352 lines
12 KiB
C
352 lines
12 KiB
C
/*
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Copyright (C) 2014 Jean-Philippe ANDRE
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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1. Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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2. Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
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INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
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OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* ETC2 decoding functions, reimplemented from scratch based on the
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* OpenGL ES 3.0 spec (annex C.1).
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*
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* @author Jean-Philippe ANDRE
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* @license BSD-2 with advertisement clause
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <Eina.h>
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#include "rg_etc1.h"
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void rg_etc2_rgb8_decode_block(const unsigned char *etc_block, unsigned int *bgra);
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void rg_etc2_rgba8_decode_block(const unsigned char *etc_block, unsigned int *bgra);
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typedef const uint8_t etc_block;
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// For T and H modes
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static const int kDistances[8] = {
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3, 6, 11, 16, 23, 32, 41, 64
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};
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// For differential mode
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static const int kSigned3bit[8] = {
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0, 1, 2, 3, -4, -3, -2, -1
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};
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// For alpha support
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static const int kAlphaModifiers[16][8] = {
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{ -3, -6, -9, -15, 2, 5, 8, 14},
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{ -3, -7, -10, -13, 2, 6, 9, 12},
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{ -2, -5, -8, -13, 1, 4, 7, 12},
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{ -2, -4, -6, -13, 1, 3, 5, 12},
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{ -3, -6, -8, -12, 2, 5, 7, 11},
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{ -3, -7, -9, -11, 2, 6, 8, 10},
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{ -4, -7, -8, -11, 3, 6, 7, 10},
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{ -3, -5, -8, -11, 2, 4, 7, 10},
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{ -2, -6, -8, -10, 1, 5, 7, 9},
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{ -2, -5, -8, -10, 1, 4, 7, 9},
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{ -2, -4, -8, -10, 1, 3, 7, 9},
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{ -2, -5, -7, -10, 1, 4, 6, 9},
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{ -3, -4, -7, -10, 2, 3, 6, 9},
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{ -1, -2, -3, -10, 0, 1, 2, 9},
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{ -4, -6, -8, -9, 3, 5, 7, 8},
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{ -3, -5, -7, -9, 2, 4, 6, 8}
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};
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// Use with static constants so the compiler can optimize everything
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#define BITS(byteval, lowbit, highbit) \
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(((byteval) >> (lowbit)) & ((1 << ((highbit) - (lowbit) + 1)) - 1))
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#define BIT(byteval, bit) \
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(((byteval) >> (bit)) & 0x1)
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// Clamps only if value is > 255
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#define CLAMPDOWN(a) ({ int _z = (a); ((_z <= 255) ? _z : 255); })
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// Clamps only if value is < 0
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#define CLAMPUP(a) ({ int _z = (a); ((_z >= 0) ? _z : 0); })
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// Real clamp
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#define CLAMP(a) ({ int _b = (a); (((_b) >= 0) ? (((_b) < 256) ? (_b) : 255) : 0); })
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// Simple min
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#ifndef MIN
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# define MIN(a,b) ({ int _z = (a), _y = (b); ((_z <= _y) ? _z : _y); })
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#endif
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// Write a BGRA value for output to Evas
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#define BGRA(r,g,b,a) ((a << 24) | (r << 16) | (g << 8) | b)
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#define _4to8(a) ({ int _a = (a) & ((1 << 4) - 1); ((_a << 4) | (_a & 0xf)); })
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#define _5to8(a) ({ int _a = (a) & ((1 << 5) - 1); ((_a << 3) | ((_a >> 2) & 0x7)); })
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#define _6to8(a) ({ int _a = (a) & ((1 << 6) - 1); ((_a << 2) | ((_a >> 4) & 0x3)); })
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#define _7to8(a) ({ int _a = (a) & ((1 << 7) - 1); ((_a << 1) | ((_a >> 6) & 0x1)); })
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#ifndef WORDS_BIGENDIAN
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/* x86 */
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#define A_VAL(p) (((uint8_t *)(p))[3])
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#define R_VAL(p) (((uint8_t *)(p))[2])
