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Evas ETC2: Add ETC2 encoder skeletton 

Implement Alpha encoding, brute force way, but doesn't scan
all possibilities either (only based on average alpha).

RGB encoding is still entirely left to the rg-etc1 encoder.
T, H and Planar mode will come in the next commits.

@feature: Implement an ETC2 encoder from scratch for RGB8 and RGBA8
This commit is contained in:
Jean-Philippe Andre 2014-05-27 15:02:23 +09:00
parent 188ffd412c
commit 6fc4c1da74
3 changed files with 282 additions and 0 deletions
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2
src/Makefile_Evas.am
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@ -1816,6 +1816,7 @@ modules/evas/savers/tgv/evas_image_save_tgv.c \
static_libs/rg_etc/rg_etc1.c \
static_libs/rg_etc/rg_etc2.c \
static_libs/rg_etc/rg_etc1.h \
static_libs/rg_etc/etc2_encoder.c \
static_libs/lz4/lz4.c \
static_libs/lz4/lz4.h \
static_libs/lz4/lz4hc.c \
@ -1871,6 +1872,7 @@ modules_evas_savers_tgv_module_la_SOURCES = \
modules/evas/savers/tgv/evas_image_save_tgv.c \
static_libs/rg_etc/rg_etc1.c \
static_libs/rg_etc/rg_etc1.h \
static_libs/rg_etc/etc2_encoder.c \
static_libs/lz4/lz4.c \
static_libs/lz4/lz4.h \
static_libs/lz4/lz4hc.c \

