Initial commit

graphics/scaler/downscaler.cpp

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+/* 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 3 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, see <http://www.gnu.org/licenses/>.
+ *
+ */
+#include "common/debug.h"
+#include "common/textconsole.h"
+#include "graphics/scaler/downscaler.h"
+#include "graphics/scaler/intern.h"
+
+namespace Graphics {
+
+#ifdef USE_ARM_SCALER_ASM
+extern "C" {
+	void downscaleAllByHalfARM(const uint8 *srcPtr, uint32 srcPitch, uint8 *dstPtr, uint32 dstPitch, int width, int height, int mask, int round);
+}
+
+void downscaleAllByHalf(const uint8 *srcPtr, uint32 srcPitch, uint8 *dstPtr, uint32 dstPitch, int width, int height, int gBitFormat) {
+	// Rounding constants and masks used for different pixel formats
+	static const int roundingconstants[] = { 0x00200802, 0x00201002 };
+	static const int redbluegreenMasks[] = { 0x03E07C1F, 0x07E0F81F };
+
+	const int maskUsed = (gBitFormat == 565);
+	downscaleAllByHalfARM(srcPtr, srcPitch, dstPtr, dstPitch, width, height, redbluegreenMasks[maskUsed], roundingconstants[maskUsed]);
+}
+
+#else
+
+template<typename ColorMask>
+void downscaleAllByHalfTemplate(const uint8 *srcPtr, uint32 srcPitch, uint8 *dstPtr, uint32 dstPitch, int width, int height) {
+	uint8 *work;
+	uint16 srcPitch16 = (uint16)(srcPitch / sizeof(uint16));
+
+	while ((height -= 2) >= 0) {
+		work = dstPtr;
+
+		for (int i=0; i<width; i+=2) {
+			// Another lame filter attempt :)
+			uint16 color1 = *(((const uint16 *)srcPtr) + i);
+			uint16 color2 = *(((const uint16 *)srcPtr) + (i + 1));
+			uint16 color3 = *(((const uint16 *)srcPtr) + (i + srcPitch16));
+			uint16 color4 = *(((const uint16 *)srcPtr) + (i + srcPitch16 + 1));
+			*(((uint16 *)work) + 0) = interpolate16_1_1_1_1<ColorMask>(color1, color2, color3, color4);
+
+			work += sizeof(uint16);
+		}
+		srcPtr += 2 * srcPitch;
+		dstPtr += dstPitch;
+	}
+}
+
+void downscaleAllByHalf(const uint8 *srcPtr, uint32 srcPitch, uint8 *dstPtr, uint32 dstPitch, int width, int height, int gBitFormat) {
+	if (gBitFormat == 565)
+		downscaleAllByHalfTemplate<Graphics::ColorMasks<565> >(srcPtr, srcPitch, dstPtr, dstPitch, width, height);
+	else
+		downscaleAllByHalfTemplate<Graphics::ColorMasks<555> >(srcPtr, srcPitch, dstPtr, dstPitch, width, height);
+}
+
+#endif
+
+namespace {
+uint32 getBrightness(byte col, const byte *pal) {
+	return pal[3 * col] * pal[3 * col] + pal[3 * col + 1] * pal[3 * col + 1] + pal[3 * col + 2] * pal[3 * col + 2];
+}
+
+void downscaleCLUT8ByHalf(const uint8 *srcPtr, uint32 srcPitch, uint8 *dstPtr, uint32 dstPitch, int maxX, int maxY, const byte *palette) {
+	const byte *src1 = srcPtr;
+	const byte *src2 = srcPtr + srcPitch;
+	byte *dst = dstPtr;
+	int32 srcSkip = 2 * srcPitch - maxX * 2;
+	int32 dstSkip = dstPitch - maxX;
+	for (int y = 0; y < maxY; y++) {
+		for (int x = 0; x < maxX; x++) {
+			// Choose the brightest pixel. Writing often is bright on
+			// a dark background, so this preserves text as much as we can.
+			byte colors[4] = {
+				*src1++,
+				*src1++,
+				*src2++,
+				*src2++
+			};
+
+			byte col = colors[0];
+			uint32 bri = getBrightness(col, palette);
+			for (uint i = 1; i < 4; i++) {
+				uint32 nbri = getBrightness(colors[i], palette);
+				if (nbri > bri) {
+					bri = nbri;
+					col = colors[i];
+				}
+			}
+
+			*dst++ = col;
+		}
+		src1 += srcSkip;
+		src2 += srcSkip;
+		dst += dstSkip;
+	}
+}
+
+} // end of anonymous namespsce
+
+void downscaleSurfaceByHalf(Surface *out, const Surface *in, const byte *palette) {
+	if (in->format.isCLUT8() && out->format.isCLUT8() && palette != nullptr) {
+		downscaleCLUT8ByHalf((const byte *) in->getBasePtr(0, 0), in->pitch, (byte *) out->getBasePtr(0, 0), out->pitch,
+				     MIN<int>(out->w, in->w / 2), MIN<int>(out->h, in->h / 2), palette);
+		return;
+	}
+
+	if ((in->format == PixelFormat(2, 5, 6, 5, 0, 11, 5, 0, 0)
+	     && out->format == PixelFormat(2, 5, 6, 5, 0, 11, 5, 0, 0))
+	    || (in->format == PixelFormat(2, 5, 6, 5, 0, 0, 5, 11, 0)
+		&& out->format == PixelFormat(2, 5, 6, 5, 0, 0, 5, 11, 0))) {
+		downscaleAllByHalf((const byte *) in->getBasePtr(0, 0), in->pitch, (byte *) out->getBasePtr(0, 0), out->pitch,
+				   MIN<int>(in->w, out->w * 2), MIN<int>(in->h, out->h * 2), 565);
+		return;
+	}
+
+	if ((in->format == PixelFormat(2, 5, 5, 5, 0, 10, 5, 0, 0)
+	     && out->format == PixelFormat(2, 5, 5, 5, 0, 10, 5, 0, 0))
+	    || (in->format == PixelFormat(2, 5, 5, 5, 0, 0, 5, 10, 0)
+		&& out->format == PixelFormat(2, 5, 5, 5, 0, 0, 5, 10, 0))) {
+		downscaleAllByHalf((const byte *) in->getBasePtr(0, 0), in->pitch, (byte *) out->getBasePtr(0, 0), out->pitch,
+				   MIN<int>(in->w, out->w * 2), MIN<int>(in->h, out->h * 2), 555);
+		return;
+	}
+
+	error("downscaleCLUT8ByHalf(): Unsupported downscale format %s->%s", in->format.toString().c_str(), out->format.toString().c_str());
+}
+
+}  // end of namespace Graphics