WINTERMUTE: Use 64k-tables for alpha-blitting.

3 files changed, 36 insertions, 5 deletions

diff --git a/engines/wintermute/base/gfx/osystem/base_render_osystem.cpp b/engines/wintermute/base/gfx/osystem/base_render_osystem.cpp
index dbcb329d64..ab4e690458 100644
--- a/engines/wintermute/base/gfx/osystem/base_render_osystem.cpp
+++ b/engines/wintermute/base/gfx/osystem/base_render_osystem.cpp
@@ -114,6 +114,7 @@ BaseRenderOSystem::~BaseRenderOSystem() {
 	delete _renderSurface;

 	_blankSurface->free();

 	delete _blankSurface;

+	TransparentSurface::destroyLookup();

 }

 

 //////////////////////////////////////////////////////////////////////////

diff --git a/engines/wintermute/graphics/transparent_surface.cpp b/engines/wintermute/graphics/transparent_surface.cpp
index 1662ff19af..6bc324dd2b 100644
--- a/engines/wintermute/graphics/transparent_surface.cpp
+++ b/engines/wintermute/graphics/transparent_surface.cpp
@@ -29,6 +29,13 @@
 
 namespace WinterMute {
 
+byte *TransparentSurface::_lookup = NULL;
+
+void TransparentSurface::destroyLookup() {
+	delete _lookup;
+	_lookup = NULL;
+}
+
 TransparentSurface::TransparentSurface() : Surface(), _enableAlphaBlit(true) {}
 
 TransparentSurface::TransparentSurface(const Surface &surf, bool copyData) : Surface(), _enableAlphaBlit(true) {
@@ -67,9 +74,22 @@ void doBlitOpaque(byte *ino, byte* outo, uint32 width, uint32 height, uint32 pit
 	}
 }
 
-void doBlitAlpha(byte *ino, byte* outo, uint32 width, uint32 height, uint32 pitch, int32 inStep, int32 inoStep) {
+void TransparentSurface::generateLookup() {
+	_lookup = new byte[256 * 256];
+	for (int i = 0; i < 256; i++) {
+		for (int j = 0; j < 256; j++) {
+			_lookup[(i << 8) + j] = (i * j) >> 8;
+		}
+	}
+}
+
+void TransparentSurface::doBlitAlpha(byte *ino, byte* outo, uint32 width, uint32 height, uint32 pitch, int32 inStep, int32 inoStep) {
 	byte *in, *out;
 
+	if (!_lookup) {
+		generateLookup();
+	}
+
 #ifdef SCUMM_LITTLE_ENDIAN
 	const int aIndex = 3;
 	const int bIndex = 0;
@@ -103,10 +123,6 @@ void doBlitAlpha(byte *ino, byte* outo, uint32 width, uint32 height, uint32 pitc
 			int a = (pix >> aShift) & 0xff;
 			int outb, outg, outr, outa;
 			in += inStep;
-
-	/*		if (ca != 255) {
-				a = a * ca >> 8;
-			}*/
 			
 			switch (a) {
 				case 0: // Full transparency
@@ -127,12 +143,22 @@ void doBlitAlpha(byte *ino, byte* outo, uint32 width, uint32 height, uint32 pitc
 
 				default: // alpha blending
 					outa = 255;
+//#define USE_LOOKUP_TABLE_FOR_ALPHA
+#ifndef USE_LOOKUP_TABLE_FOR_ALPHA
 					outb = (oPix >> bShiftTarget) & 0xff;
 					outg = (oPix >> gShiftTarget) & 0xff;
 					outr = (oPix >> rShiftTarget) & 0xff;
 					outb += ((b - outb) * a) >> 8;
 					outg += ((g - outg) * a) >> 8;
 					outr += ((r - outr) * a) >> 8;
+#else
+					outb = _lookup[(((oPix >> bShiftTarget) & 0xff)) + ((255 - a) << 8)];
+					outg = _lookup[(((oPix >> gShiftTarget) & 0xff)) + ((255 - a) << 8)];
+					outr = _lookup[(((oPix >> rShiftTarget) & 0xff)) + ((255 - a) << 8)];
+					outb += _lookup[b + (a << 8)];
+					outg += _lookup[g + (a << 8)];
+					outr += _lookup[r + (a << 8)];
+#endif
 					//*(uint32 *)out = target.format.ARGBToColor(o_a, o_r, o_g, o_b);
 					out[aIndex] = outa;
 					out[bIndex] = outb;
diff --git a/engines/wintermute/graphics/transparent_surface.h b/engines/wintermute/graphics/transparent_surface.h
index 5e70b63218..761b7ba196 100644
--- a/engines/wintermute/graphics/transparent_surface.h
+++ b/engines/wintermute/graphics/transparent_surface.h
@@ -105,7 +105,11 @@ struct TransparentSurface : public Graphics::Surface {
 	// The following scale-code supports arbitrary scaling (i.e. no repeats of column 0 at the end of lines)
 	TransparentSurface *scale(uint16 newWidth, uint16 newHeight) const;
 	TransparentSurface *scale(const Common::Rect &srcRect, const Common::Rect &dstRect) const;
+	static byte *_lookup;
+	static void destroyLookup();
 private:
+	static void doBlitAlpha(byte *ino, byte* outo, uint32 width, uint32 height, uint32 pitch, int32 inStep, int32 inoStep);
+	static void generateLookup();
 	static int *scaleLine(int size, int srcSize);
 };