274
src/static_libs/rg_etc/etc2_encoder.c Normal file
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@ -0,0 +1,274 @@
/*
Copyright (C) 2014 Jean-Philippe ANDRE
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <Eina.h>
#include "rg_etc1.h"
// For alpha support
static const int kAlphaModifiers[16][8] = {
{ -3, -6, -9, -15, 2, 5, 8, 14},
{ -3, -7, -10, -13, 2, 6, 9, 12},
{ -2, -5, -8, -13, 1, 4, 7, 12},
{ -2, -4, -6, -13, 1, 3, 5, 12},
{ -3, -6, -8, -12, 2, 5, 7, 11},
{ -3, -7, -9, -11, 2, 6, 8, 10},
{ -4, -7, -8, -11, 3, 6, 7, 10},
{ -3, -5, -8, -11, 2, 4, 7, 10},
{ -2, -6, -8, -10, 1, 5, 7, 9},
{ -2, -5, -8, -10, 1, 4, 7, 9},
{ -2, -4, -8, -10, 1, 3, 7, 9},
{ -2, -5, -7, -10, 1, 4, 6, 9},
{ -3, -4, -7, -10, 2, 3, 6, 9},
{ -1, -2, -3, -10, 0, 1, 2, 9},
{ -4, -6, -8, -9, 3, 5, 7, 8},
{ -3, -5, -7, -9, 2, 4, 6, 8}
};
// Damn OpenGL people, why don't you just pack data as on a CPU???
static const int kBlockWalk[16] = {
0, 4, 8, 12,
1, 5, 9, 13,
2, 6, 10, 14,
3, 7, 11, 15
};
// Use with static constants so the compiler can optimize everything
#define BITS(byteval, lowbit, highbit) \
(((byteval) >> (lowbit)) & ((1 << ((highbit) - (lowbit) + 1)) - 1))
#define BIT(byteval, bit) \
(((byteval) >> (bit)) & 0x1)
// Clamps only if value is > 255
#define CLAMPDOWN(a) ({ int _z = (a); ((_z <= 255) ? _z : 255); })
// Clamps only if value is < 0
#define CLAMPUP(a) ({ int _z = (a); ((_z >= 0) ? _z : 0); })
// Real clamp
#define CLAMP(a) ({ int _b = (a); (((_b) >= 0) ? (((_b) < 256) ? (_b) : 255) : 0); })
// Simple min
#define MIN(a,b) ({ int _z = (a), _y = (b); ((_z <= _y) ? _z : _y); })
// Simple abs
#define ABS(a) ({ int _a = (a); ((_a >= 0) ? _a : (-_a)); })
#ifndef WORDS_BIGENDIAN
/* x86 */
#define A_VAL(p) (((uint8_t *)(p))[3])
#define R_VAL(p) (((uint8_t *)(p))[2])
#define G_VAL(p) (((uint8_t *)(p))[1])
#define B_VAL(p) (((uint8_t *)(p))[0])
#else
/* ppc */
#define A_VAL(p) (((uint8_t *)(p))[0])
#define R_VAL(p) (((uint8_t *)(p))[1])
#define G_VAL(p) (((uint8_t *)(p))[2])
#define B_VAL(p) (((uint8_t *)(p))[3])
#endif
#ifndef DBG
# define DBG(fmt, ...) fprintf(stderr, fmt "\n", ## __VA_ARGS__)
#endif
/** Pack alpha block given a modifier table and a multiplier
* @returns Squared error
*/
static int
_etc2_alpha_block_pack(uint8_t *etc2_alpha,
const int base_codeword,
const int multiplier,
const int modifierIdx,
const uint32_t *bgra,
const Eina_Bool write)
{
const int *alphaModifiers = kAlphaModifiers[modifierIdx];
uint8_t alphaIndexes[16];
int errAcc2 = 0;
// Header
if (write)
{
etc2_alpha[0] = base_codeword & 0xFF;
etc2_alpha[1] = ((multiplier << 4) & 0xF0) | (modifierIdx & 0x0F);
}
// Compute alphas now
for (int i = 0; i < 16; i++)
{
const int realA = A_VAL(bgra + kBlockWalk[i]);
int minErr = INT_MAX, idx = 0;
// Brute force -- find modifier index
for (int k = 0; (k < 8) && minErr; k++)
{
int tryA = CLAMP(base_codeword + alphaModifiers[k] * multiplier);
int err = ABS(realA - tryA);
if (err < minErr)
{
minErr = err;
idx = k;
if (!minErr) break;
}
}
alphaIndexes[i] = idx;
// Keep some stats
errAcc2 += minErr * minErr;
}
if (write)
for (int k = 0; k < 2; k++)
{
etc2_alpha[2 + 3 * k] = alphaIndexes[0 + 8 * k] << 5; // A
etc2_alpha[2 + 3 * k] |= alphaIndexes[1 + 8 * k] << 2; // B
etc2_alpha[2 + 3 * k] |= (alphaIndexes[2 + 8 * k] >> 1) & 0x3; // C01
etc2_alpha[3 + 3 * k] = (alphaIndexes[2 + 8 * k] & 0x1) << 7; // C2
etc2_alpha[3 + 3 * k] |= alphaIndexes[3 + 8 * k] << 4; // D
etc2_alpha[3 + 3 * k] |= alphaIndexes[4 + 8 * k] << 1; // E
etc2_alpha[3 + 3 * k] |= (alphaIndexes[5 + 8 * k] >> 2) & 0x1; // F0
