/*
* Mesa 3-D graphics library
*
* Copyright (C) 1999-2006 Brian Paul All Rights Reserved.
* Copyright (c) 2008 VMware, Inc.
*
* 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
* THE AUTHORS OR COPYRIGHT HOLDERS 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 texcompress.c
* Helper functions for texture compression.
*/
#include "glheader.h"
#include "imports.h"
#include "colormac.h"
#include "context.h"
#include "formats.h"
#include "mtypes.h"
#include "context.h"
#include "texcompress.h"
#include "texcompress_fxt1.h"
#include "texcompress_rgtc.h"
#include "texcompress_s3tc.h"
#include "texcompress_etc.h"
/**
* Get the GL base format of a specified GL compressed texture format
*
* From page 232 of the OpenGL 3.3 (Compatiblity Profile) spec:
*
* "Compressed Internal Format Base Internal Format Type
* --------------------------- -------------------- ---------
* COMPRESSED_ALPHA ALPHA Generic
* COMPRESSED_LUMINANCE LUMINANCE Generic
* COMPRESSED_LUMINANCE_ALPHA LUMINANCE_ALPHA Generic
* COMPRESSED_INTENSITY INTENSITY Generic
* COMPRESSED_RED RED Generic
* COMPRESSED_RG RG Generic
* COMPRESSED_RGB RGB Generic
* COMPRESSED_RGBA RGBA Generic
* COMPRESSED_SRGB RGB Generic
* COMPRESSED_SRGB_ALPHA RGBA Generic
* COMPRESSED_SLUMINANCE LUMINANCE Generic
* COMPRESSED_SLUMINANCE_ALPHA LUMINANCE_ALPHA Generic
* COMPRESSED_RED_RGTC1 RED Specific
* COMPRESSED_SIGNED_RED_RGTC1 RED Specific
* COMPRESSED_RG_RGTC2 RG Specific
* COMPRESSED_SIGNED_RG_RGTC2 RG Specific"
*
* \return
* The base format of \c format if \c format is a compressed format (either
* generic or specific. Otherwise 0 is returned.
*/
GLenum
_mesa_gl_compressed_format_base_format(GLenum format)
{
switch (format) {
case GL_COMPRESSED_RED:
case GL_COMPRESSED_R11_EAC:
case GL_COMPRESSED_RED_RGTC1:
case GL_COMPRESSED_SIGNED_R11_EAC:
case GL_COMPRESSED_SIGNED_RED_RGTC1:
return GL_RED;
case GL_COMPRESSED_RG:
case GL_COMPRESSED_RG11_EAC:
case GL_COMPRESSED_RG_RGTC2:
case GL_COMPRESSED_SIGNED_RG11_EAC:
case GL_COMPRESSED_SIGNED_RG_RGTC2:
return GL_RG;
case GL_COMPRESSED_RGB:
case GL_COMPRESSED_SRGB:
case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
case GL_COMPRESSED_RGB_FXT1_3DFX:
case GL_COMPRESSED_SRGB_S3TC_DXT1_EXT:
case GL_ETC1_RGB8_OES:
case GL_COMPRESSED_RGB8_ETC2:
case GL_COMPRESSED_SRGB8_ETC2:
return GL_RGB;
case GL_COMPRESSED_RGBA:
case GL_COMPRESSED_SRGB_ALPHA:
case GL_COMPRESSED_RGBA_BPTC_UNORM_ARB:
case GL_COMPRESSED_SRGB_ALPHA_BPTC_UNORM_ARB:
case GL_COMPRESSED_RGB_BPTC_SIGNED_FLOAT_ARB:
case GL_COMPRESSED_RGB_BPTC_UNSIGNED_FLOAT_ARB:
case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
case GL_COMPRESSED_RGBA_FXT1_3DFX:
case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT:
case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT:
case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT:
case GL_COMPRESSED_RGBA8_ETC2_EAC:
case GL_COMPRESSED_SRGB8_ALPHA8_ETC2_EAC:
case GL_COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2:
case GL_COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2:
return GL_RGBA;
case GL_COMPRESSED_ALPHA:
return GL_ALPHA;
case GL_COMPRESSED_LUMINANCE:
case GL_COMPRESSED_SLUMINANCE:
case GL_COMPRESSED_LUMINANCE_LATC1_EXT:
case GL_COMPRESSED_SIGNED_LUMINANCE_LATC1_EXT:
return GL_LUMINANCE;
case GL_COMPRESSED_LUMINANCE_ALPHA:
case GL_COMPRESSED_SLUMINANCE_ALPHA:
case GL_COMPRESSED_LUMINANCE_ALPHA_LATC2_EXT:
case GL_COMPRESSED_SIGNED_LUMINANCE_ALPHA_LATC2_EXT:
case GL_COMPRESSED_LUMINANCE_ALPHA_3DC_ATI:
return GL_LUMINANCE_ALPHA;
case GL_COMPRESSED_INTENSITY:
return GL_INTENSITY;
default:
return 0;
}
}
/**
* Return list of (and count of) all specific texture compression
* formats that are supported.
