Put two of the WinCE downscalers into graphics/scaler/downscaler*, so that they can be used by multiple backends (more could be added as needed)

svn-id: r45974

1 files changed, 96 insertions, 0 deletions

diff --git a/graphics/scaler/downscaler.cpp b/graphics/scaler/downscaler.cpp
new file mode 100644
index 0000000000..21ba1ce36d
--- /dev/null
+++ b/graphics/scaler/downscaler.cpp
@@ -0,0 +1,96 @@
+/* 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.
+ *
+ * $URL$
+ * $Id$
+ *
+ */
+#include "graphics/scaler/downscaler.h"
+#include "graphics/scaler/intern.h"
+
+#ifdef ARM
+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) {
+	// 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<int bitFormat>
+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<Graphics::ColorMasks<bitFormat> >(color1, color2, color3, color4);
+
+			work += sizeof(uint16);
+		}
+		srcPtr += 2 * srcPitch;
+		dstPtr += dstPitch;
+	}
+}
+MAKE_WRAPPER(DownscaleAllByHalf)
+
+#endif
+
+
+/**
+ * This filter (down)scales the source image horizontally by a factor of 1/2.
+ * For example, a 320x200 image is scaled to 160x200.
+ */
+template<int bitFormat>
+void DownscaleHorizByHalfTemplate(const uint8 *srcPtr, uint32 srcPitch, uint8 *dstPtr, uint32 dstPitch, int width, int height) {
+	uint16 *work;
+
+	if (!height)
+		return;
+
+	// Various casts below go via (void *) to avoid warning. This is
+	// safe as these are all even addresses.
+	while (height--) {
+		work = (uint16 *)(void *)dstPtr;
+
+		for (int i = 0; i < width; i += 2) {
+			uint16 color1 = *(((const uint16 *)(const void *)srcPtr) + i);
+			uint16 color2 = *(((const uint16 *)(const void *)srcPtr) + (i + 1));
+			*work++ = interpolate32_1_1<bitFormat>(color1, color2);
+		}
+		srcPtr += srcPitch;
+		dstPtr += dstPitch;
+	}
+}
+MAKE_WRAPPER(DownscaleHorizByHalf)