16c354881b63935626a0700366937530d38b8b1e8krajcevski/* 26c354881b63935626a0700366937530d38b8b1e8krajcevski * Copyright 2014 Google Inc. 36c354881b63935626a0700366937530d38b8b1e8krajcevski * 46c354881b63935626a0700366937530d38b8b1e8krajcevski * Use of this source code is governed by a BSD-style license that can be 56c354881b63935626a0700366937530d38b8b1e8krajcevski * found in the LICENSE file. 66c354881b63935626a0700366937530d38b8b1e8krajcevski */ 76c354881b63935626a0700366937530d38b8b1e8krajcevski 86c354881b63935626a0700366937530d38b8b1e8krajcevski#include "SkTextureCompressor.h" 9d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski#include "SkTextureCompressor_Blitter.h" 106c354881b63935626a0700366937530d38b8b1e8krajcevski 11b8ccc2f6d258a8466f79fc418e9e0a55aeaf58cekrajcevski#include "SkBlitter.h" 126c354881b63935626a0700366937530d38b8b1e8krajcevski#include "SkEndian.h" 136c354881b63935626a0700366937530d38b8b1e8krajcevski 146c354881b63935626a0700366937530d38b8b1e8krajcevski// #define COMPRESS_R11_EAC_SLOW 1 156c354881b63935626a0700366937530d38b8b1e8krajcevski// #define COMPRESS_R11_EAC_FAST 1 166c354881b63935626a0700366937530d38b8b1e8krajcevski#define COMPRESS_R11_EAC_FASTEST 1 176c354881b63935626a0700366937530d38b8b1e8krajcevski 186c354881b63935626a0700366937530d38b8b1e8krajcevski// Blocks compressed into R11 EAC are represented as follows: 196c354881b63935626a0700366937530d38b8b1e8krajcevski// 0000000000000000000000000000000000000000000000000000000000000000 206c354881b63935626a0700366937530d38b8b1e8krajcevski// |base_cw|mod|mul| ----------------- indices ------------------- 216c354881b63935626a0700366937530d38b8b1e8krajcevski// 226c354881b63935626a0700366937530d38b8b1e8krajcevski// To reconstruct the value of a given pixel, we use the formula: 236c354881b63935626a0700366937530d38b8b1e8krajcevski// clamp[0, 2047](base_cw * 8 + 4 + mod_val*mul*8) 246c354881b63935626a0700366937530d38b8b1e8krajcevski// 256c354881b63935626a0700366937530d38b8b1e8krajcevski// mod_val is chosen from a palette of values based on the index of the 266c354881b63935626a0700366937530d38b8b1e8krajcevski// given pixel. The palette is chosen by the value stored in mod. 276c354881b63935626a0700366937530d38b8b1e8krajcevski// This formula returns a value between 0 and 2047, which is converted 286c354881b63935626a0700366937530d38b8b1e8krajcevski// to a float from 0 to 1 in OpenGL. 296c354881b63935626a0700366937530d38b8b1e8krajcevski// 306c354881b63935626a0700366937530d38b8b1e8krajcevski// If mul is zero, then we set mul = 1/8, so that the formula becomes 316c354881b63935626a0700366937530d38b8b1e8krajcevski// clamp[0, 2047](base_cw * 8 + 4 + mod_val) 326c354881b63935626a0700366937530d38b8b1e8krajcevski 336c354881b63935626a0700366937530d38b8b1e8krajcevskistatic const int kNumR11EACPalettes = 16; 346c354881b63935626a0700366937530d38b8b1e8krajcevskistatic const int kR11EACPaletteSize = 8; 356c354881b63935626a0700366937530d38b8b1e8krajcevskistatic const int kR11EACModifierPalettes[kNumR11EACPalettes][kR11EACPaletteSize] = { 366c354881b63935626a0700366937530d38b8b1e8krajcevski {-3, -6, -9, -15, 2, 5, 8, 14}, 376c354881b63935626a0700366937530d38b8b1e8krajcevski {-3, -7, -10, -13, 2, 6, 9, 12}, 386c354881b63935626a0700366937530d38b8b1e8krajcevski {-2, -5, -8, -13, 1, 4, 7, 12}, 396c354881b63935626a0700366937530d38b8b1e8krajcevski {-2, -4, -6, -13, 1, 3, 5, 12}, 406c354881b63935626a0700366937530d38b8b1e8krajcevski {-3, -6, -8, -12, 2, 5, 7, 11}, 416c354881b63935626a0700366937530d38b8b1e8krajcevski {-3, -7, -9, -11, 2, 6, 8, 10}, 426c354881b63935626a0700366937530d38b8b1e8krajcevski {-4, -7, -8, -11, 3, 6, 7, 10}, 436c354881b63935626a0700366937530d38b8b1e8krajcevski {-3, -5, -8, -11, 2, 4, 7, 10}, 446c354881b63935626a0700366937530d38b8b1e8krajcevski {-2, -6, -8, -10, 1, 5, 7, 9}, 456c354881b63935626a0700366937530d38b8b1e8krajcevski {-2, -5, -8, -10, 1, 4, 7, 9}, 466c354881b63935626a0700366937530d38b8b1e8krajcevski {-2, -4, -8, -10, 1, 3, 7, 9}, 476c354881b63935626a0700366937530d38b8b1e8krajcevski {-2, -5, -7, -10, 1, 4, 6, 9}, 486c354881b63935626a0700366937530d38b8b1e8krajcevski {-3, -4, -7, -10, 2, 3, 6, 9}, 496c354881b63935626a0700366937530d38b8b1e8krajcevski {-1, -2, -3, -10, 0, 1, 2, 9}, 506c354881b63935626a0700366937530d38b8b1e8krajcevski {-4, -6, -8, -9, 3, 5, 7, 8}, 516c354881b63935626a0700366937530d38b8b1e8krajcevski {-3, -5, -7, -9, 2, 4, 6, 8} 526c354881b63935626a0700366937530d38b8b1e8krajcevski}; 536c354881b63935626a0700366937530d38b8b1e8krajcevski 544ad76e35111585f4da662d54943f23792dd1e0aekrajcevski#if COMPRESS_R11_EAC_SLOW 554ad76e35111585f4da662d54943f23792dd1e0aekrajcevski 566c354881b63935626a0700366937530d38b8b1e8krajcevski// Pack the base codeword, palette, and multiplier into the 64 bits necessary 576c354881b63935626a0700366937530d38b8b1e8krajcevski// to decode it. 586c354881b63935626a0700366937530d38b8b1e8krajcevskistatic uint64_t pack_r11eac_block(uint16_t base_cw, uint16_t palette, uint16_t multiplier, 596c354881b63935626a0700366937530d38b8b1e8krajcevski uint64_t indices) { 606c354881b63935626a0700366937530d38b8b1e8krajcevski SkASSERT(palette < 16); 616c354881b63935626a0700366937530d38b8b1e8krajcevski SkASSERT(multiplier < 16); 626c354881b63935626a0700366937530d38b8b1e8krajcevski SkASSERT(indices < (static_cast<uint64_t>(1) << 48)); 636c354881b63935626a0700366937530d38b8b1e8krajcevski 646c354881b63935626a0700366937530d38b8b1e8krajcevski const uint64_t b = static_cast<uint64_t>(base_cw) << 56; 656c354881b63935626a0700366937530d38b8b1e8krajcevski const uint64_t m = static_cast<uint64_t>(multiplier) << 52; 666c354881b63935626a0700366937530d38b8b1e8krajcevski const uint64_t p = static_cast<uint64_t>(palette) << 48; 676c354881b63935626a0700366937530d38b8b1e8krajcevski return SkEndian_SwapBE64(b | m | p | indices); 686c354881b63935626a0700366937530d38b8b1e8krajcevski} 696c354881b63935626a0700366937530d38b8b1e8krajcevski 706c354881b63935626a0700366937530d38b8b1e8krajcevski// Given a base codeword, a modifier, and a multiplier, compute the proper 716c354881b63935626a0700366937530d38b8b1e8krajcevski// pixel value in the range [0, 2047]. 726c354881b63935626a0700366937530d38b8b1e8krajcevskistatic uint16_t compute_r11eac_pixel(int base_cw, int modifier, int multiplier) { 736c354881b63935626a0700366937530d38b8b1e8krajcevski int ret = (base_cw * 8 + 4) + (modifier * multiplier * 8); 746c354881b63935626a0700366937530d38b8b1e8krajcevski return (ret > 2047)? 2047 : ((ret < 0)? 0 : ret); 756c354881b63935626a0700366937530d38b8b1e8krajcevski} 766c354881b63935626a0700366937530d38b8b1e8krajcevski 776c354881b63935626a0700366937530d38b8b1e8krajcevski// Compress a block into R11 EAC format. 786c354881b63935626a0700366937530d38b8b1e8krajcevski// The compression works as follows: 796c354881b63935626a0700366937530d38b8b1e8krajcevski// 1. Find the center of the span of the block's values. Use this as the base codeword. 