*
* Some formats are \b not returned by this function. The
* \c GL_COMPRESSED_TEXTURE_FORMATS query only returns formats that are
* "suitable for general-purpose usage." All texture compression extensions
* have taken this to mean either linear RGB or linear RGBA.
*
* The GL_ARB_texture_compress_rgtc spec says:
*
* "19) Should the GL_NUM_COMPRESSED_TEXTURE_FORMATS and
* GL_COMPRESSED_TEXTURE_FORMATS queries return the RGTC formats?
*
* RESOLVED: No.
*
* The OpenGL 2.1 specification says "The only values returned
* by this query [GL_COMPRESSED_TEXTURE_FORMATS"] are those
* corresponding to formats suitable for general-purpose usage.
* The renderer will not enumerate formats with restrictions that
* need to be specifically understood prior to use."
*
* Compressed textures with just red or red-green components are
* not general-purpose so should not be returned by these queries
* because they have restrictions.
*
* Applications that seek to use the RGTC formats should do so
* by looking for this extension's name in the string returned by
* glGetString(GL_EXTENSIONS) rather than
* what GL_NUM_COMPRESSED_TEXTURE_FORMATS and
* GL_COMPRESSED_TEXTURE_FORMATS return."
*
* There is nearly identical wording in the GL_EXT_texture_compression_rgtc
* spec.
*
* The GL_EXT_texture_rRGB spec says:
*
* "22) Should the new COMPRESSED_SRGB_* formats be listed in an
* implementation's GL_COMPRESSED_TEXTURE_FORMATS list?
*
* RESOLVED: No. Section 3.8.1 says formats listed by
* GL_COMPRESSED_TEXTURE_FORMATS are "suitable for general-purpose
* usage." The non-linear distribution of red, green, and
* blue for these sRGB compressed formats makes them not really
* general-purpose."
*
* The GL_EXT_texture_compression_latc spec says:
*
* "16) Should the GL_NUM_COMPRESSED_TEXTURE_FORMATS and
* GL_COMPRESSED_TEXTURE_FORMATS queries return the LATC formats?
*
* RESOLVED: No.
*
* The OpenGL 2.1 specification says "The only values returned
* by this query [GL_COMPRESSED_TEXTURE_FORMATS"] are those
* corresponding to formats suitable for general-purpose usage.
* The renderer will not enumerate formats with restrictions that
* need to be specifically understood prior to use."
*
* Historically, OpenGL implementation have advertised the RGB and
* RGBA versions of the S3TC extensions compressed format tokens
* through this mechanism.
*
* The specification is not sufficiently clear about what "suitable
* for general-purpose usage" means. Historically that seems to mean
* unsigned RGB or unsigned RGBA. The DXT1 format supporting alpha
* (GL_COMPRESSED_RGBA_S3TC_DXT1_EXT) is not exposed in the list (at
* least for NVIDIA drivers) because the alpha is always 1.0 expect
* when it is 0.0 when RGB is required to be black. NVIDIA's even
* limits itself to true linear RGB or RGBA formats, specifically
* not including EXT_texture_sRGB's sRGB S3TC compressed formats.
