1054    PlayRewardMusic();
1055  }
1056  delay(2500);  
1057}
1058 
1059 
1060void PlayRewardMusic()
1061{
1062  unsigned char Notes[] = { 26, 20, 18, 22, 20, 0, 26, 0, 26 };
1063  unsigned char  NoteDurations[] = { 40, 20, 20, 40, 30, 50, 30, 10,30 };
1064  for(int i=0;i<9;i++)
1065  {
1066    tone(10, Notes[i]*10);
1067    delay(NoteDurations[i]*10);     // time  note plays for
1068    noTone(10);                     // stop note
1069    delay(20);                      // small delay between notes
1070  }
1071   noTone(10);
1072}
1073  
1074 
1075void DisplayPlayerAndLives(PlayerStruct *Player)  {
1076  display.clearBuffer();
1077  CentreText("  Player 1",8);
1078  CentreText("Score ",20);   
1079  display.print(Player->Score);
1080  CentreText("Lives ",32);   
1081  display.print(Player->Lives); 
1082  CentreText("Level  ",44);   
1083  display.print(Player->Level);   
1084  display.sendBuffer();
1085  delay(2000);
1086  Player->Ord.X=PLAYER_X_START;
1087}
1088 
1089 
1090void CentreText(const  char *Text,unsigned char Y)  {
1091  // centres text on screen
1092  display.setCursor(int((SCREEN_WIDTH  - display.getStrWidth(Text)) / 2.0), Y);
1093  display.print(Text);
1094}
1095 
1096  
1097void InitPlayer()  {
1098  Player.Ord.Y=PLAYER_Y_START;
1099  Player.Ord.X=PLAYER_X_START;
1100  Player.Ord.Status=ACTIVE;
1101  Player.Lives=LIVES;
1102  Player.Level=0;
1103  Missile.Status=DESTROYED;
1104  Player.Score=0;
1105}
1106 
1107 
1108void NextLevel(PlayerStruct *Player)  {              //  reset any dropping bombs
1109
1110  int YStart;
1111  for(int i=0;i<MAXBOMBS;i++)  
1112    AlienBomb[i].Status=DESTROYED;
1113    AnimationFrame=false;
1114    Player->Level++;
1115    YStart=(MOTHERSHIP_HEIGHT +2) + ((Player->Level-1) % LEVEL_TO_RESET_TO_START_HEIGHT)*AMOUNT_TO_DROP_BY_PER_LEVEL;
1116    InitAliens(YStart);  
1117    AlienXMoveAmount=ALIEN_X_MOVE_AMOUNT;
1118    Player->AlienSpeed=INVADERS_SPEED;
1119    Player->AliensDestroyed=0;
1120    MotherShip.Ord.X=-MOTHERSHIP_WIDTH;
1121    MotherShip.Ord.Status=DESTROYED;  
1122    Missile.Status=DESTROYED;
1123    randomSeed(100);     
1124    InitBases();
1125    DisplayPlayerAndLives(Player);  
1126    MusicIndex=0;
1127    MusicCounter=NOTELENGTH;
1128}
1129  
1130 
1131void InitBases()  {                                     // Bases need to  be re-built!
1132  
1133  byte TheByte;
1134  int Spacing=((SCREEN_WIDTH-32)-(NUM_BASES*BASE_WIDTH))/NUM_BASES;
1135  for(int i=0;i<NUM_BASES;i++)  
1136  {    
1137    for(int DataIdx=0;DataIdx<BASE_HEIGHT;DataIdx++)  
1138    {
1139        TheByte = pgm_read_byte(BaseGfx + DataIdx);
1140        Base[i].Gfx[DataIdx]=TheByte;
1141    }
1142    Base[i].Ord.X=17+(i*Spacing)+(i*BASE_WIDTH)+(Spacing/2);
1143    Base[i].Ord.Y=BASE_Y;
1144    Base[i].Ord.Status=ACTIVE;
1145  }
1146}
1147 
1148 
1149void NewGame(){
1150  InitPlayer();
1151  NextLevel(&Player);
1152}
1153 
1154void InitAliens(int YStart)  { 
1155  for(int  across=0;across<NUM_ALIEN_COLUMNS;across++)  {
1156    for(int down=0;down<NUM_ALIEN_ROWS;down++)  {
1157      Alien[across][down].Ord.X=X_START_OFFSET+(across*(LARGEST_ALIEN_WIDTH+SPACE_BETWEEN_ALIEN_COLUMNS))-(AlienWidth[down]/2);  
1158      Alien[across][down].Ord.Y=YStart+(down*SPACE_BETWEEN_ROWS);
1159      Alien[across][down].Ord.Status=ACTIVE;
1160      Alien[across][down].ExplosionGfxCounter=EXPLOSION_GFX_TIME;
1161    }
1162  }
1163  MotherShip.Ord.Y=0;
1164  MotherShip.Ord.X=-MOTHERSHIP_WIDTH;
1165  MotherShip.Ord.Status=DESTROYED;  
1166}
1167

// Space Invaders game based on the work of
// http://www.xtronical.com/projects/space-invaders/
//  and Ricardo Moreno (check out youtube video)
//
// Uses SSD1325 SPI OLED display  128x64
//
// MEGA/LEONARDO/NANO EVERY Only. Needs the Extra Ram


#include  <SPI.h>
#include <U8g2lib.h>
#include <EEPROM.h>
 
// DISPLAY SETTINGS
#define  SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

#define OLED_CLK 13
#define  OLED_MOSI 11
#define OLED_CS 3
#define OLED_DC 2
#define OLED_RST 8


U8G2_SSD1325_NHD_128X64_F_4W_HW_SPI  display(U8G2_R0, OLED_CS, OLED_DC, OLED_RST);  // 2.7 inch White/Black
  

  
// Input settings
#define FIRE_BUT 6
#define RIGHT_BUT 5
#define  LEFT_BUT 4
 
// Mothership
#define MOTHERSHIP_HEIGHT 3
#define MOTHERSHIP_WIDTH  7
#define MOTHERSHIP_SPEED 1
#define MOTHERSHIP_SPAWN_CHANCE 150                //  Was 150
#define DISPLAY_MOTHERSHIP_BONUS_TIME 20           // how long bonus  stays on screen for displaying mothership
 
