--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/engine/core/video/sdl/sdlblendingfunctions.cpp	Sun Jun 29 18:44:17 2008 +0000
@@ -0,0 +1,127 @@
+/***************************************************************************
+ *   Copyright (C) 2005-2008 by the FIFE team                              *
+ *   http://www.fifengine.de                                               *
+ *   This file is part of FIFE.                                            *
+ *                                                                         *
+ *   FIFE 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 St, Fifth Floor, Boston, MA  02110-1301  USA              *
+ ***************************************************************************/
+
+// Standard C++ library includes
+
+// 3rd party library includes
+
+// FIFE includes
+// These includes are split up in two parts, separated by one empty line
+// First block: files included from the FIFE root src directory
+// Second block: files included from the same folder
+#include "sdlblendingfunctions.h"
+
+namespace FIFE {
+
+	struct ColorRGB8 {
+		unsigned char r, g, b;
+	};
+
+	struct ColorRGBA8 {
+		unsigned char r, g, b, a;
+	};
+
+	void SDL_BlendRow_RGBA8_to_RGBA8( const unsigned char* src, unsigned char* dst, unsigned int alpha, int n ) {
+		const ColorRGBA8* srcColor = reinterpret_cast< const ColorRGBA8* >( src );
+		ColorRGBA8* dstColor = reinterpret_cast< ColorRGBA8* >( dst );
+
+		for( int i = n; 0 < i; --i ) {
+			register unsigned int aMulA = alpha * srcColor->a;
+
+			if( aMulA ) {
+				register unsigned int OneMin_aMulA = 65535 - aMulA;
+				dstColor->r = ( aMulA * srcColor->r + OneMin_aMulA * dstColor->r ) >> 16;
+				dstColor->g = ( aMulA * srcColor->g + OneMin_aMulA * dstColor->g ) >> 16;
+				dstColor->b = ( aMulA * srcColor->b + OneMin_aMulA * dstColor->b ) >> 16;
+				dstColor->a = 255;
+			}
+			++dstColor;
+			++srcColor;
+		}
+	}
+
+	void SDL_BlendRow_RGBA8_to_RGB8( const unsigned char* src, unsigned char* dst, unsigned int alpha, int n ) {
+		const ColorRGBA8* srcColor = reinterpret_cast< const ColorRGBA8* >( src );
+		ColorRGB8* dstColor = reinterpret_cast< ColorRGB8* >( dst );
+
+		for( int i = n; 0 < i; --i ) {
+			register unsigned int aMulA = alpha * srcColor->a;
+			if( aMulA ) {
+				register unsigned int OneMin_aMulA = 65535 - aMulA;
+				dstColor->r = ( aMulA * srcColor->r + OneMin_aMulA * dstColor->r ) >> 16;
+				dstColor->g = ( aMulA * srcColor->g + OneMin_aMulA * dstColor->g ) >> 16;
+				dstColor->b = ( aMulA * srcColor->b + OneMin_aMulA * dstColor->b ) >> 16;
+			}
+
+			++dstColor;
+			++srcColor;
+		}
+	}
+
+	void SDL_BlendRow_RGBA8_to_RGB565( const unsigned char* src, unsigned char* dst, unsigned int alpha, int n ) {
+		const ColorRGBA8* srcColor = reinterpret_cast< const ColorRGBA8* >( src );
+		unsigned short* dstColor = reinterpret_cast< unsigned short* >( dst );
+
+		for( int i = n; 0 < i; --i ) {
+			register unsigned int aMulA = ( alpha * srcColor->a ) >> 8;
+			if( aMulA ) {
+				register unsigned int OneMin_aMulA = 255 - aMulA;
+				register unsigned int c = *dstColor;
+				*dstColor = ( ( ( srcColor->b * aMulA ) +
+					( ( ( c & 0xF800 ) >> 8 ) * OneMin_aMulA ) ) & 0xF800 ) |
+					( ( ( ( srcColor->g * aMulA ) +
+					( ( ( c & 0x07E0 ) >> 3 ) * OneMin_aMulA ) ) >> 5 ) & 0x07E0 ) |
+					( ( ( ( srcColor->r * aMulA ) +
+					( ( ( c & 0x001F ) << 3 ) * OneMin_aMulA ) ) >> 11 ) & 0x001F );
+			}
+
+			++dstColor;
+			++srcColor;
+		}
+	}
+
+
+	void SDL_BlendRow_RGBA4_to_RGB565( const unsigned char* src, unsigned char* dst, unsigned int alpha, int n ) {
+		const unsigned short* srcColor = reinterpret_cast< const unsigned short* >( src );
+		unsigned short* dstColor = reinterpret_cast< unsigned short* >( dst );
+
+		for( int i = n; 0 < i; --i ) {
+			register unsigned int c1 = *dstColor;
+			register unsigned int c2 = *srcColor;
+
+			unsigned int aMulA = c2 & 0xF;
+			aMulA = ( alpha * aMulA ) / 15;	///< upgrade to range 0-255
+			if( aMulA ) {
+				register unsigned int OneMin_aMulA = 255 - aMulA;
+				register unsigned int result;
+				result = ( ( ( ( c2 & 0xF000 ) | 0x0800 ) * aMulA ) + ( ( c1 & 0xF800 ) * OneMin_aMulA ) ) & 0xF80000;
+				result |= ( ( ( ( ( c2 & 0x0F00 ) >> 1 ) | 0x0040 ) * aMulA ) + ( ( c1 & 0x07E0 ) * OneMin_aMulA ) ) & 0x07E000;
+				result |= ( ( ( ( ( c2 & 0x00F0 ) >> 3 ) | 0x0001 ) * aMulA ) + ( ( c1 & 0x001F ) * OneMin_aMulA ) ) & 0x001F00;
+				/// multiplying by alpha resulted in shift.
+				*dstColor = static_cast< unsigned short int >( result >> 8 );
+			}
+
+			++dstColor;
+			++srcColor;
+		}
+	}
+
+}