*
* Adding luminance and luminance-alpha texture formats (and
* certainly signed versions of luminance and luminance-alpha
* formats!) invites potential comptaibility problems with old
* applications using this mechanism since old applications are
* unlikely to expect non-RGB or non-RGBA formats to be advertised
* through this mechanism. However no specific misinteractions
* with old applications is known.
*
* Applications that seek to use the LATC formats should do so
* by looking for this extension's name in the string returned by
* glGetString(GL_EXTENSIONS) rather than
* what GL_NUM_COMPRESSED_TEXTURE_FORMATS and
* GL_COMPRESSED_TEXTURE_FORMATS return."
*
* There is no formal spec for GL_ATI_texture_compression_3dc. Since the
* formats added by this extension are luminance-alpha formats, it is
* reasonable to expect them to follow the same rules as
* GL_EXT_texture_compression_latc. At the very least, Catalyst 11.6 does not
* expose the 3dc formats through this mechanism.
*
* \param ctx the GL context
* \param formats the resulting format list (may be NULL).
*
* \return number of formats.
*/
GLuint
_mesa_get_compressed_formats(struct gl_context *ctx, GLint *formats)
{
GLuint n = 0;
if (ctx->Extensions.TDFX_texture_compression_FXT1) {
if (formats) {
formats[n++] = GL_COMPRESSED_RGB_FXT1_3DFX;
formats[n++] = GL_COMPRESSED_RGBA_FXT1_3DFX;
}
else {
n += 2;
}
}
if (ctx->Extensions.EXT_texture_compression_s3tc) {
if (formats) {
formats[n++] = GL_COMPRESSED_RGB_S3TC_DXT1_EXT;
formats[n++] = GL_COMPRESSED_RGBA_S3TC_DXT3_EXT;
formats[n++] = GL_COMPRESSED_RGBA_S3TC_DXT5_EXT;
}
else {
n += 3;
}
}
/* The GL_OES_compressed_ETC1_RGB8_texture spec says:
*
* "New State
*
* The queries for NUM_COMPRESSED_TEXTURE_FORMATS and
* COMPRESSED_TEXTURE_FORMATS include ETC1_RGB8_OES."
*/
if (_mesa_is_gles(ctx)
&& ctx->Extensions.OES_compressed_ETC1_RGB8_texture) {
if (formats) {
formats[n++] = GL_ETC1_RGB8_OES;
}
else {
n += 1;
}
}
if (ctx->API == API_OPENGLES) {
if (formats) {
formats[n++] = GL_PALETTE4_RGB8_OES;
formats[n++] = GL_PALETTE4_RGBA8_OES;
formats[n++] = GL_PALETTE4_R5_G6_B5_OES;
formats[n++] = GL_PALETTE4_RGBA4_OES;
formats[n++] = GL_PALETTE4_RGB5_A1_OES;
formats[n++] = GL_PALETTE8_RGB8_OES;
formats[n++] = GL_PALETTE8_RGBA8_OES;
formats[n++] = GL_PALETTE8_R5_G6_B5_OES;
formats[n++] = GL_PALETTE8_RGBA4_OES;
formats[n++] = GL_PALETTE8_RGB5_A1_OES;
}
else {
n += 10;
}
}
if (_mesa_is_gles3(ctx)) {
if (formats) {
formats[n++] = GL_COMPRESSED_RGB8_ETC2;
formats[n++] = GL_COMPRESSED_SRGB8_ETC2;
formats[n++] = GL_COMPRESSED_RGBA8_ETC2_EAC;
formats[n++] = GL_COMPRESSED_SRGB8_ALPHA8_ETC2_EAC;
formats[n++] = GL_COMPRESSED_R11_EAC;
formats[n++] = GL_COMPRESSED_RG11_EAC;
formats[n++] = GL_COMPRESSED_SIGNED_R11_EAC;
formats[n++] = GL_COMPRESSED_SIGNED_RG11_EAC;
formats[n++] = GL_COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2;
formats[n++] = GL_COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2;
}
else {
n += 10;
}
}
return n;
}
/**
* Convert a compressed MESA_FORMAT_x to a GLenum.