// Alien Settings
#define ALIEN_HEIGHT  3                             // Was 8
#define NUM_ALIEN_COLUMNS 11                       //  Was 7
#define NUM_ALIEN_ROWS 5
#define X_START_OFFSET 26
#define SPACE_BETWEEN_ALIEN_COLUMNS  2
#define LARGEST_ALIEN_WIDTH 5
#define SPACE_BETWEEN_ROWS 6
#define INVADERS_DROP_BY  2                          // Was 4
#define INVADERS_SPEED 10                           //  Was 6
#define INVADER_HEIGHT 3                            // Was 8 
#define  EXPLOSION_GFX_TIME 10                       // Was 7
#define AMOUNT_TO_DROP_BY_PER_LEVEL  4               // NEW How much farther down aliens start per new level
#define  LEVEL_TO_RESET_TO_START_HEIGHT 4            // EVERY MULTIPLE OF THIS LEVEL THE  ALIEN y START POSITION WILL RESET TO TOP
#define ALIEN_X_MOVE_AMOUNT 1                       //  Was 1
#define CHANCEOFBOMBDROPPING 40                     // Was 40
#define  BOMB_HEIGHT 4
#define BOMB_WIDTH 2
#define MAXBOMBS 3                                  //  Was 3
#define CHANCE_OF_BOMB_DAMAGE_TO_LEFT_OR_RIGHT 20   // higher more chance
#define  CHANCE_OF_BOMB_PENETRATING_DOWN 1           // higher more chance
 
// Player  settingsc
#define TANKGFX_WIDTH 5
#define TANKGFX_HEIGHT 3
#define PLAYER_X_MOVE_AMOUNT  2                       // Was 5
#define LIVES 3                                      //  NEW
#define PLAYER_EXPLOSION_TIME 10                     // How long an ExplosionGfx  remains on screen before dissapearing
#define PLAYER_Y_START 61
#define PLAYER_X_START  20
#define BASE_WIDTH 8               
#define BASE_HEIGHT 6
#define BASE_Y  53
#define NUM_BASES 4
 
#define MISSILE_HEIGHT 4
#define MISSILE_WIDTH  1
#define MISSILE_SPEED 3                              // Was 5
 
// Status  of a game object constants
#define ACTIVE 0
#define EXPLODING 1
#define  DESTROYED 2

unsigned long lastMillis;
unsigned long frameCount;
unsigned  int framesPerSecond;


// background dah dah dah sound setting
#define  NOTELENGTH 1                                 // larger means play note longer
  

 
// graphics
// aliens
 
 const unsigned char MotherShipGfx  [] PROGMEM = {
  B01111100,
  B10111010,
  B11101110
};
 
const  unsigned char InvaderTopGfx [] PROGMEM = {
  B00000010,
  B00000111,
  B00000101,
};
  
const unsigned char InvaderTopGfx2 [] PROGMEM = {
  B00000101,
  B00000111,
  B00000010,
};
 
const unsigned char PROGMEM InvaderMiddleGfx []=
{
  B00001010,
  B00011111,
  B00010101,
};
 
const unsigned char PROGMEM  InvaderMiddleGfx2 [] = {
  B00010101,
  B00011111,
  B00001010,
};
  
const unsigned char PROGMEM InvaderBottomGfx [] = {
  B00001010,
  B00010101,
  B00011011,
};
 
const unsigned char PROGMEM InvaderBottomGfx2 [] = {
  B00011011,
  B00010101,
  B00001110,
};
 
static const unsigned  char PROGMEM ExplosionGfx [] = {
  B00010101,
  B00001010,
  B00010101,
};
  
// Player grafix
const unsigned char PROGMEM TankGfx [] = {
  B00000100,
  B00011111,
  B00011111,
};
 
static const unsigned char PROGMEM MissileGfx  [] = {
  B00000001,
  B00000001,
  B00000001,
  B00000001,
};
  
static const unsigned char PROGMEM AlienBombGfx [] = {
  B00000010,
  B00000001,
  B00000010,
  B00000001,
};
 
static const unsigned char PROGMEM BaseGfx  [] = {
  B00111100,
  B01111110,
  B11111111,
  B11111111,
  B11100111,
  B11000011,
};
 
 
// Game structures
 
struct GameObjectStruct  {
  // base object which most other objects will include
    signed int  X;
    signed int Y;  
    unsigned char Status;  //0 active, 1 exploding,  2 destroyed
};
 
 
struct BaseStruct {
    GameObjectStruct Ord;
    unsigned char Gfx[6];
};
 
 
struct AlienStruct  {
  GameObjectStruct  Ord;
  unsigned char ExplosionGfxCounter;           // how long we want the ExplosionGfx  to last
};
 
struct PlayerStruct  {
    GameObjectStruct Ord;
    unsigned  int Score;
    unsigned char Lives;
    unsigned char Level;
    unsigned  char AliensDestroyed;              // count of how many killed so far
    unsigned  char AlienSpeed;                   // higher the number slower they go, calculated  when ever alien destroyed
    unsigned char ExplosionGfxCounter;          //  how long we want the ExplosionGfx to last
};
 
 
// general global variables
  
 
//alien global vars
//The array of aliens across the screen

AlienStruct  Alien[NUM_ALIEN_COLUMNS][NUM_ALIEN_ROWS];
AlienStruct MotherShip;
GameObjectStruct  AlienBomb[MAXBOMBS];
BaseStruct Base[NUM_BASES];
 
static const int TOTAL_ALIENS=NUM_ALIEN_COLUMNS*NUM_ALIEN_ROWS;  //NEW
 
 
// widths of aliens
// as aliens are the same type per row  we do not need to store their graphic width per alien in the structure above
//  that would take a byte per alien rather than just three entries here, 1 per row,  saving significnt memory
byte AlienWidth[]={5,5,5,5,5};  // top, middle ,bottom  widths
 
 
char AlienXMoveAmount=2;  
signed char InvadersMoveCounter;            // counts down, when 0 move invaders, set according to how many aliens  on screen
bool AnimationFrame=false;                  // two frames of animation,  if true show one if false show the other
 
