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vtf/s3tc_decode.h

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+//========= Copyright Valve Corporation, All rights reserved. ============//
+//
+// Purpose: 
+//
+//=============================================================================//
+
+#ifndef S3TC_DECODE_H
+#define S3TC_DECODE_H
+#ifdef _WIN32
+#pragma once
+#endif
+
+
+#include "bitmap/imageformat.h"
+enum ImageFormat;
+
+
+class S3RGBA
+{
+public:
+	unsigned char b, g, r, a;
+};
+
+class S3PaletteIndex
+{
+public:
+	unsigned char m_AlphaIndex;
+	unsigned char m_ColorIndex;
+};
+
+
+#define MAX_S3TC_BLOCK_BYTES	16
+
+
+S3PaletteIndex S3TC_GetPixelPaletteIndex( ImageFormat format, const char *pS3Block, int x, int y );
+
+void S3TC_SetPixelPaletteIndex( ImageFormat format, char *pS3Block, int x, int y, S3PaletteIndex iPaletteIndex );
+
+
+
+// Note: width, x, and y are in texels, not S3 blocks.
+S3PaletteIndex S3TC_GetPaletteIndex( 
+	unsigned char *pFaceData,
+	ImageFormat format,
+	int imageWidth,
+	int x,
+	int y );
+
+
+// Note: width, x, and y are in texels, not S3 blocks.
+void S3TC_SetPaletteIndex( 
+	unsigned char *pFaceData,
+	ImageFormat format,
+	int imageWidth,
+	int x,
+	int y,
+	S3PaletteIndex paletteIndex );
+
+
+const char* S3TC_GetBlock( 
+	const void *pCompressed, 
+	ImageFormat format, 
+	int nBlocksWide, // How many blocks wide is the image (pixels wide / 4).
+	int xBlock,
+	int yBlock );
+
+
+char* S3TC_GetBlock( 
+	void *pCompressed, 
+	ImageFormat format, 
+	int nBlocksWide, // How many blocks wide is the image (pixels wide / 4).
+	int xBlock,
+	int yBlock );
+
+
+// Merge the two palettes and copy the colors
+void S3TC_MergeBlocks( 
+	char **blocks,
+	S3RGBA **pOriginals,	// Original RGBA colors in the texture. This allows it to avoid doubly compressing.
+	int nBlocks,
+	int lPitch,	// (in BYTES)
+	ImageFormat format
+	);
+
+
+// Convert an RGB565 color to RGBA8888.
+inline S3RGBA S3TC_RGBAFrom565( unsigned short color, unsigned char alphaValue=255 )
+{
+	S3RGBA ret;
+	ret.a = alphaValue;
+	ret.r = (unsigned char)( (color >> 11) << 3 );
+	ret.g = (unsigned char)( ((color >> 5) & 0x3F) << 2 );
+	ret.b = (unsigned char)( (color & 0x1F) << 3 );
+	return ret;
+}
+
+// Blend from one color to another..
+inline S3RGBA S3TC_RGBABlend( const S3RGBA &a, const S3RGBA &b, int aMul, int bMul, int div )
+{
+	S3RGBA ret;
+	ret.r = (unsigned char)(( (int)a.r * aMul + (int)b.r * bMul ) / div );
+	ret.g = (unsigned char)(( (int)a.g * aMul + (int)b.g * bMul ) / div );
+	ret.b = (unsigned char)(( (int)a.b * aMul + (int)b.b * bMul ) / div );
+	ret.a = (unsigned char)(( (int)a.a * aMul + (int)b.a * bMul ) / div );
+	return ret;
+}
+
+
+#endif // S3TC_DECODE_H