AssetStudio/Texture2DDecoderNative/etc.cpp

444 lines
20 KiB
C++

#include "etc.h"
#include <stdint.h>
#include <string.h>
#include "color.h"
const uint_fast8_t WriteOrderTable[16] = {0, 4, 8, 12, 1, 5, 9, 13, 2, 6, 10, 14, 3, 7, 11, 15};
const uint_fast8_t WriteOrderTableRev[16] = {15, 11, 7, 3, 14, 10, 6, 2, 13, 9, 5, 1, 12, 8, 4, 0};
const uint_fast8_t Etc1ModifierTable[8][2] = {{2, 8}, {5, 17}, {9, 29}, {13, 42},
{18, 60}, {24, 80}, {33, 106}, {47, 183}};
const uint_fast8_t Etc2aModifierTable[2][8][2] = {
{{0, 8}, {0, 17}, {0, 29}, {0, 42}, {0, 60}, {0, 80}, {0, 106}, {0, 183}},
{{2, 8}, {5, 17}, {9, 29}, {13, 42}, {18, 60}, {24, 80}, {33, 106}, {47, 183}}};
const uint_fast8_t Etc1SubblockTable[2][16] = {{0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1},
{0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1}};
const uint_fast8_t Etc2DistanceTable[8] = {3, 6, 11, 16, 23, 32, 41, 64};
const int_fast8_t Etc2AlphaModTable[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}};
static inline uint_fast8_t clamp(const int n) {
return n < 0 ? 0 : n > 255 ? 255 : n;
}
static inline uint32_t applicate_color(uint_fast8_t c[3], int_fast16_t m) {
return color(clamp(c[0] + m), clamp(c[1] + m), clamp(c[2] + m), 255);
}
static inline uint32_t applicate_color_alpha(uint_fast8_t c[3], int_fast16_t m, int transparent) {
return color(clamp(c[0] + m), clamp(c[1] + m), clamp(c[2] + m), transparent ? 0 : 255);
}
static inline uint32_t applicate_color_raw(uint_fast8_t c[3]) {
return color(c[0], c[1], c[2], 255);
}
static void decode_etc1_block(const uint8_t *data, uint32_t *outbuf) {
const uint_fast8_t code[2] = {data[3] >> 5, data[3] >> 2 & 7}; // Table codewords
const uint_fast8_t *table = Etc1SubblockTable[data[3] & 1];
uint_fast8_t c[2][3];
if (data[3] & 2) {
// diff bit == 1
c[0][0] = data[0] & 0xf8;
c[0][1] = data[1] & 0xf8;
c[0][2] = data[2] & 0xf8;
c[1][0] = c[0][0] + (data[0] << 3 & 0x18) - (data[0] << 3 & 0x20);
c[1][1] = c[0][1] + (data[1] << 3 & 0x18) - (data[1] << 3 & 0x20);
c[1][2] = c[0][2] + (data[2] << 3 & 0x18) - (data[2] << 3 & 0x20);
c[0][0] |= c[0][0] >> 5;
c[0][1] |= c[0][1] >> 5;
c[0][2] |= c[0][2] >> 5;
c[1][0] |= c[1][0] >> 5;
c[1][1] |= c[1][1] >> 5;
c[1][2] |= c[1][2] >> 5;
} else {
// diff bit == 0
c[0][0] = (data[0] & 0xf0) | data[0] >> 4;
c[1][0] = (data[0] & 0x0f) | data[0] << 4;
c[0][1] = (data[1] & 0xf0) | data[1] >> 4;
c[1][1] = (data[1] & 0x0f) | data[1] << 4;
c[0][2] = (data[2] & 0xf0) | data[2] >> 4;
c[1][2] = (data[2] & 0x0f) | data[2] << 4;
}
uint_fast16_t j = data[6] << 8 | data[7]; // less significant pixel index bits
uint_fast16_t k = data[4] << 8 | data[5]; // more significant pixel index bits
for (int i = 0; i < 16; i++, j >>= 1, k >>= 1) {
uint_fast8_t s = table[i];
