texcompress_cpal.c revision c1a9e6010baceeff78f72ac0692aefc4312d815f 
1/*
2 * Mesa 3-D graphics library
3 *
4 * Copyright 2008 Tungsten Graphics, Inc., Cedar Park, Texas.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the "Software"),
8 * to deal in the Software without restriction, including without limitation
9 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
10 * and/or sell copies of the Software, and to permit persons to whom the
11 * Software is furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included
14 * in all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
17 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
19 * THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
20 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
21 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
22 */
23
24/**
25 * Code to convert compressed/paletted texture images to ordinary images.
26 * See the GL_OES_compressed_paletted_texture spec at
27 * http://khronos.org/registry/gles/extensions/OES/OES_compressed_paletted_texture.txt
28 *
29 * XXX this makes it impossible to add hardware support...
30 */
31
32
33#include "glheader.h"
34#include "compiler.h" /* for ASSERT */
35#include "context.h"
36#include "mfeatures.h"
37#include "mtypes.h"
38#include "imports.h"
39#include "pixelstore.h"
40#include "texcompress_cpal.h"
41#include "teximage.h"
42
43#if FEATURE_ES
44
45
46static const struct cpal_format_info {
47   GLenum cpal_format;
48   GLenum format;
49   GLenum type;
50   GLuint palette_size;
51   GLuint size;
52} formats[] = {
53   { GL_PALETTE4_RGB8_OES,     GL_RGB,  GL_UNSIGNED_BYTE,           16, 3 },
54   { GL_PALETTE4_RGBA8_OES,    GL_RGBA, GL_UNSIGNED_BYTE,           16, 4 },
55   { GL_PALETTE4_R5_G6_B5_OES, GL_RGB,  GL_UNSIGNED_SHORT_5_6_5,    16, 2 },
56   { GL_PALETTE4_RGBA4_OES,    GL_RGBA, GL_UNSIGNED_SHORT_4_4_4_4,  16, 2 },
57   { GL_PALETTE4_RGB5_A1_OES,  GL_RGBA, GL_UNSIGNED_SHORT_5_5_5_1,  16, 2 },
58   { GL_PALETTE8_RGB8_OES,     GL_RGB,  GL_UNSIGNED_BYTE,          256, 3 },
59   { GL_PALETTE8_RGBA8_OES,    GL_RGBA, GL_UNSIGNED_BYTE,          256, 4 },
60   { GL_PALETTE8_R5_G6_B5_OES, GL_RGB,  GL_UNSIGNED_SHORT_5_6_5,   256, 2 },
61   { GL_PALETTE8_RGBA4_OES,    GL_RGBA, GL_UNSIGNED_SHORT_4_4_4_4, 256, 2 },
62   { GL_PALETTE8_RGB5_A1_OES,  GL_RGBA, GL_UNSIGNED_SHORT_5_5_5_1, 256, 2 }
63};
64
65
66/**
67 * Get a color/entry from the palette.
68 */
69static GLuint
70get_palette_entry(const struct cpal_format_info *info, const GLubyte *palette,
71                  GLuint index, GLubyte *pixel)
72{
73   memcpy(pixel, palette + info->size * index, info->size);
74   return info->size;
75}
76
77
78/**
79 * Convert paletted texture to color texture.