// Mothership
signed char MotherShipSpeed;
unsigned  int MotherShipBonus;
signed int MotherShipBonusXPos;            // pos to display  bonus at
unsigned char MotherShipBonusCounter;         // how long bonus amount  left on screen
 
 
// Player global variables
PlayerStruct Player;
GameObjectStruct  Missile;
 
// game variables
unsigned int HiScore;
bool GameInPlay=false;
  
// Sound settings and variables
 
// music (dah dah dah sound) control,  these are the "pitch" of the four basic notes
const unsigned char Music[] =  {
  160,100,80,62
};
 
unsigned char MusicIndex;                     //  index pointer to next note to play
unsigned MusicCounter;                        //  how long note plays for countdown timer, is set to
                                              //  NOTELENGTH define above
bool ShootCompleted=true;                     // stops  music when this is false, so we can here shoot sound
 
 
void setup() 
{
  display.begin();
  display.clear();
  display.setBitmapMode(1);
  
  InitAliens(0); 
  InitPlayer();
  
  pinMode(RIGHT_BUT, INPUT_PULLUP);
  pinMode(LEFT_BUT, INPUT_PULLUP);
  pinMode(FIRE_BUT, INPUT_PULLUP);
 
  display.setFont(u8g2_font_t0_11b_tf);
  display.setDrawColor(1);                    //set  the color
  
  EEPROM.get(0,HiScore);
  if(HiScore==65535)                                             //  new unit never written to
  { 
    HiScore=0;
    EEPROM.put(0,HiScore);
  }
}
 
void loop()  
{  
  if(GameInPlay)                                                 //NEW
  {
    Physics();
    UpdateDisplay();
  }
  else  
    AttractScreen();
}


//  3x5 pixel 7 Seg font
const uint8_t digit[10][5] PROGMEM = {
   B00000111,    B00000101,    B00000101,    B00000101,    B00000111,
   B00000100,    B00000100,    B00000100,    B00000100,    B00000100,
   B00000111,    B00000100,    B00000111,    B00000001,    B00000111,
   B00000111,    B00000100,    B00000111,    B00000100,    B00000111,
   B00000101,    B00000101,    B00000111,    B00000100,    B00000100,
   B00000111,    B00000001,    B00000111,    B00000100,    B00000111,
   B00000111,    B00000001,    B00000111,    B00000101,    B00000111,
   B00000111,    B00000100,    B00000100,    B00000100,    B00000100,
   B00000111,    B00000101,    B00000111,    B00000101,    B00000111,   
   B00000111,    B00000101,    B00000111,    B00000100,    B00000111,
  };

 
void draw_digit(int16_t x, int16_t y, uint8_t  n) {
display.drawXBMP(x, y, 3, 5, digit[n % 10] );
}

void print_int(int16_t  x, int16_t y, uint16_t s, uint8_t digit) {
  x += 4 * (digit - 1);
  for (;  digit > 0; digit--) {
    draw_digit(x, y, s % 10);
    x -= 4;
    s /=  10;
  }
}


void AttractScreen()
{
  display.clearBuffer();

  CentreText("Play",8); 
  CentreText("Space Invaders",20); 
  CentreText("Press  Fire to start",32); 
  CentreText("Hi Score     ",44);   
  display.setCursor(80,44);
  display.print(HiScore);

  display.sendBuffer();
  
  if(digitalRead(FIRE_BUT)==0){
    GameInPlay=true;
    NewGame();
  }
 
  // CHECK FOR HIGH SCORE  RESET, PLAYER MUST HOLD LEFT AND RIGHT TOGETHER 
  if((digitalRead(LEFT_BUT)==0)&(digitalRead(RIGHT_BUT)==0))
  {
    // Reset high score, don't need to worry about debounce as will ony write  to EEPROM if changed, so writes a 0 then won't write again
    // if hiscore  still 0 which it will be
    HiScore=0;
    EEPROM.put(0,HiScore);
  }
}
  
void Physics()  {  
  if(Player.Ord.Status==ACTIVE) {
    AlienControl();  
    MotherShipPhysics();
    PlayerControl(); 
    MissileControl();
    CheckCollisions();
  }
}
 
unsigned char GetScoreForAlien(int RowNumber)
{
   // returns value for killing an alien at the row indicated
   switch (RowNumber)
   {
     case 0:return 30;
     case 1:return 20;
     case 2:return 10;
     case 3:return  5;
     case 4:return  2;

   }
}
 
void MotherShipPhysics()  {
  if(MotherShip.Ord.Status==ACTIVE)  {                   // spawned, move  it
    tone(10, ( MotherShip.Ord.X % 8)*500,200);
    MotherShip.Ord.X+=MotherShipSpeed;
    if(MotherShipSpeed>0)                                // going left to right  , check if off right hand side
    {
      if(MotherShip.Ord.X>=(SCREEN_WIDTH-26))  
      {
        MotherShip.Ord.Status=DESTROYED;
        noTone(10);
      }
    }
    else                                                 //  going right to left , check if off left hand side
    {
      if(MotherShip.Ord.X+MOTHERSHIP_WIDTH<28)  
      {
        MotherShip.Ord.Status=DESTROYED;
        noTone(10);
      }
    }
    
  }
  else  {
    // try to spawn mothership
    if(random(MOTHERSHIP_SPAWN_CHANCE)==1)
    {
      MotherShip.Ord.Status=ACTIVE;                // Spawn a mother ship, starts just off screen at top
      if(random(2)==1)                             // need to set direction
      {
        MotherShip.Ord.X=(SCREEN_WIDTH-20-MOTHERSHIP_WIDTH);
        MotherShipSpeed=-MOTHERSHIP_SPEED;         // if we go in here swaps to  right to left 
      }
      else
      {
        MotherShip.Ord.X=20;                       // -MOTHERSHIP_WIDTH;
        MotherShipSpeed=MOTHERSHIP_SPEED;          // set to go left ot right      
      }
    }
  }
}
 
