scummvm/graphics/conversion.cpp

/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */

#include "graphics/conversion.h"
#include "graphics/pixelformat.h"

namespace Graphics {

// TODO: YUV to RGB conversion function

// Function to blit a rect from one color format to another
bool crossBlit(byte *dst, const byte *src,
               const uint dstPitch, const uint srcPitch,
               const uint w, const uint h,
               const Graphics::PixelFormat &dstFmt, const Graphics::PixelFormat &srcFmt) {
	// Error out if conversion is impossible
	if ((srcFmt.bytesPerPixel == 1) || (dstFmt.bytesPerPixel == 1)
			 || (!srcFmt.bytesPerPixel) || (!dstFmt.bytesPerPixel)
			 || (srcFmt.bytesPerPixel > dstFmt.bytesPerPixel))
		return false;

	// Don't perform unnecessary conversion
	if (srcFmt == dstFmt) {
		if (dst != src) {
			if (dstPitch == srcPitch && ((w * dstFmt.bytesPerPixel) == dstPitch)) {
				memcpy(dst, src, dstPitch * h);
			} else {
				for (uint i = 0; i < h; ++i) {
					memcpy(dst, src, w * dstFmt.bytesPerPixel);
					dst += dstPitch;
					src += srcPitch;
				}
			}
		}

		return true;
	}

	// Faster, but larger, to provide optimized handling for each case.
	const uint srcDelta = (srcPitch - w * srcFmt.bytesPerPixel);
	const uint dstDelta = (dstPitch - w * dstFmt.bytesPerPixel);

	// TODO: optimized cases for dstDelta of 0
	uint8 r, g, b, a;
	if (dstFmt.bytesPerPixel == 2) {
		uint16 color;
		for (uint y = 0; y < h; ++y) {
			for (uint x = 0; x < w; ++x, src += 2, dst += 2) {
				color = *(const uint16 *)src;
				srcFmt.colorToARGB(color, a, r, g, b);
				color = dstFmt.ARGBToColor(a, r, g, b);
				*(uint16 *)dst = color;
			}
			src += srcDelta;
			dst += dstDelta;
		}
	} else if (dstFmt.bytesPerPixel == 3) {
		uint32 color;
		uint8 *col = (uint8 *) &color;
#ifdef SCUMM_BIG_ENDIAN
		col++;
#endif
		if (srcFmt.bytesPerPixel == 2) {
			for (uint y = 0; y < h; ++y) {
				for (uint x = 0; x < w; ++x, src += 2, dst += 3) {
					color = *(const uint16 *)src;
					srcFmt.colorToARGB(color, a, r, g, b);
					color = dstFmt.ARGBToColor(a, r, g, b);
					memcpy(dst, col, 3);
				}
				src += srcDelta;
				dst += dstDelta;
			}
		} else {
			for (uint y = 0; y < h; ++y) {
				for (uint x = 0; x < w; ++x, src += 3, dst += 3) {
					memcpy(col, src, 3);
					srcFmt.colorToARGB(color, a, r, g, b);
					color = dstFmt.ARGBToColor(a, r, g, b);
					memcpy(dst, col, 3);
				}
				src += srcDelta;
				dst += dstDelta;
			}
		}
	} else if (dstFmt.bytesPerPixel == 4) {
		uint32 color;
		if (srcFmt.bytesPerPixel == 2) {
			for (uint y = 0; y < h; ++y) {
				for (uint x = 0; x < w; ++x, src += 2, dst += 4) {
					color = *(const uint16 *)src;
					srcFmt.colorToARGB(color, a, r, g, b);
					color = dstFmt.ARGBToColor(a, r, g, b);
					*(uint32 *)dst = color;
				}
				src += srcDelta;
				dst += dstDelta;
			}
		} else if (srcFmt.bytesPerPixel == 3) {
			uint8 *col = (uint8 *)&color;
#ifdef SCUMM_BIG_ENDIAN
			col++;
#endif
			for (uint y = 0; y < h; ++y) {
				for (uint x = 0; x < w; ++x, src += 2, dst += 4) {
					memcpy(col, src, 3);
					srcFmt.colorToARGB(color, a, r, g, b);
					color = dstFmt.ARGBToColor(a, r, g, b);
					*(uint32 *)dst = color;
				}
				src += srcDelta;
				dst += dstDelta;
			}
		} else {
			for (uint y = 0; y < h; ++y) {
				for (uint x = 0; x < w; ++x, src += 4, dst += 4) {
					color = *(const uint32 *)src;
					srcFmt.colorToARGB(color, a, r, g, b);
					color = dstFmt.ARGBToColor(a, r, g, b);
					*(uint32 *)dst = color;
				}
				src += srcDelta;
				dst += dstDelta;
			}
		}
	} else {
		return false;
	}
	return true;
}

} // End of namespace Graphics