uint_fast8_t m = Etc1ModifierTable[code[s]][j & 1];
outbuf[WriteOrderTable[i]] = applicate_color(c[s], k & 1 ? -m : m);
}
}
static void decode_etc2_block(const uint8_t *data, uint32_t *outbuf) {
uint_fast16_t j = data[6] << 8 | data[7]; // 15 -> 0
uint_fast32_t k = data[4] << 8 | data[5]; // 31 -> 16
uint_fast8_t c[3][3] = {};
if (data[3] & 2) {
// diff bit == 1
uint_fast8_t r = data[0] & 0xf8;
int_fast16_t dr = (data[0] << 3 & 0x18) - (data[0] << 3 & 0x20);
uint_fast8_t g = data[1] & 0xf8;
int_fast16_t dg = (data[1] << 3 & 0x18) - (data[1] << 3 & 0x20);
uint_fast8_t b = data[2] & 0xf8;
int_fast16_t db = (data[2] << 3 & 0x18) - (data[2] << 3 & 0x20);
if (r + dr < 0 || r + dr > 255) {
// T
c[0][0] = (data[0] << 3 & 0xc0) | (data[0] << 4 & 0x30) | (data[0] >> 1 & 0xc) | (data[0] & 3);
c[0][1] = (data[1] & 0xf0) | data[1] >> 4;
c[0][2] = (data[1] & 0x0f) | data[1] << 4;
c[1][0] = (data[2] & 0xf0) | data[2] >> 4;
c[1][1] = (data[2] & 0x0f) | data[2] << 4;
c[1][2] = (data[3] & 0xf0) | data[3] >> 4;
const uint_fast8_t d = Etc2DistanceTable[(data[3] >> 1 & 6) | (data[3] & 1)];
uint_fast32_t color_set[4] = {applicate_color_raw(c[0]), applicate_color(c[1], d),
applicate_color_raw(c[1]), applicate_color(c[1], -d)};
k <<= 1;
for (int i = 0; i < 16; i++, j >>= 1, k >>= 1)
outbuf[WriteOrderTable[i]] = color_set[(k & 2) | (j & 1)];
} else if (g + dg < 0 || g + dg > 255) {
// H
c[0][0] = (data[0] << 1 & 0xf0) | (data[0] >> 3 & 0xf);
c[0][1] = (data[0] << 5 & 0xe0) | (data[1] & 0x10);
c[0][1] |= c[0][1] >> 4;
c[0][2] = (data[1] & 8) | (data[1] << 1 & 6) | data[2] >> 7;
c[0][2] |= c[0][2] << 4;
c[1][0] = (data[2] << 1 & 0xf0) | (data[2] >> 3 & 0xf);
c[1][1] = (data[2] << 5 & 0xe0) | (data[3] >> 3 & 0x10);
c[1][1] |= c[1][1] >> 4;
c[1][2] = (data[3] << 1 & 0xf0) | (data[3] >> 3 & 0xf);
uint_fast8_t d = (data[3] & 4) | (data[3] << 1 & 2);
if (c[0][0] > c[1][0] ||
(c[0][0] == c[1][0] && (c[0][1] > c[1][1] || (c[0][1] == c[1][1] && c[0][2] >= c[1][2]))))
++d;
d = Etc2DistanceTable[d];
uint_fast32_t color_set[4] = {applicate_color(c[0], d), applicate_color(c[0], -d), applicate_color(c[1], d),
applicate_color(c[1], -d)};
k <<= 1;
for (int i = 0; i < 16; i++, j >>= 1, k >>= 1)
outbuf[WriteOrderTable[i]] = color_set[(k & 2) | (j & 1)];
} else if (b + db < 0 || b + db > 255) {
// planar
c[0][0] = (data[0] << 1 & 0xfc) | (data[0] >> 5 & 3);
c[0][1] = (data[0] << 7 & 0x80) | (data[1] & 0x7e) | (data[0] & 1);
c[0][2] = (data[1] << 7 & 0x80) | (data[2] << 2 & 0x60) | (data[2] << 3 & 0x18) | (data[3] >> 5 & 4);
c[0][2] |= c[0][2] >> 6;
c[1][0] = (data[3] << 1 & 0xf8) | (data[3] << 2 & 4) | (data[3] >> 5 & 3);
c[1][1] = (data[4] & 0xfe) | data[4] >> 7;
c[1][2] = (data[4] << 7 & 0x80) | (data[5] >> 1 & 0x7c);
c[1][2] |= c[1][2] >> 6;
