////////////////////////////////////////////////////////////////////////////////
// DEMOGAME.C
//------------------------------------------------------------------------------
// FAIRLY MINIMAL GAME DEMO FOR GETTING STARTED WITH GBDK
// BY REFRESH GAMES
//------------------------------------------------------------------------------
// THIS IS INTENDED TO BE A BASE POINT FOR ANYONE TO CUSTOMISE AND ADD TO SO
// THEY CAN MAKE THEIR OWN GAMEBOY GAMES, HENCE THE COMMENTS!
//------------------------------------------------------------------------------
// WEB: refreshgames.co.uk
////////////////////////////////////////////////////////////////////////////////
#include // INCLUDE RANDOM FUNCTIONS
#include ; // INCLUDE GBDK FUNCTION LIBRARY
#include ; // INCLUDE HANDY HARDWARE REFERENCES
// FUNCTION DECLARATIONS
void initGame(); // INITIALISE OUR GAME
void updatePlayer(); // UPDATE OUR PLAYER
UINT8 collisionCheck(UINT8, UINT8, UINT8, UINT8, UINT8, UINT8, UINT8, UINT8); // SIMPLE RECT TO RECT CHECK
// VARIABLE DECLARATIONS - STORED IN RAM
UINT8 i, j; // GENERIC LOOPING VARIABLE
UINT8 playerX, playerY; // PLAYER CO-ORDINATES
UINT8 eX[10], eY[10]; // ENEMY CO-ORDINATES
UINT8 lastKeys; // HOLDS KEYS FOR THE PREVIOUS FRAME
UINT8 randomBkgTiles[20]; // CONTAINS RANDOM DATA FOR OUR BKG
// SPRITE DATA - 14 SPRITES - STORED IN ROM
const unsigned char sprites[] = {0x3C,0x3C,0x42,0x42,0xA9,0xA9,0xA9,0xA9,0x81,0x81,0x91,0x91,0x42,0x42,0x3C,0x3C,0x3C,0x3C,0x42,0x42,0x81,0x81,0xED,0xED,0x81,0x81,0x91,0x91,0x42,0x42,0x3C,0x3C,0x99,0x81,0x42,0x5A,0x24,0x3C,0x99,0x7E,0x99,0x7E,0x24,0x3C,0x42,0x5A,0x99,0x81,0x38,0x04,0x7C,0x02,0x5C,0x22,0x5C,0x22,0x5C,0x22,0x5C,0x22,0x7C,0x02,0x38,0x04,0x00,0x00,0x3E,0x3E,0x63,0x63,0x63,0x63,0x63,0x63,0x63,0x63,0x3E,0x3E,0x00,0x00,0x00,0x00,0x1C,0x1C,0x3C,0x3C,0x6C,0x6C,0x0C,0x0C,0x0C,0x0C,0x7F,0x7F,0x00,0x00,0x00,0x00,0x3E,0x3E,0x63,0x63,0x03,0x03,0x1E,0x1E,0x70,0x70,0x7F,0x7F,0x00,0x00,0x00,0x00,0x7F,0x7F,0x03,0x03,0x3E,0x3E,0x07,0x07,0x43,0x43,0x3E,0x3E,0x00,0x00,0x00,0x00,0x60,0x60,0x6C,0x6C,0x6C,0x6C,0x7F,0x7F,0x0C,0x0C,0x0C,0x0C,0x00,0x00,0x00,0x00,0x7F,0x7F,0x60,0x60,0x7E,0x7E,0x03,0x03,0x63,0x63,0x3E,0x3E,0x00,0x00,0x00,0x00,0x3F,0x3F,0x60,0x60,0x7E,0x7E,0x63,0x63,0x63,0x63,0x3E,0x3E,0x00,0x00,0x00,0x00,0x7F,0x7F,0x03,0x03,0x06,0x06,0x0C,0x0C,0x18,0x18,0x30,0x30,0x00,0x00,0x00,0x00,0x3E,0x3E,0x63,0x63,0x63,0x63,0x3E,0x3E,0x63,0x63,0x3E,0x3E,0x00,0x00,0x00,0x00,0x3E,0x3E,0x63,0x63,0x63,0x63,0x3F,0x3F,0x03,0x03,0x7E,0x7E,0x00,0x00};
//BACKGROUND DATA - 4 SPRITES - STORED IN ROM
const unsigned char myBkgData[] = {0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x08,0x00,0x08,0x00,0x36,0x00,0x08,0x00,0x08,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x20,0x00,0x50,0x00,0x20,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x04,0x00,0x0E,0x00,0x04,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x50,0x00,0x20,0x00,0x50,0x00,0x00,0x00};
////////////////////////////////////////////////////////////////////////////////
// MAIN FUNCTION
void main(){
initGame(); // RAN ONCE AT STARTUP
// GAME LOOP START
while(1){
updatePlayer(); // UPDATE PLAYER
HIDE_WIN; // SHOW WINDOW LAYER
SHOW_SPRITES; // HIDE SPRITES LAYER
SHOW_BKG; // SHOW BACKGROUND LAYER
