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+/*
+ * 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 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"
+
+
+/**
+ * Return list of (and count of) all specific texture compression
+ * formats that are supported.
+ *
+ * \param ctx the GL context
+ * \param formats the resulting format list (may be NULL).
+ * \param all if true return all formats, even those with some kind
+ * of restrictions/limitations (See GL_ARB_texture_compression
+ * spec for more info).
+ *
+ * \return number of formats.
+ */
+GLuint
+_mesa_get_compressed_formats(GLcontext *ctx, GLint *formats, GLboolean all)
+{
+ 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;
+ /* This format has some restrictions/limitations and so should
+ * not be returned via the GL_COMPRESSED_TEXTURE_FORMATS query.
+ * Specifically, all transparent pixels become black. NVIDIA
+ * omits this format too.
+ */
+ if (all)
+ 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 (all)
+ n += 1;
+ }
+ }
+ 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;
+ }
+ }
+#if FEATURE_EXT_texture_sRGB
+ if (ctx->Extensions.EXT_texture_sRGB) {
+ if (formats) {
+ formats[n++] = GL_COMPRESSED_SRGB_S3TC_DXT1_EXT;
+ formats[n++] = GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT;
+ formats[n++] = GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT;
+ formats[n++] = GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT;
+ }
+ else {
+ n += 4;
+ }
+ }
+#endif /* FEATURE_EXT_texture_sRGB */
+ }
+ 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 mesaFormat one of the MESA_FORMAT_* compressed formats
+ *
+ * \return size in bytes, or zero if bad format
+ */
+GLuint
+_mesa_compressed_texture_size( GLcontext *ctx,
+ GLsizei width, GLsizei height, GLsizei depth,
+ GLuint mesaFormat )
+{
+ GLuint size;
+
+ ASSERT(depth == 1);
+ (void) depth;
+
+ switch (mesaFormat) {
+ case MESA_FORMAT_RGB_FXT1:
+ case MESA_FORMAT_RGBA_FXT1:
+ /* 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 MESA_FORMAT_RGB_DXT1:
+ case MESA_FORMAT_RGBA_DXT1:
+ /* 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 MESA_FORMAT_RGBA_DXT3:
+ case MESA_FORMAT_RGBA_DXT5:
+ /* 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 mesaFormat in _mesa_compressed_texture_size");
+ return 0;
+ }
+}
+
+
+/**
+ * As above, but format is specified by a GLenum (GL_COMPRESSED_*) token.
+ *
+ * Note: This function CAN NOT return a padded hardware texture size.
+ * That's why we don't call the ctx->Driver.CompressedTextureSize() function.
+ *
+ * We use this function to validate the <imageSize> parameter
+ * of glCompressedTex[Sub]Image1/2/3D(), which must be an exact match.
+ */
+GLuint
+_mesa_compressed_texture_size_glenum(GLcontext *ctx,
+ GLsizei width, GLsizei height,
+ GLsizei depth, GLenum glformat)
+{
+ GLuint mesaFormat;
+
+ switch (glformat) {
+ case GL_COMPRESSED_RGB_FXT1_3DFX:
+ mesaFormat = MESA_FORMAT_RGB_FXT1;
+ break;
+ case GL_COMPRESSED_RGBA_FXT1_3DFX:
+ mesaFormat = MESA_FORMAT_RGBA_FXT1;
+ break;
+ case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
+ case GL_RGB_S3TC:
+ mesaFormat = MESA_FORMAT_RGB_DXT1;
+ break;
+ case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
+ case GL_RGB4_S3TC:
+ mesaFormat = MESA_FORMAT_RGBA_DXT1;
+ break;
+ case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
+ case GL_RGBA_S3TC:
+ mesaFormat = MESA_FORMAT_RGBA_DXT3;
+ break;
+ case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
+ case GL_RGBA4_S3TC:
+ mesaFormat = MESA_FORMAT_RGBA_DXT5;
+ break;
+ default:
+ return 0;
+ }
+
+ return _mesa_compressed_texture_size(ctx, width, height, depth, mesaFormat);
+}
+
+
+/*
+ * Compute the bytes per row in a compressed texture image.
+ * We use this for computing the destination address for sub-texture updates.
+ * \param mesaFormat one of the MESA_FORMAT_* compressed formats
+ * \param width image width in pixels
+ * \return stride, in bytes, between rows for compressed image
+ */
+GLint
+_mesa_compressed_row_stride(GLuint mesaFormat, GLsizei width)
+{
+ GLint stride;
+
+ switch (mesaFormat) {
+ case MESA_FORMAT_RGB_FXT1:
+ case MESA_FORMAT_RGBA_FXT1:
+ stride = ((width + 7) / 8) * 16; /* 16 bytes per 8x4 tile */
+ break;
+ case MESA_FORMAT_RGB_DXT1:
+ case MESA_FORMAT_RGBA_DXT1:
+ stride = ((width + 3) / 4) * 8; /* 8 bytes per 4x4 tile */
+ break;
+ case MESA_FORMAT_RGBA_DXT3:
+ case MESA_FORMAT_RGBA_DXT5:
+ stride = ((width + 3) / 4) * 16; /* 16 bytes per 4x4 tile */
+ break;
+ default:
+ _mesa_problem(NULL, "bad mesaFormat in _mesa_compressed_row_stride");
+ 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,
+ GLuint mesaFormat,
+ 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 (mesaFormat) {
+ case MESA_FORMAT_RGB_FXT1:
+ case MESA_FORMAT_RGBA_FXT1:
+ addr = (GLubyte *) image + 16 * (((width + 7) / 8) * (row / 4) + col / 8);
+ break;
+ case MESA_FORMAT_RGB_DXT1:
+ case MESA_FORMAT_RGBA_DXT1:
+ addr = (GLubyte *) image + 8 * (((width + 3) / 4) * (row / 4) + col / 4);
+ break;
+ case MESA_FORMAT_RGBA_DXT3:
+ case MESA_FORMAT_RGBA_DXT5:
+ addr = (GLubyte *) image + 16 * (((width + 3) / 4) * (row / 4) + col / 4);
+ break;
+ default:
+ _mesa_problem(NULL, "bad mesaFormat in _mesa_compressed_image_address");
+ addr = NULL;
+ }
+
+ return addr;
+}