806c354881b63935626a0700366937530d38b8b1e8krajcevski// 2. Choose a multiplier based roughly on the size of the span of block values 816c354881b63935626a0700366937530d38b8b1e8krajcevski// 3. Iterate through each palette and choose the one with the most accurate 826c354881b63935626a0700366937530d38b8b1e8krajcevski// modifiers. 836c354881b63935626a0700366937530d38b8b1e8krajcevskistatic inline uint64_t compress_heterogeneous_r11eac_block(const uint8_t block[16]) { 846c354881b63935626a0700366937530d38b8b1e8krajcevski // Find the center of the data... 856c354881b63935626a0700366937530d38b8b1e8krajcevski uint16_t bmin = block[0]; 866c354881b63935626a0700366937530d38b8b1e8krajcevski uint16_t bmax = block[0]; 876c354881b63935626a0700366937530d38b8b1e8krajcevski for (int i = 1; i < 16; ++i) { 886c354881b63935626a0700366937530d38b8b1e8krajcevski bmin = SkTMin<uint16_t>(bmin, block[i]); 896c354881b63935626a0700366937530d38b8b1e8krajcevski bmax = SkTMax<uint16_t>(bmax, block[i]); 906c354881b63935626a0700366937530d38b8b1e8krajcevski } 916c354881b63935626a0700366937530d38b8b1e8krajcevski 926c354881b63935626a0700366937530d38b8b1e8krajcevski uint16_t center = (bmax + bmin) >> 1; 936c354881b63935626a0700366937530d38b8b1e8krajcevski SkASSERT(center <= 255); 946c354881b63935626a0700366937530d38b8b1e8krajcevski 956c354881b63935626a0700366937530d38b8b1e8krajcevski // Based on the min and max, we can guesstimate a proper multiplier 966c354881b63935626a0700366937530d38b8b1e8krajcevski // This is kind of a magic choice to start with. 976c354881b63935626a0700366937530d38b8b1e8krajcevski uint16_t multiplier = (bmax - center) / 10; 986c354881b63935626a0700366937530d38b8b1e8krajcevski 996c354881b63935626a0700366937530d38b8b1e8krajcevski // Now convert the block to 11 bits and transpose it to match 1006c354881b63935626a0700366937530d38b8b1e8krajcevski // the proper layout 1016c354881b63935626a0700366937530d38b8b1e8krajcevski uint16_t cblock[16]; 1026c354881b63935626a0700366937530d38b8b1e8krajcevski for (int i = 0; i < 4; ++i) { 1036c354881b63935626a0700366937530d38b8b1e8krajcevski for (int j = 0; j < 4; ++j) { 1046c354881b63935626a0700366937530d38b8b1e8krajcevski int srcIdx = i*4+j; 1056c354881b63935626a0700366937530d38b8b1e8krajcevski int dstIdx = j*4+i; 1066c354881b63935626a0700366937530d38b8b1e8krajcevski cblock[dstIdx] = (block[srcIdx] << 3) | (block[srcIdx] >> 5); 1076c354881b63935626a0700366937530d38b8b1e8krajcevski } 1086c354881b63935626a0700366937530d38b8b1e8krajcevski } 1096c354881b63935626a0700366937530d38b8b1e8krajcevski 1106c354881b63935626a0700366937530d38b8b1e8krajcevski // Finally, choose the proper palette and indices 1116c354881b63935626a0700366937530d38b8b1e8krajcevski uint32_t bestError = 0xFFFFFFFF; 1126c354881b63935626a0700366937530d38b8b1e8krajcevski uint64_t bestIndices = 0; 1136c354881b63935626a0700366937530d38b8b1e8krajcevski uint16_t bestPalette = 0; 1146c354881b63935626a0700366937530d38b8b1e8krajcevski for (uint16_t paletteIdx = 0; paletteIdx < kNumR11EACPalettes; ++paletteIdx) { 1156c354881b63935626a0700366937530d38b8b1e8krajcevski const int *palette = kR11EACModifierPalettes[paletteIdx]; 1166c354881b63935626a0700366937530d38b8b1e8krajcevski 1176c354881b63935626a0700366937530d38b8b1e8krajcevski // Iterate through each pixel to find the best palette index 1186c354881b63935626a0700366937530d38b8b1e8krajcevski // and update the indices with the choice. Also store the error 1196c354881b63935626a0700366937530d38b8b1e8krajcevski // for this palette to be compared against the best error... 1206c354881b63935626a0700366937530d38b8b1e8krajcevski uint32_t error = 0; 1216c354881b63935626a0700366937530d38b8b1e8krajcevski uint64_t indices = 0; 1226c354881b63935626a0700366937530d38b8b1e8krajcevski for (int pixelIdx = 0; pixelIdx < 16; ++pixelIdx) { 1236c354881b63935626a0700366937530d38b8b1e8krajcevski const uint16_t pixel = cblock[pixelIdx]; 1246c354881b63935626a0700366937530d38b8b1e8krajcevski 1256c354881b63935626a0700366937530d38b8b1e8krajcevski // Iterate through each palette value to find the best index 1266c354881b63935626a0700366937530d38b8b1e8krajcevski // for this particular pixel for this particular palette. 1276c354881b63935626a0700366937530d38b8b1e8krajcevski uint16_t bestPixelError = 1286c354881b63935626a0700366937530d38b8b1e8krajcevski abs_diff(pixel, compute_r11eac_pixel(center, palette[0], multiplier)); 1296c354881b63935626a0700366937530d38b8b1e8krajcevski int bestIndex = 0; 1306c354881b63935626a0700366937530d38b8b1e8krajcevski for (int i = 1; i < kR11EACPaletteSize; ++i) { 1316c354881b63935626a0700366937530d38b8b1e8krajcevski const uint16_t p = compute_r11eac_pixel(center, palette[i], multiplier); 1326c354881b63935626a0700366937530d38b8b1e8krajcevski const uint16_t perror = abs_diff(pixel, p); 1336c354881b63935626a0700366937530d38b8b1e8krajcevski 1346c354881b63935626a0700366937530d38b8b1e8krajcevski // Is this index better? 1356c354881b63935626a0700366937530d38b8b1e8krajcevski if (perror < bestPixelError) { 1366c354881b63935626a0700366937530d38b8b1e8krajcevski bestIndex = i; 1376c354881b63935626a0700366937530d38b8b1e8krajcevski bestPixelError = perror; 1386c354881b63935626a0700366937530d38b8b1e8krajcevski } 1396c354881b63935626a0700366937530d38b8b1e8krajcevski } 1406c354881b63935626a0700366937530d38b8b1e8krajcevski 1416c354881b63935626a0700366937530d38b8b1e8krajcevski SkASSERT(bestIndex < 8); 1426c354881b63935626a0700366937530d38b8b1e8krajcevski 1436c354881b63935626a0700366937530d38b8b1e8krajcevski error += bestPixelError; 1446c354881b63935626a0700366937530d38b8b1e8krajcevski indices <<= 3; 1456c354881b63935626a0700366937530d38b8b1e8krajcevski indices |= bestIndex; 1466c354881b63935626a0700366937530d38b8b1e8krajcevski } 1476c354881b63935626a0700366937530d38b8b1e8krajcevski 1486c354881b63935626a0700366937530d38b8b1e8krajcevski SkASSERT(indices < (static_cast<uint64_t>(1) << 48)); 1496c354881b63935626a0700366937530d38b8b1e8krajcevski 1506c354881b63935626a0700366937530d38b8b1e8krajcevski // Is this palette better? 1516c354881b63935626a0700366937530d38b8b1e8krajcevski if (error < bestError) { 1526c354881b63935626a0700366937530d38b8b1e8krajcevski bestPalette = paletteIdx; 1536c354881b63935626a0700366937530d38b8b1e8krajcevski bestIndices = indices; 1546c354881b63935626a0700366937530d38b8b1e8krajcevski bestError = error; 1556c354881b63935626a0700366937530d38b8b1e8krajcevski } 1566c354881b63935626a0700366937530d38b8b1e8krajcevski } 1576c354881b63935626a0700366937530d38b8b1e8krajcevski 1586c354881b63935626a0700366937530d38b8b1e8krajcevski // Finally, pack everything together... 