void  PlayerControl()  {
  // user input checks
  if((digitalRead(RIGHT_BUT)==0)&(Player.Ord.X+TANKGFX_WIDTH<(SCREEN_WIDTH-20)))
    Player.Ord.X+=PLAYER_X_MOVE_AMOUNT;
  if((digitalRead(LEFT_BUT)==0)&(Player.Ord.X>PLAYER_X_START))
    Player.Ord.X-=PLAYER_X_MOVE_AMOUNT;
  if((digitalRead(FIRE_BUT)==0)&(Missile.Status!=ACTIVE))  
  {
    tone(10, 1000,100);
    Missile.X=Player.Ord.X+(TANKGFX_WIDTH/2);
    Missile.Y=PLAYER_Y_START;
    Missile.Status=ACTIVE;
  }
}
 
void  MissileControl()
{ 
  if(Missile.Status==ACTIVE)  
  {
    Missile.Y-=MISSILE_SPEED;
    if(Missile.Y+MISSILE_HEIGHT<0)       // If off top of screen destroy so can  be used again
      Missile.Status=DESTROYED;
  }
}
 
 
void AlienControl()
{
  if((InvadersMoveCounter--)<0)
  {
    bool Dropped=false;
    if((RightMostPos()+AlienXMoveAmount>=(SCREEN_WIDTH-18))  |(LeftMostPos()+AlienXMoveAmount<21)) // at edge of screen
    {
      AlienXMoveAmount=-AlienXMoveAmount;               // reverse direction
      Dropped=true;                                     //  and indicate we are dropping
    }
 
    // play background music note  if other higher priority sounds not playing
    if((ShootCompleted)&(MotherShip.Ord.Status!=ACTIVE))  {
      tone(10, Music[MusicIndex],100);
      MusicIndex++;
      if(MusicIndex==sizeof(Music))
        MusicIndex=0;
      MusicCounter=NOTELENGTH;
    }
    // update  the alien postions
    for(int Across=0;Across<NUM_ALIEN_COLUMNS;Across++) 
    {
      for(int Down=0;Down<NUM_ALIEN_ROWS;Down++)
      {
        if(Alien[Across][Down].Ord.Status==ACTIVE)
        {
          if(Dropped==false)
            Alien[Across][Down].Ord.X+=AlienXMoveAmount;
          else
            Alien[Across][Down].Ord.Y+=INVADERS_DROP_BY;
        }
      }
    }  
    InvadersMoveCounter=Player.AlienSpeed;
    AnimationFrame=!AnimationFrame;                      //swap to other frame
  }
  // should the alien drop  a bomb
  if(random(CHANCEOFBOMBDROPPING)==1)  
    DropBomb();
  MoveBombs();
}
  
 
void MoveBombs(){
  for(int i=0;i<MAXBOMBS;i++){
    if(AlienBomb[i].Status==ACTIVE)
      AlienBomb[i].Y+=1;
  }
}
 
 
void DropBomb()  {
  // if  there is a free bomb slot then drop a bomb else nothing happens
  bool Free=false;
  unsigned char ActiveCols[NUM_ALIEN_COLUMNS];  
  unsigned char BombIdx=0;
  // find a free bomb slot
  while((Free==false)&(BombIdx<MAXBOMBS)){
    if(AlienBomb[BombIdx].Status==DESTROYED)
      Free=true;
    else
      BombIdx++;
  }
  if(Free)  {
    unsigned  char Columns=0;
    // now pick and alien at random to drop the bomb
    //  we first pick a column, obviously some columns may not exist, so we count number  of remaining cols 
    // first, this adds time but then also picking columns  randomly that don't exist may take time also
    unsigned char ActiveColCount=0;
    signed char Row;
    unsigned char ChosenColumn;
    
    while(Columns<NUM_ALIEN_COLUMNS){
      Row=(NUM_ALIEN_ROWS-1);
      while(Row>=0)  {
        if(Alien[Columns][Row].Ord.Status==ACTIVE)
        {
          ActiveCols[ActiveColCount]=Columns;
          ActiveColCount++;
          break;
        }
        Row--;
      }
      Columns++;
    }
    // we have ActiveCols array filled with the column numbers of the active  cols and we have how many
    // in ActiveColCount, now choose a column at random
    ChosenColumn=random(ActiveColCount);  // random number between 0 and the amount  of columns
    // we now find the first available alien in this column to drop  the bomb from
    Row=(NUM_ALIEN_ROWS-1);
    while(Row>=0)  {
      if(Alien[ActiveCols[ChosenColumn]][Row].Ord.Status==ACTIVE)  {
        // Set the bomb from this alien
        AlienBomb[BombIdx].Status=ACTIVE;
        AlienBomb[BombIdx].X=Alien[ActiveCols[ChosenColumn]][Row].Ord.X+int(AlienWidth[Row]/2);
        // above sets bomb to drop around invaders centre, here we add a litrle  randomness around this pos
        AlienBomb[BombIdx].X=(AlienBomb[BombIdx].X-2)+random(0,4);
        AlienBomb[BombIdx].Y=Alien[ActiveCols[ChosenColumn]][Row].Ord.Y+4;        
        break;
      }
      Row--;
    }
  }
}
 
 
 
void  BombCollisions()
{
  //check bombs collisions
  for(int i=0;i<MAXBOMBS;i++)
  {
    if(AlienBomb[i].Status==ACTIVE)
    {
      if(AlienBomb[i].Y>64)                            // gone off bottom of screen
        AlienBomb[i].Status=DESTROYED;
      else  
      {
        // HAS IT HIT PLAYERS missile
          if(Collision(AlienBomb[i],BOMB_WIDTH,BOMB_HEIGHT,Missile,MISSILE_WIDTH,MISSILE_HEIGHT))
          {
              // destroy missile and bomb
              AlienBomb[i].Status=EXPLODING;
              Missile.Status=DESTROYED;
          }
          else
          {      
             // has it hit players ship          
            if(Collision(AlienBomb[i],BOMB_WIDTH,BOMB_HEIGHT,Player.Ord,TANKGFX_WIDTH,TANKGFX_HEIGHT))
            {
               PlayerHit();
               AlienBomb[i].Status=DESTROYED;
            }
            else  
              BombAndBasesCollision(&AlienBomb[i]);
          }
       }
    }
  }  
}
 
void BombAndBasesCollision(GameObjectStruct  *Bomb)  {            // check and handle any bomb and base collision

