git.y1.nz

commit 6b38c535755b4ff2b069efac404b2844292249b7
parent a7b218f638d02574653280d644106cdcc4bfbd79
Author: Lior Halphon <LIJI32@gmail.com>
Date:   Sun, 14 Sep 2025 22:28:59 +0300

Prevent abnormal vblank events from updating the SNES-side buffers prematurely. Fixes #721

Diffstat:
M
Core/display.c
6
+++---
M
Core/memory.c
2
+-
M
Core/sgb.c
4
++--
M
Core/sgb.h
2
+-

4 files changed, 7 insertions(+), 7 deletions(-)
diff --git a/Core/display.c b/Core/display.c
@@ -193,7 +193,7 @@ void GB_display_vblank(GB_gameboy_t *gb, GB_vblank_type_t type)
     
     /* TODO: Slow in turbo mode! */
     if (GB_is_hle_sgb(gb)) {
-        GB_sgb_render(gb);
+        GB_sgb_render(gb, type != GB_VBLANK_TYPE_NORMAL_FRAME);
     }
     
     if (gb->turbo) {
@@ -2186,7 +2186,7 @@ skip_slow_mode_3:
                         gb->frame_skip_state = GB_FRAMESKIP_FIRST_FRAME_RENDERED;
                     }
                     else {
-                        if (!GB_is_sgb(gb) || gb->current_lcd_line < LINES) {
+                        if (!GB_is_sgb(gb)) {
                             update_frame_parity(gb); // TODO: test actual timing
                             GB_display_vblank(gb, GB_VBLANK_TYPE_NORMAL_FRAME);
                         }
@@ -2194,7 +2194,7 @@ skip_slow_mode_3:
                     }
                 }
                 else {
-                    if (!GB_is_sgb(gb) || gb->current_lcd_line < LINES) {
+                    if (!GB_is_sgb(gb)) {
                         update_frame_parity(gb); // TODO: test actual timing
                         GB_display_vblank(gb, GB_VBLANK_TYPE_NORMAL_FRAME);
                     }
diff --git a/Core/memory.c b/Core/memory.c
@@ -1494,7 +1494,7 @@ static void write_high_memory(GB_gameboy_t *gb, uint16_t addr, uint8_t value)
                         gb->lcd_status_callback(gb, true);
                     }
                     if (!gb->lcd_disabled_outside_of_vblank &&
-                        (gb->cycles_since_vblank_callback > 10 * 456 || GB_is_sgb(gb))) {
+                        (gb->cycles_since_vblank_callback > 10 * 456)) {
                         // Trigger a vblank here so we don't exceed LCDC_PERIOD
                         GB_display_vblank(gb, GB_VBLANK_TYPE_ARTIFICIAL);
                     }
diff --git a/Core/sgb.c b/Core/sgb.c
@@ -593,7 +593,7 @@ static void render_boot_animation (GB_gameboy_t *gb)
 }
 
 static void render_jingle(GB_gameboy_t *gb, size_t count);
-void GB_sgb_render(GB_gameboy_t *gb)
+void GB_sgb_render(GB_gameboy_t *gb, bool incomplete)
 {
     if (gb->apu_output.sample_rate) {
         render_jingle(gb, gb->apu_output.sample_rate / GB_get_usual_frame_rate(gb));
@@ -670,7 +670,7 @@ void GB_sgb_render(GB_gameboy_t *gb)
         colors[i] = convert_rgb15(gb, LE16(gb->sgb->effective_palettes[i]));
     }
     
-    if (gb->sgb->mask_mode != MASK_FREEZE) {
+    if (gb->sgb->mask_mode != MASK_FREEZE && !incomplete) {
         memcpy(gb->sgb->effective_screen_buffer,
                gb->sgb->screen_buffer,
                sizeof(gb->sgb->effective_screen_buffer));
diff --git a/Core/sgb.h b/Core/sgb.h
@@ -63,7 +63,7 @@ struct GB_sgb_s {
 };
 
 internal void GB_sgb_write(GB_gameboy_t *gb, uint8_t value);
-internal void GB_sgb_render(GB_gameboy_t *gb);
+internal void GB_sgb_render(GB_gameboy_t *gb, bool incomplete);
 internal void GB_sgb_load_default_data(GB_gameboy_t *gb);
 
 #endif

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