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More accurate timing emulation of window-objects interaction

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This commit is contained in:
Lior Halphon 2020-02-27 22:49:34 +02:00
parent 89303ab046
commit 0c716bd970
1 changed files with 31 additions and 19 deletions
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50
Core/display.c
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@ -729,6 +729,7 @@ void GB_display_run(GB_gameboy_t *gb, uint8_t cycles)
return;
}
GB_object_t *objects = (GB_object_t *) &gb->oam;
bool window_got_activated = false;
GB_STATE_MACHINE(gb, display, cycles, 2) {
GB_STATE(gb, display, 1);
@ -771,6 +772,7 @@ void GB_display_run(GB_gameboy_t *gb, uint8_t cycles)
GB_STATE(gb, display, 39);
GB_STATE(gb, display, 40);
GB_STATE(gb, display, 41);
GB_STATE(gb, display, 42);
}
@ -948,6 +950,26 @@ void GB_display_run(GB_gameboy_t *gb, uint8_t cycles)
gb->bg_fifo_paused = false;
gb->oam_fifo_paused = false;
while (true) {
/* Handle window */
/* Todo: verify timings */
if (!gb->wx_triggered && gb->wy_triggered && (gb->io_registers[GB_IO_LCDC] & 0x20)) {
if (gb->io_registers[GB_IO_WX] >= 167) {
// Too late to enable the window
}
else if (gb->io_registers[GB_IO_WX] == (uint8_t) (gb->position_in_line + 7) ||
(gb->io_registers[GB_IO_WX] == (uint8_t) (gb->position_in_line + 6) && !gb->wx_just_changed)) {
gb->window_y++;
if (gb->io_registers[GB_IO_WX] != 166) {
gb->wx_triggered = true;
fifo_clear(&gb->bg_fifo);
gb->bg_fifo_paused = true;
gb->oam_fifo_paused = true;
gb->fetcher_state = 1;
window_got_activated = true;
}
}
}
/* Handle objects */
/* When the sprite enabled bit is off, this proccess is skipped entirely on the DMG, but not on the CGB.
On the CGB, this bit is checked only when the pixel is actually popped from the FIFO. */
@ -962,6 +984,15 @@ void GB_display_run(GB_gameboy_t *gb, uint8_t cycles)
while (gb->n_visible_objs != 0 &&
(gb->io_registers[GB_IO_LCDC] & 2 || GB_is_cgb(gb)) &&
gb->obj_comparators[gb->n_visible_objs - 1] == (uint8_t)(gb->position_in_line + 8)) {
/* TODO: This is wrong. It is only correct for a single object, not for more than one. */
if (window_got_activated) {
window_got_activated = false;
gb->fetcher_state = 0;
gb->cycles_for_line += 6;
GB_SLEEP(gb, display, 42, 6);
}
while (gb->fetcher_state < 5) {
advance_fetcher_state_machine(gb);
gb->cycles_for_line++;
@ -1035,25 +1066,6 @@ abort_fetching_object:
gb->object_fetch_aborted = false;
gb->during_object_fetch = false;
/* Handle window */
/* Todo: verify timings */
if (!gb->wx_triggered && gb->wy_triggered && (gb->io_registers[GB_IO_LCDC] & 0x20)) {
if (gb->io_registers[GB_IO_WX] >= 167) {
// Too late to enable the window
}
else if (gb->io_registers[GB_IO_WX] == (uint8_t) (gb->position_in_line + 7) ||
(gb->io_registers[GB_IO_WX] == (uint8_t) (gb->position_in_line + 6) && !gb->wx_just_changed)) {
gb->window_y++;
if (gb->io_registers[GB_IO_WX] != 166) {
gb->wx_triggered = true;
fifo_clear(&gb->bg_fifo);
gb->bg_fifo_paused = true;
gb->oam_fifo_paused = true;
gb->fetcher_state = 1;
}
}
}
render_pixel_if_possible(gb);
advance_fetcher_state_machine(gb);