c[2][0] = (data[5] << 5 & 0xe0) | (data[6] >> 3 & 0x1c) | (data[5] >> 1 & 3);
c[2][1] = (data[6] << 3 & 0xf8) | (data[7] >> 5 & 0x6) | (data[6] >> 4 & 1);
c[2][2] = data[7] << 2 | (data[7] >> 4 & 3);
for (int y = 0, i = 0; y < 4; y++) {
for (int x = 0; x < 4; x++, i++) {
uint8_t r = clamp((x * (c[1][0] - c[0][0]) + y * (c[2][0] - c[0][0]) + 4 * c[0][0] + 2) >> 2);
uint8_t g = clamp((x * (c[1][1] - c[0][1]) + y * (c[2][1] - c[0][1]) + 4 * c[0][1] + 2) >> 2);
uint8_t b = clamp((x * (c[1][2] - c[0][2]) + y * (c[2][2] - c[0][2]) + 4 * c[0][2] + 2) >> 2);
outbuf[i] = color(r, g, b, 255);
}
}
} else {
// differential
const uint_fast8_t code[2] = {data[3] >> 5, data[3] >> 2 & 7};
const uint_fast8_t *table = Etc1SubblockTable[data[3] & 1];
c[0][0] = r | r >> 5;
c[0][1] = g | g >> 5;
c[0][2] = b | b >> 5;
c[1][0] = r + dr;
c[1][1] = g + dg;
c[1][2] = b + db;
c[1][0] |= c[1][0] >> 5;
c[1][1] |= c[1][1] >> 5;
c[1][2] |= c[1][2] >> 5;
for (int i = 0; i < 16; i++, j >>= 1, k >>= 1) {
uint_fast8_t s = table[i];
uint_fast8_t m = Etc1ModifierTable[code[s]][j & 1];
outbuf[WriteOrderTable[i]] = applicate_color(c[s], k & 1 ? -m : m);
}
}
} else {
// individual (diff bit == 0)
const uint_fast8_t code[2] = {data[3] >> 5, data[3] >> 2 & 7};
const uint_fast8_t *table = Etc1SubblockTable[data[3] & 1];
c[0][0] = (data[0] & 0xf0) | data[0] >> 4;
c[1][0] = (data[0] & 0x0f) | data[0] << 4;
c[0][1] = (data[1] & 0xf0) | data[1] >> 4;
c[1][1] = (data[1] & 0x0f) | data[1] << 4;
c[0][2] = (data[2] & 0xf0) | data[2] >> 4;
c[1][2] = (data[2] & 0x0f) | data[2] << 4;
for (int i = 0; i < 16; i++, j >>= 1, k >>= 1) {
uint_fast8_t s = table[i];
uint_fast8_t m = Etc1ModifierTable[code[s]][j & 1];
outbuf[WriteOrderTable[i]] = applicate_color(c[s], k & 1 ? -m : m);
}
}
}
static void decode_etc2a1_block(const uint8_t *data, uint32_t *outbuf) {
uint_fast16_t j = data[6] << 8 | data[7]; // 15 -> 0
uint_fast32_t k = data[4] << 8 | data[5]; // 31 -> 16
uint_fast8_t c[3][3] = {};
int obaq = data[3] >> 1 & 1;
// diff bit == 1
uint_fast8_t r = data[0] & 0xf8;
int_fast16_t dr = (data[0] << 3 & 0x18) - (data[0] << 3 & 0x20);
uint_fast8_t g = data[1] & 0xf8;
int_fast16_t dg = (data[1] << 3 & 0x18) - (data[1] << 3 & 0x20);
uint_fast8_t b = data[2] & 0xf8;
int_fast16_t db = (data[2] << 3 & 0x18) - (data[2] << 3 & 0x20);
if (r + dr < 0 || r + dr > 255) {
// T
c[0][0] = (data[0] << 3 & 0xc0) | (data[0] << 4 & 0x30) | (data[0] >> 1 & 0xc) | (data[0] & 3);
c[0][1] = (data[1] & 0xf0) | data[1] >> 4;
c[0][2] = (data[1] & 0x0f) | data[1] << 4;
c[1][0] = (data[2] & 0xf0) | data[2] >> 4;
c[1][1] = (data[2] & 0x0f) | data[2] << 4;
c[1][2] = (data[3] & 0xf0) | data[3] >> 4;
const uint_fast8_t d = Etc2DistanceTable[(data[3] >> 1 & 6) | (data[3] & 1)];
