2 * Mesa 3-D graphics library
5 * Copyright (C) 1999-2004 Brian Paul All Rights Reserved.
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8 * copy of this software and associated documentation files (the "Software"),
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28 * Helper functions for texture compression.
37 #include "texcompress.h"
38 #include "texformat.h"
42 * Get the list of supported internal compression formats.
44 * \param ctx GL context.
45 * \param formats the resulting format list (may be NULL).
47 * \return number of formats.
50 _mesa_get_compressed_formats( GLcontext
*ctx
, GLint
*formats
)
53 if (ctx
->Extensions
.ARB_texture_compression
) {
54 if (ctx
->Extensions
.TDFX_texture_compression_FXT1
) {
56 formats
[n
++] = GL_COMPRESSED_RGB_FXT1_3DFX
;
57 formats
[n
++] = GL_COMPRESSED_RGBA_FXT1_3DFX
;
63 if (ctx
->Extensions
.EXT_texture_compression_s3tc
) {
65 formats
[n
++] = GL_COMPRESSED_RGB_S3TC_DXT1_EXT
;
66 /* Skip this one because it has a restriction (all transparent
67 * pixels become black). See the texture compressions spec for
68 * a detailed explanation. This is what NVIDIA does.
69 formats[n++] = GL_COMPRESSED_RGBA_S3TC_DXT1_EXT;
71 formats
[n
++] = GL_COMPRESSED_RGBA_S3TC_DXT3_EXT
;
72 formats
[n
++] = GL_COMPRESSED_RGBA_S3TC_DXT5_EXT
;
78 if (ctx
->Extensions
.S3_s3tc
) {
80 formats
[n
++] = GL_RGB_S3TC
;
81 formats
[n
++] = GL_RGB4_S3TC
;
82 formats
[n
++] = GL_RGBA_S3TC
;
83 formats
[n
++] = GL_RGBA4_S3TC
;
96 * Return number of bytes needed to store a texture of the given size
97 * using the specified compressed format.
98 * This is called via the ctx->Driver.CompressedTextureSize function,
99 * unless a device driver overrides it.
101 * \param width texture width in texels.
102 * \param height texture height in texels.
103 * \param depth texture depth in texels.
104 * \param mesaFormat one of the MESA_FORMAT_* compressed formats
106 * \return size in bytes, or zero if bad format
109 _mesa_compressed_texture_size( GLcontext
*ctx
,
110 GLsizei width
, GLsizei height
, GLsizei depth
,
118 switch (mesaFormat
) {
119 case MESA_FORMAT_RGB_FXT1
:
120 case MESA_FORMAT_RGBA_FXT1
:
121 /* round up width to next multiple of 8, height to next multiple of 4 */
122 width
= (width
+ 7) & ~7;
123 height
= (height
+ 3) & ~3;
124 /* 16 bytes per 8x4 tile of RGB[A] texels */
125 size
= width
* height
/ 2;
126 /* Textures smaller than 8x4 will effectively be made into 8x4 and
132 case MESA_FORMAT_RGB_DXT1
:
133 case MESA_FORMAT_RGBA_DXT1
:
134 /* round up width, height to next multiple of 4 */
135 width
= (width
+ 3) & ~3;
136 height
= (height
+ 3) & ~3;
137 /* 8 bytes per 4x4 tile of RGB[A] texels */
138 size
= width
* height
/ 2;
139 /* Textures smaller than 4x4 will effectively be made into 4x4 and
145 case MESA_FORMAT_RGBA_DXT3
:
146 case MESA_FORMAT_RGBA_DXT5
:
147 /* round up width, height to next multiple of 4 */
148 width
= (width
+ 3) & ~3;
149 height
= (height
+ 3) & ~3;
150 /* 16 bytes per 4x4 tile of RGBA texels */
151 size
= width
* height
; /* simple! */
152 /* Textures smaller than 4x4 will effectively be made into 4x4 and
159 _mesa_problem(ctx
, "bad mesaFormat in _mesa_compressed_texture_size");
166 * As above, but format is specified by a GLenum (GL_COMPRESSED_*) token.
168 * Note: This function CAN NOT return a padded hardware texture size.