*/
gl_format
_mesa_glenum_to_compressed_format(GLenum format)
{
switch (format) {
case GL_COMPRESSED_RGB_FXT1_3DFX:
return MESA_FORMAT_RGB_FXT1;
case GL_COMPRESSED_RGBA_FXT1_3DFX:
return MESA_FORMAT_RGBA_FXT1;
case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
case GL_RGB_S3TC:
return MESA_FORMAT_RGB_DXT1;
case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
case GL_RGB4_S3TC:
return MESA_FORMAT_RGBA_DXT1;
case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
case GL_RGBA_S3TC:
return MESA_FORMAT_RGBA_DXT3;
case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
case GL_RGBA4_S3TC:
return MESA_FORMAT_RGBA_DXT5;
case GL_COMPRESSED_SRGB_S3TC_DXT1_EXT:
return MESA_FORMAT_SRGB_DXT1;
case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT:
return MESA_FORMAT_SRGBA_DXT1;
case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT:
return MESA_FORMAT_SRGBA_DXT3;
case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT:
return MESA_FORMAT_SRGBA_DXT5;
case GL_COMPRESSED_RED_RGTC1:
return MESA_FORMAT_RED_RGTC1;
case GL_COMPRESSED_SIGNED_RED_RGTC1:
return MESA_FORMAT_SIGNED_RED_RGTC1;
case GL_COMPRESSED_RG_RGTC2:
return MESA_FORMAT_RG_RGTC2;
case GL_COMPRESSED_SIGNED_RG_RGTC2:
return MESA_FORMAT_SIGNED_RG_RGTC2;
case GL_COMPRESSED_LUMINANCE_LATC1_EXT:
return MESA_FORMAT_L_LATC1;
case GL_COMPRESSED_SIGNED_LUMINANCE_LATC1_EXT:
return MESA_FORMAT_SIGNED_L_LATC1;
case GL_COMPRESSED_LUMINANCE_ALPHA_LATC2_EXT:
case GL_COMPRESSED_LUMINANCE_ALPHA_3DC_ATI:
return MESA_FORMAT_LA_LATC2;
case GL_COMPRESSED_SIGNED_LUMINANCE_ALPHA_LATC2_EXT:
return MESA_FORMAT_SIGNED_LA_LATC2;
case GL_ETC1_RGB8_OES:
return MESA_FORMAT_ETC1_RGB8;
case GL_COMPRESSED_RGB8_ETC2:
return MESA_FORMAT_ETC2_RGB8;
case GL_COMPRESSED_SRGB8_ETC2:
return MESA_FORMAT_ETC2_SRGB8;
case GL_COMPRESSED_RGBA8_ETC2_EAC:
return MESA_FORMAT_ETC2_RGBA8_EAC;
case GL_COMPRESSED_SRGB8_ALPHA8_ETC2_EAC:
return MESA_FORMAT_ETC2_SRGB8_ALPHA8_EAC;
case GL_COMPRESSED_R11_EAC:
return MESA_FORMAT_ETC2_R11_EAC;
case GL_COMPRESSED_RG11_EAC:
return MESA_FORMAT_ETC2_RG11_EAC;
case GL_COMPRESSED_SIGNED_R11_EAC:
return MESA_FORMAT_ETC2_SIGNED_R11_EAC;
case GL_COMPRESSED_SIGNED_RG11_EAC:
return MESA_FORMAT_ETC2_SIGNED_RG11_EAC;
case GL_COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2:
return MESA_FORMAT_ETC2_RGB8_PUNCHTHROUGH_ALPHA1;
case GL_COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2:
return MESA_FORMAT_ETC2_SRGB8_PUNCHTHROUGH_ALPHA1;
default:
return MESA_FORMAT_NONE;
}
}
/**
* Given a compressed MESA_FORMAT_x value, return the corresponding
* GLenum for that format.