1596c354881b63935626a0700366937530d38b8b1e8krajcevski return pack_r11eac_block(center, bestPalette, multiplier, bestIndices); 1606c354881b63935626a0700366937530d38b8b1e8krajcevski} 1616c354881b63935626a0700366937530d38b8b1e8krajcevski#endif // COMPRESS_R11_EAC_SLOW 1626c354881b63935626a0700366937530d38b8b1e8krajcevski 1636c354881b63935626a0700366937530d38b8b1e8krajcevski#if COMPRESS_R11_EAC_FAST 1646c354881b63935626a0700366937530d38b8b1e8krajcevski// This function takes into account that most blocks that we compress have a gradation from 1656c354881b63935626a0700366937530d38b8b1e8krajcevski// fully opaque to fully transparent. The compression scheme works by selecting the 1666c354881b63935626a0700366937530d38b8b1e8krajcevski// palette and multiplier that has the tightest fit to the 0-255 range. This is encoded 1676c354881b63935626a0700366937530d38b8b1e8krajcevski// as the block header (0x8490). The indices are then selected by considering the top 1686c354881b63935626a0700366937530d38b8b1e8krajcevski// three bits of each alpha value. For alpha masks, this reduces the dynamic range from 1696c354881b63935626a0700366937530d38b8b1e8krajcevski// 17 to 8, but the quality is still acceptable. 1706c354881b63935626a0700366937530d38b8b1e8krajcevski// 1716c354881b63935626a0700366937530d38b8b1e8krajcevski// There are a few caveats that need to be taken care of... 1726c354881b63935626a0700366937530d38b8b1e8krajcevski// 1736c354881b63935626a0700366937530d38b8b1e8krajcevski// 1. The block is read in as scanlines, so the indices are stored as: 1746c354881b63935626a0700366937530d38b8b1e8krajcevski// 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 1756c354881b63935626a0700366937530d38b8b1e8krajcevski// However, the decomrpession routine reads them in column-major order, so they 1766c354881b63935626a0700366937530d38b8b1e8krajcevski// need to be packed as: 1776c354881b63935626a0700366937530d38b8b1e8krajcevski// 0 4 8 12 1 5 9 13 2 6 10 14 3 7 11 15 1786c354881b63935626a0700366937530d38b8b1e8krajcevski// So when reading, they must be transposed. 1796c354881b63935626a0700366937530d38b8b1e8krajcevski// 1806c354881b63935626a0700366937530d38b8b1e8krajcevski// 2. We cannot use the top three bits as an index directly, since the R11 EAC palettes 1816c354881b63935626a0700366937530d38b8b1e8krajcevski// above store the modulation values first decreasing and then increasing: 1826c354881b63935626a0700366937530d38b8b1e8krajcevski// e.g. {-3, -6, -9, -15, 2, 5, 8, 14} 1836c354881b63935626a0700366937530d38b8b1e8krajcevski// Hence, we need to convert the indices with the following mapping: 1846c354881b63935626a0700366937530d38b8b1e8krajcevski// From: 0 1 2 3 4 5 6 7 1856c354881b63935626a0700366937530d38b8b1e8krajcevski// To: 3 2 1 0 4 5 6 7 1866c354881b63935626a0700366937530d38b8b1e8krajcevskistatic inline uint64_t compress_heterogeneous_r11eac_block(const uint8_t block[16]) { 1876c354881b63935626a0700366937530d38b8b1e8krajcevski uint64_t retVal = static_cast<uint64_t>(0x8490) << 48; 1886c354881b63935626a0700366937530d38b8b1e8krajcevski for(int i = 0; i < 4; ++i) { 1896c354881b63935626a0700366937530d38b8b1e8krajcevski for(int j = 0; j < 4; ++j) { 1906c354881b63935626a0700366937530d38b8b1e8krajcevski const int shift = 45-3*(j*4+i); 1916c354881b63935626a0700366937530d38b8b1e8krajcevski SkASSERT(shift <= 45); 1926c354881b63935626a0700366937530d38b8b1e8krajcevski const uint64_t idx = block[i*4+j] >> 5; 1936c354881b63935626a0700366937530d38b8b1e8krajcevski SkASSERT(idx < 8); 1946c354881b63935626a0700366937530d38b8b1e8krajcevski 1956c354881b63935626a0700366937530d38b8b1e8krajcevski // !SPEED! This is slightly faster than having an if-statement. 1966c354881b63935626a0700366937530d38b8b1e8krajcevski switch(idx) { 1976c354881b63935626a0700366937530d38b8b1e8krajcevski case 0: 1986c354881b63935626a0700366937530d38b8b1e8krajcevski case 1: 1996c354881b63935626a0700366937530d38b8b1e8krajcevski case 2: 2006c354881b63935626a0700366937530d38b8b1e8krajcevski case 3: 2016c354881b63935626a0700366937530d38b8b1e8krajcevski retVal |= (3-idx) << shift; 2026c354881b63935626a0700366937530d38b8b1e8krajcevski break; 2036c354881b63935626a0700366937530d38b8b1e8krajcevski default: 2046c354881b63935626a0700366937530d38b8b1e8krajcevski retVal |= idx << shift; 2056c354881b63935626a0700366937530d38b8b1e8krajcevski break; 2066c354881b63935626a0700366937530d38b8b1e8krajcevski } 2076c354881b63935626a0700366937530d38b8b1e8krajcevski } 2086c354881b63935626a0700366937530d38b8b1e8krajcevski } 2096c354881b63935626a0700366937530d38b8b1e8krajcevski 2106c354881b63935626a0700366937530d38b8b1e8krajcevski return SkEndian_SwapBE64(retVal); 2116c354881b63935626a0700366937530d38b8b1e8krajcevski} 2126c354881b63935626a0700366937530d38b8b1e8krajcevski#endif // COMPRESS_R11_EAC_FAST 2136c354881b63935626a0700366937530d38b8b1e8krajcevski 2146c354881b63935626a0700366937530d38b8b1e8krajcevski#if (COMPRESS_R11_EAC_SLOW) || (COMPRESS_R11_EAC_FAST) 2156c354881b63935626a0700366937530d38b8b1e8krajcevskistatic uint64_t compress_r11eac_block(const uint8_t block[16]) { 2166c354881b63935626a0700366937530d38b8b1e8krajcevski // Are all blocks a solid color? 2176c354881b63935626a0700366937530d38b8b1e8krajcevski bool solid = true; 2186c354881b63935626a0700366937530d38b8b1e8krajcevski for (int i = 1; i < 16; ++i) { 2196c354881b63935626a0700366937530d38b8b1e8krajcevski if (block[i] != block[0]) { 2206c354881b63935626a0700366937530d38b8b1e8krajcevski solid = false; 2216c354881b63935626a0700366937530d38b8b1e8krajcevski break; 2226c354881b63935626a0700366937530d38b8b1e8krajcevski } 2236c354881b63935626a0700366937530d38b8b1e8krajcevski } 2246c354881b63935626a0700366937530d38b8b1e8krajcevski 2256c354881b63935626a0700366937530d38b8b1e8krajcevski if (solid) { 2266c354881b63935626a0700366937530d38b8b1e8krajcevski switch(block[0]) { 2276c354881b63935626a0700366937530d38b8b1e8krajcevski // Fully transparent? We know the encoding... 2286c354881b63935626a0700366937530d38b8b1e8krajcevski case 0: 2296c354881b63935626a0700366937530d38b8b1e8krajcevski // (0x0020 << 48) produces the following: 2306c354881b63935626a0700366937530d38b8b1e8krajcevski // basw_cw: 0 2316c354881b63935626a0700366937530d38b8b1e8krajcevski // mod: 0, palette: {-3, -6, -9, -15, 2, 5, 8, 14} 2326c354881b63935626a0700366937530d38b8b1e8krajcevski // multiplier: 2 2336c354881b63935626a0700366937530d38b8b1e8krajcevski // mod_val: -3 2346c354881b63935626a0700366937530d38b8b1e8krajcevski // 2356c354881b63935626a0700366937530d38b8b1e8krajcevski // this gives the following formula: 2366c354881b63935626a0700366937530d38b8b1e8krajcevski // clamp[0, 2047](0*8+4+(-3)*2*8) = 0 2376c354881b63935626a0700366937530d38b8b1e8krajcevski // 2386c354881b63935626a0700366937530d38b8b1e8krajcevski // Furthermore, it is impervious to endianness: 2396c354881b63935626a0700366937530d38b8b1e8krajcevski // 0x0020000000002000ULL 2406c354881b63935626a0700366937530d38b8b1e8krajcevski // Will produce one pixel with index 2, which gives: 2416c354881b63935626a0700366937530d38b8b1e8krajcevski // clamp[0, 2047](0*8+4+(-9)*2*8) = 0 2426c354881b63935626a0700366937530d38b8b1e8krajcevski return 0x0020000000002000ULL; 2436c354881b63935626a0700366937530d38b8b1e8krajcevski 2446c354881b63935626a0700366937530d38b8b1e8krajcevski // Fully opaque? We know this encoding too... 2456c354881b63935626a0700366937530d38b8b1e8krajcevski case 255: 2466c354881b63935626a0700366937530d38b8b1e8krajcevski 2476c354881b63935626a0700366937530d38b8b1e8krajcevski // -1 produces the following: 2486c354881b63935626a0700366937530d38b8b1e8krajcevski // basw_cw: 255 2496c354881b63935626a0700366937530d38b8b1e8krajcevski // mod: 