uint_fast32_t color_set[4] = {applicate_color_raw(c[0]), applicate_color(c[1], d), applicate_color_raw(c[1]),
applicate_color(c[1], -d)};
k <<= 1;
for (int i = 0; i < 16; i++, j >>= 1, k >>= 1) {
int index = (k & 2) | (j & 1);
outbuf[WriteOrderTable[i]] = color_set[index];
if (!obaq && index == 2)
outbuf[WriteOrderTable[i]] &= TRANSPARENT_MASK;
}
} else if (g + dg < 0 || g + dg > 255) {
// H
c[0][0] = (data[0] << 1 & 0xf0) | (data[0] >> 3 & 0xf);
c[0][1] = (data[0] << 5 & 0xe0) | (data[1] & 0x10);
c[0][1] |= c[0][1] >> 4;
c[0][2] = (data[1] & 8) | (data[1] << 1 & 6) | data[2] >> 7;
c[0][2] |= c[0][2] << 4;
c[1][0] = (data[2] << 1 & 0xf0) | (data[2] >> 3 & 0xf);
c[1][1] = (data[2] << 5 & 0xe0) | (data[3] >> 3 & 0x10);
c[1][1] |= c[1][1] >> 4;
c[1][2] = (data[3] << 1 & 0xf0) | (data[3] >> 3 & 0xf);
uint_fast8_t d = (data[3] & 4) | (data[3] << 1 & 2);
if (c[0][0] > c[1][0] ||
(c[0][0] == c[1][0] && (c[0][1] > c[1][1] || (c[0][1] == c[1][1] && c[0][2] >= c[1][2]))))
++d;
d = Etc2DistanceTable[d];
uint_fast32_t color_set[4] = {applicate_color(c[0], d), applicate_color(c[0], -d), applicate_color(c[1], d),
applicate_color(c[1], -d)};
k <<= 1;
for (int i = 0; i < 16; i++, j >>= 1, k >>= 1) {
int index = (k & 2) | (j & 1);
outbuf[WriteOrderTable[i]] = color_set[index];
if (!obaq && index == 2)
outbuf[WriteOrderTable[i]] &= TRANSPARENT_MASK;
}
} else if (b + db < 0 || b + db > 255) {
// planar
c[0][0] = (data[0] << 1 & 0xfc) | (data[0] >> 5 & 3);
c[0][1] = (data[0] << 7 & 0x80) | (data[1] & 0x7e) | (data[0] & 1);
c[0][2] = (data[1] << 7 & 0x80) | (data[2] << 2 & 0x60) | (data[2] << 3 & 0x18) | (data[3] >> 5 & 4);
c[0][2] |= c[0][2] >> 6;
c[1][0] = (data[3] << 1 & 0xf8) | (data[3] << 2 & 4) | (data[3] >> 5 & 3);
c[1][1] = (data[4] & 0xfe) | data[4] >> 7;
c[1][2] = (data[4] << 7 & 0x80) | (data[5] >> 1 & 0x7c);
c[1][2] |= c[1][2] >> 6;
c[2][0] = (data[5] << 5 & 0xe0) | (data[6] >> 3 & 0x1c) | (data[5] >> 1 & 3);
c[2][1] = (data[6] << 3 & 0xf8) | (data[7] >> 5 & 0x6) | (data[6] >> 4 & 1);
c[2][2] = data[7] << 2 | (data[7] >> 4 & 3);
for (int y = 0, i = 0; y < 4; y++) {
for (int x = 0; x < 4; x++, i++) {
uint8_t r = clamp((x * (c[1][0] - c[0][0]) + y * (c[2][0] - c[0][0]) + 4 * c[0][0] + 2) >> 2);
uint8_t g = clamp((x * (c[1][1] - c[0][1]) + y * (c[2][1] - c[0][1]) + 4 * c[0][1] + 2) >> 2);
uint8_t b = clamp((x * (c[1][2] - c[0][2]) + y * (c[2][2] - c[0][2]) + 4 * c[0][2] + 2) >> 2);
outbuf[i] = color(r, g, b, 255);
}
}
} else {
// differential
const uint_fast8_t code[2] = {data[3] >> 5, data[3] >> 2 & 7};
const uint_fast8_t *table = Etc1SubblockTable[data[3] & 1];
c[0][0] = r | r >> 5;
c[0][1] = g | g >> 5;
c[0][2] = b | b >> 5;
c[1][0] = r + dr;
c[1][1] = g + dg;
c[1][2] = b + db;
c[1][0] |= c[1][0] >> 5;
c[1][1] |= c[1][1] >> 5;
