-/* $Id: texcompress.c,v 1.3 2002/10/24 23:57:21 brianp Exp $ */
+/**
+ * \file texcompress.c
+ * Compressed textures functions.
+ */
/*
* Mesa 3-D graphics library
- * Version: 4.1
+ * Version: 5.1
*
- * Copyright (C) 1999-2002 Brian Paul All Rights Reserved.
+ * 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"),
/**
* Get the list of supported internal compression formats.
- * \param formats - the results list (may be NULL)
+ *
+ * \param ctx GL context.
+ * \param formats the resulting format list (may be NULL).
+ *
* \return number of formats.
*/
GLuint
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 bytes of storage needed for the given texture size and compressed
- * format.
- * \param width, height, depth - texture size in texels
- * \param texFormat - one of the compressed format enums
- * \return size in bytes, or zero if bad texFormat
+ * 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,
{
GLuint size;
+ if (ctx->Driver.CompressedTextureSize) {
+ return ctx->Driver.CompressedTextureSize(ctx, width, height, depth, format);
+ }
+
+ ASSERT(depth == 1);
+
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;
+ /* 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");
}
-/*
+/**
* 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;
+ 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;
}
- stride = ((width + 3) / 4) * bytesPerTile;
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)
+ *
+ * \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;
+ /* 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 0;
}
- stride = ((width + 3) / 4) * bytesPerTile;
-
- addr = (GLubyte *) image + (row / 4) * stride + (col / 4) * bytesPerTile;
return addr;
}
-
-/*
- * \param srcRowStride - source stride, in pixels
+/**
+ * \param srcRowStride source stride, in pixels
*/
void
_mesa_compress_teximage( GLcontext *ctx, GLsizei width, GLsizei height,
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