15, palette: {-3, -5, -7, -9, 2, 4, 6, 8} 2506c354881b63935626a0700366937530d38b8b1e8krajcevski // mod_val: 8 2516c354881b63935626a0700366937530d38b8b1e8krajcevski // 2526c354881b63935626a0700366937530d38b8b1e8krajcevski // this gives the following formula: 2536c354881b63935626a0700366937530d38b8b1e8krajcevski // clamp[0, 2047](255*8+4+8*8*8) = clamp[0, 2047](2556) = 2047 2546c354881b63935626a0700366937530d38b8b1e8krajcevski return 0xFFFFFFFFFFFFFFFFULL; 2556c354881b63935626a0700366937530d38b8b1e8krajcevski 2566c354881b63935626a0700366937530d38b8b1e8krajcevski default: 2576c354881b63935626a0700366937530d38b8b1e8krajcevski // !TODO! krajcevski: 2586c354881b63935626a0700366937530d38b8b1e8krajcevski // This will probably never happen, since we're using this format 2596c354881b63935626a0700366937530d38b8b1e8krajcevski // primarily for compressing alpha maps. Usually the only 2606c354881b63935626a0700366937530d38b8b1e8krajcevski // non-fullly opaque or fully transparent blocks are not a solid 2616c354881b63935626a0700366937530d38b8b1e8krajcevski // intermediate color. If we notice that they are, then we can 2626c354881b63935626a0700366937530d38b8b1e8krajcevski // add another optimization... 2636c354881b63935626a0700366937530d38b8b1e8krajcevski break; 2646c354881b63935626a0700366937530d38b8b1e8krajcevski } 2656c354881b63935626a0700366937530d38b8b1e8krajcevski } 2666c354881b63935626a0700366937530d38b8b1e8krajcevski 2676c354881b63935626a0700366937530d38b8b1e8krajcevski return compress_heterogeneous_r11eac_block(block); 2686c354881b63935626a0700366937530d38b8b1e8krajcevski} 2696c354881b63935626a0700366937530d38b8b1e8krajcevski 2706c354881b63935626a0700366937530d38b8b1e8krajcevski// This function is used by R11 EAC to compress 4x4 blocks 2716c354881b63935626a0700366937530d38b8b1e8krajcevski// of 8-bit alpha into 64-bit values that comprise the compressed data. 2726c354881b63935626a0700366937530d38b8b1e8krajcevski// We need to make sure that the dimensions of the src pixels are divisible 2736c354881b63935626a0700366937530d38b8b1e8krajcevski// by 4, and copy 4x4 blocks one at a time for compression. 2746c354881b63935626a0700366937530d38b8b1e8krajcevskitypedef uint64_t (*A84x4To64BitProc)(const uint8_t block[]); 2756c354881b63935626a0700366937530d38b8b1e8krajcevski 2766c354881b63935626a0700366937530d38b8b1e8krajcevskistatic bool compress_4x4_a8_to_64bit(uint8_t* dst, const uint8_t* src, 2776c354881b63935626a0700366937530d38b8b1e8krajcevski int width, int height, int rowBytes, 2786c354881b63935626a0700366937530d38b8b1e8krajcevski A84x4To64BitProc proc) { 2796c354881b63935626a0700366937530d38b8b1e8krajcevski // Make sure that our data is well-formed enough to be considered for compression 2806c354881b63935626a0700366937530d38b8b1e8krajcevski if (0 == width || 0 == height || (width % 4) != 0 || (height % 4) != 0) { 2816c354881b63935626a0700366937530d38b8b1e8krajcevski return false; 2826c354881b63935626a0700366937530d38b8b1e8krajcevski } 2836c354881b63935626a0700366937530d38b8b1e8krajcevski 2846c354881b63935626a0700366937530d38b8b1e8krajcevski int blocksX = width >> 2; 2856c354881b63935626a0700366937530d38b8b1e8krajcevski int blocksY = height >> 2; 2866c354881b63935626a0700366937530d38b8b1e8krajcevski 2876c354881b63935626a0700366937530d38b8b1e8krajcevski uint8_t block[16]; 2886c354881b63935626a0700366937530d38b8b1e8krajcevski uint64_t* encPtr = reinterpret_cast<uint64_t*>(dst); 2896c354881b63935626a0700366937530d38b8b1e8krajcevski for (int y = 0; y < blocksY; ++y) { 2906c354881b63935626a0700366937530d38b8b1e8krajcevski for (int x = 0; x < blocksX; ++x) { 2916c354881b63935626a0700366937530d38b8b1e8krajcevski // Load block 2926c354881b63935626a0700366937530d38b8b1e8krajcevski for (int k = 0; k < 4; ++k) { 2936c354881b63935626a0700366937530d38b8b1e8krajcevski memcpy(block + k*4, src + k*rowBytes + 4*x, 4); 2946c354881b63935626a0700366937530d38b8b1e8krajcevski } 2956c354881b63935626a0700366937530d38b8b1e8krajcevski 2966c354881b63935626a0700366937530d38b8b1e8krajcevski // Compress it 2976c354881b63935626a0700366937530d38b8b1e8krajcevski *encPtr = proc(block); 2986c354881b63935626a0700366937530d38b8b1e8krajcevski ++encPtr; 2996c354881b63935626a0700366937530d38b8b1e8krajcevski } 3006c354881b63935626a0700366937530d38b8b1e8krajcevski src += 4 * rowBytes; 3016c354881b63935626a0700366937530d38b8b1e8krajcevski } 3026c354881b63935626a0700366937530d38b8b1e8krajcevski 3036c354881b63935626a0700366937530d38b8b1e8krajcevski return true; 3046c354881b63935626a0700366937530d38b8b1e8krajcevski} 3056c354881b63935626a0700366937530d38b8b1e8krajcevski#endif // (COMPRESS_R11_EAC_SLOW) || (COMPRESS_R11_EAC_FAST) 3066c354881b63935626a0700366937530d38b8b1e8krajcevski 307d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski// This function converts an integer containing four bytes of alpha 308d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski// values into an integer containing four bytes of indices into R11 EAC. 309d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski// Note, there needs to be a mapping of indices: 310d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski// 0 1 2 3 4 5 6 7 311d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski// 3 2 1 0 4 5 6 7 312d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski// 313d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski// To compute this, we first negate each byte, and then add three, which 314d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski// gives the mapping 315d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski// 3 2 1 0 -1 -2 -3 -4 316d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski// 317d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski// Then we mask out the negative values, take their absolute value, and 318d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski// add three. 319d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski// 320d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski// Most of the voodoo in this function comes from Hacker's Delight, section 2-18 321d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevskistatic inline uint32_t convert_indices(uint32_t x) { 322d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski // Take the top three bits... 323d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski x = (x & 0xE0E0E0E0) >> 5; 324d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski 325d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski // Negate... 