80 */
81static void
82paletted_to_color(const struct cpal_format_info *info, const GLubyte *palette,
83                  const void *indices, GLuint num_pixels, GLubyte *image)
84{
85   GLubyte *pix = image;
86   GLuint remain, i;
87
88   if (info->palette_size == 16) {
89      /* 4 bits per index */
90      const GLubyte *ind = (const GLubyte *) indices;
91
92      /* two pixels per iteration */
93      remain = num_pixels % 2;
94      for (i = 0; i < num_pixels / 2; i++) {
95         pix += get_palette_entry(info, palette, (ind[i] >> 4) & 0xf, pix);
96         pix += get_palette_entry(info, palette, ind[i] & 0xf, pix);
97      }
98      if (remain) {
99         get_palette_entry(info, palette, (ind[i] >> 4) & 0xf, pix);
100      }
101   }
102   else {
103      /* 8 bits per index */
104      const GLubyte *ind = (const GLubyte *) indices;
105      for (i = 0; i < num_pixels; i++)
106         pix += get_palette_entry(info, palette, ind[i], pix);
107   }
108}
109
110unsigned
111_mesa_cpal_compressed_size(int level, GLenum internalFormat,
112			   unsigned width, unsigned height)
113{
114   const struct cpal_format_info *info;
115   const int num_levels = -level + 1;
116   int lvl;
117   unsigned w, h, expect_size;
118
119   if (internalFormat < GL_PALETTE4_RGB8_OES
120       || internalFormat > GL_PALETTE8_RGB5_A1_OES) {
121      return 0;
122   }
123
124   info = &formats[internalFormat - GL_PALETTE4_RGB8_OES];
125   ASSERT(info->cpal_format == internalFormat);
126
127   expect_size = info->palette_size * info->size;
128   for (lvl = 0; lvl < num_levels; lvl++) {
129      w = width >> lvl;
130      if (!w)
131         w = 1;
132      h = height >> lvl;
133      if (!h)
134         h = 1;
135
136      if (info->palette_size == 16)
137         expect_size += (w * h  + 1) / 2;
138      else
139         expect_size += w * h;
140   }
141
142   return expect_size;
143}
144
145void
146_mesa_cpal_compressed_format_type(GLenum internalFormat, GLenum *format,
147				  GLenum *type)
148{
149   const struct cpal_format_info *info;
150
151   if (internalFormat < GL_PALETTE4_RGB8_OES
152       || internalFormat > GL_PALETTE8_RGB5_A1_OES) {
153      return;
154   }
155
156   info = &formats[internalFormat - GL_PALETTE4_RGB8_OES];
157   *format = info->format;
158   *type = info->type;
159}
160
161/**
162 * Convert a call to glCompressedTexImage2D() where internalFormat is a
163 *  compressed palette format into a regular GLubyte/RGBA glTexImage2D() call.
164 */
165void
166_mesa_cpal_compressed_teximage2d(GLenum target, GLint level,
167				 GLenum internalFormat,
168				 GLsizei width, GLsizei height,
169				 GLsizei imageSize, const void *palette)
170{
171   const struct cpal_format_info *info;
172   GLint lvl, num_levels;
173   const GLubyte *indices;
174   GLint saved_align, align;
175   GET_CURRENT_CONTEXT(ctx);
176
177   /* By this point, the internalFormat should have been validated.
178    */
179   assert(internalFormat >= GL_PALETTE4_RGB8_OES
180	  && internalFormat <= GL_PALETTE8_RGB5_A1_OES);
181
182   info = &formats[internalFormat - GL_PALETTE4_RGB8_OES];
183
184   num_levels = -level + 1;
185
186   /* first image follows the palette */
187   indices = (const GLubyte *) palette + info->palette_size * info->size;
188
189   saved_align = ctx->Unpack.Alignment;
190   align = saved_align;
191
192   for (lvl = 0; lvl < num_levels; lvl++) {
193      GLsizei w, h;
194      GLuint num_texels;
195      GLubyte *image = NULL;
196
197      w = width >> lvl;
198      if (!w)
199         w = 1;
200      h = height >> lvl;
201      if (!h)
202         h = 1;
203      num_texels = w * h;
204      if (w * info->size % align) {
205         _mesa_PixelStorei(GL_UNPACK_ALIGNMENT, 1);
206         align = 1;
207      }
208
209      /* allocate and fill dest image buffer */
210      if (palette) {
211         image = (GLubyte *) malloc(num_texels * info->size);
212         paletted_to_color(info, palette, indices, num_texels, image);
213      }
214
215      _mesa_TexImage2D(target, lvl, info->format, w, h, 0,
216                       info->format, info->type, image);
217      if (image)
218         free(image);
219
220      /* advance index pointer to point to next src mipmap */
221      if (info->palette_size == 16)
222         indices += (num_texels + 1) / 2;
223      else
224         indices += num_texels;
225   }
226
227   if (saved_align != align)
228      _mesa_PixelStorei(GL_UNPACK_ALIGNMENT, saved_align);
229}
230
231#endif
232