  for(int  i=0;i<NUM_BASES;i++)
  {
      if(Collision(*Bomb,BOMB_WIDTH,BOMB_HEIGHT,Base[i].Ord,BASE_WIDTH,BASE_HEIGHT))  
      {
        unsigned char X=Bomb->X-Base[i].Ord.X;
        signed  char Bomb_Y=(Bomb->Y+BOMB_HEIGHT)-Base[i].Ord.Y;
        unsigned char Base_Y=0;
  
        while((Base_Y <= Bomb_Y) & (Base_Y<BASE_HEIGHT) & (Bomb->Status==ACTIVE))
        {
          unsigned char Idx=(Base_Y);                             //  this gets the index for the byte in question from the gfx array
          unsigned  char TheByte=Base[i].Gfx[Idx];                 // we now have the byte to inspect,  but need to only look at the 2 bits where the bomb is colliding
          unsigned  char Mask=B00000011;
          if (X>6) {X=6; };
          Mask=(Mask<<(X));
          TheByte=TheByte & Mask;
          
          if(TheByte>0) 
          { 
            Mask=~Mask; 
            Base[i].Gfx[Idx]=Base[i].Gfx[Idx]  & Mask;
            if (random(CHANCE_OF_BOMB_PENETRATING_DOWN) == false) //  if false BOMB EXPLODES else carries on destroying more
            Bomb->Status  = EXPLODING;
          }
        else
          Base_Y++;
         }
        }
      }
    }
 
void MissileAndBasesCollisions()  {
  for(int  i=0;i<NUM_BASES;i++)
  { 
      if(Collision(Missile,MISSILE_WIDTH,MISSILE_HEIGHT,Base[i].Ord,BASE_WIDTH,BASE_HEIGHT))  
      {
        unsigned char X=Missile.X-Base[i].Ord.X;
        signed  char Missile_Y=Missile.Y-Base[i].Ord.Y;
        signed char Base_Y=BASE_HEIGHT-1;
        while((Base_Y>=Missile_Y)&(Base_Y>=0)&(Missile.Status==ACTIVE))
        {
          unsigned char Idx=(Base_Y);
          unsigned char TheByte=Base[i].Gfx[Idx];
          unsigned char Mask = B00000011;
          if (X>6) {X=6; }
          Mask=(Mask<<(X));
          TheByte=TheByte & Mask;
          
          if(TheByte>0) 
          { 
            Mask=~Mask; 
            Base[i].Gfx[Idx]=Base[i].Gfx[Idx]  & Mask;
           if(random(CHANCE_OF_BOMB_PENETRATING_DOWN)==false)   // if  false BOMB EXPLODES else carries on destroying more
              Missile.Status=EXPLODING;
          }
          else
            Base_Y--;
        }
      }
  }
}
 
void PlayerHit()  {
  Player.Ord.Status=EXPLODING;
  Player.ExplosionGfxCounter=PLAYER_EXPLOSION_TIME;
  Missile.Status=DESTROYED;
}
 
void CheckCollisions()
{
  MissileAndAlienCollisions();
  MotherShipCollisions();
  MissileAndBasesCollisions();
  BombCollisions();  
  AlienAndBaseCollisions();
}
 
char GetAlienBaseCollisionMask(int  AlienX, int AlienWidth,int BaseX)
{
  signed int DamageWidth;
  unsigned  char LeftMask,RightMask,FullMask;
  
 
  // this routine uses a 1 to mean  remove bit and 0 to preserve, this is kind of opposite of what we would 
  //  normally think of, but it's done this way as when we perform bit shifting to show  which bits are preserved
  // it will shift in 0's in (as that's just was the  C shift operater ">>" and "<<" does
  // at the end we will flip all the  bits 0 becomes 1, 1 becomes 0 etc. so that the mask then works correctly
  //  with the calling code
  
  LeftMask=B11111111;     // initially set to remove  all
  RightMask=B11111111;    // unless change in code below                
  // if Alien X more than base x then some start bits are unaffected
  if(AlienX>BaseX)  
  {                    
    // we shift the bits above to the right by  the amount unaffected, thus putting 0's into the bits
    // not to delete
    DamageWidth=AlienX-BaseX;
    LeftMask>>=DamageWidth;          
  }
  
  // now work out how much of remaining byte is affected
  
  // if  right hand side of alien is less than BaseX right hand side then some preserved  at the right hand end
  if(AlienX+AlienWidth<BaseX+(BASE_WIDTH/2))
  {
    DamageWidth=(BaseX+(BASE_WIDTH/2))-(AlienX+AlienWidth);
    RightMask<<=DamageWidth;      
    
  }
  // we now have two masks, one showing which bits to preserve  on left of the byte, the other the right hand side, 
  // we need to combine  them to one mask, the code in the brackets does this combining
 
  // at the  moment a 0 means keep, 1 destroy, but this is actually makes it difficult to implement  later on, so we flip
  // the bits to be a more logical 1= keep bit and 0 remove  bit (pixel) and then return the mask
  // the tilde (~) flips the bits that resulted  from combining the two masks
  
  return ~(LeftMask & RightMask);
}
  
void DestroyBase(GameObjectStruct *Alien,BaseStruct *Base,char Mask,int BaseByteOffset)
{
  signed char Y;
  // go down "removing" bits to the depth that the alien is  down into the base
  Y=(Alien->Y+ALIEN_HEIGHT)-Base->Ord.Y;
  if(Y>BASE_HEIGHT-1)  Y=BASE_HEIGHT-1;
  for(;Y>=0;Y--){
    Base->Gfx[(Y)+BaseByteOffset]=Base->Gfx[(Y)+BaseByteOffset]  & Mask;
  }
}
 