326d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski x = ~((0x80808080 - x) ^ 0x7F7F7F7F); 327d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski 328d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski // Add three 329d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski const uint32_t s = (x & 0x7F7F7F7F) + 0x03030303; 330d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski x = ((x ^ 0x03030303) & 0x80808080) ^ s; 331d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski 332d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski // Absolute value 333d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski const uint32_t a = x & 0x80808080; 334d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski const uint32_t b = a >> 7; 335d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski 336d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski // Aside: mask negatives (m is three if the byte was negative) 337d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski const uint32_t m = (a >> 6) | b; 338d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski 339d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski // .. continue absolute value 340d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski x = (x ^ ((a - b) | a)) + b; 341d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski 342d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski // Add three 343d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski return x + m; 344d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski} 345d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski 3466c354881b63935626a0700366937530d38b8b1e8krajcevski#if COMPRESS_R11_EAC_FASTEST 3476c354881b63935626a0700366937530d38b8b1e8krajcevskitemplate<unsigned shift> 3486c354881b63935626a0700366937530d38b8b1e8krajcevskistatic inline uint64_t swap_shift(uint64_t x, uint64_t mask) { 3496c354881b63935626a0700366937530d38b8b1e8krajcevski const uint64_t t = (x ^ (x >> shift)) & mask; 3506c354881b63935626a0700366937530d38b8b1e8krajcevski return x ^ t ^ (t << shift); 3516c354881b63935626a0700366937530d38b8b1e8krajcevski} 3526c354881b63935626a0700366937530d38b8b1e8krajcevski 3536c354881b63935626a0700366937530d38b8b1e8krajcevskistatic inline uint64_t interleave6(uint64_t topRows, uint64_t bottomRows) { 3546c354881b63935626a0700366937530d38b8b1e8krajcevski // If our 3-bit block indices are laid out as: 3556c354881b63935626a0700366937530d38b8b1e8krajcevski // a b c d 3566c354881b63935626a0700366937530d38b8b1e8krajcevski // e f g h 3576c354881b63935626a0700366937530d38b8b1e8krajcevski // i j k l 3586c354881b63935626a0700366937530d38b8b1e8krajcevski // m n o p 3596c354881b63935626a0700366937530d38b8b1e8krajcevski // 3606c354881b63935626a0700366937530d38b8b1e8krajcevski // This function expects topRows and bottomRows to contain the first two rows 3616c354881b63935626a0700366937530d38b8b1e8krajcevski // of indices interleaved in the least significant bits of a and b. In other words... 3626c354881b63935626a0700366937530d38b8b1e8krajcevski // 3636c354881b63935626a0700366937530d38b8b1e8krajcevski // If the architecture is big endian, then topRows and bottomRows will contain the following: 3646c354881b63935626a0700366937530d38b8b1e8krajcevski // Bits 31-0: 3656c354881b63935626a0700366937530d38b8b1e8krajcevski // a: 00 a e 00 b f 00 c g 00 d h 3666c354881b63935626a0700366937530d38b8b1e8krajcevski // b: 00 i m 00 j n 00 k o 00 l p 3676c354881b63935626a0700366937530d38b8b1e8krajcevski // 3686c354881b63935626a0700366937530d38b8b1e8krajcevski // If the architecture is little endian, then topRows and bottomRows will contain 3696c354881b63935626a0700366937530d38b8b1e8krajcevski // the following: 3706c354881b63935626a0700366937530d38b8b1e8krajcevski // Bits 31-0: 3716c354881b63935626a0700366937530d38b8b1e8krajcevski // a: 00 d h 00 c g 00 b f 00 a e 3726c354881b63935626a0700366937530d38b8b1e8krajcevski // b: 00 l p 00 k o 00 j n 00 i m 3736c354881b63935626a0700366937530d38b8b1e8krajcevski // 3746c354881b63935626a0700366937530d38b8b1e8krajcevski // This function returns a 48-bit packing of the form: 3756c354881b63935626a0700366937530d38b8b1e8krajcevski // a e i m b f j n c g k o d h l p 3766c354881b63935626a0700366937530d38b8b1e8krajcevski // 3776c354881b63935626a0700366937530d38b8b1e8krajcevski // !SPEED! this function might be even faster if certain SIMD intrinsics are 3786c354881b63935626a0700366937530d38b8b1e8krajcevski // used.. 3796c354881b63935626a0700366937530d38b8b1e8krajcevski 3806c354881b63935626a0700366937530d38b8b1e8krajcevski // For both architectures, we can figure out a packing of the bits by 3816c354881b63935626a0700366937530d38b8b1e8krajcevski // using a shuffle and a few shift-rotates... 3826c354881b63935626a0700366937530d38b8b1e8krajcevski uint64_t x = (static_cast<uint64_t>(topRows) << 32) | static_cast<uint64_t>(bottomRows); 3836c354881b63935626a0700366937530d38b8b1e8krajcevski 3846c354881b63935626a0700366937530d38b8b1e8krajcevski // x: 00 a e 00 b f 00 c g 00 d h 00 i m 00 j n 00 k o 00 l p 3856c354881b63935626a0700366937530d38b8b1e8krajcevski 3866c354881b63935626a0700366937530d38b8b1e8krajcevski x = swap_shift<10>(x, 0x3FC0003FC00000ULL); 3876c354881b63935626a0700366937530d38b8b1e8krajcevski 3886c354881b63935626a0700366937530d38b8b1e8krajcevski // x: b f 00 00 00 a e c g i m 00 00 00 d h j n 00 k o 00 l p 3896c354881b63935626a0700366937530d38b8b1e8krajcevski 3906c354881b63935626a0700366937530d38b8b1e8krajcevski x = (x | ((x << 52) & (0x3FULL << 52)) | ((x << 20) & (0x3FULL << 28))) >> 16; 3916c354881b63935626a0700366937530d38b8b1e8krajcevski 3926c354881b63935626a0700366937530d38b8b1e8krajcevski // x: 00 00 00 00 00 00 00 00 b f l p a e c g i m k o d h j n 3936c354881b63935626a0700366937530d38b8b1e8krajcevski 3946c354881b63935626a0700366937530d38b8b1e8krajcevski x = swap_shift<6>(x, 0xFC0000ULL); 3956c354881b63935626a0700366937530d38b8b1e8krajcevski 3966c354881b63935626a0700366937530d38b8b1e8krajcevski#if defined (SK_CPU_BENDIAN) 3976c354881b63935626a0700366937530d38b8b1e8krajcevski // x: 00 00 00 00 00 00 00 00 b f l p a e i m c g k o d h j n 3986c354881b63935626a0700366937530d38b8b1e8krajcevski 3996c354881b63935626a0700366937530d38b8b1e8krajcevski x = swap_shift<36>(x, 0x3FULL); 4006c354881b63935626a0700366937530d38b8b1e8krajcevski 4016c354881b63935626a0700366937530d38b8b1e8krajcevski // x: 00 00 00 00 00 00 00 00 b f j n a e i m c g k o d h l p 4026c354881b63935626a0700366937530d38b8b1e8krajcevski 4036c354881b63935626a0700366937530d38b8b1e8krajcevski x = swap_shift<12>(x, 0xFFF000000ULL); 4046c354881b63935626a0700366937530d38b8b1e8krajcevski#else 4056c354881b63935626a0700366937530d38b8b1e8krajcevski // If our CPU is little endian, then the above logic will 4066c354881b63935626a0700366937530d38b8b1e8krajcevski // produce the following indices: 4076c354881b63935626a0700366937530d38b8b1e8krajcevski // x: 00 00 00 00 00 00 00 00 c g i m d h l p b f j n a e k o 4086c354881b63935626a0700366937530d38b8b1e8krajcevski 4096c354881b63935626a0700366937530d38b8b1e8krajcevski x = swap_shift<36>(x, 0xFC0ULL); 4106c354881b63935626a0700366937530d38b8b1e8krajcevski 4116c354881b63935626a0700366937530d38b8b1e8krajcevski // x: 00 00 00 00 00 00 00 00 a e i m d h l p b f j n c g k o 4126c354881b63935626a0700366937530d38b8b1e8krajcevski 4136c354881b63935626a0700366937530d38b8b1e8krajcevski x = (x & (0xFFFULL << 36)) | ((x & 0xFFFFFFULL) << 12) | ((x >> 24) & 0xFFFULL); 4146c354881b63935626a0700366937530d38b8b1e8krajcevski#endif 4156c354881b63935626a0700366937530d38b8b1e8krajcevski 