texformat.c

Mesa is an open-source implementation of the OpenGL specification - a system for rendering interacti

/*
 * Mesa 3-D graphics library
 * Version:  6.5.1
 *
 * Copyright (C) 1999-2006  Brian Paul   All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */


/**
 * \file texformat.c
 * Texture formats.
 *
 * \author Gareth Hughes
 */


#include "colormac.h"
#include "context.h"
#include "texformat.h"
#include "texstore.h"


#if FEATURE_EXT_texture_sRGB

/**
 * Convert an 8-bit sRGB value from non-linear space to a
 * linear RGB value in [0, 1].
 * Implemented with a 256-entry lookup table.
 */
static INLINE GLfloat
nonlinear_to_linear(GLubyte cs8)
{
   static GLfloat table[256];
   static GLboolean tableReady = GL_FALSE;
   if (!tableReady) {
      /* compute lookup table now */
      GLuint i;
      for (i = 0; i < 256; i++) {
         const GLfloat cs = UBYTE_TO_FLOAT(i);
         if (cs <= 0.04045) {
            table[i] = cs / 12.92;
         }
         else {
            table[i] = _mesa_pow((cs + 0.055) / 1.055, 2.4);
         }
      }
      tableReady = GL_TRUE;
   }
   return table[cs8];
}


#endif /* FEATURE_EXT_texture_sRGB */


/* Texel fetch routines for all supported formats
 */
#define DIM 1
#include "texformat_tmp.h"

#define DIM 2
#include "texformat_tmp.h"

#define DIM 3
#include "texformat_tmp.h"

/**
 * Null texel fetch function.
 *
 * Have to have this so the FetchTexel function pointer is never NULL.
 */
static void fetch_null_texel( const struct gl_texture_image *texImage,
			      GLint i, GLint j, GLint k, GLchan *texel )
{
   (void) texImage; (void) i; (void) j; (void) k;
   texel[RCOMP] = 0;
   texel[GCOMP] = 0;
   texel[BCOMP] = 0;
   texel[ACOMP] = 0;
   _mesa_warning(NULL, "fetch_null_texel() called!");
}

static void fetch_null_texelf( const struct gl_texture_image *texImage,
                               GLint i, GLint j, GLint k, GLfloat *texel )
{
   (void) texImage; (void) i; (void) j; (void) k;
   texel[RCOMP] = 0.0;
   texel[GCOMP] = 0.0;
   texel[BCOMP] = 0.0;
   texel[ACOMP] = 0.0;
   _mesa_warning(NULL, "fetch_null_texelf() called!");
}

static void store_null_texel(struct gl_texture_image *texImage,
                             GLint i, GLint j, GLint k, const void *texel)
{
   (void) texImage;
   (void) i;
   (void) j;
   (void) k;
   (void) texel;
   /* no-op */
}


/**
 * Notes about the predefined gl_texture_formats:
 *
 * 1. There are 1D, 2D and 3D functions for fetching texels from texture
 *    images, returning both GLchan values and GLfloat values.  (six
 *    functions in total)
 *    You don't have to provide both the GLchan and GLfloat functions;
 *    just one or the other is OK.  Mesa will use an "adaptor" to convert
 *    between GLchan/GLfloat when needed.
 *    Since the adaptors have small performance penalty, we provide both
 *    GLchan and GLfloat functions for some common formats like RGB, RGBA.
 */


/***************************************************************/
/** \name Default GLchan-based formats */
/*@{*/

