/* * sprites.c * program which demonstrates GBA sprites */ #define SCREEN_WIDTH 240 #define SCREEN_HEIGHT 160 /* include the background image we are using */ #include "background.h" /* include the sprite image we are using */ #include "koopa.h" /* include the tile map we are using */ #include "map.h" /* the tile mode flags needed for display control register */ #define MODE0 0x00 #define BG0_ENABLE 0x100 /* flags to set sprite handling in display control register */ #define SPRITE_MAP_2D 0x0 #define SPRITE_MAP_1D 0x40 #define SPRITE_ENABLE 0x1000 /* the control registers for the four tile layers */ volatile unsigned short* bg0_control = (volatile unsigned short*) 0x4000008; /* palette is always 256 colors */ #define PALETTE_SIZE 256 /* there are 128 sprites on the GBA */ #define NUM_SPRITES 128 /* the display control pointer points to the gba graphics register */ volatile unsigned long* display_control = (volatile unsigned long*) 0x4000000; /* the memory location which controls sprite attributes */ volatile unsigned short* sprite_attribute_memory = (volatile unsigned short*) 0x7000000; /* the memory location which stores sprite image data */ volatile unsigned short* sprite_image_memory = (volatile unsigned short*) 0x6010000; /* the address of the color palettes used for backgrounds and sprites */ volatile unsigned short* bg_palette = (volatile unsigned short*) 0x5000000; volatile unsigned short* sprite_palette = (volatile unsigned short*) 0x5000200; /* the button register holds the bits which indicate whether each button has * been pressed - this has got to be volatile as well */ volatile unsigned short* buttons = (volatile unsigned short*) 0x04000130; /* scrolling registers for backgrounds */ volatile short* bg0_x_scroll = (unsigned short*) 0x4000010; volatile short* bg0_y_scroll = (unsigned short*) 0x4000012; /* the bit positions indicate each button - the first bit is for A, second for * B, and so on, each constant below can be ANDED into the register to get the * status of any one button */ #define BUTTON_A (1 << 0) #define BUTTON_B (1 << 1) #define BUTTON_SELECT (1 << 2) #define BUTTON_START (1 << 3) #define BUTTON_RIGHT (1 << 4) #define BUTTON_LEFT (1 << 5) #define BUTTON_UP (1 << 6) #define BUTTON_DOWN (1 << 7) #define BUTTON_R (1 << 8) #define BUTTON_L (1 << 9) /* the scanline counter is a memory cell which is updated to indicate how * much of the screen has been drawn */ volatile unsigned short* scanline_counter = (volatile unsigned short*) 0x4000006; /* wait for the screen to be fully drawn so we can do something during vblank */ void wait_vblank() { /* wait until all 160 lines have been updated */ while (*scanline_counter < 160) { } } /* this function checks whether a particular button has been pressed */ unsigned char button_pressed(unsigned short button) { /* and the button register with the button constant we want */ unsigned short pressed = *buttons & button; /* if this value is zero, then it's not pressed */ if (pressed == 0) { return 1; } else { return 0; } } /* return a pointer to one of the 4 character blocks (0-3) */ volatile unsigned short* char_block(unsigned long block) { /* they are each 16K big */ return (volatile unsigned short*) (0x6000000 + (block * 0x4000)); } /* return a pointer to one of the 32 screen blocks (0-31) */ volatile unsigned short* screen_block(unsigned long block) { /* they are each 2K big */ return (volatile unsigned short*) (0x6000000 + (block * 0x800)); } /* flag for turning on DMA */ #define DMA_ENABLE 0x80000000 /* flags for the sizes to transfer, 16 or 32 bits */ #define DMA_16 0x00000000 #define DMA_32 0x04000000 /* pointer to the DMA source location */ volatile unsigned int* dma_source = (volatile unsigned int*) 0x40000D4; /* pointer to the DMA destination location */ volatile unsigned int* dma_destination = (volatile unsigned int*) 0x40000D8; /* pointer to the DMA count/control */ volatile unsigned int* dma_count = (volatile unsigned int*) 0x40000DC; /* copy data using DMA */ void memcpy16_dma(unsigned short* dest, unsigned short* source, int amount) { *dma_source = (unsigned int) source; *dma_destination = (unsigned int) dest; *dma_count = amount | DMA_16 | DMA_ENABLE; } /* function to setup background 0 for this program */ void setup_background() { /* load the palette from the image into palette memory*/ memcpy16_dma((unsigned short*) bg_palette, (unsigned short*) background_palette, PALETTE_SIZE); /* load the image into char block 0 */ memcpy16_dma((unsigned short*) char_block(0), (unsigned short*) background_data, (background_width * background_height) / 2); /* set all control the bits in this register */ *bg0_control = 0 | /* priority, 0 is highest, 3 is lowest */ (0 << 2) | /* the char block the image data is stored in */ (0 << 6) | /* the mosaic flag */ (1 << 7) | /* color mode, 0 is 16 colors, 1 is 256 colors */ (16 << 8) | /* the screen block the tile data is stored in */ (1 << 13) | /* wrapping flag */ (0 << 14); /* bg size, 0 is 256x256 */ /* load the tile data into screen block 16 */ memcpy16_dma((unsigned short*) screen_block(16), (unsigned short*) map, map_width * map_height); } /* just kill time */ void delay(unsigned int amount) { for (int i = 0; i < amount * 10; i++); } /* a sprite is a moveable image on the screen */ struct Sprite { unsigned short attribute0; unsigned short attribute1; unsigned short attribute2; unsigned short attribute3; }; /* array of all the sprites available on the GBA */ struct Sprite sprites[NUM_SPRITES]; int next_sprite_index = 0; /* the different sizes of sprites which are possible */ enum SpriteSize { SIZE_8_8, SIZE_16_16, SIZE_32_32, SIZE_64_64, SIZE_16_8, SIZE_32_8, SIZE_32_16, SIZE_64_32, SIZE_8_16, SIZE_8_32, SIZE_16_32, SIZE_32_64 }; /* function to initialize a sprite with its properties, and return a pointer */ struct Sprite* sprite_init(int x, int y, enum SpriteSize size, int horizontal_flip, int vertical_flip, int tile_index, int priority) { /* grab the next index */ int index = next_sprite_index++; /* setup the bits used for each shape/size possible */ int size_bits, shape_bits; switch (size) { case SIZE_8_8: size_bits = 0; shape_bits = 0; break; case SIZE_16_16: size_bits = 1; shape_bits = 0; break; case SIZE_32_32: size_bits = 2; shape_bits = 0; break; case SIZE_64_64: size_bits = 3; shape_bits = 0; break; case SIZE_16_8: size_bits = 0; shape_bits = 1; break; case SIZE_32_8: size_bits = 1; shape_bits = 1; break; case SIZE_32_16: size_bits = 2; shape_bits = 1; break; case SIZE_64_32: size_bits = 3; shape_bits = 1; break; case SIZE_8_16: size_bits = 0; shape_bits = 2; break; case SIZE_8_32: size_bits = 1; shape_bits = 2; break; case SIZE_16_32: size_bits = 2; shape_bits = 2; break; case SIZE_32_64: size_bits = 3; shape_bits = 2; break; } int h = horizontal_flip ? 1 : 0; int v = vertical_flip ? 1 : 0; /* set up the first attribute */ sprites[index].attribute0 = y | /* y coordinate */ (0 << 8) | /* rendering mode */ (0 << 10) | /* gfx mode */ (0 << 12) | /* mosaic */ (1 << 13) | /* color mode, 0:16, 1:256 */ (shape_bits << 14); /* shape */ /* set up the second attribute */ sprites[index].attribute1 = x | /* x coordinate */ (0 << 9) | /* affine flag */ (h << 12) | /* horizontal flip flag */ (v << 13) | /* vertical flip flag */ (size_bits << 14); /* size */ /* setup the second attribute */ sprites[index].attribute2 = tile_index | // tile index */ (priority << 10) | // priority */ (0 << 12); // palette bank (only 16 color)*/ /* return pointer to this sprite */ return &sprites[index]; } /* update all of the spries on the screen */ void sprite_update_all() { /* copy them all over */ memcpy16_dma((unsigned short*) sprite_attribute_memory, (unsigned short*) sprites, NUM_SPRITES * 4); } /* setup all sprites */ void sprite_clear() { /* clear the index counter */ next_sprite_index = 0; /* move all sprites offscreen to hide them */ for(int i = 0; i < NUM_SPRITES; i++) { sprites[i].attribute0 = SCREEN_HEIGHT; sprites[i].attribute1 = SCREEN_WIDTH; } } /* set a sprite postion */ void sprite_position(struct Sprite* sprite, int x, int y) { /* clear out the y coordinate */ sprite->attribute0 &= 0xff00; /* set the new y coordinate */ sprite->attribute0 |= (y & 0xff); /* clear out the x coordinate */ sprite->attribute1 &= 0xfe00; /* set the new x coordinate */ sprite->attribute1 |= (x & 0x1ff); } /* move a sprite in a direction */ void