etc2_alpha[4 + 3 * k] = (alphaIndexes[5 + 8 * k] & 0x3) << 6; // F12
etc2_alpha[4 + 3 * k] |= alphaIndexes[6 + 8 * k] << 3; // G
etc2_alpha[4 + 3 * k] |= alphaIndexes[7 + 8 * k]; // H
}
return errAcc2;
}
static int
_etc2_alpha_encode(uint8_t *etc2_alpha, const uint32_t *bgra,
rg_etc1_pack_params *params EINA_UNUSED)
{
int alphas[16], avg = 0, diff = 0, maxDiff = INT_MAX, minErr = INT_MAX;
int base_codeword;
int multiplier, bestMult = 0;
int modifierIdx, bestIdx = 0;
int err, base_range, base_step = 1, max_error = 0;
// Try to select the best alpha value (avg)
for (int i = 0; i < 16; i++)
{
alphas[i] = A_VAL(bgra + kBlockWalk[i]);
avg += alphas[i];
}
avg /= 16;
for (int i = 0; i < 16; i++)
{
int thisDiff = ABS(alphas[i] - avg);
maxDiff = MIN(thisDiff, maxDiff);
diff += thisDiff;
}
base_codeword = alphas[0];
if (!diff)
{
// All same alphas
etc2_alpha[0] = base_codeword;
memset(etc2_alpha + 1, 0, 7);
return 0;
}
// Bruteforce -- try all tables and all multipliers, oh my god this will be slow.
switch (params->m_quality)
{
// The follow parameters are completely arbitrary.
// Need some real testing.
case rg_etc1_high_quality:
base_range = 15;
base_step = 0;
max_error = 0;
break;
case rg_etc1_medium_quality:
base_range = 6;
base_step = 2;
max_error = 2 * 2 * 16; // 42dB
break;
case rg_etc1_low_quality:
base_range = 0;
max_error = 5 * 5 * 16; // 34dB
break;
}
// for loop avg, avg-1, avg+1, avg-2, avg+2, ...
for (int step = 0; step < base_range; step += base_step)
for (base_codeword = avg - step; base_codeword <= avg + step; base_codeword += 2 * step)
{
for (modifierIdx = 0; modifierIdx < 16; modifierIdx++)
for (multiplier = 0; multiplier < 16; multiplier++)
{
if ((ABS(multiplier * kAlphaModifiers[modifierIdx][3])) < maxDiff)
continue;
err = _etc2_alpha_block_pack(etc2_alpha, base_codeword,
multiplier, modifierIdx, bgra, EINA_FALSE);
if (err < minErr)
{
minErr = err;
bestMult = multiplier;
bestIdx = modifierIdx;
if (err < max_error)
goto pack_now;
}
}
if (step <= 0) break;
}
pack_now:
err = _etc2_alpha_block_pack(etc2_alpha, base_codeword,
bestMult, bestIdx, bgra, EINA_TRUE);
return err;
}
unsigned int
etc2_rgba8_block_pack(unsigned char *etc2, const unsigned int *bgra,
rg_etc1_pack_params *params)
{
unsigned int error;
// FIXME/TODO: For now, encode use rg_etc1 only!
error = rg_etc1_pack_block(etc2 + 8, bgra, params);
error += _etc2_alpha_encode(etc2, bgra, params);
return error;
}
unsigned int
etc2_rgb8_block_pack(unsigned char *etc2, const unsigned int *bgra,
rg_etc1_pack_params *params)
{
unsigned int error;
// FIXME/TODO: For now, encode use rg_etc1 only!
error = rg_etc1_pack_block(etc2, bgra, params);
return error;
}

6
src/static_libs/rg_etc/rg_etc1.h
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@ -37,6 +37,12 @@ void rg_etc1_pack_block_init();
// pack_etc1_block() does not currently support "perceptual" colorspace metrics - it primarily optimizes for RGB RMSE.
unsigned int rg_etc1_pack_block(void* pETC1_block, const unsigned int* pSrc_pixels_BGRA, rg_etc1_pack_params *pack_params);
// Pack a 4x4 block of 32bpp BGRA pixels to a 16-byte RGBA8_ETC2_EAC block (supports alpha).
unsigned int etc2_rgba8_block_pack(unsigned char *etc2, const unsigned int *bgra, rg_etc1_pack_params *params);
// Pack a 4x4 block of 32bpp BGRA pixels to a 8-byte RGB8_ETC2 block (opaque).
unsigned int etc2_rgb8_block_pack(unsigned char *etc2, const unsigned int *bgra, rg_etc1_pack_params *params);
// ETC2 support: RGB8_ETC2
void rg_etc2_rgb8_decode_block(const unsigned char *etc_block, unsigned int *bgra);