port: don't render garbage in the first blur frame (fixes #287)

port/src/pdsched.c

@@ -104,6 +104,7 @@ bool g_SchedIsFirstTask = true;
 s32 g_PrevFrameFb = -1;
 s32 g_BlurFb = -1;
 s32 g_BlurFbCapTimer = -1;
+bool g_BlurFbDirty = true;
 
 void schedSetCrashEnable1(bool enable)
 {
@@ -390,8 +391,12 @@ void schedConsiderScreenshot(void)
 	if (g_BlurFbCapTimer == 0) {
 		videoCopyFramebuffer(g_BlurFb, 0, -1, -1);
 		g_BlurFbCapTimer = -1;
+		g_BlurFbDirty = false;
 	} else if (g_BlurFbCapTimer > 0) {
 		--g_BlurFbCapTimer;
+	} else if (g_BlurFbCapTimer < 0) {
+		// no blur requested this frame, mark blur fb dirty
+		g_BlurFbDirty = true;
 	}
 
 	if (g_MenuData.screenshottimer >= 2) {

src/game/bondview.c

@@ -289,6 +289,14 @@ Gfx *bviewDrawMotionBlur(Gfx *gdl, u32 colour, u32 alpha)
 	if (!videoFramebuffersSupported()) {
 		return gdl;
 	}
+
+	// capture fb at the end of this frame
+	g_BlurFbCapTimer = 0;
+
+	// don't render first blur frame as we haven't captured the fb yet
+	if (g_BlurFbDirty) {
+		return gdl;
+	}
 #endif
 
 	mainOverrideVariable("sfxxx", &sfxxx);
@@ -312,7 +320,6 @@ Gfx *bviewDrawMotionBlur(Gfx *gdl, u32 colour, u32 alpha)
 		viewleft << 2, viewtop << 2, viewleft, viewtop,
 		(viewleft + viewwidth) << 2, (viewtop + viewheight) << 2, viewleft + viewwidth, viewtop + viewheight,
 		0, videoGetNativeWidth(), videoGetNativeHeight());
-	g_BlurFbCapTimer = 0;
 #endif
 
 	return gdl;
@@ -521,6 +528,14 @@ Gfx *bviewDrawZoomBlur(Gfx *gdl, u32 colour, s32 alpha, f32 arg3, f32 arg4)
 	if (!videoFramebuffersSupported()) {
 		return gdl;
 	}
+
+	// capture fb at the end of this frame
+	g_BlurFbCapTimer = 0;
+
+	// don't render first blur frame as we haven't captured the fb yet
+	if (g_BlurFbDirty) {
+		return gdl;
+	}
 #endif
 
 	strcpy(var800a41c0, "stretchBlurGfx");
@@ -550,7 +565,6 @@ Gfx *bviewDrawZoomBlur(Gfx *gdl, u32 colour, s32 alpha, f32 arg3, f32 arg4)
 		left << 2, top << 2, viewleft, viewtop,
 		right << 2, bottom << 2, viewleft + viewwidth, viewtop + viewheight,
 		0, videoGetNativeWidth(), videoGetNativeHeight());
-	g_BlurFbCapTimer = 0;
 #endif
 
 	return gdl;

src/game/texreset.c

@@ -139,6 +139,9 @@ void texReset(void)
 
 	// get backend texture settings
 	g_TexFilter2D = videoGetTextureFilter2D() ? G_TF_BILERP : G_TF_POINT;
+
+	// notify blur code that the blur framebuffer is probably full of garbage
+	g_BlurFbDirty = true;
 #endif
 
 	g_TexWords = mempAlloc(ALIGN16(g_TexNumConfigs * 4), MEMPOOL_STAGE);

src/include/data.h

@@ -545,6 +545,7 @@ extern u32 g_HudAlignModeR;
 extern s32 g_PrevFrameFb;
 extern s32 g_BlurFb;
 extern s32 g_BlurFbCapTimer;
+extern bool g_BlurFbDirty;
 extern s32 g_TickRateDiv;
 extern s32 g_MusicDisableMpDeath;