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-// Copyright 2009 Google Inc.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-#include <ETC1/etc1.h>
-
-#include <string.h>
-
-/* From http://www.khronos.org/registry/gles/extensions/OES/OES_compressed_ETC1_RGB8_texture.txt
-
- The number of bits that represent a 4x4 texel block is 64 bits if
- <internalformat> is given by ETC1_RGB8_OES.
-
- The data for a block is a number of bytes,
-
- {q0, q1, q2, q3, q4, q5, q6, q7}
-
- where byte q0 is located at the lowest memory address and q7 at
- the highest. The 64 bits specifying the block is then represented
- by the following 64 bit integer:
-
- int64bit = 256*(256*(256*(256*(256*(256*(256*q0+q1)+q2)+q3)+q4)+q5)+q6)+q7;
-
- ETC1_RGB8_OES:
-
- a) bit layout in bits 63 through 32 if diffbit = 0
-
- 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 48
- -----------------------------------------------
- | base col1 | base col2 | base col1 | base col2 |
- | R1 (4bits)| R2 (4bits)| G1 (4bits)| G2 (4bits)|
- -----------------------------------------------
-
- 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32
- ---------------------------------------------------
- | base col1 | base col2 | table | table |diff|flip|
- | B1 (4bits)| B2 (4bits)| cw 1 | cw 2 |bit |bit |
- ---------------------------------------------------
-
-
- b) bit layout in bits 63 through 32 if diffbit = 1
-
- 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 48
- -----------------------------------------------
- | base col1 | dcol 2 | base col1 | dcol 2 |
- | R1' (5 bits) | dR2 | G1' (5 bits) | dG2 |
- -----------------------------------------------
-
- 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32
- ---------------------------------------------------
- | base col 1 | dcol 2 | table | table |diff|flip|
- | B1' (5 bits) | dB2 | cw 1 | cw 2 |bit |bit |
- ---------------------------------------------------
-
-
- c) bit layout in bits 31 through 0 (in both cases)
-
- 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
- -----------------------------------------------
- | most significant pixel index bits |
- | p| o| n| m| l| k| j| i| h| g| f| e| d| c| b| a|
- -----------------------------------------------
-
- 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
- --------------------------------------------------
- | least significant pixel index bits |
- | p| o| n| m| l| k| j| i| h| g| f| e| d| c | b | a |
- --------------------------------------------------
-
-
- Add table 3.17.2: Intensity modifier sets for ETC1 compressed textures:
-
- table codeword modifier table
- ------------------ ----------------------
- 0 -8 -2 2 8
- 1 -17 -5 5 17
- 2 -29 -9 9 29
- 3 -42 -13 13 42
- 4 -60 -18 18 60
- 5 -80 -24 24 80
- 6 -106 -33 33 106
- 7 -183 -47 47 183
-
-
- Add table 3.17.3 Mapping from pixel index values to modifier values for
- ETC1 compressed textures:
-
- pixel index value
- ---------------
- msb lsb resulting modifier value
- ----- ----- -------------------------
- 1 1 -b (large negative value)
- 1 0 -a (small negative value)
- 0 0 a (small positive value)
- 0 1 b (large positive value)
-
-
- */
-
-static const int kModifierTable[] = {
-/* 0 */2, 8, -2, -8,
-/* 1 */5, 17, -5, -17,
-/* 2 */9, 29, -9, -29,
-/* 3 */13, 42, -13, -42,
-/* 4 */18, 60, -18, -60,
