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Implemented some obscure PPU rendering quirks, verified some timings

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This commit is contained in:
Lior Halphon 2018-04-05 15:33:21 +03:00
parent d785e45308
commit 9aadc80f75
3 changed files with 41 additions and 15 deletions
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53
Core/display.c
View File

@ -394,6 +394,11 @@ static void render_pixel_if_possible(GB_gameboy_t *gb)
Todo: Add support to CPU C and older */
static inline uint8_t fetcher_y(GB_gameboy_t *gb)
{
return gb->current_line + (gb->in_window? - gb->io_registers[GB_IO_WY] - gb->wy_diff : gb->io_registers[GB_IO_SCY]);
}
void GB_display_run(GB_gameboy_t *gb, uint8_t cycles)
{
GB_object_t *objects = (GB_object_t *) &gb->oam;
@ -632,23 +637,29 @@ void GB_display_run(GB_gameboy_t *gb, uint8_t cycles)
}
bool push = false;
if (gb->fetcher_divisor) {
switch (gb->fetcher_state) {
case GB_FETCHER_GET_TILE: {
uint16_t map = 0x1800;
/* Todo: Verify access timings */
/* Todo: Verified for DMG (Tested: SGB2), CGB timing is wrong. */
if (gb->io_registers[GB_IO_LCDC] & 0x08 && !gb->in_window) {
map = 0x1C00;
}
else if (gb->io_registers[GB_IO_LCDC] & 0x40 && gb->in_window) {
map = 0x1C00;
}
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_tile = gb->vram[map + gb->fetcher_x + gb->fetcher_y / 8 * 32];
/* Todo: Verified for DMG (Tested: SGB2), CGB timing is wrong. */
uint8_t y = fetcher_y(gb);
if (gb->is_cgb) {
/* This value is cached on the CGB, so it cannot be used to mix tiles together */
gb->fetcher_y = y;
}
gb->current_tile = gb->vram[map + gb->fetcher_x + 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->current_tile_attributes = gb->vram[map + gb->fetcher_x + y / 8 * 32 + 0x2000];
}
gb->fetcher_x++;
gb->fetcher_x &= 0x1f;
@ -657,32 +668,50 @@ void GB_display_run(GB_gameboy_t *gb, uint8_t cycles)
case GB_FETCHER_GET_TILE_DATA_LOWER: {
uint8_t y_flip = 0;
/* Todo: Verify access timings */
uint16_t tile_address = 0;
uint8_t y = gb->is_cgb? gb->fetcher_y : fetcher_y(gb);
/* Todo: Verified for DMG (Tested: SGB2), CGB timing is wrong. */
if (gb->io_registers[GB_IO_LCDC] & 0x10) {
gb->current_tile_address = gb->current_tile * 0x10;
tile_address = gb->current_tile * 0x10;
}
else {
gb->current_tile_address = (int8_t)gb->current_tile * 0x10 + 0x1000;
tile_address = (int8_t)gb->current_tile * 0x10 + 0x1000;
}
if (gb->current_tile_attributes & 8) {
gb->current_tile_address += 0x2000;
tile_address += 0x2000;
}
if (gb->current_tile_attributes & 0x40) {
y_flip = 0x7;
}
gb->current_tile_data[0] =
gb->vram[gb->current_tile_address + ((gb->fetcher_y & 7) ^ y_flip) * 2];
gb->vram[tile_address + ((y & 7) ^ y_flip) * 2];
}
break;
case GB_FETCHER_GET_TILE_DATA_HIGH: {
/* Todo: Verified for DMG (Tested: SGB2), CGB timing is wrong.
Additionally, on the CGB mixing two tiles by changing the tileset bit
mid-fetching causes a glitched mixing of the two, in comparison to the
more logical DMG version. */
uint16_t tile_address = 0;
uint8_t y = gb->is_cgb? gb->fetcher_y : fetcher_y(gb);
if (gb->io_registers[GB_IO_LCDC] & 0x10) {
tile_address = gb->current_tile * 0x10;
}
else {
tile_address = (int8_t)gb->current_tile * 0x10 + 0x1000;
}
if (gb->current_tile_attributes & 8) {
tile_address += 0x2000;
}
uint8_t y_flip = 0;
if (gb->current_tile_attributes & 0x40) {
y_flip = 0x7;
}
gb->current_tile_data[1] =
gb->vram[gb->current_tile_address + ((gb->fetcher_y & 7) ^ y_flip) * 2 + 1];
gb->vram[tile_address + ((y & 7) ^ y_flip) * 2 + 1];
}
break;

1
Core/gb.h
View File

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

2
Core/save_state.c
View File

@ -222,7 +222,6 @@ int GB_load_state(GB_gameboy_t *gb, const char *path)
gb->bg_fifo.write_end &= 0xF;
gb->oam_fifo.read_end &= 0xF;
gb->oam_fifo.write_end &= 0xF;
gb->current_tile_address &= (gb->vram_size - 1);
error:
fclose(f);
@ -318,7 +317,6 @@ int GB_load_state_from_buffer(GB_gameboy_t *gb, const uint8_t *buffer, size_t le
gb->bg_fifo.write_end &= 0xF;
gb->oam_fifo.read_end &= 0xF;
gb->oam_fifo.write_end &= 0xF;
gb->current_tile_address &= (gb->vram_size - 1);
return 0;
}