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/*
* Mesa 3-D graphics library
* Version: 6.1
*
* Copyright (C) 1999-2004 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 texcompress.c
* Helper functions for texture compression.
*/
#include "glheader.h"
#include "imports.h"
#include "colormac.h"
#include "context.h"
#include "image.h"
#include "texcompress.h"
#include "texformat.h"
#include "texstore.h"
/**
* Get the list of supported internal compression formats.
*
* \param ctx GL context.
* \param formats the resulting format list (may be NULL).
*
* \return number of formats.
*/
GLuint
_mesa_get_compressed_formats( GLcontext *ctx, GLint *formats )
{
GLuint n = 0;
if (ctx->Extensions.ARB_texture_compression) {
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;
/* Skip this one because it has a restriction (all transparent
* pixels become black). See the texture compressions spec for
* a detailed explanation. This is what NVIDIA does.
formats[n++] = GL_COMPRESSED_RGBA_S3TC_DXT1_EXT;
*/
formats[n++] = GL_COMPRESSED_RGBA_S3TC_DXT3_EXT;
formats[n++] = GL_COMPRESSED_RGBA_S3TC_DXT5_EXT;
}
else {
n += 3;
}
}
if (ctx->Extensions.S3_s3tc) {
if (formats) {
formats[n++] = GL_RGB_S3TC;
formats[n++] = GL_RGB4_S3TC;
formats[n++] = GL_RGBA_S3TC;
formats[n++] = GL_RGBA4_S3TC;
}
else {
n += 4;
}
}
}
return n;
}
/**
* Return number of bytes needed to store a texture of the given size
* using the specified compressed format.
* This is called via the ctx->Driver.CompressedTextureSize function,
* unless a device driver overrides it.
*
* \param width texture width in texels.
* \param height texture height in texels.
* \param depth texture depth in texels.
* \param format - one of the specific compressed texture formats
*
* \return size in bytes, or zero if bad format
*/
GLuint
_mesa_compressed_texture_size( GLcontext *ctx,
GLsizei width, GLsizei height, GLsizei depth,
GLenum format )
{
GLuint size;
ASSERT(depth == 1);
(void) depth;
switch (format) {
case GL_COMPRESSED_RGB_FXT1_3DFX:
case GL_COMPRESSED_RGBA_FXT1_3DFX:
/* round up width to next multiple of 8, height to next multiple of 4 */
width = (width + 7) & ~7;
height = (height + 3) & ~3;
/* 16 bytes per 8x4 tile of RGB[A] texels */
size = width * height / 2;
/* Textures smaller than 8x4 will effectively be made into 8x4 and
* take 16 bytes.
*/
if (size < 16)
size = 16;
return size;
case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
case GL_RGB_S3TC:
case GL_RGB4_S3TC:
/* round up width, height to next multiple of 4 */
width = (width + 3) & ~3;
height = (height + 3) & ~3;
/* 8 bytes per 4x4 tile of RGB[A] texels */
size = width * height / 2;
/* Textures smaller than 4x4 will effectively be made into 4x4 and
* take 8 bytes.
*/
if (size < 8)
size = 8;
return size;
case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
case GL_RGBA_S3TC:
case GL_RGBA4_S3TC:
/* round up width, height to next multiple of 4 */
width = (width + 3) & ~3;
height = (height + 3) & ~3;
/* 16 bytes per 4x4 tile of RGBA texels */
size = width * height; /* simple! */
/* Textures smaller than 4x4 will effectively be made into 4x4 and
* take 16 bytes.
*/
if (size < 16)
size = 16;
return size;
default:
_mesa_problem(ctx, "bad texformat in compressed_texture_size");
return 0;
}
}
/*
* Compute the bytes per row in a compressed texture image.
* We use this for computing the destination address for sub-texture updates.
* \param format one of the specific texture compression formats
* \param width image width in pixels
* \return stride, in bytes, between rows for compressed image
*/
GLint
_mesa_compressed_row_stride(GLenum format, GLsizei width)
{
GLint stride;
switch (format) {
case GL_COMPRESSED_RGB_FXT1_3DFX:
case GL_COMPRESSED_RGBA_FXT1_3DFX:
stride = ((width + 7) / 8) * 16; /* 16 bytes per 8x4 tile */
break;
case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
case GL_RGB_S3TC:
case GL_RGB4_S3TC:
stride = ((width + 3) / 4) * 8; /* 8 bytes per 4x4 tile */
break;
case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
case GL_RGBA_S3TC:
case GL_RGBA4_S3TC:
stride = ((width + 3) / 4) * 16; /* 16 bytes per 4x4 tile */
break;
default:
return 0;
}
return stride;
}
/*
* Return the address of the pixel at (col, row, img) in a
* compressed texture image.
* \param col, row, img - image position (3D)
* \param format - compressed image format
* \param width - image width
* \param image - the image address
* \return address of pixel at (row, col)
*/
GLubyte *
_mesa_compressed_image_address(GLint col, GLint row, GLint img,
GLenum format,
GLsizei width, const GLubyte *image)
{
GLubyte *addr;
(void) img;
/* We try to spot a "complete" subtexture "above" ROW, COL;
* this texture is given by appropriate rounding of WIDTH x ROW.
* Then we just add the amount left (usually on the left).
*
* Example for X*Y microtiles (Z bytes each)
* offset = Z * (((width + X - 1) / X) * (row / Y) + col / X);
*/
switch (format) {
case GL_COMPRESSED_RGB_FXT1_3DFX:
case GL_COMPRESSED_RGBA_FXT1_3DFX:
addr = (GLubyte *) image + 16 * (((width + 7) / 8) * (row / 4) + col / 8);
break;
case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
case GL_RGB_S3TC:
case GL_RGB4_S3TC:
addr = (GLubyte *) image + 8 * (((width + 3) / 4) * (row / 4) + col / 4);
break;
case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
case GL_RGBA_S3TC:
case GL_RGBA4_S3TC:
addr = (GLubyte *) image + 16 * (((width + 3) / 4) * (row / 4) + col / 4);
break;
default:
return NULL;
}
return addr;
}
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