4166c354881b63935626a0700366937530d38b8b1e8krajcevski // x: 00 00 00 00 00 00 00 00 a e i m b f j n c g k o d h l p 4176c354881b63935626a0700366937530d38b8b1e8krajcevski return x; 4186c354881b63935626a0700366937530d38b8b1e8krajcevski} 4196c354881b63935626a0700366937530d38b8b1e8krajcevski 4206c354881b63935626a0700366937530d38b8b1e8krajcevski// This function follows the same basic procedure as compress_heterogeneous_r11eac_block 4216c354881b63935626a0700366937530d38b8b1e8krajcevski// above when COMPRESS_R11_EAC_FAST is defined, but it avoids a few loads/stores and 4226c354881b63935626a0700366937530d38b8b1e8krajcevski// tries to optimize where it can using SIMD. 4236c354881b63935626a0700366937530d38b8b1e8krajcevskistatic uint64_t compress_r11eac_block_fast(const uint8_t* src, int rowBytes) { 4246c354881b63935626a0700366937530d38b8b1e8krajcevski // Store each row of alpha values in an integer 4256c354881b63935626a0700366937530d38b8b1e8krajcevski const uint32_t alphaRow1 = *(reinterpret_cast<const uint32_t*>(src)); 4266c354881b63935626a0700366937530d38b8b1e8krajcevski const uint32_t alphaRow2 = *(reinterpret_cast<const uint32_t*>(src + rowBytes)); 4276c354881b63935626a0700366937530d38b8b1e8krajcevski const uint32_t alphaRow3 = *(reinterpret_cast<const uint32_t*>(src + 2*rowBytes)); 4286c354881b63935626a0700366937530d38b8b1e8krajcevski const uint32_t alphaRow4 = *(reinterpret_cast<const uint32_t*>(src + 3*rowBytes)); 4296c354881b63935626a0700366937530d38b8b1e8krajcevski 4306c354881b63935626a0700366937530d38b8b1e8krajcevski // Check for solid blocks. The explanations for these values 4316c354881b63935626a0700366937530d38b8b1e8krajcevski // can be found in the comments of compress_r11eac_block above 4326c354881b63935626a0700366937530d38b8b1e8krajcevski if (alphaRow1 == alphaRow2 && alphaRow1 == alphaRow3 && alphaRow1 == alphaRow4) { 4336c354881b63935626a0700366937530d38b8b1e8krajcevski if (0 == alphaRow1) { 4346c354881b63935626a0700366937530d38b8b1e8krajcevski // Fully transparent block 4356c354881b63935626a0700366937530d38b8b1e8krajcevski return 0x0020000000002000ULL; 4366c354881b63935626a0700366937530d38b8b1e8krajcevski } else if (0xFFFFFFFF == alphaRow1) { 4376c354881b63935626a0700366937530d38b8b1e8krajcevski // Fully opaque block 4386c354881b63935626a0700366937530d38b8b1e8krajcevski return 0xFFFFFFFFFFFFFFFFULL; 4396c354881b63935626a0700366937530d38b8b1e8krajcevski } 4406c354881b63935626a0700366937530d38b8b1e8krajcevski } 4416c354881b63935626a0700366937530d38b8b1e8krajcevski 4426c354881b63935626a0700366937530d38b8b1e8krajcevski // Convert each integer of alpha values into an integer of indices 4436c354881b63935626a0700366937530d38b8b1e8krajcevski const uint32_t indexRow1 = convert_indices(alphaRow1); 4446c354881b63935626a0700366937530d38b8b1e8krajcevski const uint32_t indexRow2 = convert_indices(alphaRow2); 4456c354881b63935626a0700366937530d38b8b1e8krajcevski const uint32_t indexRow3 = convert_indices(alphaRow3); 4466c354881b63935626a0700366937530d38b8b1e8krajcevski const uint32_t indexRow4 = convert_indices(alphaRow4); 4476c354881b63935626a0700366937530d38b8b1e8krajcevski 4486c354881b63935626a0700366937530d38b8b1e8krajcevski // Interleave the indices from the top two rows and bottom two rows 4496c354881b63935626a0700366937530d38b8b1e8krajcevski // prior to passing them to interleave6. Since each index is at most 4506c354881b63935626a0700366937530d38b8b1e8krajcevski // three bits, then each byte can hold two indices... The way that the 4516c354881b63935626a0700366937530d38b8b1e8krajcevski // compression scheme expects the packing allows us to efficiently pack 4526c354881b63935626a0700366937530d38b8b1e8krajcevski // the top two rows and bottom two rows. Interleaving each 6-bit sequence 4536c354881b63935626a0700366937530d38b8b1e8krajcevski // and tightly packing it into a uint64_t is a little trickier, which is 4546c354881b63935626a0700366937530d38b8b1e8krajcevski // taken care of in interleave6. 4556c354881b63935626a0700366937530d38b8b1e8krajcevski const uint32_t r1r2 = (indexRow1 << 3) | indexRow2; 4566c354881b63935626a0700366937530d38b8b1e8krajcevski const uint32_t r3r4 = (indexRow3 << 3) | indexRow4; 4576c354881b63935626a0700366937530d38b8b1e8krajcevski const uint64_t indices = interleave6(r1r2, r3r4); 4586c354881b63935626a0700366937530d38b8b1e8krajcevski 4596c354881b63935626a0700366937530d38b8b1e8krajcevski // Return the packed incdices in the least significant bits with the magic header 4606c354881b63935626a0700366937530d38b8b1e8krajcevski return SkEndian_SwapBE64(0x8490000000000000ULL | indices); 4616c354881b63935626a0700366937530d38b8b1e8krajcevski} 4626c354881b63935626a0700366937530d38b8b1e8krajcevski 4636c354881b63935626a0700366937530d38b8b1e8krajcevskistatic bool compress_a8_to_r11eac_fast(uint8_t* dst, const uint8_t* src, 4646c354881b63935626a0700366937530d38b8b1e8krajcevski int width, int height, int rowBytes) { 4656c354881b63935626a0700366937530d38b8b1e8krajcevski // Make sure that our data is well-formed enough to be considered for compression 4666c354881b63935626a0700366937530d38b8b1e8krajcevski if (0 == width || 0 == height || (width % 4) != 0 || (height % 4) != 0) { 4676c354881b63935626a0700366937530d38b8b1e8krajcevski return false; 4686c354881b63935626a0700366937530d38b8b1e8krajcevski } 4696c354881b63935626a0700366937530d38b8b1e8krajcevski 4706c354881b63935626a0700366937530d38b8b1e8krajcevski const int blocksX = width >> 2; 4716c354881b63935626a0700366937530d38b8b1e8krajcevski const int blocksY = height >> 2; 4726c354881b63935626a0700366937530d38b8b1e8krajcevski 4736c354881b63935626a0700366937530d38b8b1e8krajcevski uint64_t* encPtr = reinterpret_cast<uint64_t*>(dst); 4746c354881b63935626a0700366937530d38b8b1e8krajcevski for (int y = 0; y < blocksY; ++y) { 4756c354881b63935626a0700366937530d38b8b1e8krajcevski for (int x = 0; x < blocksX; ++x) { 4766c354881b63935626a0700366937530d38b8b1e8krajcevski // Compress it 4776c354881b63935626a0700366937530d38b8b1e8krajcevski *encPtr = compress_r11eac_block_fast(src + 4*x, rowBytes); 4786c354881b63935626a0700366937530d38b8b1e8krajcevski ++encPtr; 4796c354881b63935626a0700366937530d38b8b1e8krajcevski } 4806c354881b63935626a0700366937530d38b8b1e8krajcevski src += 4 * rowBytes; 4816c354881b63935626a0700366937530d38b8b1e8krajcevski } 4826c354881b63935626a0700366937530d38b8b1e8krajcevski return true; 4836c354881b63935626a0700366937530d38b8b1e8krajcevski} 4846c354881b63935626a0700366937530d38b8b1e8krajcevski#endif // COMPRESS_R11_EAC_FASTEST 4856c354881b63935626a0700366937530d38b8b1e8krajcevski 4866c354881b63935626a0700366937530d38b8b1e8krajcevski//////////////////////////////////////////////////////////////////////////////// 4876c354881b63935626a0700366937530d38b8b1e8krajcevski// 4886c354881b63935626a0700366937530d38b8b1e8krajcevski// Utility functions used by the blitter 4896c354881b63935626a0700366937530d38b8b1e8krajcevski// 4906c354881b63935626a0700366937530d38b8b1e8krajcevski//////////////////////////////////////////////////////////////////////////////// 4916c354881b63935626a0700366937530d38b8b1e8krajcevski 4926c354881b63935626a0700366937530d38b8b1e8krajcevski// The R11 EAC format expects that indices are given in column-major order. Since 4936c354881b63935626a0700366937530d38b8b1e8krajcevski// we receive alpha values in raster order, this usually means that we have to use 4946c354881b63935626a0700366937530d38b8b1e8krajcevski// pack6 above to properly pack our indices. However, if our indices come from the 4956c354881b63935626a0700366937530d38b8b1e8krajcevski// blitter, then each integer will be a column of indices, and hence can be efficiently 4966c354881b63935626a0700366937530d38b8b1e8krajcevski// packed. This function takes the bottom three bits of each byte and places them in 4976c354881b63935626a0700366937530d38b8b1e8krajcevski// the least significant 12 bits of the resulting integer. 