Method HeliIntro_BlitMaskedAlignedX

Source/PC/Graphics_PC.cpp:814–879

}

void cGraphics_PC::HeliIntro_BlitMaskedAlignedX(tSharedBuffer pSource, int16 pCx)
{
	uint8* pDs = pSource->data();
	uint8* pDsEnd = pSource->data() + pSource->size();

	// Original works in 4-pixel groups
	const int16 groupX = (pCx >> 2);
	int16 ax = groupX;
	int16 dx = ax;

	ax -= 80;
	int16 word_4285F = -ax;

	const int planeShift = (pCx & 3); // <-- sub-pixel (0..3)

	// first 4-pixel group for pCx
	uint8* base = mSurface->GetSurfaceBuffer() + mMission_Intro_DrawY + (dx * 4);

	++dx;

	// Loop the 4 source planes, but map them to dest planes with shift
	for (uint8 srcPlane = 0; srcPlane < 4; ++srcPlane)
	{
		const int dstPlane = (srcPlane + planeShift) & 3;
		const int groupCarry = ((srcPlane + planeShift) >> 2) & 1;

		uint8* destPtr = base + (groupCarry * 4) + dstPlane;
		uint8* di = destPtr;

		for (int16 bx = mMission_Intro_DrawX; bx > 0; --bx)
		{
			int16 cx;

			for (cx = word_4285F; cx > 0; --cx)
			{
				if (pDs >= pDsEnd)
					return;

				uint8 al = *pDs;
				if (al)
					*di = al;

				++pDs;
				di += 4;
			}

			di -= mSurface->GetWidth() - 12 - 16;
			--pDs;

			for (cx = dx; cx > 0; --cx)
			{
				if (pDs >= pDsEnd)
					return;

				uint8 al = *pDs;
				if (al)
					*di = al;