lastKeys = joypad(); // UPDATE OUR KEYPRESSES
wait_vbl_done(); // WAIT FOR VBLANK TO FINISH - ENSURES 60 FRAMES PER SECOND MAXIMUM
}
// GAME LOOP END
}
////////////////////////////////////////////////////////////////////////////////
// INIT GAME
void initGame(){
DISPLAY_ON; // TURNS ON THE GAMEBOY LCD
NR52_REG = 0x8F; // TURN SOUND ON
NR51_REG = 0x11; // ENABLE SOUND CHANNELS
NR50_REG = 0x1F; // VOLUME MAX = 0x77, MIN = 0x00
initrand(DIV_REG); // SEED OUR RANDOMIZER
set_sprite_data(0, 14, sprites); // STORE OUR SPRITE DATA AT THE START OF SPRITE VRAM
set_bkg_data(0, 4, myBkgData); // STORE OUR BKG DATA AT THE START OF BKG VRAM - NOTE, THE WINDOW LAYER SHARED THE BKG VRAM BY DEFAULT
playerX = 64; // PLAYERS INITAL X POSITION
playerY = 64; // PLAYERS INITAL Y POSITION
set_sprite_tile(0,0); //PLAYERS SPRITE TILE - 0
for (i=0; i !=10; i++){ // OUR ENEMY POSITION LOOP - NOTE, USE !=, NOT < TO SCRAPE BACK SOME CPU TIME eX[i] = 16+(rand() >> 1); // RANDOM X POSITION 16 - 144
eY[i] = 16+(rand() >> 1); // RANDOM Y POSITION 16 - 144
set_sprite_tile(i+1, 2); // ENEMIES SRITE TILE - SET TO SPRITE 2
move_sprite(i+1,eX[i], eY[i]); // POSITION ENEMIES
}
// GENERATE RANDOM BKG TILE DATA - SO STARRY!
for (j=0; j != 18; j++){
for (i=0; i != 20; i++){
randomBkgTiles[i] = rand() % 4;
}
set_bkg_tiles(0,j,20,1,randomBkgTiles); // SET A LINE OF BKG DATA (X, Y, W, H, DATA)
}
}
////////////////////////////////////////////////////////////////////////////////
// UPDATE PLAYER
void updatePlayer(){
// MOTION VIA DPAD - LIMITED TO A CERTAIN AREA ON SCREEN
// UP
if (joypad() & J_UP){
playerY--;
if (playerY == 15){
playerY = 16;
}
}
// DOWN
if (joypad() & J_DOWN){
playerY++;
if (playerY == 153){
playerY = 152;
}
}
// LEFT
if (joypad() & J_LEFT){
playerX--;
if (playerX == 7){
playerX = 8;
}
}
// RIGHT
if (joypad() & J_RIGHT){
playerX++;
if (playerX == 161){
playerX = 160;
}
}
// END MOTION VIA DPAD
// TAP A - PLAYS A RANDOM BEEP THROUGH SOUND CHANNEL 1 - SQUARE WAVE CHANNEL
if (joypad() & J_A){
NR11_REG = 0x7f; // SQUARE WAVE DUTY
NR12_REG = 0x7f; // VOLUME 0 = quietest, 255 = loudest
NR13_REG = DIV_REG; // LOWER BITS OF SOUND FREQ
NR14_REG = 0x80 + (DIV_REG % 8); // LARGER SOUND FREQ - MINIMUM OF 128 - TOP 3 BYTES - ANY LESS = SOUND CHANNEL SWITCHES OFF
} else {
NR11_REG = 0x00; // NO A BUTTON - NO SOUND
NR12_REG = 0x00;
NR13_REG = 0x00;
NR14_REG = 0x00;
}
//MOVE OUR SPRITE
move_sprite(0,playerX,playerY); // POSITION OUR SPRITE ON THE SCREEN
j=0; // RE-USE J AS A FLAG TO SEE IF WE HAVE COLLIDED WITH AN ENEMY
for (i=0; i != 10; i++){ // LOOP THROUGH OUR 10 ENEMIES
if (collisionCheck(playerX, playerY, 8, 8, eX[i], eY[i], 8, 8) == 1){
j= 1; // IF WE COLLIDED, SET OUR FLAG VARIABLE, J TO 1
}
}
// ADJUST OUR PLAYER SPRITES FRAME IF THEY HIT SOMETHING
switch (j){
// NO HIT
case 0:
set_sprite_tile(0,0);
break;
// HIT ENEMY
default:
set_sprite_tile(0,1);
break;
}
}
////////////////////////////////////////////////////////////////////////////////
// COLLISION CHECKER - SIMPLE RECTANGLE COLLISION CHECKING
// RETURNS 1 IF OVERLAPPING
UINT8 collisionCheck(UINT8 x1, UINT8 y1, UINT8 w1, UINT8 h1, UINT8 x2, UINT8 y2, UINT8 w2, UINT8 h2){
if ((x1 < (x2+w2)) && ((x1+w1) > x2) && (y1 < (h2+y2)) && ((y1+h1) > y2)){
return 1;
} else {
return 0;
}
}