sprite_move(struct Sprite* sprite, int dx, int dy) { /* get the current y coordinate */ int y = sprite->attribute0 & 0xff; /* get the current x coordinate */ int x = sprite->attribute1 & 0x1ff; /* move to the new location */ sprite_position(sprite, x + dx, y + dy); } /* change the vertical flip flag */ void sprite_set_vertical_flip(struct Sprite* sprite, int vertical_flip) { if (vertical_flip) { /* set the bit */ sprite->attribute1 |= 0x2000; } else { /* clear the bit */ sprite->attribute1 &= 0xdfff; } } /* change the vertical flip flag */ void sprite_set_horizontal_flip(struct Sprite* sprite, int horizontal_flip) { if (horizontal_flip) { /* set the bit */ sprite->attribute1 |= 0x1000; } else { /* clear the bit */ sprite->attribute1 &= 0xefff; } } /* change the tile offset of a sprite */ void sprite_set_offset(struct Sprite* sprite, int offset) { /* clear the old offset */ sprite->attribute2 &= 0xfc00; /* apply the new one */ sprite->attribute2 |= (offset & 0x03ff); } /* setup the sprite image and palette */ void setup_sprite_image() { /* load the palette from the image into palette memory*/ memcpy16_dma((unsigned short*) sprite_palette, (unsigned short*) koopa_palette, PALETTE_SIZE); /* load the image into sprite image memory */ memcpy16_dma((unsigned short*) sprite_image_memory, (unsigned short*) koopa_data, (koopa_width * koopa_height) / 2); } /* a struct for the koopa's logic and behavior */ struct Koopa { /* the actual sprite attribute info */ struct Sprite* sprite; /* the x and y postion */ int x, y; /* which frame of the animation he is on */ int frame; /* the number of frames to wait before flipping */ int animation_delay; /* the animation counter counts how many frames until we flip */ int counter; /* whether the koopa is moving right now or not */ int move; /* the number of pixels away from the edge of the screen the koopa stays */ int border; }; /* initialize the koopa */ void koopa_init(struct Koopa* koopa) { koopa->x = 100; koopa->y = 113; koopa->border = 40; koopa->frame = 0; koopa->move = 0; koopa->counter = 0; koopa->animation_delay = 8; koopa->sprite = sprite_init(koopa->x, koopa->y, SIZE_16_32, 0, 0, koopa->frame, 0); } /* move the koopa left or right returns if it is at edge of the screen */ int koopa_left(struct Koopa* koopa) { /* face left */ sprite_set_horizontal_flip(koopa->sprite, 1); koopa->move = 1; /* if we are at the left end, just scroll the screen */ if (koopa->x < koopa->border) { return 1; } else { /* else move left */ koopa->x--; return 0; } } int koopa_right(struct Koopa* koopa) { /* face right */ sprite_set_horizontal_flip(koopa->sprite, 0); koopa->move = 1; /* if we are at the right end, just scroll the screen */ if (koopa->x > (SCREEN_WIDTH - 16 - koopa->border)) { return 1; } else { /* else move right */ koopa->x++; return 0; } } void koopa_stop(struct Koopa* koopa) { koopa->move = 0; koopa->frame = 0; koopa->counter = 7; sprite_set_offset(koopa->sprite, koopa->frame); } /* update the koopa */ void koopa_update(struct Koopa* koopa) { if (koopa->move) { koopa->counter++; if (koopa->counter >= koopa->animation_delay) { koopa->frame = koopa->frame + 16; if (koopa->frame > 16) { koopa->frame = 0; } sprite_set_offset(koopa->sprite, koopa->frame); koopa->counter = 0; } } sprite_position(koopa->sprite, koopa->x, koopa->y); } /* the main function */ int main() { /* we set the mode to mode 0 with bg0 on */ *display_control = MODE0 | BG0_ENABLE | SPRITE_ENABLE | SPRITE_MAP_1D; /* setup the background 0 */ setup_background(); /* setup the sprite image data */ setup_sprite_image(); /* clear all the sprites on screen now */ sprite_clear(); /* create the koopa */ struct Koopa koopa; koopa_init(&koopa); /* set initial scroll to 0 */ int xscroll = 0; /* loop forever */ while (1) { /* update the koopa */ koopa_update(&koopa); /* now the arrow keys move the koopa */ if (button_pressed(BUTTON_RIGHT)) { if (koopa_right(&koopa)) { xscroll++; } } else if (button_pressed(BUTTON_LEFT)) { if (koopa_left(&koopa)) { xscroll--; } } else { koopa_stop(&koopa); } /* wait for vblank before scrolling and moving sprites */ wait_vblank(); *bg0_x_scroll = xscroll; sprite_update_all(); /* delay some */ delay(100); } }