-/* 5 */24, 80, -24, -80,
-/* 6 */33, 106, -33, -106,
-/* 7 */47, 183, -47, -183 };
-
-static const int kLookup[8] = { 0, 1, 2, 3, -4, -3, -2, -1 };
-
-static inline etc1_byte clamp(int x) {
- return (etc1_byte) (x >= 0 ? (x < 255 ? x : 255) : 0);
-}
-
-static
-inline int convert4To8(int b) {
- int c = b & 0xf;
- return (c << 4) | c;
-}
-
-static
-inline int convert5To8(int b) {
- int c = b & 0x1f;
- return (c << 3) | (c >> 2);
-}
-
-static
-inline int convert6To8(int b) {
- int c = b & 0x3f;
- return (c << 2) | (c >> 4);
-}
-
-static
-inline int divideBy255(int d) {
- return (d + 128 + (d >> 8)) >> 8;
-}
-
-static
-inline int convert8To4(int b) {
- int c = b & 0xff;
- return divideBy255(c * 15);
-}
-
-static
-inline int convert8To5(int b) {
- int c = b & 0xff;
- return divideBy255(c * 31);
-}
-
-static
-inline int convertDiff(int base, int diff) {
- return convert5To8((0x1f & base) + kLookup[0x7 & diff]);
-}
-
-static
-void decode_subblock(etc1_byte* pOut, int r, int g, int b, const int* table,
- etc1_uint32 low, bool second, bool flipped) {
- int baseX = 0;
- int baseY = 0;
- if (second) {
- if (flipped) {
- baseY = 2;
- } else {
- baseX = 2;
- }
- }
- for (int i = 0; i < 8; i++) {
- int x, y;
- if (flipped) {
- x = baseX + (i >> 1);
- y = baseY + (i & 1);
- } else {
- x = baseX + (i >> 2);
- y = baseY + (i & 3);
- }
- int k = y + (x * 4);
- int offset = ((low >> k) & 1) | ((low >> (k + 15)) & 2);
- int delta = table[offset];
- etc1_byte* q = pOut + 3 * (x + 4 * y);
- *q++ = clamp(r + delta);
- *q++ = clamp(g + delta);
- *q++ = clamp(b + delta);
- }
-}
-
-// Input is an ETC1 compressed version of the data.
-// Output is a 4 x 4 square of 3-byte pixels in form R, G, B
-
-void etc1_decode_block(const etc1_byte* pIn, etc1_byte* pOut) {
- etc1_uint32 high = (pIn[0] << 24) | (pIn[1] << 16) | (pIn[2] << 8) | pIn[3];
- etc1_uint32 low = (pIn[4] << 24) | (pIn[5] << 16) | (pIn[6] << 8) | pIn[7];
- int r1, r2, g1, g2, b1, b2;
- if (high & 2) {
- // differential
- int rBase = high >> 27;
- int gBase = high >> 19;
- int bBase = high >> 11;
- r1 = convert5To8(rBase);
- r2 = convertDiff(rBase, high >> 24);
- g1 = convert5To8(gBase);
- g2 = convertDiff(gBase, high >> 16);
- b1 = convert5To8(bBase);
- b2 = convertDiff(bBase, high >> 8);
- } else {
- // not differential
- r1 = convert4To8(high >> 28);
- r2 = convert4To8(high >> 24);
- g1 = convert4To8(high >> 20);
- g2 = convert4To8(high >> 16);
- b1 = convert4To8(high >> 12);
- b2 = convert4To8(high >> 8);
- }
- int tableIndexA = 7 & (high >> 5);
- int tableIndexB = 7 & (high >> 2);
- const int* tableA = kModifierTable + tableIndexA * 4;
- const int* tableB = kModifierTable + tableIndexB * 4;
- bool flipped = (high & 1) != 0;
- decode_subblock(pOut, r1, g1, b1, tableA, low, false, flipped);
- decode_subblock(pOut, r2, g2, b2, tableB, low, true, flipped);
-}
-
-typedef struct {
- etc1_uint32 high;
- etc1_uint32 low;
- etc1_uint32 score; // Lower is more accurate
-} etc_compressed;
-
-static
-inline void take_best(etc_compressed* a, const etc_compressed* b) {
- if (a->score > b->score) {
- *a = *b;
- }
-}
-
-static
-void etc_average_colors_subblock(const etc1_byte* pIn, etc1_uint32 inMask,
- etc1_byte* pColors, bool flipped, bool second) {
- int r = 0;
- int g = 0;
- int b = 0;
-
- if (flipped) {
- int by = 0;
- if (second) {
- by = 2;
