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 } 171
