Support for PAL killing color-burst during TEXT video mode (#763, PR #823)

tested with:
. AppleWin-Test repo -> Tests-Various.dsk (tests E, F)
. FT's ANSI STORY & TRIBU demos

source/NTSC.cpp

@@ -808,6 +808,9 @@ inline void updateVideoScannerHorzEOL()
 //===========================================================================
 inline void updateVideoScannerAddress()
 {
+	if (g_nVideoMixed && g_nVideoClockVert >= VIDEO_SCANNER_Y_MIXED && GetVideoRefreshRate() == VR_50HZ)
+		g_nColorBurstPixels = 0;	// instantaneously kill color-burst!
+
 	g_pVideoAddress = g_nVideoClockVert < VIDEO_SCANNER_Y_DISPLAY ? g_pScanLines[2*g_nVideoClockVert] : g_pScanLines[0];
 
 	// Adjust, as these video styles have 2x 14M pixels of pre-render
@@ -1143,24 +1146,28 @@ void updateMonochromeTables( uint16_t r, uint16_t g, uint16_t b )
 static void updatePixelBnWMonitorSingleScanline (uint16_t compositeSignal)
 {
 	updateFramebufferMonitorSingleScanline(compositeSignal, g_aBnWMonitorCustom);
+	updateColorPhase();	// Maintain color-phase, as could be switching graphics/text video modes mid-scanline
 }
 
 //===========================================================================
 static void updatePixelBnWMonitorDoubleScanline (uint16_t compositeSignal)
 {
 	updateFramebufferMonitorDoubleScanline(compositeSignal, g_aBnWMonitorCustom);
+	updateColorPhase();	// Maintain color-phase, as could be switching graphics/text video modes mid-scanline
 }
 
 //===========================================================================
 static void updatePixelBnWColorTVSingleScanline (uint16_t compositeSignal)
 {
 	updateFramebufferTVSingleScanline(compositeSignal, g_aBnWColorTVCustom);
+	updateColorPhase();	// Maintain color-phase, as could be switching graphics/text video modes mid-scanline
 }
 
 //===========================================================================
 static void updatePixelBnWColorTVDoubleScanline (uint16_t compositeSignal)
 {
 	updateFramebufferTVDoubleScanline(compositeSignal, g_aBnWColorTVCustom);
+	updateColorPhase();	// Maintain color-phase, as could be switching graphics/text video modes mid-scanline
 }
 
 //===========================================================================
@@ -1601,7 +1608,6 @@ void updateScreenText40 (long cycles6502)
 					bits ^= g_nTextFlashMask;
 
 				updatePixels( bits );
-
 			}
 		}
 		updateVideoScannerHorzEOL();
@@ -1642,6 +1648,7 @@ void updateScreenText80 (long cycles6502)
 				uint16_t bits = (main << 7) | (aux & 0x7f);
 				if (g_eVideoType != VT_COLOR_MONITOR_RGB)			// No extra 14M bit needed for VT_COLOR_MONITOR_RGB
 					bits = (bits << 1) | g_nLastColumnPixelNTSC;	// GH#555: Align TEXT80 chars with DHGR
+
 				updatePixels( bits );
 				g_nLastColumnPixelNTSC = (bits >> 14) & 1;
 			}
@@ -1762,6 +1769,32 @@ void NTSC_SetVideoMode( uint32_t uVideoModeFlags, bool bDelay/*=false*/ )
 		}
 	}
 
+	if (GetVideoRefreshRate() == VR_50HZ)
+	{
+		if (uVideoModeFlags & VF_TEXT)
+		{
+			g_nColorBurstPixels = 0;		// (For mid-line video mode change) Instantaneously kill color-burst! (not correct as TV's can take many lines)
+
+			// Switching mid-line from graphics to TEXT
+			if (g_eVideoType == VT_COLOR_MONITOR_NTSC &&
+				g_pFuncUpdateGraphicsScreen != updateScreenText40 && g_pFuncUpdateGraphicsScreen != updateScreenText80)
+			{
+					g_pVideoAddress += 2;	// eg. FT's TRIBU demo & ANSI STORY (at "turn the disk over!")
+			}
+		}
+		else
+		{
+			g_nColorBurstPixels = 1024;		// (For mid-line video mode change)
+
+			// Switching mid-line from TEXT to graphics
+			if (g_eVideoType == VT_COLOR_MONITOR_NTSC &&
+				(g_pFuncUpdateGraphicsScreen == updateScreenText40 || g_pFuncUpdateGraphicsScreen == updateScreenText80))
+			{
+					g_pVideoAddress -= 2;	// eg. FT's TRIBU demo & ANSI STORY (at "turn the disk over!")
+			}
+		}
+	}
+
 	if (uVideoModeFlags & VF_TEXT)
 	{
 		if (uVideoModeFlags & VF_80COL)
@@ -1821,9 +1854,10 @@ void NTSC_SetVideoMode( uint32_t uVideoModeFlags, bool bDelay/*=false*/ )
 
 //===========================================================================
 
-void NTSC_SetVideoStyle() // (int v, int s)
+void NTSC_SetVideoStyle(void)
 {
-    int half = IsVideoStyle(VS_HALF_SCANLINES);
+	const bool half = IsVideoStyle(VS_HALF_SCANLINES);
+	const VideoRefreshRate_e refresh = GetVideoRefreshRate();
 	uint8_t r, g, b;
 
 	switch ( g_eVideoType )
@@ -1838,7 +1872,8 @@ void NTSC_SetVideoStyle() // (int v, int s)
 				g_pFuncUpdateBnWPixel = updatePixelBnWColorTVSingleScanline;
 				g_pFuncUpdateHuePixel = updatePixelHueColorTVSingleScanline;
 			}
-			else {
+			else
+			{
 				g_pFuncUpdateBnWPixel = updatePixelBnWColorTVDoubleScanline;
 				g_pFuncUpdateHuePixel = updatePixelHueColorTVDoubleScanline;
 			}
@@ -1855,7 +1890,8 @@ void NTSC_SetVideoStyle() // (int v, int s)
 				g_pFuncUpdateBnWPixel = updatePixelBnWMonitorSingleScanline;
 				g_pFuncUpdateHuePixel = updatePixelHueMonitorSingleScanline;
 			}
-			else {
+			else
+			{
 				g_pFuncUpdateBnWPixel = updatePixelBnWMonitorDoubleScanline;
 				g_pFuncUpdateHuePixel = updatePixelHueMonitorDoubleScanline;
 			}
@@ -1867,12 +1903,9 @@ void NTSC_SetVideoStyle() // (int v, int s)
 			b = 0xFF;
 			updateMonochromeTables( r, g, b ); // Custom Monochrome color
 			if (half)
-			{
 				g_pFuncUpdateBnWPixel = g_pFuncUpdateHuePixel = updatePixelBnWColorTVSingleScanline;
-			}
+			else
-			else {
 				g_pFuncUpdateBnWPixel = g_pFuncUpdateHuePixel = updatePixelBnWColorTVDoubleScanline;
-			}
 			break;
 
 		case VT_MONO_AMBER:
@@ -1906,13 +1939,9 @@ void NTSC_SetVideoStyle() // (int v, int s)
 _mono:
 			updateMonochromeTables( r, g, b ); // Custom Monochrome color
 			if (half)
-			{
 				g_pFuncUpdateBnWPixel = g_pFuncUpdateHuePixel = updatePixelBnWMonitorSingleScanline;
-			}
 			else
-			{
 				g_pFuncUpdateBnWPixel = g_pFuncUpdateHuePixel = updatePixelBnWMonitorDoubleScanline;
-			}
 			break;
 		}
 }