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/**
* \file texcompress.c
* Compressed textures functions.
*/
/*
* Mesa 3-D graphics library
* Version: 5.1
*
* Copyright (C) 1999-2003 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.
*/
#include "glheader.h"
#include "imports.h"
#include "context.h"
#include "image.h"
#include "texcompress.h"
#include "texformat.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;
}
}
}
return n;
}
/**
* Return bytes of storage needed for the given texture size and
* compressed format.
*
* \param width texture width in texels.
* \param height texture height in texels.
* \param depth texture depth in texels.
* \param texFormat one of the compressed format enums
*
* \return size in bytes, or zero if bad \p texFormat.
*/
GLuint
_mesa_compressed_texture_size( GLcontext *ctx,
GLsizei width, GLsizei height, GLsizei depth,
GLenum format )
{
GLuint size;
switch (format) {
case GL_COMPRESSED_RGB_FXT1_3DFX:
case GL_COMPRESSED_RGBA_FXT1_3DFX:
/* round up to multiple of 4 */
size = ((width + 7) / 8) * ((height + 3) / 4) * 16;
return size;
case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
/* round up width, height to next multiple of 4 */
width = (width + 3) & ~3;
height = (height + 3) & ~3;
ASSERT(depth == 1);
/* 8 bytes per 4x4 tile of RGB[A] texels */
size = (width * height * 8) / 16;
/* 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:
/* round up width, height to next multiple of 4 */
width = (width + 3) & ~3;
height = (height + 3) & ~3;
ASSERT(depth == 1);
/* 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 bytesPerTile, stride;
switch (format) {
case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
bytesPerTile = 8;
break;
case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
bytesPerTile = 16;
break;
default:
return 0;
}
stride = ((width + 3) / 4) * bytesPerTile;
return stride;
}
/**
* Return the address of the pixel at (col, row, img) in a
* compressed texture image.
*
* \param col image position.
* \param row image position.
* \param img image position.
* \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)
{
GLint bytesPerTile, stride;
GLubyte *addr;
ASSERT((row & 3) == 0);
ASSERT((col & 3) == 0);
(void) img;
switch (format) {
case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
bytesPerTile = 8;
break;
case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
bytesPerTile = 16;
break;
default:
return 0;
}
stride = ((width + 3) / 4) * bytesPerTile;
addr = (GLubyte *) image + (row / 4) * stride + (col / 4) * bytesPerTile;
return addr;
}
/**
* \param srcRowStride source stride, in pixels
*/
void
_mesa_compress_teximage( GLcontext *ctx, GLsizei width, GLsizei height,
GLenum srcFormat, const GLchan *source,
GLint srcRowStride,
const struct gl_texture_format *dstFormat,
GLubyte *dest, GLint dstRowStride )
{
switch (dstFormat->MesaFormat) {
default:
_mesa_problem(ctx, "Bad dstFormat in _mesa_compress_teximage()");
return;
}
}
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