void AlienAndBaseCollisions()  
{
  unsigned char  Mask;
  // checks if aliens are in collision with the tank
  // start at bottom  row as they are most likely to be in contact or not and if not then none further  up are either
  for(int row=(NUM_ALIEN_ROWS-1);row>=0;row--)
  {
    for(int  column=0;column<NUM_ALIEN_COLUMNS;column++)
    {
      if(Alien[column][row].Ord.Status==ACTIVE)
      {
        // now scan for a collision with each base in turn
        for(int  BaseIdx=0;BaseIdx<NUM_BASES;BaseIdx++)
        {          
          if(Collision(Alien[column][row].Ord,AlienWidth[row],ALIEN_HEIGHT,Base[BaseIdx].Ord,BASE_WIDTH,BASE_HEIGHT))
          {
            // WE HAVE A COLLSISION, REMOVE BITS OF BUILDING
            // process left half (first byte) of base first
            Mask=GetAlienBaseCollisionMask(Alien[column][row].Ord.X,AlienWidth[row],Base[BaseIdx].Ord.X);
            DestroyBase(&Alien[column][row].Ord,&Base[BaseIdx],Mask,0);
          }
        }
      }
    }
  }
}
 
void MotherShipCollisions()
{
  if((Missile.Status==ACTIVE)&(MotherShip.Ord.Status==ACTIVE))
  {
    if(Collision(Missile,MISSILE_WIDTH,MISSILE_HEIGHT,MotherShip.Ord,MOTHERSHIP_WIDTH,MOTHERSHIP_HEIGHT))
    {
      MotherShip.Ord.Status=EXPLODING;
      MotherShip.ExplosionGfxCounter=EXPLOSION_GFX_TIME;
      Missile.Status=DESTROYED;
      // generate the score for the mothership  hit, note in the real arcade space invaders the score was not random but 
      //  just appeared so, a player could infulence its value with clever play, but we'll  keep it a little simpler
      MotherShipBonus=random(4); // a random number  between 0 and 3
      switch(MotherShipBonus)
      {
        case 0:MotherShipBonus=50;break;
        case 1:MotherShipBonus=100;break;
        case 2:MotherShipBonus=150;break;
        case 3:MotherShipBonus=300;break;
      }
      Player.Score+=MotherShipBonus;
      MotherShipBonusXPos=MotherShip.Ord.X;    
      if(MotherShipBonusXPos>100)                   // to ensure isn't half off right hand side of screen
        MotherShipBonusXPos=100;       
      if(MotherShipBonusXPos<0)                   // to ensure isn't  half off right hand side of screen
        MotherShipBonusXPos=0;       
      MotherShipBonusCounter=DISPLAY_MOTHERSHIP_BONUS_TIME;        
    }
  }
}
 
 
void MissileAndAlienCollisions()
{
   for(int across=0;across<NUM_ALIEN_COLUMNS;across++)
  {
    for(int down=0;down<NUM_ALIEN_ROWS;down++)
    {
      if(Alien[across][down].Ord.Status==ACTIVE)
      {
        if(Missile.Status==ACTIVE)
        {
          if(Collision(Missile,MISSILE_WIDTH,MISSILE_HEIGHT,Alien[across][down].Ord,AlienWidth[down],INVADER_HEIGHT))
          {
              // missile hit
              Alien[across][down].Ord.Status=EXPLODING;
             tone(10, 700,100);
              Missile.Status=DESTROYED;
              Player.Score+=GetScoreForAlien(down);
              Player.AliensDestroyed++;
              // calc new speed of aliens,  note (float) must be before TOTAL_ALIENS to force float calc else
              //  you will get an incorrect result
              Player.AlienSpeed=((1-(Player.AliensDestroyed/(float)TOTAL_ALIENS))*INVADERS_SPEED);              
              // for very last alien make to  fast!
              if(Player.AliensDestroyed==TOTAL_ALIENS-2)
                if(AlienXMoveAmount>0)
                  AlienXMoveAmount=ALIEN_X_MOVE_AMOUNT*2;
                else
                  AlienXMoveAmount=-(ALIEN_X_MOVE_AMOUNT*2);
              // for very last alien make to super fast!
              if(Player.AliensDestroyed==TOTAL_ALIENS-1)
                if(AlienXMoveAmount>0)
                  AlienXMoveAmount=ALIEN_X_MOVE_AMOUNT*4;
                else
                  AlienXMoveAmount=-(ALIEN_X_MOVE_AMOUNT*4);
                  
              if(Player.AliensDestroyed==TOTAL_ALIENS)
                NextLevel(&Player);            
          }
        }
          if(Alien[across][down].Ord.Status==ACTIVE)      // double check still  active afer above code
        {
          // check if this alien is in contact  with TankGfx
          if(Collision(Player.Ord,TANKGFX_WIDTH,TANKGFX_HEIGHT,Alien[across][down].Ord,AlienWidth[down],ALIEN_HEIGHT))
             PlayerHit();  
          else 
          {
            //  check if alien is below bottom of screen
             if(Alien[across][down].Ord.Y+8>SCREEN_HEIGHT)
                 PlayerHit();                   
          }
        }
      }
    }
  }
}
 
bool Collision(GameObjectStruct Obj1,unsigned  char Width1,unsigned char Height1,GameObjectStruct Obj2,unsigned char Width2,unsigned  char Height2)
{
  return ((Obj1.X+Width1>Obj2.X)&(Obj1.X<Obj2.X+Width2)&(Obj1.Y+Height1>Obj2.Y)&(Obj1.Y<Obj2.Y+Height2));
}
  
int RightMostPos()  {
  //returns x pos of right most alien
  int Across=NUM_ALIEN_COLUMNS-1;
  int Down;
  int Largest=0;
  int RightPos;
  while(Across>=0){
    Down=0;
    while(Down<NUM_ALIEN_ROWS){
      if(Alien[Across][Down].Ord.Status==ACTIVE)
      {
        // different aliens have different widths, add to x pos to get  rightpos
        RightPos= Alien[Across][Down].Ord.X+AlienWidth[Down];
        if(RightPos>Largest)
          Largest=RightPos;
      }
      Down++;
    }
    if(Largest>0)  // we have found largest for this coloum
      return Largest;
    Across--;
  }
  return 0;  // should never get this far
}
 
int LeftMostPos()  {
  //returns x pos of left most alien
  int Across=0;
  int Down;
  int Smallest=SCREEN_WIDTH*2;
  while(Across<NUM_ALIEN_COLUMNS){
    Down=0;
    while(Down<NUM_ALIEN_ROWS){
      if(Alien[Across][Down].Ord.Status==ACTIVE)
        if(Alien[Across][Down].Ord.X<Smallest)
          Smallest=Alien[Across][Down].Ord.X;
      Down++;
    }
    if(Smallest<SCREEN_WIDTH*2)  // we have found smalest  for this coloum
      return Smallest;
    Across++;
  }
  return 0;  // should nevr get this far
}
 
void UpdateDisplay()  
{
  int  i;
  
  display.clearBuffer();
  