const struct gl_texture_format _mesa_texformat_rgba = {
   MESA_FORMAT_RGBA,			/* MesaFormat */
   GL_RGBA,				/* BaseFormat */
   GL_UNSIGNED_NORMALIZED_ARB,		/* DataType */
   CHAN_BITS,				/* RedBits */
   CHAN_BITS,				/* GreenBits */
   CHAN_BITS,				/* BlueBits */
   CHAN_BITS,				/* AlphaBits */
   0,					/* LuminanceBits */
   0,					/* IntensityBits */
   0,					/* IndexBits */
   0,					/* DepthBits */
   0,					/* StencilBits */
   4 * sizeof(GLchan),			/* TexelBytes */
   _mesa_texstore_rgba,			/* StoreTexImageFunc */
   fetch_texel_1d_rgba,			/* FetchTexel1D */
   fetch_texel_2d_rgba,			/* FetchTexel2D */
   fetch_texel_3d_rgba,			/* FetchTexel3D */
   fetch_texel_1d_f_rgba,		/* FetchTexel1Df */
   fetch_texel_2d_f_rgba,		/* FetchTexel2Df */
   fetch_texel_3d_f_rgba,		/* FetchTexel3Df */
   store_texel_rgba			/* StoreTexel */
};

const struct gl_texture_format _mesa_texformat_rgb = {
   MESA_FORMAT_RGB,			/* MesaFormat */
   GL_RGB,				/* BaseFormat */
   GL_UNSIGNED_NORMALIZED_ARB,		/* DataType */
   CHAN_BITS,				/* RedBits */
   CHAN_BITS,				/* GreenBits */
   CHAN_BITS,				/* BlueBits */
   0,					/* AlphaBits */
   0,					/* LuminanceBits */
   0,					/* IntensityBits */
   0,					/* IndexBits */
   0,					/* DepthBits */
   0,					/* StencilBits */
   3 * sizeof(GLchan),			/* TexelBytes */
   _mesa_texstore_rgba,/*yes*/		/* StoreTexImageFunc */
   fetch_texel_1d_rgb,			/* FetchTexel1D */
   fetch_texel_2d_rgb,			/* FetchTexel2D */
   fetch_texel_3d_rgb,			/* FetchTexel3D */
   fetch_texel_1d_f_rgb,		/* FetchTexel1Df */
   fetch_texel_2d_f_rgb,		/* FetchTexel2Df */
   fetch_texel_3d_f_rgb,		/* FetchTexel3Df */
   store_texel_rgb			/* StoreTexel */
};

const struct gl_texture_format _mesa_texformat_alpha = {
   MESA_FORMAT_ALPHA,			/* MesaFormat */
   GL_ALPHA,				/* BaseFormat */
   GL_UNSIGNED_NORMALIZED_ARB,		/* DataType */
   0,					/* RedBits */
   0,					/* GreenBits */
   0,					/* BlueBits */
   CHAN_BITS,				/* AlphaBits */
   0,					/* LuminanceBits */
   0,					/* IntensityBits */
   0,					/* IndexBits */
   0,					/* DepthBits */
   0,					/* StencilBits */
   sizeof(GLchan),			/* TexelBytes */
   _mesa_texstore_rgba,/*yes*/		/* StoreTexImageFunc */
   fetch_texel_1d_alpha,		/* FetchTexel1D */
   fetch_texel_2d_alpha,		/* FetchTexel2D */
   fetch_texel_3d_alpha,		/* FetchTexel3D */
   NULL,				/* FetchTexel1Df */
   NULL,				/* FetchTexel2Df */
   NULL,				/* FetchTexel3Df */
   store_texel_alpha			/* StoreTexel */
};

const struct gl_texture_format _mesa_texformat_luminance = {
   MESA_FORMAT_LUMINANCE,		/* MesaFormat */
   GL_LUMINANCE,			/* BaseFormat */
   GL_UNSIGNED_NORMALIZED_ARB,		/* DataType */
   0,					/* RedBits */
   0,					/* GreenBits */
   0,					/* BlueBits */
   0,					/* AlphaBits */
   CHAN_BITS,				/* LuminanceBits */
   0,					/* IntensityBits */
   0,					/* IndexBits */
   0,					/* DepthBits */
   0,					/* StencilBits */
   sizeof(GLchan),			/* TexelBytes */
   _mesa_texstore_rgba,/*yes*/		/* StoreTexImageFunc */
   fetch_texel_1d_luminance,		/* FetchTexel1D */
   fetch_texel_2d_luminance,		/* FetchTexel2D */
   fetch_texel_3d_luminance,		/* FetchTexel3D */
   NULL,				/* FetchTexel1Df */
   NULL,				/* FetchTexel2Df */
   NULL,				/* FetchTexel3Df */
   store_texel_luminance		/* StoreTexel */
};

