Fix screen redraws during effects

Normal redraws can overwrite effect frames with gfx_texture, causing
brief flashes during fade-out. Suppress redraws while an effect is
running and clear pending redraws at effect boundaries.

modules/lib/sactcg.c

@@ -35,7 +35,6 @@
 #include "ags.h"
 #include "variable.h"
 #include "sactcg.h"
-#include "ald_manager.h"
 #include "cg.h"
 #include "gfx.h"
 
@@ -329,27 +328,24 @@ void scg_free(int no) {
 // CGの種類を取得
 int scg_querytype(int wNumCG) {
 	if (wNumCG >= (CGMAX -1)) return CG_NOTUSED;
-	if (cg_store && cg_store[wNumCG])
+	if (!cg_store || !cg_store[wNumCG]) return CG_NOTUSED;
-		return cg_store[wNumCG]->type;
+	return cg_store[wNumCG]->type;
-	// Linked CGs are valid even before they are loaded into cg_store.
-	return ald_is_linked(DRIFILE_CG, wNumCG - 1) ? CG_LINKED : CG_NOTUSED;
 }
 
 // CGの大きさを取得
 bool scg_querysize(int wNumCG, vmvar_t *w, vmvar_t *h) {
-	*w = *h = 0;
+	if (wNumCG >= (CGMAX -1)) goto errexit;
+	if (!cg_store || !cg_store[wNumCG]) goto errexit;
+	if (cg_store[wNumCG]->sf == NULL) goto errexit;
 
-	if (wNumCG >= (CGMAX - 1))
+	*w = cg_store[wNumCG]->sf->w;
-		return false;
+	*h = cg_store[wNumCG]->sf->h;
-	cginfo_t *cg = cg_store ? cg_store[wNumCG] : NULL;
-	if (!cg && ald_is_linked(DRIFILE_CG, wNumCG - 1))
-		cg = scg_get(wNumCG);
-	if (!cg || !cg->sf)
-		return false;
 	
-	*w = cg->sf->w;
-	*h = cg->sf->h;
 	return true;
+
+ errexit:
+	*w = *h = 0;
+	return false;
 }
 
 // CGのBPPを取得

src/effect.c

@@ -191,6 +191,7 @@ static void eff_init(struct effect *eff, SDL_Rect *rect, EffectTexture *old, Eff
 
 	if (!eff->is_fullscreen)
 		gfx_updateScreen();  // Flush pending display changes.
+	gfx_setEffectRunning(true);
 }
 
 static void eff_finish(struct effect *eff, bool present) {
@@ -1912,4 +1913,5 @@ void effect_step(struct effect *eff, float progress) {
 
 void effect_finish(struct effect *eff) {
 	eff->finish(eff);
+	gfx_setEffectRunning(false);
 }

src/gfx_draw.c

@@ -45,6 +45,7 @@
 #include "debugger.h"
 
 static bool gfx_dirty;
+static bool gfx_effect_running;
 
 static void gfx_pal_check(void) {
 	if (nact->ags.pal_changed) {
@@ -64,7 +65,7 @@ SDL_Color gfx_getPaletteColor(uint8_t color) {
 }
 
 void gfx_updateScreen(void) {
-	if (!gfx_dirty)
+	if (!gfx_dirty || gfx_effect_running)
 		return;
 	SDL_RenderClear(gfx_renderer);
 	SDL_RenderCopy(gfx_renderer, gfx_texture, NULL, NULL);
@@ -73,6 +74,12 @@ void gfx_updateScreen(void) {
 	gfx_dirty = false;
 }
 
+void gfx_setEffectRunning(bool running) {
+	gfx_effect_running = running;
+	// Effects present directly. Do not replay pending redraws over their frames.
+	gfx_dirty = false;
+}
+
 void gfx_requestRedraw(void) {
 	gfx_dirty = true;
 }

src/gfx_private.h

@@ -37,6 +37,8 @@ extern surface_t *gfx_dibinfo;
 extern int view_w;
 extern int view_h;
 
+void gfx_setEffectRunning(bool running);
+
 SDL_Surface *gfx_dib_to_surface_with_alpha(int x, int y, int w, int h);
 SDL_Surface *gfx_dib_to_surface_colorkey(int x, int y, int w, int h, int col);