4986c354881b63935626a0700366937530d38b8b1e8krajcevskistatic inline uint32_t pack_indices_vertical(uint32_t x) { 4996c354881b63935626a0700366937530d38b8b1e8krajcevski#if defined (SK_CPU_BENDIAN) 5006c354881b63935626a0700366937530d38b8b1e8krajcevski return 5016c354881b63935626a0700366937530d38b8b1e8krajcevski (x & 7) | 5026c354881b63935626a0700366937530d38b8b1e8krajcevski ((x >> 5) & (7 << 3)) | 5036c354881b63935626a0700366937530d38b8b1e8krajcevski ((x >> 10) & (7 << 6)) | 5046c354881b63935626a0700366937530d38b8b1e8krajcevski ((x >> 15) & (7 << 9)); 5056c354881b63935626a0700366937530d38b8b1e8krajcevski#else 5066c354881b63935626a0700366937530d38b8b1e8krajcevski return 5076c354881b63935626a0700366937530d38b8b1e8krajcevski ((x >> 24) & 7) | 5086c354881b63935626a0700366937530d38b8b1e8krajcevski ((x >> 13) & (7 << 3)) | 5096c354881b63935626a0700366937530d38b8b1e8krajcevski ((x >> 2) & (7 << 6)) | 5106c354881b63935626a0700366937530d38b8b1e8krajcevski ((x << 9) & (7 << 9)); 5116c354881b63935626a0700366937530d38b8b1e8krajcevski#endif 5126c354881b63935626a0700366937530d38b8b1e8krajcevski} 5136c354881b63935626a0700366937530d38b8b1e8krajcevski 5146c354881b63935626a0700366937530d38b8b1e8krajcevski// This function returns the compressed format of a block given as four columns of 5156c354881b63935626a0700366937530d38b8b1e8krajcevski// alpha values. Each column is assumed to be loaded from top to bottom, and hence 5166c354881b63935626a0700366937530d38b8b1e8krajcevski// must first be converted to indices and then packed into the resulting 64-bit 5176c354881b63935626a0700366937530d38b8b1e8krajcevski// integer. 518d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevskiinline void compress_block_vertical(uint8_t* dstPtr, const uint8_t *block) { 519d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski 520d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski const uint32_t* src = reinterpret_cast<const uint32_t*>(block); 521d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski uint64_t* dst = reinterpret_cast<uint64_t*>(dstPtr); 522d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski 523d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski const uint32_t alphaColumn0 = src[0]; 524d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski const uint32_t alphaColumn1 = src[1]; 525d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski const uint32_t alphaColumn2 = src[2]; 526d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski const uint32_t alphaColumn3 = src[3]; 5276c354881b63935626a0700366937530d38b8b1e8krajcevski 5286c354881b63935626a0700366937530d38b8b1e8krajcevski if (alphaColumn0 == alphaColumn1 && 5296c354881b63935626a0700366937530d38b8b1e8krajcevski alphaColumn2 == alphaColumn3 && 5306c354881b63935626a0700366937530d38b8b1e8krajcevski alphaColumn0 == alphaColumn2) { 5316c354881b63935626a0700366937530d38b8b1e8krajcevski 5326c354881b63935626a0700366937530d38b8b1e8krajcevski if (0 == alphaColumn0) { 5336c354881b63935626a0700366937530d38b8b1e8krajcevski // Transparent 534d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski *dst = 0x0020000000002000ULL; 535d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski return; 5366c354881b63935626a0700366937530d38b8b1e8krajcevski } 5376c354881b63935626a0700366937530d38b8b1e8krajcevski else if (0xFFFFFFFF == alphaColumn0) { 5386c354881b63935626a0700366937530d38b8b1e8krajcevski // Opaque 539d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski *dst = 0xFFFFFFFFFFFFFFFFULL; 540d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski return; 5416c354881b63935626a0700366937530d38b8b1e8krajcevski } 5426c354881b63935626a0700366937530d38b8b1e8krajcevski } 5436c354881b63935626a0700366937530d38b8b1e8krajcevski 5446c354881b63935626a0700366937530d38b8b1e8krajcevski const uint32_t indexColumn0 = convert_indices(alphaColumn0); 5456c354881b63935626a0700366937530d38b8b1e8krajcevski const uint32_t indexColumn1 = convert_indices(alphaColumn1); 5466c354881b63935626a0700366937530d38b8b1e8krajcevski const uint32_t indexColumn2 = convert_indices(alphaColumn2); 5476c354881b63935626a0700366937530d38b8b1e8krajcevski const uint32_t indexColumn3 = convert_indices(alphaColumn3); 5486c354881b63935626a0700366937530d38b8b1e8krajcevski 5496c354881b63935626a0700366937530d38b8b1e8krajcevski const uint32_t packedIndexColumn0 = pack_indices_vertical(indexColumn0); 5506c354881b63935626a0700366937530d38b8b1e8krajcevski const uint32_t packedIndexColumn1 = pack_indices_vertical(indexColumn1); 5516c354881b63935626a0700366937530d38b8b1e8krajcevski const uint32_t packedIndexColumn2 = pack_indices_vertical(indexColumn2); 5526c354881b63935626a0700366937530d38b8b1e8krajcevski const uint32_t packedIndexColumn3 = pack_indices_vertical(indexColumn3); 5536c354881b63935626a0700366937530d38b8b1e8krajcevski 554d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski *dst = SkEndian_SwapBE64(0x8490000000000000ULL | 5556c354881b63935626a0700366937530d38b8b1e8krajcevski (static_cast<uint64_t>(packedIndexColumn0) << 36) | 5566c354881b63935626a0700366937530d38b8b1e8krajcevski (static_cast<uint64_t>(packedIndexColumn1) << 24) | 5576c354881b63935626a0700366937530d38b8b1e8krajcevski static_cast<uint64_t>(packedIndexColumn2 << 12) | 5586c354881b63935626a0700366937530d38b8b1e8krajcevski static_cast<uint64_t>(packedIndexColumn3)); 5596c354881b63935626a0700366937530d38b8b1e8krajcevski} 5606c354881b63935626a0700366937530d38b8b1e8krajcevski 5614ad76e35111585f4da662d54943f23792dd1e0aekrajcevskistatic inline int get_r11_eac_index(uint64_t block, int x, int y) { 5624ad76e35111585f4da662d54943f23792dd1e0aekrajcevski SkASSERT(x >= 0 && x < 4); 5634ad76e35111585f4da662d54943f23792dd1e0aekrajcevski SkASSERT(y >= 0 && y < 4); 5644ad76e35111585f4da662d54943f23792dd1e0aekrajcevski const int idx = x*4 + y; 5654ad76e35111585f4da662d54943f23792dd1e0aekrajcevski return (block >> ((15-idx)*3)) & 0x7; 5664ad76e35111585f4da662d54943f23792dd1e0aekrajcevski} 5674ad76e35111585f4da662d54943f23792dd1e0aekrajcevski 5684ad76e35111585f4da662d54943f23792dd1e0aekrajcevskistatic void decompress_r11_eac_block(uint8_t* dst, int dstRowBytes, const uint8_t* src) { 5694ad76e35111585f4da662d54943f23792dd1e0aekrajcevski const uint64_t