- }
- for (int y = 0; y < 2; y++) {
- int yy = by + y;
- for (int x = 0; x < 4; x++) {
- int i = x + 4 * yy;
- if (inMask & (1 << i)) {
- const etc1_byte* p = pIn + i * 3;
- r += *(p++);
- g += *(p++);
- b += *(p++);
- }
- }
- }
- } else {
- int bx = 0;
- if (second) {
- bx = 2;
- }
- for (int y = 0; y < 4; y++) {
- for (int x = 0; x < 2; x++) {
- int xx = bx + x;
- int i = xx + 4 * y;
- if (inMask & (1 << i)) {
- const etc1_byte* p = pIn + i * 3;
- r += *(p++);
- g += *(p++);
- b += *(p++);
- }
- }
- }
- }
- pColors[0] = (etc1_byte)((r + 4) >> 3);
- pColors[1] = (etc1_byte)((g + 4) >> 3);
- pColors[2] = (etc1_byte)((b + 4) >> 3);
-}
-
-static
-inline int square(int x) {
- return x * x;
-}
-
-static etc1_uint32 chooseModifier(const etc1_byte* pBaseColors,
- const etc1_byte* pIn, etc1_uint32 *pLow, int bitIndex,
- const int* pModifierTable) {
- etc1_uint32 bestScore = ~0;
- int bestIndex = 0;
- int pixelR = pIn[0];
- int pixelG = pIn[1];
- int pixelB = pIn[2];
- int r = pBaseColors[0];
- int g = pBaseColors[1];
- int b = pBaseColors[2];
- for (int i = 0; i < 4; i++) {
- int modifier = pModifierTable[i];
- int decodedG = clamp(g + modifier);
- etc1_uint32 score = (etc1_uint32) (6 * square(decodedG - pixelG));
- if (score >= bestScore) {
- continue;
- }
- int decodedR = clamp(r + modifier);
- score += (etc1_uint32) (3 * square(decodedR - pixelR));
- if (score >= bestScore) {
- continue;
- }
- int decodedB = clamp(b + modifier);
- score += (etc1_uint32) square(decodedB - pixelB);
- if (score < bestScore) {
- bestScore = score;
- bestIndex = i;
- }
- }
- etc1_uint32 lowMask = (((bestIndex >> 1) << 16) | (bestIndex & 1))
- << bitIndex;
- *pLow |= lowMask;
- return bestScore;
-}
-
-static
-void etc_encode_subblock_helper(const etc1_byte* pIn, etc1_uint32 inMask,
- etc_compressed* pCompressed, bool flipped, bool second,
- const etc1_byte* pBaseColors, const int* pModifierTable) {
- int score = pCompressed->score;
- if (flipped) {
- int by = 0;
- if (second) {
- by = 2;
- }
- for (int y = 0; y < 2; y++) {
- int yy = by + y;
- for (int x = 0; x < 4; x++) {
- int i = x + 4 * yy;
- if (inMask & (1 << i)) {
- score += chooseModifier(pBaseColors, pIn + i * 3,
- &pCompressed->low, yy + x * 4, pModifierTable);
- }
- }
- }
- } else {
- int bx = 0;
- if (second) {
- bx = 2;
- }
- for (int y = 0; y < 4; y++) {
- for (int x = 0; x < 2; x++) {
- int xx = bx + x;
- int i = xx + 4 * y;
- if (inMask & (1 << i)) {
- score += chooseModifier(pBaseColors, pIn + i * 3,
- &pCompressed->low, y + xx * 4, pModifierTable);
- }
- }
- }
- }
- pCompressed->score = score;
-}
-
-static bool inRange4bitSigned(int color) {
- return color >= -4 && color <= 3;
-}
-
-static void etc_encodeBaseColors(etc1_byte* pBaseColors,
- const etc1_byte* pColors, etc_compressed* pCompressed) {
- int r1, g1, b1, r2, g2, b2; // 8 bit base colors for sub-blocks
- bool differential;
- {
- int r51 = convert8To5(pColors[0]);
- int g51 = convert8To5(pColors[1]);
- int b51 = convert8To5(pColors[2]);
- int r52 = convert8To5(pColors[3]);
- int g52 = convert8To5(pColors[4]);
- int b52 = convert8To5(pColors[5]);
-
- r1 = convert5To8(r51);
- g1 = convert5To8(g51);
- b1 = convert5To8(b51);
-
- int dr = r52 - r51;
- int dg = g52 - g51;
- int db = b52 - b51;
-
- differential = inRange4bitSigned(dr) && inRange4bitSigned(dg)
