src/mesa/main/texcompress_etc.c

   1 /*
   2  * Copyright (C) 2011 LunarG, Inc.
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  21  * DEALINGS IN THE SOFTWARE.
  22  */
  23
  24 /**
  25  * \file texcompress_etc.c
  26  * GL_OES_compressed_ETC1_RGB8_texture support.
  27  */
  28
  29
  30 #include "mfeatures.h"
  31 #include "texcompress.h"
  32 #include "texcompress_etc.h"
  33 #include "texstore.h"
  34 #include "macros.h"
  35 #include "swrast/s_context.h"
  36
  37 GLboolean
  38 _mesa_texstore_etc1_rgb8(TEXSTORE_PARAMS)
  39 {
  40    /* GL_ETC1_RGB8_OES is only valid in glCompressedTexImage2D */
  41    ASSERT(0);
  42
  43    return GL_FALSE;
  44 }
  45
  46 /* define etc1_parse_block and etc. */
  47 #define UINT8_TYPE GLubyte
  48 #define TAG(x) x
  49 #include "texcompress_etc_tmp.h"
  50 #undef TAG
  51 #undef UINT8_TYPE
  52
  53 void
  54 _mesa_fetch_texel_2d_f_etc1_rgb8(const struct swrast_texture_image *texImage,
  55                                  GLint i, GLint j, GLint k, GLfloat *texel)
  56 {
  57    struct etc1_block block;
  58    GLubyte dst[3];
  59    const GLubyte *src;
  60
  61    src = (const GLubyte *) texImage->Map +
  62       (((texImage->RowStride + 3) / 4) * (j / 4) + (i / 4)) * 8;
  63
  64    etc1_parse_block(&block, src);
  65    etc1_fetch_texel(&block, i % 4, j % 4, dst);
  66
  67    texel[RCOMP] = UBYTE_TO_FLOAT(dst[0]);
  68    texel[GCOMP] = UBYTE_TO_FLOAT(dst[1]);
  69    texel[BCOMP] = UBYTE_TO_FLOAT(dst[2]);
  70    texel[ACOMP] = 1.0f;
  71 }
  72
  73 /**
  74  * Decode texture data in format `MESA_FORMAT_ETC1_RGB8` to
  75  * `MESA_FORMAT_ABGR8888`.
  76  *
  77  * The size of the source data must be a multiple of the ETC1 block size,
  78  * which is 8, even if the texture image's dimensions are not aligned to 4.
  79  * From the GL_OES_compressed_ETC1_RGB8_texture spec:
  80  *   The texture is described as a number of 4x4 pixel blocks. If the
  81  *   texture (or a particular mip-level) is smaller than 4 pixels in
  82  *   any dimension (such as a 2x2 or a 8x1 texture), the texture is
  83  *   found in the upper left part of the block(s), and the rest of the
  84  *   pixels are not used. For instance, a texture of size 4x2 will be
  85  *   placed in the upper half of a 4x4 block, and the lower half of the
  86  *   pixels in the block will not be accessed.
  87  *
  88  * \param src_width in pixels
  89  * \param src_height in pixels
  90  * \param dst_stride in bytes
  91  */
  92 void
  93 _mesa_etc1_unpack_rgba8888(uint8_t *dst_row,
  94                            unsigned dst_stride,
  95                            const uint8_t *src_row,
  96                            unsigned src_stride,
  97                            unsigned src_width,
  98                            unsigned src_height)
  99 {
 100    etc1_unpack_rgba8888(dst_row, dst_stride,
 101                         src_row, src_stride,
 102                         src_width, src_height);
 103 }