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CGB BG rendering

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This commit is contained in:
Lior Halphon 2018-03-09 18:52:36 +02:00
parent a32f232bb1
commit 9083e883fe
2 changed files with 52 additions and 17 deletions
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68
Core/display.c
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@ -24,20 +24,37 @@ static GB_fifo_item_t *fifo_pop(GB_fifo_t *fifo)
return ret; return ret;
} }
static void fifo_push_bg_row(GB_fifo_t *fifo, uint8_t lower, uint8_t upper, uint8_t palette, bool bg_priority) static void fifo_push_bg_row(GB_fifo_t *fifo, uint8_t lower, uint8_t upper, uint8_t palette, bool bg_priority, bool flip_x)
{ {
for (unsigned i = 8; i--;) { if (!flip_x) {
fifo->fifo[fifo->write_end] = (GB_fifo_item_t) { for (unsigned i = 8; i--;) {
(lower >> 7) | ((upper >> 7) << 1), fifo->fifo[fifo->write_end] = (GB_fifo_item_t) {
palette, (lower >> 7) | ((upper >> 7) << 1),
0, palette,
bg_priority, 0,
}; bg_priority,
lower <<= 1; };
upper <<= 1; lower <<= 1;
upper <<= 1;
fifo->write_end++;
fifo->write_end &= 0xF; fifo->write_end++;
fifo->write_end &= 0xF;
}
}
else {
for (unsigned i = 8; i--;) {
fifo->fifo[fifo->write_end] = (GB_fifo_item_t) {
(lower & 1) | ((upper & 1) << 1),
palette,
0,
bg_priority,
};
lower >>= 1;
upper >>= 1;
fifo->write_end++;
fifo->write_end &= 0xF;
}
} }
} }
@ -475,6 +492,7 @@ static void render_pixel_if_possible(GB_gameboy_t *gb)
if (!gb->bg_fifo_paused) { if (!gb->bg_fifo_paused) {
fifo_item = fifo_pop(&gb->bg_fifo); fifo_item = fifo_pop(&gb->bg_fifo);
bg_priority = fifo_item->bg_priority;
} }
if (!gb->oam_fifo_paused && fifo_size(&gb->oam_fifo)) { if (!gb->oam_fifo_paused && fifo_size(&gb->oam_fifo)) {
@ -517,7 +535,7 @@ static void render_pixel_if_possible(GB_gameboy_t *gb)
if (!gb->cgb_mode) { if (!gb->cgb_mode) {
pixel = ((gb->io_registers[GB_IO_BGP] >> (pixel << 1)) & 3); pixel = ((gb->io_registers[GB_IO_BGP] >> (pixel << 1)) & 3);
} }
gb->screen[gb->position_in_line + gb->current_line * WIDTH] = gb->background_palettes_rgb[pixel]; gb->screen[gb->position_in_line + gb->current_line * WIDTH] = gb->background_palettes_rgb[fifo_item->palette * 4 + pixel];
} }
if (draw_oam) { if (draw_oam) {
@ -732,26 +750,41 @@ void GB_display_run(GB_gameboy_t *gb, uint8_t cycles)
gb->fetcher_y = gb->fetcher_y =
gb->current_line + (gb->in_window? - gb->io_registers[GB_IO_WY] - gb->wy_diff : gb->io_registers[GB_IO_SCY]); gb->current_line + (gb->in_window? - gb->io_registers[GB_IO_WY] - gb->wy_diff : gb->io_registers[GB_IO_SCY]);
gb->current_tile = gb->vram[map + gb->fetcher_x + gb->fetcher_y / 8 * 32]; gb->current_tile = gb->vram[map + gb->fetcher_x + gb->fetcher_y / 8 * 32];
if (gb->is_cgb) {
/* TODO: The timing is wrong (two reads a the same time)*/
gb->current_tile_attributes = gb->vram[map + gb->fetcher_x + gb->fetcher_y / 8 * 32 + 0x2000];
}
gb->fetcher_x++; gb->fetcher_x++;
gb->fetcher_x &= 0x1f; gb->fetcher_x &= 0x1f;
} }
break; break;
case GB_FETCHER_GET_TILE_DATA_LOWER: { case GB_FETCHER_GET_TILE_DATA_LOWER: {
uint8_t y_flip = 0;
if (gb->io_registers[GB_IO_LCDC] & 0x10) { if (gb->io_registers[GB_IO_LCDC] & 0x10) {
gb->current_tile_address = gb->current_tile * 0x10; gb->current_tile_address = gb->current_tile * 0x10;
} }
else { else {
gb->current_tile_address = (int8_t)gb->current_tile * 0x10 + 0x1000; gb->current_tile_address = (int8_t)gb->current_tile * 0x10 + 0x1000;
} }
if (gb->current_tile_attributes & 8) {
gb->current_tile_address += 0x2000;
}
if (gb->current_tile_attributes & 0x40) {
y_flip = 0x7;
}
gb->current_tile_data[0] = gb->current_tile_data[0] =
gb->vram[gb->current_tile_address + (gb->fetcher_y & 7) * 2]; gb->vram[gb->current_tile_address + ((gb->fetcher_y & 7) ^ y_flip) * 2];
} }
break; break;
case GB_FETCHER_GET_TILE_DATA_HIGH: { case GB_FETCHER_GET_TILE_DATA_HIGH: {
uint8_t y_flip = 0;
if (gb->current_tile_attributes & 0x40) {
y_flip = 0x7;
}
gb->current_tile_data[1] = gb->current_tile_data[1] =
gb->vram[gb->current_tile_address + (gb->fetcher_y & 7) * 2 + 1]; gb->vram[gb->current_tile_address + ((gb->fetcher_y & 7) ^ y_flip) * 2 + 1];
} }
break; break;
@ -766,7 +799,8 @@ void GB_display_run(GB_gameboy_t *gb, uint8_t cycles)
render_pixel_if_possible(gb); render_pixel_if_possible(gb);
if (push) { if (push) {
fifo_push_bg_row(&gb->bg_fifo, gb->current_tile_data[0], gb->current_tile_data[1], 0, false); fifo_push_bg_row(&gb->bg_fifo, gb->current_tile_data[0], gb->current_tile_data[1],
gb->current_tile_attributes & 7, gb->current_tile_attributes & 0x80, gb->current_tile_attributes & 0x20);
gb->bg_fifo_paused = false; gb->bg_fifo_paused = false;
gb->oam_fifo_paused = false; gb->oam_fifo_paused = false;
} }

1
Core/gb.h
View File

@ -409,6 +409,7 @@ struct GB_gameboy_internal_s {
uint8_t fetcher_y; uint8_t fetcher_y;
uint16_t cycles_for_line; uint16_t cycles_for_line;
uint8_t current_tile; uint8_t current_tile;
uint8_t current_tile_attributes;
uint16_t current_tile_address; uint16_t current_tile_address;
uint8_t current_tile_data[2]; uint8_t current_tile_data[2];
enum { enum {