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/**************************************************************************

 *

 * Copyright 2008 Tungsten Graphics, Inc., Cedar Park, Texas.

 * All Rights Reserved.

 *

 **************************************************************************/

/**

 * Code to convert compressed/paletted texture images to ordinary images.

 * See the GL_OES_compressed_paletted_texture spec at

 * http://khronos.org/registry/gles/extensions/OES/OES_compressed_paletted_texture.txt

 *

 * XXX this makes it impossible to add hardware support...

 */

#include "glheader.h"

#include "compiler.h" /* for ASSERT */

#include "context.h"

#include "mtypes.h"

#include "imports.h"

#include "pixelstore.h"

#include "teximage.h"

#include "texpal.h"

#if FEATURE_ES

static const struct cpal_format_info {

   GLenum cpal_format;

   GLenum format;

   GLenum type;

   GLuint palette_size;

   GLuint size;

} formats[] = {

   { GL_PALETTE4_RGB8_OES,     GL_RGB,  GL_UNSIGNED_BYTE,           16, 3 },

   { GL_PALETTE4_RGBA8_OES,    GL_RGBA, GL_UNSIGNED_BYTE,           16, 4 },

   { GL_PALETTE4_R5_G6_B5_OES, GL_RGB,  GL_UNSIGNED_SHORT_5_6_5,    16, 2 },

   { GL_PALETTE4_RGBA4_OES,    GL_RGBA, GL_UNSIGNED_SHORT_4_4_4_4,  16, 2 },

   { GL_PALETTE4_RGB5_A1_OES,  GL_RGBA, GL_UNSIGNED_SHORT_5_5_5_1,  16, 2 },

   { GL_PALETTE8_RGB8_OES,     GL_RGB,  GL_UNSIGNED_BYTE,          256, 3 },

   { GL_PALETTE8_RGBA8_OES,    GL_RGBA, GL_UNSIGNED_BYTE,          256, 4 },

   { GL_PALETTE8_R5_G6_B5_OES, GL_RGB,  GL_UNSIGNED_SHORT_5_6_5,   256, 2 },

   { GL_PALETTE8_RGBA4_OES,    GL_RGBA, GL_UNSIGNED_SHORT_4_4_4_4, 256, 2 },

   { GL_PALETTE8_RGB5_A1_OES,  GL_RGBA, GL_UNSIGNED_SHORT_5_5_5_1, 256, 2 }

};

/**

 * Get a color/entry from the palette.

 */

static GLuint

get_palette_entry(const struct cpal_format_info *info, const GLubyte *palette,

                  GLuint index, GLubyte *pixel)

{

   memcpy(pixel, palette + info->size * index, info->size);

   return info->size;

}

/**

 * Convert paletted texture to color texture.

 */

static void

paletted_to_color(const struct cpal_format_info *info, const GLubyte *palette,

                  const void *indices, GLuint num_pixels, GLubyte *image)

{

   GLubyte *pix = image;

   GLuint remain, i;

   if (info->palette_size == 16) {

      /* 4 bits per index */

      const GLubyte *ind = (const GLubyte *) indices;

      /* two pixels per iteration */

      remain = num_pixels % 2;

      for (i = 0; i < num_pixels / 2; i++) {

         pix += get_palette_entry(info, palette, (ind[i] >> 4) & 0xf, pix);

         pix += get_palette_entry(info, palette, ind[i] & 0xf, pix);

      }

      if (remain) {

         get_palette_entry(info, palette, (ind[i] >> 4) & 0xf, pix);

      }

   }

   else {

      /* 8 bits per index */

      const GLubyte *ind = (const GLubyte *) indices;

      for (i = 0; i < num_pixels; i++)

         pix += get_palette_entry(info, palette, ind[i], pix);

   }

}

static const struct cpal_format_info *

cpal_get_info(GLint level, GLenum internalFormat,

              GLsizei width, GLsizei height, GLsizei imageSize)

{

   const struct cpal_format_info *info;

   GLint lvl, num_levels;

   GLsizei w, h, expect_size;

   info = &formats[internalFormat - GL_PALETTE4_RGB8_OES];

   ASSERT(info->cpal_format == internalFormat);

   if (level > 0) {

      _mesa_error(_mesa_get_current_context(), GL_INVALID_VALUE,

            "glCompressedTexImage2D(level=%d)", level);

      return NULL;

   }

   num_levels = -level + 1;

   expect_size = info->palette_size * info->size;

   for (lvl = 0; lvl < num_levels; lvl++) {

      w = width >> lvl;

      if (!w)

         w = 1;

      h = height >> lvl;

      if (!h)

         h = 1;

      if (info->palette_size == 16)

         expect_size += (w * h  + 1) / 2;

      else

         expect_size += w * h;

   }

   if (expect_size > imageSize) {

      _mesa_error(_mesa_get_current_context(), GL_INVALID_VALUE,

            "glCompressedTexImage2D(imageSize=%d)", imageSize);

      return NULL;

   }

   return info;

}

/**

 * Convert a call to glCompressedTexImage2D() where internalFormat is a

 *  compressed palette format into a regular GLubyte/RGBA glTexImage2D() call.

 */

void

_mesa_cpal_compressed_teximage2d(GLenum target, GLint level,

				 GLenum internalFormat,

				 GLsizei width, GLsizei height,

				 GLsizei imageSize, const void *palette)

{

   const struct cpal_format_info *info;

   GLint lvl, num_levels;

   const GLubyte *indices;

   GLint saved_align, align;

   GET_CURRENT_CONTEXT(ctx);

   info = cpal_get_info(level, internalFormat, width, height, imageSize);

   if (!info)

      return;

   info = &formats[internalFormat - GL_PALETTE4_RGB8_OES];

   ASSERT(info->cpal_format == internalFormat);

   num_levels = -level + 1;

   /* first image follows the palette */

   indices = (const GLubyte *) palette + info->palette_size * info->size;

   saved_align = ctx->Unpack.Alignment;

   align = saved_align;

   for (lvl = 0; lvl < num_levels; lvl++) {

      GLsizei w, h;

      GLuint num_texels;

      GLubyte *image = NULL;

      w = width >> lvl;

      if (!w)

         w = 1;

      h = height >> lvl;

      if (!h)

         h = 1;

      num_texels = w * h;

      if (w * info->size % align) {

         _mesa_PixelStorei(GL_UNPACK_ALIGNMENT, 1);

         align = 1;

      }

      /* allocate and fill dest image buffer */

      if (palette) {

         image = (GLubyte *) malloc(num_texels * info->size);

         paletted_to_color(info, palette, indices, num_texels, image);

      }

      _mesa_TexImage2D(target, lvl, info->format, w, h, 0,

                       info->format, info->type, image);

      if (image)

         free(image);

      /* advance index pointer to point to next src mipmap */

      if (info->palette_size == 16)

         indices += (num_texels + 1) / 2;

      else

         indices += num_texels;

   }

   if (saved_align != align)

      _mesa_PixelStorei(GL_UNPACK_ALIGNMENT, saved_align);

}

#endif