  // Mothership bonus display if required
  if(MotherShipBonusCounter>0)
  {
    print_int(MotherShipBonusXPos, 0, MotherShipBonus,  3);
    MotherShipBonusCounter--;   
  }

    print_int(0, 0, Player.Score,  5);                          // draw score and lives, anything else can go above  them
    print_int(0, 20, HiScore, 5);
    print_int(125, 0, Player.Lives,  1);
    display.drawXBMP(115, 2, TANKGFX_WIDTH, TANKGFX_HEIGHT, TankGfx );
    display.drawVLine(20,0,64 );
    display.drawVLine(109,0,64 );

    print_int(0,  59, framesPerSecond, 3);

    frameCount ++;
    if ((millis() - lastMillis)  > (1000)) {
      framesPerSecond = (frameCount );
      frameCount = 0;
      lastMillis = millis();
    }
 
  //BOMBS
  // draw bombs next  as aliens have priority of overlapping them
  for(i=0;i<MAXBOMBS;i++)  {
      if(AlienBomb[i].Status==ACTIVE)
        display.drawXBMP(AlienBomb[i].X,  AlienBomb[i].Y, 2, 4 , AlienBombGfx);
      else  {// must be destroyed
        if(AlienBomb[i].Status==EXPLODING)
         display.drawXBMP(AlienBomb[i].X-4, AlienBomb[i].Y, 5, 3, ExplosionGfx );
        // Ensure on next draw that ExplosionGfx dissapears
        AlienBomb[i].Status=DESTROYED;
      }
  }
  
  //Invaders
  for(int across=0;across<NUM_ALIEN_COLUMNS;across++)
  {
    for(int down=0;down<NUM_ALIEN_ROWS;down++)
    {
      if(Alien[across][down].Ord.Status==ACTIVE){

        switch(down)  {
          case 0: 
            if(AnimationFrame)
              display.drawXBMP(Alien[across][down].Ord.X, Alien[across][down].Ord.Y,  AlienWidth[down],INVADER_HEIGHT, InvaderTopGfx );
            else
              display.drawXBMP(Alien[across][down].Ord.X,  Alien[across][down].Ord.Y, AlienWidth[down],INVADER_HEIGHT, InvaderTopGfx2 );
            break;
          case 1: 
            if(AnimationFrame)
              display.drawXBMP(Alien[across][down].Ord.X,  Alien[across][down].Ord.Y, AlienWidth[down],INVADER_HEIGHT,  InvaderMiddleGfx );
            else
              display.drawXBMP(Alien[across][down].Ord.X, Alien[across][down].Ord.Y,  AlienWidth[down],INVADER_HEIGHT,  InvaderMiddleGfx2 );
            break;
          case 2: 
            if(AnimationFrame)
              display.drawXBMP(Alien[across][down].Ord.X,  Alien[across][down].Ord.Y, AlienWidth[down],INVADER_HEIGHT, InvaderMiddleGfx );
            else
              display.drawXBMP(Alien[across][down].Ord.X, Alien[across][down].Ord.Y,  AlienWidth[down],INVADER_HEIGHT, InvaderMiddleGfx2);
            break;
          case  3: 
            if(AnimationFrame)
              display.drawXBMP(Alien[across][down].Ord.X,  Alien[across][down].Ord.Y, AlienWidth[down],INVADER_HEIGHT, InvaderBottomGfx );
            else
              display.drawXBMP(Alien[across][down].Ord.X, Alien[across][down].Ord.Y,  AlienWidth[down],INVADER_HEIGHT, InvaderBottomGfx2 );
          case 4: 
            if(AnimationFrame)
              display.drawXBMP(Alien[across][down].Ord.X,  Alien[across][down].Ord.Y, AlienWidth[down],INVADER_HEIGHT, InvaderBottomGfx );
            else
              display.drawXBMP(Alien[across][down].Ord.X, Alien[across][down].Ord.Y,  AlienWidth[down],INVADER_HEIGHT, InvaderBottomGfx2 );
        }
      }
      else  {
        if(Alien[across][down].Ord.Status==EXPLODING){
          Alien[across][down].ExplosionGfxCounter--;
          if(Alien[across][down].ExplosionGfxCounter>0)  {
            tone(10,  Alien[across][down].ExplosionGfxCounter*100,100);
            display.drawXBMP(Alien[across][down].Ord.X,  Alien[across][down].Ord.Y, 5, 3,  ExplosionGfx );
          }
          else
            Alien[across][down].Ord.Status=DESTROYED;
        }
      }
    }
  }  
  
  // player
  if(Player.Ord.Status==ACTIVE)
    display.drawXBMP(Player.Ord.X,  Player.Ord.Y, TANKGFX_WIDTH, TANKGFX_HEIGHT,  TankGfx );
  else {    
    if(Player.Ord.Status==EXPLODING)  {
        display.drawXBMP(Player.Ord.X, Player.Ord.Y, 5, 3,  ExplosionGfx  );
        tone(10, Player.ExplosionGfxCounter*250,50);
      Player.ExplosionGfxCounter--;
      if(Player.ExplosionGfxCounter==0)  {
        Player.Ord.Status=DESTROYED;
        LoseLife();
      }
    }
  }
  //missile  
  if(Missile.Status==ACTIVE)
    display.drawXBMP(Missile.X, Missile.Y, MISSILE_WIDTH, MISSILE_HEIGHT , MissileGfx);
  
  // mothership (not bonus if hit)
  if(MotherShip.Ord.Status==ACTIVE)
    display.drawXBMP(MotherShip.Ord.X, MotherShip.Ord.Y, MOTHERSHIP_WIDTH, MOTHERSHIP_HEIGHT,  MotherShipGfx );
  else
  {
    if(MotherShip.Ord.Status==EXPLODING)  
    {
      tone(10, MotherShip.ExplosionGfxCounter*250,50);
      MotherShip.ExplosionGfxCounter--;
      if(MotherShip.ExplosionGfxCounter==0)  {
        MotherShip.Ord.Status=DESTROYED;
      }
    }
  }
 
