texcompress_cpal.c revision 7179a822628963d8cfa0817cf072c5acb70638a7 
1/**************************************************************************
2 *
3 * Copyright 2008 Tungsten Graphics, Inc., Cedar Park, Texas.
4 * All Rights Reserved.
5 *
6 **************************************************************************/
7
8
9/**
10 * Code to convert compressed/paletted texture images to ordinary images.
11 * See the GL_OES_compressed_paletted_texture spec at
12 * http://khronos.org/registry/gles/extensions/OES/OES_compressed_paletted_texture.txt
13 *
14 * XXX this makes it impossible to add hardware support...
15 */
16
17
18#include "glheader.h"
19#include "compiler.h" /* for ASSERT */
20#include "context.h"
21#include "mtypes.h"
22#include "imports.h"
23#include "pixelstore.h"
24#include "teximage.h"
25#include "texpal.h"
26
27#if FEATURE_ES
28
29
30static const struct cpal_format_info {
31   GLenum cpal_format;
32   GLenum format;
33   GLenum type;
34   GLuint palette_size;
35   GLuint size;
36} formats[] = {
37   { GL_PALETTE4_RGB8_OES,     GL_RGB,  GL_UNSIGNED_BYTE,           16, 3 },
38   { GL_PALETTE4_RGBA8_OES,    GL_RGBA, GL_UNSIGNED_BYTE,           16, 4 },
39   { GL_PALETTE4_R5_G6_B5_OES, GL_RGB,  GL_UNSIGNED_SHORT_5_6_5,    16, 2 },
40   { GL_PALETTE4_RGBA4_OES,    GL_RGBA, GL_UNSIGNED_SHORT_4_4_4_4,  16, 2 },
41   { GL_PALETTE4_RGB5_A1_OES,  GL_RGBA, GL_UNSIGNED_SHORT_5_5_5_1,  16, 2 },
42   { GL_PALETTE8_RGB8_OES,     GL_RGB,  GL_UNSIGNED_BYTE,          256, 3 },
43   { GL_PALETTE8_RGBA8_OES,    GL_RGBA, GL_UNSIGNED_BYTE,          256, 4 },
44   { GL_PALETTE8_R5_G6_B5_OES, GL_RGB,  GL_UNSIGNED_SHORT_5_6_5,   256, 2 },
45   { GL_PALETTE8_RGBA4_OES,    GL_RGBA, GL_UNSIGNED_SHORT_4_4_4_4, 256, 2 },
46   { GL_PALETTE8_RGB5_A1_OES,  GL_RGBA, GL_UNSIGNED_SHORT_5_5_5_1, 256, 2 }
47};
48
49
50/**
51 * Get a color/entry from the palette.
52 */
53static GLuint
54get_palette_entry(const struct cpal_format_info *info, const GLubyte *palette,
55                  GLuint index, GLubyte *pixel)
56{
57   memcpy(pixel, palette + info->size * index, info->size);
58   return info->size;
59}
60
61
62/**
63 * Convert paletted texture to color texture.