* This is needed for glGetTexLevelParameter(GL_TEXTURE_INTERNAL_FORMAT)
* which must return the specific texture format used when the user might
* have originally specified a generic compressed format in their
* glTexImage2D() call.
* For non-compressed textures, we always return the user-specified
* internal format unchanged.
*/
GLenum
_mesa_compressed_format_to_glenum(struct gl_context *ctx, gl_format mesaFormat)
{
switch (mesaFormat) {
case MESA_FORMAT_RGB_FXT1:
return GL_COMPRESSED_RGB_FXT1_3DFX;
case MESA_FORMAT_RGBA_FXT1:
return GL_COMPRESSED_RGBA_FXT1_3DFX;
case MESA_FORMAT_RGB_DXT1:
return GL_COMPRESSED_RGB_S3TC_DXT1_EXT;
case MESA_FORMAT_RGBA_DXT1:
return GL_COMPRESSED_RGBA_S3TC_DXT1_EXT;
case MESA_FORMAT_RGBA_DXT3:
return GL_COMPRESSED_RGBA_S3TC_DXT3_EXT;
case MESA_FORMAT_RGBA_DXT5:
return GL_COMPRESSED_RGBA_S3TC_DXT5_EXT;
case MESA_FORMAT_SRGB_DXT1:
return GL_COMPRESSED_SRGB_S3TC_DXT1_EXT;
case MESA_FORMAT_SRGBA_DXT1:
return GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT;
case MESA_FORMAT_SRGBA_DXT3:
return GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT;
case MESA_FORMAT_SRGBA_DXT5:
return GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT;
case MESA_FORMAT_RED_RGTC1:
return GL_COMPRESSED_RED_RGTC1;
case MESA_FORMAT_SIGNED_RED_RGTC1:
return GL_COMPRESSED_SIGNED_RED_RGTC1;
case MESA_FORMAT_RG_RGTC2:
return GL_COMPRESSED_RG_RGTC2;
case MESA_FORMAT_SIGNED_RG_RGTC2:
return GL_COMPRESSED_SIGNED_RG_RGTC2;
case MESA_FORMAT_L_LATC1:
return GL_COMPRESSED_LUMINANCE_LATC1_EXT;
case MESA_FORMAT_SIGNED_L_LATC1:
return GL_COMPRESSED_SIGNED_LUMINANCE_LATC1_EXT;
case MESA_FORMAT_LA_LATC2:
return GL_COMPRESSED_LUMINANCE_ALPHA_LATC2_EXT;
case MESA_FORMAT_SIGNED_LA_LATC2:
return GL_COMPRESSED_SIGNED_LUMINANCE_ALPHA_LATC2_EXT;
case MESA_FORMAT_ETC1_RGB8:
return GL_ETC1_RGB8_OES;
case MESA_FORMAT_ETC2_RGB8:
return GL_COMPRESSED_RGB8_ETC2;
case MESA_FORMAT_ETC2_SRGB8:
return GL_COMPRESSED_SRGB8_ETC2;
case MESA_FORMAT_ETC2_RGBA8_EAC:
return GL_COMPRESSED_RGBA8_ETC2_EAC;
case MESA_FORMAT_ETC2_SRGB8_ALPHA8_EAC:
return GL_COMPRESSED_SRGB8_ALPHA8_ETC2_EAC;
case MESA_FORMAT_ETC2_R11_EAC:
return GL_COMPRESSED_R11_EAC;
case MESA_FORMAT_ETC2_RG11_EAC:
return GL_COMPRESSED_RG11_EAC;
case MESA_FORMAT_ETC2_SIGNED_R11_EAC:
return GL_COMPRESSED_SIGNED_R11_EAC;
case MESA_FORMAT_ETC2_SIGNED_RG11_EAC:
return GL_COMPRESSED_SIGNED_RG11_EAC;
case MESA_FORMAT_ETC2_RGB8_PUNCHTHROUGH_ALPHA1:
return GL_COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2;
case MESA_FORMAT_ETC2_SRGB8_PUNCHTHROUGH_ALPHA1:
return GL_COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2;
default:
_mesa_problem(ctx, "Unexpected mesa texture format in"
" _mesa_compressed_format_to_glenum()");
return 0;
}
}
/*
* Return the address of the pixel at (col, row, img) in a
* compressed texture image.
