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SCY latching is now correctly emulated, rendering mode timing refined.

This commit is contained in:
Lior Halphon 2017-09-04 00:16:12 +03:00
parent a1a13c61bf
commit 9bde98dede
2 changed files with 8 additions and 3 deletions
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10
Core/display.c
View File

@ -133,7 +133,7 @@ static uint32_t get_pixel(GB_gameboy_t *gb, uint8_t x, uint8_t y)
}
else {
x += gb->effective_scx;
y += gb->io_registers[GB_IO_SCY];
y += gb->effective_scy;
}
if (gb->io_registers[GB_IO_LCDC] & 0x08 && !in_window) {
map = 0x1C00;
@ -619,13 +619,17 @@ void GB_display_run(GB_gameboy_t *gb, uint8_t cycles)
/* Render */
/* Todo: it appears that the actual rendering starts 4 cycles after mode 3 starts. Is this correct? */
int16_t current_lcdc_x = gb->display_cycles % LINE_LENGTH - MODE2_LENGTH - (gb->effective_scx & 0x7) - 4;
int16_t current_lcdc_x = gb->display_cycles % LINE_LENGTH - MODE2_LENGTH - (gb->effective_scx & 0x7) - 7;
for (;gb->previous_lcdc_x < current_lcdc_x; gb->previous_lcdc_x++) {
if (gb->previous_lcdc_x >= WIDTH) {
continue;
}
if (((gb->previous_lcdc_x + gb->effective_scx) & 7) == 0) {
gb->effective_scy = gb->io_registers[GB_IO_SCY];
}
if (gb->previous_lcdc_x < 0) {
continue;
}

1
Core/gb.h
View File

@ -385,6 +385,7 @@ struct GB_gameboy_internal_s {
bool oam_write_blocked;
bool vram_write_blocked;
bool window_disabled_while_active;
uint8_t effective_scy; // SCY is latched when starting to draw a tile
);
/* Unsaved data. This includes all pointers, as well as everything that shouldn't be on a save state */