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#define G_VAL(p) (((uint8_t *)(p))[1])
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#define B_VAL(p) (((uint8_t *)(p))[0])
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#else
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/* ppc */
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#define A_VAL(p) (((uint8_t *)(p))[0])
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#define R_VAL(p) (((uint8_t *)(p))[1])
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#define G_VAL(p) (((uint8_t *)(p))[2])
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#define B_VAL(p) (((uint8_t *)(p))[3])
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#endif
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static inline void
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_T_mode_color_read(const uint8_t *etc, uint32_t *paint_colors)
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{
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// 4 bit colors
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const int r1_4 = (BITS(etc[0], 3, 4) << 2) | BITS(etc[0], 0, 1);
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const int g1_4 = BITS(etc[1], 4, 7);
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const int b1_4 = BITS(etc[1], 0, 3);
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const int r2_4 = BITS(etc[2], 4, 7);
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const int g2_4 = BITS(etc[2], 0, 3);
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const int b2_4 = BITS(etc[3], 4, 7);
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// Distance index
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const int didx = (BITS(etc[3], 2, 3) << 1) | BIT(etc[3], 0);
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const int d = kDistances[didx];
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// Write out paint colors for T mode
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paint_colors[0] = BGRA(_4to8(r1_4), _4to8(g1_4), _4to8(b1_4), 255);
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paint_colors[1] = BGRA(CLAMPDOWN(_4to8(r2_4) + d),
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CLAMPDOWN(_4to8(g2_4) + d),
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CLAMPDOWN(_4to8(b2_4) + d),
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255);
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paint_colors[2] = BGRA(_4to8(r2_4), _4to8(g2_4), _4to8(b2_4), 255);
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paint_colors[3] = BGRA(CLAMPUP(_4to8(r2_4) - d),
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CLAMPUP(_4to8(g2_4) - d),
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CLAMPUP(_4to8(b2_4) - d),
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255);
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}
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static inline void
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_H_mode_color_read(const uint8_t *etc, uint32_t *paint_colors)
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{
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// 4 bit colors
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const int r1_4 = BITS(etc[0], 3, 6);
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const int g1_4 = (BITS(etc[0], 0, 2) << 1) | (BIT(etc[1], 4));
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const int b1_4 = (BIT(etc[1], 3) << 3) | (BITS(etc[1], 0, 1) << 1) | (BIT(etc[2], 7));
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const int r2_4 = BITS(etc[2], 3, 6);
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const int g2_4 = (BITS(etc[2], 0, 2) << 1) | (BIT(etc[3], 7));
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const int b2_4 = BITS(etc[3], 3, 6);
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// Distance index
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const int basecol1 = (_4to8(r1_4) << 16) | (_4to8(g1_4) << 8) | _4to8(b1_4);
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const int basecol2 = (_4to8(r2_4) << 16) | (_4to8(g2_4) << 8) | _4to8(b2_4);
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const int didx =
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(BIT(etc[3], 2) << 2) |
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(BIT(etc[3], 0) << 1) |
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((basecol1 >= basecol2) ? 1 : 0);
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const int d = kDistances[didx];
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// Write out paint colors for H mode
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paint_colors[0] = BGRA(CLAMPDOWN(_4to8(r1_4) + d),
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CLAMPDOWN(_4to8(g1_4) + d),
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CLAMPDOWN(_4to8(b1_4) + d),
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255);
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paint_colors[1] = BGRA(CLAMPUP(_4to8(r1_4) - d),
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CLAMPUP(_4to8(g1_4) - d),
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CLAMPUP(_4to8(b1_4) - d),
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255);
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paint_colors[2] = BGRA(CLAMPDOWN(_4to8(r2_4) + d),
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CLAMPDOWN(_4to8(g2_4) + d),
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CLAMPDOWN(_4to8(b2_4) + d),
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255);
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paint_colors[3] = BGRA(CLAMPUP(_4to8(r2_4) - d),
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CLAMPUP(_4to8(g2_4) - d),
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CLAMPUP(_4to8(b2_4) - d),
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255);
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}
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static inline void
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_planar_mode_color_read(const uint8_t *etc, uint32_t *bgra)