169 * That's why we don't call the ctx->Driver.CompressedTextureSize() function.
171 * We use this function to validate the <imageSize> parameter
172 * of glCompressedTex[Sub]Image1/2/3D(), which must be an exact match.
175 _mesa_compressed_texture_size_glenum(GLcontext
*ctx
,
176 GLsizei width
, GLsizei height
,
177 GLsizei depth
, GLenum glformat
)
182 case GL_COMPRESSED_RGB_FXT1_3DFX
:
183 mesaFormat
= MESA_FORMAT_RGB_FXT1
;
185 case GL_COMPRESSED_RGBA_FXT1_3DFX
:
186 mesaFormat
= MESA_FORMAT_RGBA_FXT1
;
188 case GL_COMPRESSED_RGB_S3TC_DXT1_EXT
:
190 mesaFormat
= MESA_FORMAT_RGB_DXT1
;
192 case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT
:
194 mesaFormat
= MESA_FORMAT_RGBA_DXT1
;
196 case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT
:
198 mesaFormat
= MESA_FORMAT_RGBA_DXT3
;
200 case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT
:
202 mesaFormat
= MESA_FORMAT_RGBA_DXT5
;
208 return _mesa_compressed_texture_size(ctx
, width
, height
, depth
, mesaFormat
);
213 * Compute the bytes per row in a compressed texture image.
214 * We use this for computing the destination address for sub-texture updates.
215 * \param mesaFormat one of the MESA_FORMAT_* compressed formats
216 * \param width image width in pixels
217 * \return stride, in bytes, between rows for compressed image
220 _mesa_compressed_row_stride(GLuint mesaFormat
, GLsizei width
)
224 switch (mesaFormat
) {
225 case MESA_FORMAT_RGB_FXT1
:
226 case MESA_FORMAT_RGBA_FXT1
:
227 stride
= ((width
+ 7) / 8) * 16; /* 16 bytes per 8x4 tile */
229 case MESA_FORMAT_RGB_DXT1
:
230 case MESA_FORMAT_RGBA_DXT1
:
231 stride
= ((width
+ 3) / 4) * 8; /* 8 bytes per 4x4 tile */
233 case MESA_FORMAT_RGBA_DXT3
:
234 case MESA_FORMAT_RGBA_DXT5
:
235 stride
= ((width
+ 3) / 4) * 16; /* 16 bytes per 4x4 tile */
238 _mesa_problem(NULL
, "bad mesaFormat in _mesa_compressed_row_stride");
247 * Return the address of the pixel at (col, row, img) in a
248 * compressed texture image.
249 * \param col, row, img - image position (3D)
250 * \param format - compressed image format
251 * \param width - image width
252 * \param image - the image address
253 * \return address of pixel at (row, col)
256 _mesa_compressed_image_address(GLint col
, GLint row
, GLint img
,
258 GLsizei width
, const GLubyte
*image
)
264 /* We try to spot a "complete" subtexture "above" ROW, COL;
265 * this texture is given by appropriate rounding of WIDTH x ROW.
266 * Then we just add the amount left (usually on the left).
268 * Example for X*Y microtiles (Z bytes each)
269 * offset = Z * (((width + X - 1) / X) * (row / Y) + col / X);
272 switch (mesaFormat
) {
273 case MESA_FORMAT_RGB_FXT1
:
274 case MESA_FORMAT_RGBA_FXT1
:
275 addr
= (GLubyte
*) image
+ 16 * (((width
+ 7) / 8) * (row
/ 4) + col
/ 8);
277 case MESA_FORMAT_RGB_DXT1
:
278 case MESA_FORMAT_RGBA_DXT1
:
279 addr
= (GLubyte
*) image
+ 8 * (((width
+ 3) / 4) * (row
/ 4) + col
/ 4);
281 case MESA_FORMAT_RGBA_DXT3
:
282 case MESA_FORMAT_RGBA_DXT5
:
283 addr
= (GLubyte
*) image
+ 16 * (((width
+ 3) / 4) * (row
/ 4) + col
/ 4);
286 _mesa_problem(NULL
, "bad mesaFormat in _mesa_compressed_image_address");