const struct gl_texture_format _mesa_texformat_luminance_alpha = {
   MESA_FORMAT_LUMINANCE_ALPHA,		/* MesaFormat */
   GL_LUMINANCE_ALPHA,			/* BaseFormat */
   GL_UNSIGNED_NORMALIZED_ARB,		/* DataType */
   0,					/* RedBits */
   0,					/* GreenBits */
   0,					/* BlueBits */
   CHAN_BITS,				/* AlphaBits */
   CHAN_BITS,				/* LuminanceBits */
   0,					/* IntensityBits */
   0,					/* IndexBits */
   0,					/* DepthBits */
   0,					/* StencilBits */
   2 * sizeof(GLchan),			/* TexelBytes */
   _mesa_texstore_rgba,/*yes*/		/* StoreTexImageFunc */
   fetch_texel_1d_luminance_alpha,	/* FetchTexel1D */
   fetch_texel_2d_luminance_alpha,	/* FetchTexel2D */
   fetch_texel_3d_luminance_alpha,	/* FetchTexel3D */
   NULL,				/* FetchTexel1Df */
   NULL,				/* FetchTexel2Df */
   NULL,				/* FetchTexel3Df */
   store_texel_luminance_alpha		/* StoreTexel */
};

const struct gl_texture_format _mesa_texformat_intensity = {
   MESA_FORMAT_INTENSITY,		/* MesaFormat */
   GL_INTENSITY,			/* BaseFormat */
   GL_UNSIGNED_NORMALIZED_ARB,		/* DataType */
   0,					/* RedBits */
   0,					/* GreenBits */
   0,					/* BlueBits */
   0,					/* AlphaBits */
   0,					/* LuminanceBits */
   CHAN_BITS,				/* IntensityBits */
   0,					/* IndexBits */
   0,					/* DepthBits */
   0,					/* StencilBits */
   sizeof(GLchan),			/* TexelBytes */
   _mesa_texstore_rgba,/*yes*/		/* StoreTexImageFunc */
   fetch_texel_1d_intensity,		/* FetchTexel1D */
   fetch_texel_2d_intensity,		/* FetchTexel2D */
   fetch_texel_3d_intensity,		/* FetchTexel3D */
   NULL,				/* FetchTexel1Df */
   NULL,				/* FetchTexel2Df */
   NULL,				/* FetchTexel3Df */
   store_texel_intensity		/* StoreTexel */
};


#if FEATURE_EXT_texture_sRGB

const struct gl_texture_format _mesa_texformat_srgb8 = {
   MESA_FORMAT_SRGB8,			/* MesaFormat */
   GL_RGB,				/* BaseFormat */
   GL_UNSIGNED_NORMALIZED_ARB,		/* DataType */
   8,					/* RedBits */
   8,					/* GreenBits */
   8,					/* BlueBits */
   0,					/* AlphaBits */
   0,					/* LuminanceBits */
   0,					/* IntensityBits */
   0,					/* IndexBits */
   0,					/* DepthBits */
   0,					/* StencilBits */
   3,					/* TexelBytes */
   _mesa_texstore_srgb8,		/* StoreTexImageFunc */
   NULL,				/* FetchTexel1D */
   NULL,				/* FetchTexel2D */
   NULL,				/* FetchTexel3D */
   fetch_texel_1d_srgb8,		/* FetchTexel1Df */
   fetch_texel_2d_srgb8,		/* FetchTexel2Df */
   fetch_texel_3d_srgb8,		/* FetchTexel3Df */
   store_texel_srgb8			/* StoreTexel */
};