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{
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// RO: Bits 57-62
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const int RO = _6to8(BITS(etc[0], 1, 6));
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// GO: Bits 49-54,56
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const int GO = _7to8((BIT(etc[0], 0) << 6) | (BITS(etc[1], 1, 6)));
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// BO: Bits 39,40-41,43-44,48
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const int BO = _6to8((BIT(etc[1], 0) << 5) | (BITS(etc[2], 3, 4) << 3) | (BITS(etc[2], 0, 1) << 1) | BIT(etc[3], 7));
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// RH: Bits 32,34-38
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const int RH = _6to8((BITS(etc[3], 2, 6) << 1) | BIT(etc[3], 0));
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// GH: Bits 25-31
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const int GH = _7to8(BITS(etc[4], 1, 7));
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// BH: Bits 19-23,24
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const int BH = _6to8((BIT(etc[4], 0) << 5) | (BITS(etc[5], 3, 7)));
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// RV: Bits 13-15,16-18
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const int RV = _6to8((BITS(etc[5], 0, 2) << 3) | (BITS(etc[6], 5, 7)));
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// GV: Bits 6-7,8-12
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const int GV = _7to8((BITS(etc[6], 0, 4) << 2) | (BITS(etc[7], 6, 7)));
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// BV: Bits 0-5
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const int BV = _6to8(BITS(etc[7], 0, 5));
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for (int y = 0; y < 4; y++)
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for (int x = 0; x < 4; x++)
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{
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// Formulas straight from the spec
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const int R = CLAMP(((x * (RH - RO)) + y * (RV - RO) + 4 * RO + 2) >> 2);
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const int G = CLAMP(((x * (GH - GO)) + y * (GV - GO) + 4 * GO + 2) >> 2);
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const int B = CLAMP(((x * (BH - BO)) + y * (BV - BO) + 4 * BO + 2) >> 2);
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*bgra++ = BGRA(R, G, B, 255);
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}
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}
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static inline void
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_TH_paint(const uint8_t *etc, uint32_t paint_colors[4], uint32_t *bgra)
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{
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// Common code for modes T and H.
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// a,b,c,d
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bgra[ 0] = paint_colors[(BIT(etc[5], 0) << 1) | (BIT(etc[7], 0))];
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bgra[ 4] = paint_colors[(BIT(etc[5], 1) << 1) | (BIT(etc[7], 1))];
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bgra[ 8] = paint_colors[(BIT(etc[5], 2) << 1) | (BIT(etc[7], 2))];
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bgra[12] = paint_colors[(BIT(etc[5], 3) << 1) | (BIT(etc[7], 3))];
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// e,f,g,h
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bgra[ 1] = paint_colors[(BIT(etc[5], 4) << 1) | (BIT(etc[7], 4))];
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bgra[ 5] = paint_colors[(BIT(etc[5], 5) << 1) | (BIT(etc[7], 5))];
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bgra[ 9] = paint_colors[(BIT(etc[5], 6) << 1) | (BIT(etc[7], 6))];
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bgra[13] = paint_colors[(BIT(etc[5], 7) << 1) | (BIT(etc[7], 7))];
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// i,j,k,l
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bgra[ 2] = paint_colors[(BIT(etc[4], 0) << 1) | (BIT(etc[6], 0))];
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bgra[ 6] = paint_colors[(BIT(etc[4], 1) << 1) | (BIT(etc[6], 1))];
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bgra[10] = paint_colors[(BIT(etc[4], 2) << 1) | (BIT(etc[6], 2))];
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bgra[14] = paint_colors[(BIT(etc[4], 3) << 1) | (BIT(etc[6], 3))];
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// m,n,o,p
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bgra[ 3] = paint_colors[(BIT(etc[4], 4) << 1) | (BIT(etc[6], 4))];
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bgra[ 7] = paint_colors[(BIT(etc[4], 5) << 1) | (BIT(etc[6], 5))];
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bgra[11] = paint_colors[(BIT(etc[4], 6) << 1) | (BIT(etc[6], 6))];
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bgra[15] = paint_colors[(BIT(etc[4], 7) << 1) | (BIT(etc[6], 7))];
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}
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void
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rg_etc2_rgb8_decode_block(const unsigned char *etc, unsigned int *bgra)
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{
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// Check differential mode bit
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if ((etc[3] & 0x2) == 0)
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goto etc1;
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// Read R,G,B
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const int R = BITS(etc[0], 3, 7);
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const int dR = kSigned3bit[BITS(etc[0], 0, 2)];
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const int G = BITS(etc[1], 3, 7);
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const int dG = kSigned3bit[BITS(etc[1], 0, 2)];
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const int B = BITS(etc[2], 3, 7);