- && inRange4bitSigned(db);
- if (differential) {
- r2 = convert5To8(r51 + dr);
- g2 = convert5To8(g51 + dg);
- b2 = convert5To8(b51 + db);
- pCompressed->high |= (r51 << 27) | ((7 & dr) << 24) | (g51 << 19)
- | ((7 & dg) << 16) | (b51 << 11) | ((7 & db) << 8) | 2;
- }
- }
-
- if (!differential) {
- int r41 = convert8To4(pColors[0]);
- int g41 = convert8To4(pColors[1]);
- int b41 = convert8To4(pColors[2]);
- int r42 = convert8To4(pColors[3]);
- int g42 = convert8To4(pColors[4]);
- int b42 = convert8To4(pColors[5]);
- r1 = convert4To8(r41);
- g1 = convert4To8(g41);
- b1 = convert4To8(b41);
- r2 = convert4To8(r42);
- g2 = convert4To8(g42);
- b2 = convert4To8(b42);
- pCompressed->high |= (r41 << 28) | (r42 << 24) | (g41 << 20) | (g42
- << 16) | (b41 << 12) | (b42 << 8);
- }
- pBaseColors[0] = r1;
- pBaseColors[1] = g1;
- pBaseColors[2] = b1;
- pBaseColors[3] = r2;
- pBaseColors[4] = g2;
- pBaseColors[5] = b2;
-}
-
-static
-void etc_encode_block_helper(const etc1_byte* pIn, etc1_uint32 inMask,
- const etc1_byte* pColors, etc_compressed* pCompressed, bool flipped) {
- pCompressed->score = ~0;
- pCompressed->high = (flipped ? 1 : 0);
- pCompressed->low = 0;
-
- etc1_byte pBaseColors[6];
-
- etc_encodeBaseColors(pBaseColors, pColors, pCompressed);
-
- int originalHigh = pCompressed->high;
-
- const int* pModifierTable = kModifierTable;
- for (int i = 0; i < 8; i++, pModifierTable += 4) {
- etc_compressed temp;
- temp.score = 0;
- temp.high = originalHigh | (i << 5);
- temp.low = 0;
- etc_encode_subblock_helper(pIn, inMask, &temp, flipped, false,
- pBaseColors, pModifierTable);
- take_best(pCompressed, &temp);
- }
- pModifierTable = kModifierTable;
- etc_compressed firstHalf = *pCompressed;
- for (int i = 0; i < 8; i++, pModifierTable += 4) {
- etc_compressed temp;
- temp.score = firstHalf.score;
- temp.high = firstHalf.high | (i << 2);
- temp.low = firstHalf.low;
- etc_encode_subblock_helper(pIn, inMask, &temp, flipped, true,
- pBaseColors + 3, pModifierTable);
- if (i == 0) {
- *pCompressed = temp;
- } else {
- take_best(pCompressed, &temp);
- }
- }
-}
-
-static void writeBigEndian(etc1_byte* pOut, etc1_uint32 d) {
- pOut[0] = (etc1_byte)(d >> 24);
- pOut[1] = (etc1_byte)(d >> 16);
- pOut[2] = (etc1_byte)(d >> 8);
- pOut[3] = (etc1_byte) d;
-}
-
-// Input is a 4 x 4 square of 3-byte pixels in form R, G, B
-// inmask is a 16-bit mask where bit (1 << (x + y * 4)) tells whether the corresponding (x,y)
-// pixel is valid or not. Invalid pixel color values are ignored when compressing.
-// Output is an ETC1 compressed version of the data.
-
-void etc1_encode_block(const etc1_byte* pIn, etc1_uint32 inMask,
- etc1_byte* pOut) {
- etc1_byte colors[6];
- etc1_byte flippedColors[6];
- etc_average_colors_subblock(pIn, inMask, colors, false, false);
- etc_average_colors_subblock(pIn, inMask, colors + 3, false, true);
- etc_average_colors_subblock(pIn, inMask, flippedColors, true, false);
- etc_average_colors_subblock(pIn, inMask, flippedColors + 3, true, true);
-
- etc_compressed a, b;
- etc_encode_block_helper(pIn, inMask, colors, &a, false);
- etc_encode_block_helper(pIn, inMask, flippedColors, &b, true);
- take_best(&a, &b);
- writeBigEndian(pOut, a.high);
- writeBigEndian(pOut + 4, a.low);
-}
-
-// Return the size of the encoded image data (does not include size of PKM header).