64 */
65static void
66paletted_to_color(const struct cpal_format_info *info, const GLubyte *palette,
67                  const void *indices, GLuint num_pixels, GLubyte *image)
68{
69   GLubyte *pix = image;
70   GLuint remain, i;
71
72   if (info->palette_size == 16) {
73      /* 4 bits per index */
74      const GLubyte *ind = (const GLubyte *) indices;
75
76      /* two pixels per iteration */
77      remain = num_pixels % 2;
78      for (i = 0; i < num_pixels / 2; i++) {
79         pix += get_palette_entry(info, palette, (ind[i] >> 4) & 0xf, pix);
80         pix += get_palette_entry(info, palette, ind[i] & 0xf, pix);
81      }
82      if (remain) {
83         get_palette_entry(info, palette, (ind[i] >> 4) & 0xf, pix);
84      }
85   }
86   else {
87      /* 8 bits per index */
88      const GLubyte *ind = (const GLubyte *) indices;
89      for (i = 0; i < num_pixels; i++)
90         pix += get_palette_entry(info, palette, ind[i], pix);
91   }
92}
93
94
95static const struct cpal_format_info *
96cpal_get_info(GLint level, GLenum internalFormat,
97              GLsizei width, GLsizei height, GLsizei imageSize)
98{
99   const struct cpal_format_info *info;
100   GLint lvl, num_levels;
101   GLsizei w, h, expect_size;
102
103   info = &formats[internalFormat - GL_PALETTE4_RGB8_OES];
104   ASSERT(info->cpal_format == internalFormat);
105
106   if (level > 0) {
107      _mesa_error(_mesa_get_current_context(), GL_INVALID_VALUE,
108            "glCompressedTexImage2D(level=%d)", level);
109      return NULL;
110   }
111
112   num_levels = -level + 1;
113   expect_size = info->palette_size * info->size;
114   for (lvl = 0; lvl < num_levels; lvl++) {
115      w = width >> lvl;
116      if (!w)
117         w = 1;
118      h = height >> lvl;
119      if (!h)
120         h = 1;
121
122      if (info->palette_size == 16)
123         expect_size += (w * h  + 1) / 2;
124      else
125         expect_size += w * h;
126   }
127   if (expect_size > imageSize) {
128      _mesa_error(_mesa_get_current_context(), GL_INVALID_VALUE,
129            "glCompressedTexImage2D(imageSize=%d)", imageSize);
130      return NULL;
131   }
132   return info;
133}
134
135/**
136 * Convert a call to glCompressedTexImage2D() where internalFormat is a
137 *  compressed palette format into a regular GLubyte/RGBA glTexImage2D() call.
138 */
139void
140_mesa_cpal_compressed_teximage2d(GLenum target, GLint level,
141				 GLenum internalFormat,
142				 GLsizei width, GLsizei height,
143				 GLsizei imageSize, const void *palette)
144{
145   const struct cpal_format_info *info;
146   GLint lvl, num_levels;
147   const GLubyte *indices;
148   GLint saved_align, align;
149   GET_CURRENT_CONTEXT(ctx);
150
151   info = cpal_get_info(level, internalFormat, width, height, imageSize);
152   if (!info)
153      return;
154
155   info = &formats[internalFormat - GL_PALETTE4_RGB8_OES];
156   ASSERT(info->cpal_format == internalFormat);
157   num_levels = -level + 1;
158
159   /* first image follows the palette */
160   indices = (const GLubyte *) palette + info->palette_size * info->size;
161
162   saved_align = ctx->Unpack.Alignment;
163   align = saved_align;
164
165   for (lvl = 0; lvl < num_levels; lvl++) {
166      GLsizei w, h;
167      GLuint num_texels;
168      GLubyte *image = NULL;
169
170      w = width >> lvl;
171      if (!w)
172         w = 1;
173      h = height >> lvl;
174      if (!h)
175         h = 1;
176      num_texels = w * h;
177      if (w * info->size % align) {
178         _mesa_PixelStorei(GL_UNPACK_ALIGNMENT, 1);
179         align = 1;
180      }
181
182      /* allocate and fill dest image buffer */
183      if (palette) {
184         image = (GLubyte *) malloc(num_texels * info->size);
185         paletted_to_color(info, palette, indices, num_texels, image);
186      }
187
188      _mesa_TexImage2D(target, lvl, info->format, w, h, 0,
189                       info->format, info->type, image);
190      if (image)
191         free(image);
192
193      /* advance index pointer to point to next src mipmap */
194      if (info->palette_size == 16)
195         indices += (num_texels + 1) / 2;
196      else
197         indices += num_texels;
198   }
199
200   if (saved_align != align)
201      _mesa_PixelStorei(GL_UNPACK_ALIGNMENT, saved_align);
202}
203
204#endif
205