c[1][2] |= c[1][2] >> 5;
for (int i = 0; i < 16; i++, j >>= 1, k >>= 1) {
uint_fast8_t s = table[i];
uint_fast8_t m = Etc2aModifierTable[obaq][code[s]][j & 1];
outbuf[WriteOrderTable[i]] = applicate_color_alpha(c[s], k & 1 ? -m : m, !obaq && (k & 1) && !(j & 1));
}
}
}
static void decode_etc2a8_block(const uint8_t *data, uint32_t *outbuf) {
if (data[1] & 0xf0) {
// multiplier != 0
const uint_fast8_t multiplier = data[1] >> 4;
const int_fast8_t *table = Etc2AlphaModTable[data[1] & 0xf];
uint_fast64_t l = bton64(*(uint64_t*)data);
for (int i = 0; i < 16; i++, l >>= 3)
((uint8_t *)(outbuf + WriteOrderTableRev[i]))[3] = clamp(data[0] + multiplier * table[l & 7]);
} else {
// multiplier == 0 (always same as base codeword)
for (int i = 0; i < 16; i++, outbuf++)
((uint8_t *)outbuf)[3] = data[0];
}
}
static void decode_eac_block(const uint8_t *data, int color, uint32_t *outbuf) {
uint_fast8_t multiplier = data[1] >> 1 & 0x78;
if (multiplier == 0)
multiplier = 1;
const int_fast8_t *table = Etc2AlphaModTable[data[1] & 0xf];
uint_fast64_t l = bton64(*(uint64_t*)data);
for (int i = 0; i < 16; i++, l >>= 3) {
int_fast16_t val = data[0] * 8 + multiplier * table[l & 7] + 4;
((uint8_t *)(outbuf + WriteOrderTableRev[i]))[color] = val < 0 ? 0 : val >= 2048 ? 0xff : val >> 3;
}
}
static void decode_eac_signed_block(const uint8_t *data, int color, uint32_t *outbuf) {
int8_t base = (int8_t)data[0];
uint_fast8_t multiplier = data[1] >> 1 & 0x78;
if (multiplier == 0)
multiplier = 1;
const int_fast8_t *table = Etc2AlphaModTable[data[1] & 0xf];
uint_fast64_t l = bton64(*(uint64_t*)data);
for (int i = 0; i < 16; i++, l >>= 3) {
int_fast16_t val = base * 8 + multiplier * table[l & 7] + 1023;
((uint8_t *)(outbuf + WriteOrderTableRev[i]))[color] = val < 0 ? 0 : val >= 2048 ? 0xff : val >> 3;
}
}
int decode_etc1(const uint8_t *data, const long w, const long h, uint32_t *image) {
long num_blocks_x = (w + 3) / 4;
long num_blocks_y = (h + 3) / 4;
uint32_t buffer[16];
for (long by = 0; by < num_blocks_y; by++) {
for (long bx = 0; bx < num_blocks_x; bx++, data += 8) {
decode_etc1_block(data, buffer);
copy_block_buffer(bx, by, w, h, 4, 4, buffer, image);
}
}
return 1;
}
int decode_etc2(const uint8_t *data, const long w, const long h, uint32_t *image) {
long num_blocks_x = (w + 3) / 4;
long num_blocks_y = (h + 3) / 4;
uint32_t buffer[16];
for (long by = 0; by < num_blocks_y; by++) {
for (long bx = 0; bx < num_blocks_x; bx++, data += 8) {
decode_etc2_block(data, buffer);
copy_block_buffer(bx, by, w, h, 4, 4, buffer, image);
}
}
return 1;
}
int decode_etc2a1(const uint8_t *data, const long w, const long h, uint32_t *image) {
long num_blocks_x = (w + 3) / 4;
long num_blocks_y = (h + 3) / 4;
uint32_t buffer[16];
for (long by = 0; by < num_blocks_y; by++) {
