BIOS logo: Fix corrupted palette issues with MDA/Hercules/CGA/PCjr/Ta…

…ndy after rebooting the VM
maron2000 · Dec 30, 2024 · 24e0d70 · 24e0d70
1 parent 34e64d8
commit 24e0d70
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Showing 2 changed files with 27 additions and 10 deletions.
diff --git a/src/hardware/vga_draw.cpp b/src/hardware/vga_draw.cpp
@@ -3451,6 +3451,8 @@ struct BIOSlogo_t {
 	unsigned int		width = 0,height = 0;
 	unsigned char*		palette = NULL; /* 256 colors (NOTE: Except for VGA and PC-98, not all 256 colors available!) */
 	VGA_Line_Handler	DrawLine = NULL;
+	bool			visible = false;
+	bool			vsync_enable = false;
 
 	BIOSlogo_t() {
 	}
@@ -3462,6 +3464,8 @@ struct BIOSlogo_t {
 		bmp = NULL;
 		if (palette) delete[] palette;
 		palette = NULL;
+		visible = false;
+		vsync_enable = false;
 	}
 	void position(unsigned int new_x,unsigned int new_y) {
 		x = new_x;
@@ -3491,7 +3495,7 @@ static uint8_t *VGA_DrawLineBiosLogoOverlay(Bitu vidstart, Bitu line) {
 	 * causing random garbage on the VGA graphics RAM. As usual, modifying through pointer "r" causes
 	 * corruption. Modifying TempLine, which is basically the same exact memory "r" points to, does not. */
 
-	if (BIOSlogo.bmp != NULL && BIOSlogo.palette != NULL) {
+	if (BIOSlogo.bmp != NULL && BIOSlogo.palette != NULL && BIOSlogo.visible && BIOSlogo.vsync_enable) {
 		if (vga.draw.lines_done >= BIOSlogo.y && r >= TempLine && r < (TempLine+sizeof(TempLine))) {
 			const unsigned int rel = vga.draw.lines_done - BIOSlogo.y;
 			const unsigned int bofs = (unsigned int)(r - TempLine);
@@ -3523,22 +3527,30 @@ static uint8_t *VGA_DrawLineBiosLogoOverlay(Bitu vidstart, Bitu line) {
 	return r;
 }
 
-void BiosLogoHookVGADrawLine(void) {
-	if (VGA_DrawLine != VGA_DrawLineBiosLogoOverlay) {
-		BIOSlogo.DrawLine = VGA_DrawLine;
-		VGA_DrawLine = VGA_DrawLineBiosLogoOverlay;
-
-		if (vga.draw.bpp == 8) {
-			for (unsigned int i=0;i < 0x40;i++) {
-				RENDER_SetPal(0xC0+i,
+void VGA_BIOSLogoUpdatePalette(void) {
+	if (vga.draw.bpp == 8) {
+		for (unsigned int i=0;i < 0x40;i++) {
+			RENDER_SetPal(0xC0+i,
 					BIOSlogo.palette[(i*3)+0],
 					BIOSlogo.palette[(i*3)+1],
 					BIOSlogo.palette[(i*3)+2]);
-			}
 		}
 	}
 }
 
+void BiosLogoHookVGADrawLine(void) {
+	if (VGA_DrawLine != VGA_DrawLineBiosLogoOverlay) {
+		BIOSlogo.DrawLine = VGA_DrawLine;
+		VGA_DrawLine = VGA_DrawLineBiosLogoOverlay;
+		VGA_BIOSLogoUpdatePalette();
+	}
+}
+
+void VGA_ShowBIOSLogo(void) {
+	VGA_BIOSLogoUpdatePalette();
+	BIOSlogo.visible = true;
+}
+
 bool VGA_InitBiosLogo(unsigned int w,unsigned int h,unsigned int x,unsigned int y) {
 	BIOSlogo.allocate(w,h);
 	BIOSlogo.position(x,y);
@@ -3558,6 +3570,7 @@ void VGA_WriteBiosLogoPalette(unsigned int start,unsigned int count,unsigned cha
 			BIOSlogo.palette[((i+start)*3)+1] = rgb[(i*3)+1];
 			BIOSlogo.palette[((i+start)*3)+2] = rgb[(i*3)+2];
 		}
+		if (BIOSlogo.visible) VGA_BIOSLogoUpdatePalette();
 	}
 }
 
@@ -5799,6 +5812,8 @@ static void VGA_VerticalTimer(Bitu /*val*/) {
 	}
 #endif
 
+	if (BIOSlogo.visible) BIOSlogo.vsync_enable = true;
+
 	dbg_event_maxscan = false;
 	dbg_event_scanstep = false;
 	dbg_event_hretrace = false;

diff --git a/src/ints/bios.cpp b/src/ints/bios.cpp
@@ -95,6 +95,7 @@ bool VGA_InitBiosLogo(unsigned int w,unsigned int h,unsigned int x,unsigned int
 void VGA_WriteBiosLogoBMP(unsigned int y,unsigned char *scanline,unsigned int w);
 void VGA_WriteBiosLogoPalette(unsigned int start,unsigned int count,unsigned char *rgb);
 void VGA_FreeBiosLogo(void);
+void VGA_ShowBIOSLogo(void);
 
 extern bool ega200;
 
@@ -11007,6 +11008,7 @@ class BIOS:public Module_base{
                             png_read_rows(png_context,rows,NULL,1);
                             VGA_WriteBiosLogoBMP(y,row,png_width);
                         }
+                        VGA_ShowBIOSLogo();
                     }
 
                     delete[] row;