* \param col, row, img - image position (3D), should be a multiple of the
* format's block size.
* \param format - compressed image format
* \param width - image width (stride) in pixels
* \param image - the image address
* \return address of pixel at (row, col, img)
*/
GLubyte *
_mesa_compressed_image_address(GLint col, GLint row, GLint img,
gl_format mesaFormat,
GLsizei width, const GLubyte *image)
{
/* XXX only 2D images implemented, not 3D */
const GLuint blockSize = _mesa_get_format_bytes(mesaFormat);
GLuint bw, bh;
GLint offset;
_mesa_get_format_block_size(mesaFormat, &bw, &bh);
ASSERT(col % bw == 0);
ASSERT(row % bh == 0);
offset = ((width + bw - 1) / bw) * (row / bh) + col / bw;
offset *= blockSize;
return (GLubyte *) image + offset;
}
/**
* Return a texel-fetch function for the given format, or NULL if
* invalid format.
*/
compressed_fetch_func
_mesa_get_compressed_fetch_func(gl_format format)
{
switch (format) {
case MESA_FORMAT_RGB_DXT1:
case MESA_FORMAT_RGBA_DXT1:
case MESA_FORMAT_RGBA_DXT3:
case MESA_FORMAT_RGBA_DXT5:
case MESA_FORMAT_SRGB_DXT1:
case MESA_FORMAT_SRGBA_DXT1:
case MESA_FORMAT_SRGBA_DXT3:
case MESA_FORMAT_SRGBA_DXT5:
return _mesa_get_dxt_fetch_func(format);
case MESA_FORMAT_RGB_FXT1:
case MESA_FORMAT_RGBA_FXT1:
return _mesa_get_fxt_fetch_func(format);
case MESA_FORMAT_RED_RGTC1:
case MESA_FORMAT_L_LATC1:
case MESA_FORMAT_SIGNED_RED_RGTC1:
case MESA_FORMAT_SIGNED_L_LATC1:
case MESA_FORMAT_RG_RGTC2:
case MESA_FORMAT_LA_LATC2:
case MESA_FORMAT_SIGNED_RG_RGTC2:
case MESA_FORMAT_SIGNED_LA_LATC2:
return _mesa_get_compressed_rgtc_func(format);
case MESA_FORMAT_ETC1_RGB8:
return _mesa_get_etc_fetch_func(format);
default:
return NULL;
}
}
/**
* Decompress a compressed texture image, returning a GL_RGBA/GL_FLOAT image.
* \param srcRowStride stride in bytes between rows of blocks in the
* compressed source image.
*/
void
_mesa_decompress_image(gl_format format, GLuint width, GLuint height,
const GLubyte *src, GLint srcRowStride,
GLfloat *dest)
{
compressed_fetch_func fetch;
GLuint i, j;
GLuint bytes, bw, bh;
GLint stride;
bytes = _mesa_get_format_bytes(format);
_mesa_get_format_block_size(format, &bw, &bh);
fetch = _mesa_get_compressed_fetch_func(format);
if (!fetch) {
_mesa_problem(NULL, "Unexpected format in _mesa_decompress_image()");
return;
}
stride = srcRowStride * bh / bytes;
for (j = 0; j < height; j++) {
for (i = 0; i < width; i++) {
fetch(src, stride, i, j, dest);
dest += 4;
}
}
}