for (long bx = 0; bx < num_blocks_x; bx++, data += 8) {
decode_etc2a1_block(data, buffer);
copy_block_buffer(bx, by, w, h, 4, 4, buffer, image);
}
}
return 1;
}
int decode_etc2a8(const uint8_t *data, const long w, const long h, uint32_t *image) {
long num_blocks_x = (w + 3) / 4;
long num_blocks_y = (h + 3) / 4;
uint32_t buffer[16];
for (long by = 0; by < num_blocks_y; by++) {
for (long bx = 0; bx < num_blocks_x; bx++, data += 16) {
decode_etc2_block(data + 8, buffer);
decode_etc2a8_block(data, buffer);
copy_block_buffer(bx, by, w, h, 4, 4, buffer, image);
}
}
return 1;
}
int decode_eacr(const uint8_t *data, const long w, const long h, uint32_t *image) {
long num_blocks_x = (w + 3) / 4;
long num_blocks_y = (h + 3) / 4;
uint32_t buffer[16];
uint32_t base_buffer[16];
for (int i = 0; i < 16; i++)
base_buffer[i] = color(0, 0, 0, 255);
for (long by = 0; by < num_blocks_y; by++) {
for (long bx = 0; bx < num_blocks_x; bx++, data += 8) {
memcpy(buffer, base_buffer, sizeof(buffer));
decode_eac_block(data, 2, buffer);
copy_block_buffer(bx, by, w, h, 4, 4, buffer, image);
}
}
return 1;
}
int decode_eacr_signed(const uint8_t *data, const long w, const long h, uint32_t *image) {
long num_blocks_x = (w + 3) / 4;
long num_blocks_y = (h + 3) / 4;
uint32_t buffer[16];
uint32_t base_buffer[16];
for (int i = 0; i < 16; i++)
base_buffer[i] = color(0, 0, 0, 255);
for (long by = 0; by < num_blocks_y; by++) {
for (long bx = 0; bx < num_blocks_x; bx++, data += 8) {
memcpy(buffer, base_buffer, sizeof(buffer));
decode_eac_signed_block(data, 2, buffer);
copy_block_buffer(bx, by, w, h, 4, 4, buffer, image);
}
}
return 1;
}
int decode_eacrg(const uint8_t *data, const long w, const long h, uint32_t *image) {
long num_blocks_x = (w + 3) / 4;
long num_blocks_y = (h + 3) / 4;
uint32_t buffer[16];
uint32_t base_buffer[16];
for (int i = 0; i < 16; i++)
base_buffer[i] = color(0, 0, 0, 255);
for (long by = 0; by < num_blocks_y; by++) {
for (long bx = 0; bx < num_blocks_x; bx++, data += 16) {
memcpy(buffer, base_buffer, sizeof(buffer));
decode_eac_block(data, 2, buffer);
decode_eac_block(data + 8, 1, buffer);
copy_block_buffer(bx, by, w, h, 4, 4, buffer, image);
}
}
return 1;
}
int decode_eacrg_signed(const uint8_t *data, const long w, const long h, uint32_t *image) {
long num_blocks_x = (w + 3) / 4;
long num_blocks_y = (h + 3) / 4;
uint32_t buffer[16];
uint32_t base_buffer[16];
for (int i = 0; i < 16; i++)
base_buffer[i] = color(0, 0, 0, 255);
for (long by = 0; by < num_blocks_y; by++) {
for (long bx = 0; bx < num_blocks_x; bx++, data += 16) {
memcpy(buffer, base_buffer, sizeof(buffer));
decode_eac_signed_block(data, 2, buffer);
decode_eac_signed_block(data + 8, 1, buffer);
copy_block_buffer(bx, by, w, h, 4, 4, buffer, image);
}
}
return 1;
}