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const int dB = kSigned3bit[BITS(etc[2], 0, 2)];
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uint32_t paint_colors[4];
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if ((R + dR) < 0 || (R + dR) >= 32)
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{
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// T mode
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_T_mode_color_read(etc, paint_colors);
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_TH_paint(etc, paint_colors, bgra);
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return;
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}
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if ((G + dG) < 0 || (G + dG) >= 32)
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{
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// H mode
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_H_mode_color_read(etc, paint_colors);
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_TH_paint(etc, paint_colors, bgra);
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return;
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}
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if ((B + dB) < 0 || (B + dB) >= 32)
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{
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// Planar mode
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_planar_mode_color_read(etc, bgra);
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return;
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}
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etc1:
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// Valid differential mode or individual mode: ETC1
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if (!rg_etc1_unpack_block(etc, bgra, 0))
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fprintf(stderr, "ETC2: Something very strange is happening here!\n");
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}
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void
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rg_etc2_rgba8_decode_block(const unsigned char *etc, unsigned int *bgra)
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{
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const uint8_t zeros[7] = {0};
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uint32_t table_index;
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int base_codeword;
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int multiplier;
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base_codeword = etc[0];
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// Fast path if alpha is the same for all pixels
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if (!memcmp(etc + 1, zeros, 7))
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{
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if (!base_codeword)
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memset(bgra, 0, 64);
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else
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{
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rg_etc2_rgb8_decode_block(etc + 8, bgra);
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if (base_codeword != 255)
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for (int k = 0; k < 16; k++)
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{
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const uint32_t rgb = *bgra;
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const int R = MIN(R_VAL(&rgb), base_codeword);
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const int G = MIN(G_VAL(&rgb), base_codeword);
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const int B = MIN(B_VAL(&rgb), base_codeword);
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*bgra++ = BGRA(R, G, B, base_codeword);
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}
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}
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return;
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}
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rg_etc2_rgb8_decode_block(etc + 8, bgra);
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multiplier = BITS(etc[1], 4, 7);
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table_index = BITS(etc[1], 0, 3);
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for (int x = 0, k = 0; x < 4; x++)
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for (int y = 0; y < 4; y++, k += 3)
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{
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const uint32_t byte = (k >> 3); // = [k/8]
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const uint32_t bit = k - (byte << 3); // = k%8
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const uint32_t rgb = bgra[(y << 2) + x];
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uint32_t index, alpha, R, G, B;
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if (bit < 6)
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index = BITS(etc[byte + 2], 5 - bit, 7 - bit);
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else if (bit == 6)
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index = (BITS(etc[byte + 2], 0, 1) << 1) | BIT(etc[byte + 3], 7);
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else // bit == 7
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index = (BIT(etc[byte + 2], 0) << 2) | BITS(etc[byte + 3], 6, 7);
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alpha = CLAMP(base_codeword + kAlphaModifiers[table_index][index] * multiplier);
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R = MIN(R_VAL(&rgb), alpha);
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G = MIN(G_VAL(&rgb), alpha);
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B = MIN(B_VAL(&rgb), alpha);
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bgra[(y << 2) + x] = BGRA(R, G, B, alpha);
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}
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}
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