const struct gl_texture_format _mesa_texformat_srgba8 = {
   MESA_FORMAT_SRGBA8,			/* MesaFormat */
   GL_RGBA,				/* BaseFormat */
   GL_UNSIGNED_NORMALIZED_ARB,		/* DataType */
   8,					/* RedBits */
   8,					/* GreenBits */
   8,					/* BlueBits */
   8,					/* AlphaBits */
   0,					/* LuminanceBits */
   0,					/* IntensityBits */
   0,					/* IndexBits */
   0,					/* DepthBits */
   0,					/* StencilBits */
   4,					/* TexelBytes */
   _mesa_texstore_srgba8,		/* StoreTexImageFunc */
   NULL,				/* FetchTexel1D */
   NULL,				/* FetchTexel2D */
   NULL,				/* FetchTexel3D */
   fetch_texel_1d_srgba8,		/* FetchTexel1Df */
   fetch_texel_2d_srgba8,		/* FetchTexel2Df */
   fetch_texel_3d_srgba8,		/* FetchTexel3Df */
   store_texel_srgba8			/* StoreTexel */
};

const struct gl_texture_format _mesa_texformat_sl8 = {
   MESA_FORMAT_SL8,			/* MesaFormat */
   GL_LUMINANCE,			/* BaseFormat */
   GL_UNSIGNED_NORMALIZED_ARB,		/* DataType */
   0,					/* RedBits */
   0,					/* GreenBits */
   0,					/* BlueBits */
   0,					/* AlphaBits */
   8,					/* LuminanceBits */
   0,					/* IntensityBits */
   0,					/* IndexBits */
   0,					/* DepthBits */
   0,					/* StencilBits */
   1,					/* TexelBytes */
   _mesa_texstore_sl8,			/* StoreTexImageFunc */
   NULL,				/* FetchTexel1D */
   NULL,				/* FetchTexel2D */
   NULL,				/* FetchTexel3D */
   fetch_texel_1d_sl8,			/* FetchTexel1Df */
   fetch_texel_2d_sl8,			/* FetchTexel2Df */
   fetch_texel_3d_sl8,			/* FetchTexel3Df */
   store_texel_sl8			/* StoreTexel */
};

const struct gl_texture_format _mesa_texformat_sla8 = {
   MESA_FORMAT_SLA8,			/* MesaFormat */
   GL_LUMINANCE_ALPHA,			/* BaseFormat */
   GL_UNSIGNED_NORMALIZED_ARB,		/* DataType */
   0,					/* RedBits */
   0,					/* GreenBits */
   0,					/* BlueBits */
   8,					/* AlphaBits */
   8,					/* LuminanceBits */
   0,					/* IntensityBits */
   0,					/* IndexBits */
   0,					/* DepthBits */
   0,					/* StencilBits */
   2,					/* TexelBytes */
   _mesa_texstore_sla8,			/* StoreTexImageFunc */
   NULL,				/* FetchTexel1D */
   NULL,				/* FetchTexel2D */
   NULL,				/* FetchTexel3D */
   fetch_texel_1d_sla8,			/* FetchTexel1Df */
   fetch_texel_2d_sla8,			/* FetchTexel2Df */
   fetch_texel_3d_sla8,			/* FetchTexel3Df */
   store_texel_sla8			/* StoreTexel */
};

#endif /* FEATURE_EXT_texture_sRGB */

const struct gl_texture_format _mesa_texformat_rgba_float32 = {
   MESA_FORMAT_RGBA_FLOAT32,		/* MesaFormat */
   GL_RGBA,				/* BaseFormat */
   GL_FLOAT,				/* DataType */
   8 * sizeof(GLfloat),			/* RedBits */
   8 * sizeof(GLfloat),			/* GreenBits */
   8 * sizeof(GLfloat),			/* BlueBits */
   8 * sizeof(GLfloat),			/* AlphaBits */
   0,					/* LuminanceBits */
   0,					/* IntensityBits */
   0,					/* IndexBits */
   0,					/* DepthBits */
   0,					/* StencilBits */
   4 * sizeof(GLfloat),			/* TexelBytes */