Implemented LCD first-frame-skip behavior, fixes a visual glitch in Pokémon Pinball

This commit is contained in:
Lior Halphon 2017-06-03 16:42:42 +03:00
parent 48acc09e91
commit d72807dd67
3 changed files with 18 additions and 1 deletions

View File

@ -318,7 +318,13 @@ static void update_display_state(GB_gameboy_t *gb, uint8_t cycles)
if (gb->io_registers[GB_IO_STAT] & 0x20) {
gb->stat_interrupt_line = true;
}
display_vblank(gb);
if (gb->frame_skip_state == GB_FRAMESKIP_LCD_TURNED_ON) {
gb->frame_skip_state = GB_FRAMESKIP_FIRST_FRAME_SKIPPED;
}
else {
gb->frame_skip_state = GB_FRAMESKIP_SECOND_FRAME_RENDERED;
display_vblank(gb);
}
}
/* Handle STAT changes for lines 0-143 */

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@ -365,6 +365,14 @@ struct GB_gameboy_internal_s {
bool stat_interrupt_line;
uint8_t effective_scx;
uint8_t current_window_line;
/* The LCDC will skip the first frame it renders after turning it on, unless the previous
frame was skipped as well.
See https://www.reddit.com/r/EmuDev/comments/6exyxu/ */
enum {
GB_FRAMESKIP_LCD_TURNED_ON,
GB_FRAMESKIP_FIRST_FRAME_SKIPPED,
GB_FRAMESKIP_SECOND_FRAME_RENDERED,
} frame_skip_state;
);
/* Unsaved data. This includes all pointers, as well as everything that shouldn't be on a save state */

View File

@ -439,6 +439,9 @@ static void write_high_memory(GB_gameboy_t *gb, uint16_t addr, uint8_t value)
/* It appears that there's a slight delay after enabling the screen? */
/* Todo: verify this. */
gb->display_cycles = gb->cgb_double_speed? -2 : -4;
if (gb->frame_skip_state == GB_FRAMESKIP_SECOND_FRAME_RENDERED) {
gb->frame_skip_state = GB_FRAMESKIP_LCD_TURNED_ON;
}
}
else if (!(value & 0x80) && (gb->io_registers[GB_IO_LCDC] & 0x80)) {
/* Sync after turning off LCD */