171 lines
5.2 KiB
C
171 lines
5.2 KiB
C
/*
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* Copyright (C) 2011 LunarG, Inc.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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*/
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/*
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* Included by texcompress_etc1 and gallium to define ETC1 decoding routines.
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*/
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struct TAG(etc1_block) {
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uint32_t pixel_indices;
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int flipped;
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const int *modifier_tables[2];
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UINT8_TYPE base_colors[2][3];
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};
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static UINT8_TYPE
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TAG(etc1_base_color_diff_hi)(UINT8_TYPE in)
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{
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return (in & 0xf8) | (in >> 5);
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}
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static UINT8_TYPE
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TAG(etc1_base_color_diff_lo)(UINT8_TYPE in)
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{
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static const int lookup[8] = { 0, 1, 2, 3, -4, -3, -2, -1 };
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in = (in >> 3) + lookup[in & 0x7];
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return (in << 3) | (in >> 2);
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}
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static UINT8_TYPE
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TAG(etc1_base_color_ind_hi)(UINT8_TYPE in)
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{
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return (in & 0xf0) | ((in & 0xf0) >> 4);
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}
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static UINT8_TYPE
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TAG(etc1_base_color_ind_lo)(UINT8_TYPE in)
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{
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return ((in & 0xf) << 4) | (in & 0xf);
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}
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static UINT8_TYPE
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TAG(etc1_clamp)(UINT8_TYPE base, int modifier)
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{
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int tmp = (int) base + modifier;
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/* CLAMP(tmp, 0, 255) */
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return (UINT8_TYPE) ((tmp < 0) ? 0 : ((tmp > 255) ? 255 : tmp));
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}
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static const int TAG(etc1_modifier_tables)[8][4] = {
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{ 2, 8, -2, -8},
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{ 5, 17, -5, -17},
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{ 9, 29, -9, -29},
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{ 13, 42, -13, -42},
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{ 18, 60, -18, -60},
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{ 24, 80, -24, -80},
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{ 33, 106, -33, -106},
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{ 47, 183, -47, -183}
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};
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static void
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TAG(etc1_parse_block)(struct TAG(etc1_block) *block, const UINT8_TYPE *src)
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{
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if (src[3] & 0x2) {
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/* differential mode */
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block->base_colors[0][0] = (int) TAG(etc1_base_color_diff_hi)(src[0]);
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block->base_colors[1][0] = (int) TAG(etc1_base_color_diff_lo)(src[0]);
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block->base_colors[0][1] = (int) TAG(etc1_base_color_diff_hi)(src[1]);
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block->base_colors[1][1] = (int) TAG(etc1_base_color_diff_lo)(src[1]);
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block->base_colors[0][2] = (int) TAG(etc1_base_color_diff_hi)(src[2]);
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block->base_colors[1][2] = (int) TAG(etc1_base_color_diff_lo)(src[2]);
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}
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else {
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/* individual mode */
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block->base_colors[0][0] = (int) TAG(etc1_base_color_ind_hi)(src[0]);
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block->base_colors[1][0] = (int) TAG(etc1_base_color_ind_lo)(src[0]);
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block->base_colors[0][1] = (int) TAG(etc1_base_color_ind_hi)(src[1]);
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block->base_colors[1][1] = (int) TAG(etc1_base_color_ind_lo)(src[1]);
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block->base_colors[0][2] = (int) TAG(etc1_base_color_ind_hi)(src[2]);
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block->base_colors[1][2] = (int) TAG(etc1_base_color_ind_lo)(src[2]);
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}
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/* pick modifier tables */
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block->modifier_tables[0] = TAG(etc1_modifier_tables)[(src[3] >> 5) & 0x7];
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block->modifier_tables[1] = TAG(etc1_modifier_tables)[(src[3] >> 2) & 0x7];
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block->flipped = (src[3] & 0x1);
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block->pixel_indices =
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(src[4] << 24) | (src[5] << 16) | (src[6] << 8) | src[7];
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}
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static void
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TAG(etc1_fetch_texel)(const struct TAG(etc1_block) *block,
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int x, int y, UINT8_TYPE *dst)
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{
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const UINT8_TYPE *base_color;
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int modifier, bit, idx, blk;
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/* get pixel index */
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bit = y + x * 4;
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idx = ((block->pixel_indices >> (15 + bit)) & 0x2) |
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((block->pixel_indices >> (bit)) & 0x1);
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/* get subblock */
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blk = (block->flipped) ? (y >= 2) : (x >= 2);
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base_color = block->base_colors[blk];
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modifier = block->modifier_tables[blk][idx];
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dst[0] = TAG(etc1_clamp)(base_color[0], modifier);
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dst[1] = TAG(etc1_clamp)(base_color[1], modifier);
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dst[2] = TAG(etc1_clamp)(base_color[2], modifier);
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}
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static void
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etc1_unpack_rgba8888(uint8_t *dst_row,
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unsigned dst_stride,
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const uint8_t *src_row,
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unsigned src_stride,
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unsigned width,
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unsigned height)
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{
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const unsigned bw = 4, bh = 4, bs = 8, comps = 4;
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struct etc1_block block;
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unsigned x, y, i, j;
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for (y = 0; y < height; y += bh) {
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const uint8_t *src = src_row;
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for (x = 0; x < width; x+= bw) {
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etc1_parse_block(&block, src);
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for (j = 0; j < MIN2(bh, height - y); j++) {
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uint8_t *dst = dst_row + (y + j) * dst_stride + x * comps;
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for (i = 0; i < MIN2(bw, width - x); i++) {
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etc1_fetch_texel(&block, i, j, dst);
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dst[3] = 255;
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dst += comps;
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}
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}
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src += bs;
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}
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src_row += src_stride;
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}
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}
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