  // plot bases
  
  for(i=0; i <NUM_BASES;  i++)  {    
    if (Base[i].Ord.Status == ACTIVE)
      display.drawXBM(Base[i].Ord.X,  Base[i].Ord.Y, BASE_WIDTH, BASE_HEIGHT, Base[i].Gfx );
  }
  display.sendBuffer();
}
  
void LoseLife()  {
  Player.Lives--;
  if(Player.Lives>0)  {
    DisplayPlayerAndLives(&Player);
    // clear alien missiles
    for(int i=0;i<MAXBOMBS;i++)  {
      AlienBomb[i].Status=DESTROYED;
      AlienBomb[i].Y=0;
    }
    // ENABLE PLAYER
    Player.Ord.Status=ACTIVE;
    Player.Ord.X=PLAYER_X_START;
  }
  else  {
    GameOver();
  }
}
  
 
void GameOver()  {  
  GameInPlay=false;
  display.clearBuffer();
  CentreText("Player 1",8); 
  CentreText("Game Over",20);   
  CentreText("Score     ",32);   
  display.setCursor(72,32);
  display.print(Player.Score);
  if(Player.Score>HiScore)
  {
    CentreText("NEW HIGH SCORE!!!",44);
    CentreText("**CONGRATULATIONS**",56);    
  }
  display.sendBuffer();
  if(Player.Score>HiScore){    
    HiScore=Player.Score;
    EEPROM.put(0,HiScore);
    PlayRewardMusic();
  }
  delay(2500);  
}
 
 
void PlayRewardMusic()
{
  unsigned char Notes[] = { 26, 20, 18, 22, 20, 0, 26, 0, 26 };
  unsigned char  NoteDurations[] = { 40, 20, 20, 40, 30, 50, 30, 10,30 };
  for(int i=0;i<9;i++)
  {
    tone(10, Notes[i]*10);
    delay(NoteDurations[i]*10);     // time  note plays for
    noTone(10);                     // stop note
    delay(20);                      // small delay between notes
  }
   noTone(10);
}
  
 
void DisplayPlayerAndLives(PlayerStruct *Player)  {
  display.clearBuffer();
  CentreText("  Player 1",8);
  CentreText("Score ",20);   
  display.print(Player->Score);
  CentreText("Lives ",32);   
  display.print(Player->Lives); 
  CentreText("Level  ",44);   
  display.print(Player->Level);   
  display.sendBuffer();
  delay(2000);
  Player->Ord.X=PLAYER_X_START;
}
 
 
void CentreText(const  char *Text,unsigned char Y)  {
  // centres text on screen
  display.setCursor(int((SCREEN_WIDTH  - display.getStrWidth(Text)) / 2.0), Y);
  display.print(Text);
}
 
  
void InitPlayer()  {
  Player.Ord.Y=PLAYER_Y_START;
  Player.Ord.X=PLAYER_X_START;
  Player.Ord.Status=ACTIVE;
  Player.Lives=LIVES;
  Player.Level=0;
  Missile.Status=DESTROYED;
  Player.Score=0;
}
 
 
void NextLevel(PlayerStruct *Player)  {              //  reset any dropping bombs

  int YStart;
  for(int i=0;i<MAXBOMBS;i++)  
    AlienBomb[i].Status=DESTROYED;
    AnimationFrame=false;
    Player->Level++;
    YStart=(MOTHERSHIP_HEIGHT +2) + ((Player->Level-1) % LEVEL_TO_RESET_TO_START_HEIGHT)*AMOUNT_TO_DROP_BY_PER_LEVEL;
    InitAliens(YStart);  
    AlienXMoveAmount=ALIEN_X_MOVE_AMOUNT;
    Player->AlienSpeed=INVADERS_SPEED;
    Player->AliensDestroyed=0;
    MotherShip.Ord.X=-MOTHERSHIP_WIDTH;
    MotherShip.Ord.Status=DESTROYED;  
    Missile.Status=DESTROYED;
    randomSeed(100);     
    InitBases();
    DisplayPlayerAndLives(Player);  
    MusicIndex=0;
    MusicCounter=NOTELENGTH;
}
  
 
void InitBases()  {                                     // Bases need to  be re-built!
  
  byte TheByte;
  int Spacing=((SCREEN_WIDTH-32)-(NUM_BASES*BASE_WIDTH))/NUM_BASES;
  for(int i=0;i<NUM_BASES;i++)  
  {    
    for(int DataIdx=0;DataIdx<BASE_HEIGHT;DataIdx++)  
    {
        TheByte = pgm_read_byte(BaseGfx + DataIdx);
        Base[i].Gfx[DataIdx]=TheByte;
    }
    Base[i].Ord.X=17+(i*Spacing)+(i*BASE_WIDTH)+(Spacing/2);
    Base[i].Ord.Y=BASE_Y;
    Base[i].Ord.Status=ACTIVE;
  }
}
 
 
void NewGame(){
  InitPlayer();
  NextLevel(&Player);
}
 
void InitAliens(int YStart)  { 
  for(int  across=0;across<NUM_ALIEN_COLUMNS;across++)  {
    for(int down=0;down<NUM_ALIEN_ROWS;down++)  {
      Alien[across][down].Ord.X=X_START_OFFSET+(across*(LARGEST_ALIEN_WIDTH+SPACE_BETWEEN_ALIEN_COLUMNS))-(AlienWidth[down]/2);  
      Alien[across][down].Ord.Y=YStart+(down*SPACE_BETWEEN_ROWS);
      Alien[across][down].Ord.Status=ACTIVE;
      Alien[across][down].ExplosionGfxCounter=EXPLOSION_GFX_TIME;
    }
  }
  MotherShip.Ord.Y=0;
  MotherShip.Ord.X=-MOTHERSHIP_WIDTH;
  MotherShip.Ord.Status=DESTROYED;  
}

Downloadable files

Nano_Vaders Schematic

Schematic to build a Nano Every Space Invaders game

Nano_Vaders Schematic

Photo of Finished Project

Finished Project

Photo of Finished Project

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