Function ClearOverscanVideoArea

source/NTSC.cpp:815–855

#endif

static void ClearOverscanVideoArea(void)
{
	if (g_pFuncUpdateGraphicsScreen == updateScreenSHR)
		return;

	bgra_t* pSaveVideoAddress = g_pVideoAddress;	// save g_pVideoAddress
	g_pVideoAddress = g_pScanLines[0];
	uint32_t* pLine1Prev = getScanlinePreviousInbetween();
	g_pVideoAddress = pSaveVideoAddress;			// restore g_pVideoAddress

	const int kOverscanOffsetL = 3;	// In updateVideoScannerAddress(), g_pVideoAddress could be adjusted by: -2 + -1 = -3
	const int kOverscanSpanL = 3;
	const int kOverscanOverlapL = kOverscanSpanL - kOverscanOffsetL;

	const int kOverscanOffsetR = 2;
	const int kOverscanSpanR = 4;		// In updateVideoScannerHorzEOL() it writes 4 extra pixels
	const int kOverscanOverlapR = kOverscanSpanR - kOverscanOffsetR;

	const int kHorzPixels = (VIDEO_SCANNER_MAX_HORZ - VIDEO_SCANNER_HORZ_START) * 14;

	pLine1Prev += GetVideo().GetFrameBufferCentringValue() - kOverscanOffsetL;		// Centre the older //e video modes when running with a VidHD

	// Clear this line at Y=-1
	for (uint32_t i = 0; i < (kHorzPixels + (kOverscanSpanL - kOverscanOverlapL) + (kOverscanSpanR - kOverscanOverlapR)); i++)
		*pLine1Prev++ = CLEAR_COLOUR_TOP | ALPHA32_MASK;

	// Clear overscan before & after display area
	for (uint32_t i = 0; i < VIDEO_SCANNER_Y_DISPLAY*2; i++)
	{
		uint32_t* pScanLine = ((uint32_t*)g_pScanLines[i]);
		pScanLine += GetVideo().GetFrameBufferCentringValue() - kOverscanOffsetL;		// Centre the older //e video modes when running with a VidHD

		for (uint32_t j = 0; j < kOverscanSpanL + 1; j++)
			pScanLine[j] = CLEAR_COLOUR_SIDE | ALPHA32_MASK;

		pScanLine += kOverscanOffsetL + kHorzPixels - kOverscanOffsetR;

		for (uint32_t j = 0; j < kOverscanSpanR; j++)
			pScanLine[j] = CLEAR_COLOUR_SIDE | ALPHA32_MASK;
	}
}

//===========================================================================
INLINE uint16_t getVideoScannerAddressTXT()