-
-etc1_uint32 etc1_get_encoded_data_size(etc1_uint32 width, etc1_uint32 height) {
- return (((width + 3) & ~3) * ((height + 3) & ~3)) >> 1;
-}
-
-// Encode an entire image.
-// pIn - pointer to the image data. Formatted such that the Red component of
-// pixel (x,y) is at pIn + pixelSize * x + stride * y + redOffset;
-// pOut - pointer to encoded data. Must be large enough to store entire encoded image.
-
-int etc1_encode_image(const etc1_byte* pIn, etc1_uint32 width, etc1_uint32 height,
- etc1_uint32 pixelSize, etc1_uint32 stride, etc1_byte* pOut) {
- if (pixelSize < 2 || pixelSize > 3) {
- return -1;
- }
- static const unsigned short kYMask[] = { 0x0, 0xf, 0xff, 0xfff, 0xffff };
- static const unsigned short kXMask[] = { 0x0, 0x1111, 0x3333, 0x7777,
- 0xffff };
- etc1_byte block[ETC1_DECODED_BLOCK_SIZE];
- etc1_byte encoded[ETC1_ENCODED_BLOCK_SIZE];
-
- etc1_uint32 encodedWidth = (width + 3) & ~3;
- etc1_uint32 encodedHeight = (height + 3) & ~3;
-
- for (etc1_uint32 y = 0; y < encodedHeight; y += 4) {
- etc1_uint32 yEnd = height - y;
- if (yEnd > 4) {
- yEnd = 4;
- }
- int ymask = kYMask[yEnd];
- for (etc1_uint32 x = 0; x < encodedWidth; x += 4) {
- etc1_uint32 xEnd = width - x;
- if (xEnd > 4) {
- xEnd = 4;
- }
- int mask = ymask & kXMask[xEnd];
- for (etc1_uint32 cy = 0; cy < yEnd; cy++) {
- etc1_byte* q = block + (cy * 4) * 3;
- const etc1_byte* p = pIn + pixelSize * x + stride * (y + cy);
- if (pixelSize == 3) {
- memcpy(q, p, xEnd * 3);
- } else {
- for (etc1_uint32 cx = 0; cx < xEnd; cx++) {
- int pixel = (p[1] << 8) | p[0];
- *q++ = convert5To8(pixel >> 11);
- *q++ = convert6To8(pixel >> 5);
- *q++ = convert5To8(pixel);
- p += pixelSize;
- }
- }
- }
- etc1_encode_block(block, mask, encoded);
- memcpy(pOut, encoded, sizeof(encoded));
- pOut += sizeof(encoded);
- }
- }
- return 0;
-}
-
-// Decode an entire image.
-// pIn - pointer to encoded data.
-// pOut - pointer to the image data. Will be written such that the Red component of
-// pixel (x,y) is at pIn + pixelSize * x + stride * y + redOffset. Must be
-// large enough to store entire image.
