src/mesa/main/texcompress_etc_tmp.h

   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  * Included by texcompress_etc1 and gallium to define ETC1 decoding routines.
  26  */
  27
  28 struct TAG(etc1_block) {
  29    uint32_t pixel_indices;
  30    int flipped;
  31    const int *modifier_tables[2];
  32    UINT8_TYPE base_colors[2][3];
  33 };
  34
  35 static UINT8_TYPE
  36 TAG(etc1_base_color_diff_hi)(UINT8_TYPE in)
  37 {
  38    return (in & 0xf8) | (in >> 5);
  39 }
  40
  41 static UINT8_TYPE
  42 TAG(etc1_base_color_diff_lo)(UINT8_TYPE in)
  43 {
  44    static const int lookup[8] = { 0, 1, 2, 3, -4, -3, -2, -1 };
  45
  46    in = (in >> 3) + lookup[in & 0x7];
  47
  48    return (in << 3) | (in >> 2);
  49 }
  50
  51 static UINT8_TYPE
  52 TAG(etc1_base_color_ind_hi)(UINT8_TYPE in)
  53 {
  54    return (in & 0xf0) | ((in & 0xf0) >> 4);
  55 }
  56
  57 static UINT8_TYPE
  58 TAG(etc1_base_color_ind_lo)(UINT8_TYPE in)
  59 {
  60    return ((in & 0xf) << 4) | (in & 0xf);
  61 }
  62
  63 static UINT8_TYPE
  64 TAG(etc1_clamp)(UINT8_TYPE base, int modifier)
  65 {
  66    int tmp = (int) base + modifier;
  67
  68    /* CLAMP(tmp, 0, 255) */
  69    return (UINT8_TYPE) ((tmp < 0) ? 0 : ((tmp > 255) ? 255 : tmp));
  70 }
  71
  72 static const int TAG(etc1_modifier_tables)[8][4] = {
  73    {  2,   8,  -2,   -8},
  74    {  5,  17,  -5,  -17},
  75    {  9,  29,  -9,  -29},
  76    { 13,  42, -13,  -42},
  77    { 18,  60, -18,  -60},
  78    { 24,  80, -24,  -80},
  79    { 33, 106, -33, -106},
  80    { 47, 183, -47, -183}
  81 };
  82
  83 static void
  84 TAG(etc1_parse_block)(struct TAG(etc1_block) *block, const UINT8_TYPE *src)
  85 {
  86    if (src[3] & 0x2) {
  87       /* differential mode */
  88       block->base_colors[0][0] = (int) TAG(etc1_base_color_diff_hi)(src[0]);
  89       block->base_colors[1][0] = (int) TAG(etc1_base_color_diff_lo)(src[0]);
  90       block->base_colors[0][1] = (int) TAG(etc1_base_color_diff_hi)(src[1]);
  91       block->base_colors[1][1] = (int) TAG(etc1_base_color_diff_lo)(src[1]);
  92       block->base_colors[0][2] = (int) TAG(etc1_base_color_diff_hi)(src[2]);
  93       block->base_colors[1][2] = (int) TAG(etc1_base_color_diff_lo)(src[2]);
  94    }
  95    else {
  96       /* individual mode */
  97       block->base_colors[0][0] = (int) TAG(etc1_base_color_ind_hi)(src[0]);
  98       block->base_colors[1][0] = (int) TAG(etc1_base_color_ind_lo)(src[0]);
  99       block->base_colors[0][1] = (int) TAG(etc1_base_color_ind_hi)(src[1]);
 100       block->base_colors[1][1] = (int) TAG(etc1_base_color_ind_lo)(src[1]);
 101       block->base_colors[0][2] = (int) TAG(etc1_base_color_ind_hi)(src[2]);
 102       block->base_colors[1][2] = (int) TAG(etc1_base_color_ind_lo)(src[2]);
 103    }
 104
 105    /* pick modifier tables */
 106    block->modifier_tables[0] = TAG(etc1_modifier_tables)[(src[3] >> 5) & 0x7];
 107    block->modifier_tables[1] = TAG(etc1_modifier_tables)[(src[3] >> 2) & 0x7];
 108
 109    block->flipped = (src[3] & 0x1);
 110
 111    block->pixel_indices =
 112       (src[4] << 24) | (src[5] << 16) | (src[6] << 8) | src[7];
 113 }
 114
 115 static void
 116 TAG(etc1_fetch_texel)(const struct TAG(etc1_block) *block,
 117       int x, int y, UINT8_TYPE *dst)
 118 {
 119    const UINT8_TYPE *base_color;
 120    int modifier, bit, idx, blk;
 121
 122    /* get pixel index */
 123    bit = y + x * 4;
 124    idx = ((block->pixel_indices >> (15 + bit)) & 0x2) |
 125          ((block->pixel_indices >>      (bit)) & 0x1);
 126
 127    /* get subblock */
 128    blk = (block->flipped) ? (y >= 2) : (x >= 2);
 129
 130    base_color = block->base_colors[blk];
 131    modifier = block->modifier_tables[blk][idx];
 132
 133    dst[0] = TAG(etc1_clamp)(base_color[0], modifier);
 134    dst[1] = TAG(etc1_clamp)(base_color[1], modifier);
 135    dst[2] = TAG(etc1_clamp)(base_color[2], modifier);
 136 }
 137
 138 static void
 139 etc1_unpack_rgba8888(uint8_t *dst_row,
 140                      unsigned dst_stride,
 141                      const uint8_t *src_row,
 142                      unsigned src_stride,
 143                      unsigned width,
 144                      unsigned height)
 145 {
 146    const unsigned bw = 4, bh = 4, bs = 8, comps = 4;
 147    struct etc1_block block;
 148    unsigned x, y, i, j;
 149
 150    for (y = 0; y < height; y += bh) {
 151       const uint8_t *src = src_row;
 152
 153       for (x = 0; x < width; x+= bw) {
 154          etc1_parse_block(&block, src);
 155
 156          for (j = 0; j < MIN2(bh, height - y); j++) {
 157             uint8_t *dst = dst_row + (y + j) * dst_stride + x * comps;
 158             for (i = 0; i < MIN2(bw, width - x); i++) {
 159                etc1_fetch_texel(&block, i, j, dst);
 160                dst[3] = 255;
 161                dst += comps;
 162             }
 163          }
 164
 165          src += bs;
 166       }
 167
 168       src_row += src_stride;
 169    }
 170 }