-
-
-int etc1_decode_image(const etc1_byte* pIn, etc1_byte* pOut,
- etc1_uint32 width, etc1_uint32 height,
- etc1_uint32 pixelSize, etc1_uint32 stride) {
- if (pixelSize < 2 || pixelSize > 3) {
- return -1;
- }
- etc1_byte block[ETC1_DECODED_BLOCK_SIZE];
-
- etc1_uint32 encodedWidth = (width + 3) & ~3;
- etc1_uint32 encodedHeight = (height + 3) & ~3;
-
- for (etc1_uint32 y = 0; y < encodedHeight; y += 4) {
- etc1_uint32 yEnd = height - y;
- if (yEnd > 4) {
- yEnd = 4;
- }
- for (etc1_uint32 x = 0; x < encodedWidth; x += 4) {
- etc1_uint32 xEnd = width - x;
- if (xEnd > 4) {
- xEnd = 4;
- }
- etc1_decode_block(pIn, block);
- pIn += ETC1_ENCODED_BLOCK_SIZE;
- for (etc1_uint32 cy = 0; cy < yEnd; cy++) {
- const etc1_byte* q = block + (cy * 4) * 3;
- etc1_byte* p = pOut + pixelSize * x + stride * (y + cy);
- if (pixelSize == 3) {
- memcpy(p, q, xEnd * 3);
- } else {
- for (etc1_uint32 cx = 0; cx < xEnd; cx++) {
- etc1_byte r = *q++;
- etc1_byte g = *q++;
- etc1_byte b = *q++;
- etc1_uint32 pixel = ((r >> 3) << 11) | ((g >> 2) << 5) | (b >> 3);
- *p++ = (etc1_byte) pixel;
- *p++ = (etc1_byte) (pixel >> 8);
- }
- }
- }
- }
- }
- return 0;
-}
-
-static const char kMagic[] = { 'P', 'K', 'M', ' ', '1', '0' };
-
-static const etc1_uint32 ETC1_PKM_FORMAT_OFFSET = 6;
-static const etc1_uint32 ETC1_PKM_ENCODED_WIDTH_OFFSET = 8;
-static const etc1_uint32 ETC1_PKM_ENCODED_HEIGHT_OFFSET = 10;
-static const etc1_uint32 ETC1_PKM_WIDTH_OFFSET = 12;
-static const etc1_uint32 ETC1_PKM_HEIGHT_OFFSET = 14;
-
-static const etc1_uint32 ETC1_RGB_NO_MIPMAPS = 0;
-
-static void writeBEUint16(etc1_byte* pOut, etc1_uint32 data) {
- pOut[0] = (etc1_byte) (data >> 8);
- pOut[1] = (etc1_byte) data;
-}
-
-static etc1_uint32 readBEUint16(const etc1_byte* pIn) {
- return (pIn[0] << 8) | pIn[1];
-}
-
-// Format a PKM header
-
-void etc1_pkm_format_header(etc1_byte* pHeader, etc1_uint32 width, etc1_uint32 height) {
- memcpy(pHeader, kMagic, sizeof(kMagic));
- etc1_uint32 encodedWidth = (width + 3) & ~3;
- etc1_uint32 encodedHeight = (height + 3) & ~3;
- writeBEUint16(pHeader + ETC1_PKM_FORMAT_OFFSET, ETC1_RGB_NO_MIPMAPS);
- writeBEUint16(pHeader + ETC1_PKM_ENCODED_WIDTH_OFFSET, encodedWidth);
- writeBEUint16(pHeader + ETC1_PKM_ENCODED_HEIGHT_OFFSET, encodedHeight);
- writeBEUint16(pHeader + ETC1_PKM_WIDTH_OFFSET, width);
- writeBEUint16(pHeader + ETC1_PKM_HEIGHT_OFFSET, height);
-}
-
-// Check if a PKM header is correctly formatted.
-
-etc1_bool etc1_pkm_is_valid(const etc1_byte* pHeader) {
- if (memcmp(pHeader, kMagic, sizeof(kMagic))) {
- return false;
- }
- etc1_uint32 format = readBEUint16(pHeader + ETC1_PKM_FORMAT_OFFSET);
- etc1_uint32 encodedWidth = readBEUint16(pHeader + ETC1_PKM_ENCODED_WIDTH_OFFSET);
- etc1_uint32 encodedHeight = readBEUint16(pHeader + ETC1_PKM_ENCODED_HEIGHT_OFFSET);
- etc1_uint32 width = readBEUint16(pHeader + ETC1_PKM_WIDTH_OFFSET);
- etc1_uint32 height = readBEUint16(pHeader + ETC1_PKM_HEIGHT_OFFSET);
- return format == ETC1_RGB_NO_MIPMAPS &&
- encodedWidth >= width && encodedWidth - width < 4 &&
- encodedHeight >= height && encodedHeight - height < 4;
-}
-
-// Read the image width from a PKM header
-
-etc1_uint32 etc1_pkm_get_width(const etc1_byte* pHeader) {
- return readBEUint16(pHeader + ETC1_PKM_WIDTH_OFFSET);
-}
-
-// Read the image height from a PKM header
-
-etc1_uint32 etc1_pkm_get_height(const etc1_byte* pHeader){
- return readBEUint16(pHeader + ETC1_PKM_HEIGHT_OFFSET);
-}
generated by cgit v1.1 at 2024-05-18 13:57:57 +0000