block = SkEndian_SwapBE64(*(reinterpret_cast<const uint64_t *>(src))); 5704ad76e35111585f4da662d54943f23792dd1e0aekrajcevski 5714ad76e35111585f4da662d54943f23792dd1e0aekrajcevski const int base_cw = (block >> 56) & 0xFF; 5724ad76e35111585f4da662d54943f23792dd1e0aekrajcevski const int mod = (block >> 52) & 0xF; 5734ad76e35111585f4da662d54943f23792dd1e0aekrajcevski const int palette_idx = (block >> 48) & 0xF; 5744ad76e35111585f4da662d54943f23792dd1e0aekrajcevski 5754ad76e35111585f4da662d54943f23792dd1e0aekrajcevski const int* palette = kR11EACModifierPalettes[palette_idx]; 5764ad76e35111585f4da662d54943f23792dd1e0aekrajcevski 5774ad76e35111585f4da662d54943f23792dd1e0aekrajcevski for (int j = 0; j < 4; ++j) { 5784ad76e35111585f4da662d54943f23792dd1e0aekrajcevski for (int i = 0; i < 4; ++i) { 5794ad76e35111585f4da662d54943f23792dd1e0aekrajcevski const int idx = get_r11_eac_index(block, i, j); 5804ad76e35111585f4da662d54943f23792dd1e0aekrajcevski const int val = base_cw*8 + 4 + palette[idx]*mod*8; 5814ad76e35111585f4da662d54943f23792dd1e0aekrajcevski if (val < 0) { 5824ad76e35111585f4da662d54943f23792dd1e0aekrajcevski dst[i] = 0; 5834ad76e35111585f4da662d54943f23792dd1e0aekrajcevski } else if (val > 2047) { 5844ad76e35111585f4da662d54943f23792dd1e0aekrajcevski dst[i] = 0xFF; 5854ad76e35111585f4da662d54943f23792dd1e0aekrajcevski } else { 5864ad76e35111585f4da662d54943f23792dd1e0aekrajcevski dst[i] = (val >> 3) & 0xFF; 5874ad76e35111585f4da662d54943f23792dd1e0aekrajcevski } 5884ad76e35111585f4da662d54943f23792dd1e0aekrajcevski } 5894ad76e35111585f4da662d54943f23792dd1e0aekrajcevski dst += dstRowBytes; 5904ad76e35111585f4da662d54943f23792dd1e0aekrajcevski } 5914ad76e35111585f4da662d54943f23792dd1e0aekrajcevski} 5924ad76e35111585f4da662d54943f23792dd1e0aekrajcevski 59345a0bf505914adf0ee8c69e2647230618bbb3a63krajcevski// This is the type passed as the CompressorType argument of the compressed 59445a0bf505914adf0ee8c69e2647230618bbb3a63krajcevski// blitter for the R11 EAC format. The static functions required to be in this 59545a0bf505914adf0ee8c69e2647230618bbb3a63krajcevski// struct are documented in SkTextureCompressor_Blitter.h 59645a0bf505914adf0ee8c69e2647230618bbb3a63krajcevskistruct CompressorR11EAC { 59745a0bf505914adf0ee8c69e2647230618bbb3a63krajcevski static inline void CompressA8Vertical(uint8_t* dst, const uint8_t* src) { 59845a0bf505914adf0ee8c69e2647230618bbb3a63krajcevski compress_block_vertical(dst, src); 59945a0bf505914adf0ee8c69e2647230618bbb3a63krajcevski } 60045a0bf505914adf0ee8c69e2647230618bbb3a63krajcevski 60145a0bf505914adf0ee8c69e2647230618bbb3a63krajcevski static inline void CompressA8Horizontal(uint8_t* dst, const uint8_t* src, 60245a0bf505914adf0ee8c69e2647230618bbb3a63krajcevski int srcRowBytes) { 60345a0bf505914adf0ee8c69e2647230618bbb3a63krajcevski *(reinterpret_cast<uint64_t*>(dst)) = compress_r11eac_block_fast(src, srcRowBytes); 60445a0bf505914adf0ee8c69e2647230618bbb3a63krajcevski } 60545a0bf505914adf0ee8c69e2647230618bbb3a63krajcevski 606a10555a354cf294bde217044472d33c3161df249krajcevski#if PEDANTIC_BLIT_RECT 607a10555a354cf294bde217044472d33c3161df249krajcevski static inline void UpdateBlock(uint8_t* dst, const uint8_t* src, int srcRowBytes, 608a10555a354cf294bde217044472d33c3161df249krajcevski const uint8_t* mask) { 609a10555a354cf294bde217044472d33c3161df249krajcevski // TODO: krajcevski 610a10555a354cf294bde217044472d33c3161df249krajcevski // The implementation of this function should be similar to that of LATC, since 611a10555a354cf294bde217044472d33c3161df249krajcevski // the R11EAC indices directly correspond to pixel values. 612a10555a354cf294bde217044472d33c3161df249krajcevski SkFAIL("Implement me!"); 61345a0bf505914adf0ee8c69e2647230618bbb3a63krajcevski } 614a10555a354cf294bde217044472d33c3161df249krajcevski#endif 61545a0bf505914adf0ee8c69e2647230618bbb3a63krajcevski}; 61645a0bf505914adf0ee8c69e2647230618bbb3a63krajcevski 6176c354881b63935626a0700366937530d38b8b1e8krajcevski//////////////////////////////////////////////////////////////////////////////// 6186c354881b63935626a0700366937530d38b8b1e8krajcevski 6196c354881b63935626a0700366937530d38b8b1e8krajcevskinamespace SkTextureCompressor { 6206c354881b63935626a0700366937530d38b8b1e8krajcevski 6216c354881b63935626a0700366937530d38b8b1e8krajcevskibool CompressA8ToR11EAC(uint8_t* dst, const uint8_t* src, int width, int height, int rowBytes) { 6226c354881b63935626a0700366937530d38b8b1e8krajcevski 6236c354881b63935626a0700366937530d38b8b1e8krajcevski#if (COMPRESS_R11_EAC_SLOW) || (COMPRESS_R11_EAC_FAST) 6246c354881b63935626a0700366937530d38b8b1e8krajcevski 6256c354881b63935626a0700366937530d38b8b1e8krajcevski return compress_4x4_a8_to_64bit(dst, src, width, height, rowBytes, compress_r11eac_block); 6266c354881b63935626a0700366937530d38b8b1e8krajcevski 6276c354881b63935626a0700366937530d38b8b1e8krajcevski#elif COMPRESS_R11_EAC_FASTEST 6286c354881b63935626a0700366937530d38b8b1e8krajcevski 6296c354881b63935626a0700366937530d38b8b1e8krajcevski return compress_a8_to_r11eac_fast(dst, src, width, height, rowBytes); 6306c354881b63935626a0700366937530d38b8b1e8krajcevski 6316c354881b63935626a0700366937530d38b8b1e8krajcevski#else 6326c354881b63935626a0700366937530d38b8b1e8krajcevski#error "Must choose R11 EAC algorithm" 6336c354881b63935626a0700366937530d38b8b1e8krajcevski#endif 6346c354881b63935626a0700366937530d38b8b1e8krajcevski} 6356c354881b63935626a0700366937530d38b8b1e8krajcevski 636b8ccc2f6d258a8466f79fc418e9e0a55aeaf58cekrajcevskiSkBlitter* CreateR11EACBlitter(int width, int height, void* outputBuffer, 637b8ccc2f6d258a8466f79fc418e9e0a55aeaf58cekrajcevski SkTBlitterAllocator* allocator) { 638b8ccc2f6d258a8466f79fc418e9e0a55aeaf58cekrajcevski 639b8ccc2f6d258a8466f79fc418e9e0a55aeaf58cekrajcevski if ((width % 4) != 0 || (height % 4) != 0) { 640b8ccc2f6d258a8466f79fc418e9e0a55aeaf58cekrajcevski return NULL; 641b8ccc2f6d258a8466f79fc418e9e0a55aeaf58cekrajcevski } 642b8ccc2f6d258a8466f79fc418e9e0a55aeaf58cekrajcevski 643b8ccc2f6d258a8466f79fc418e9e0a55aeaf58cekrajcevski // Memset the output buffer to an encoding that decodes to zero. We must do this 644b8ccc2f6d258a8466f79fc418e9e0a55aeaf58cekrajcevski // in order to avoid having uninitialized values in the buffer if the blitter 645b8ccc2f6d258a8466f79fc418e9e0a55aeaf58cekrajcevski // decides not to write certain scanlines (and skip entire rows of blocks). 646b8ccc2f6d258a8466f79fc418e9e0a55aeaf58cekrajcevski // In the case of R11, we use the encoding from recognizing all zero pixels from above. 647b8ccc2f6d258a8466f79fc418e9e0a55aeaf58cekrajcevski const int nBlocks = (width * height / 16); // 4x4 pixel blocks. 648b8ccc2f6d258a8466f79fc418e9e0a55aeaf58cekrajcevski uint64_t *dst = reinterpret_cast<uint64_t *>(outputBuffer); 649b8ccc2f6d258a8466f79fc418e9e0a55aeaf58cekrajcevski for (int i = 0; i < nBlocks; ++i) { 650b8ccc2f6d258a8466f79fc418e9e0a55aeaf58cekrajcevski *dst = 0x0020000000002000ULL; 651b8ccc2f6d258a8466f79fc418e9e0a55aeaf58cekrajcevski ++dst; 652b8ccc2f6d258a8466f79fc418e9e0a55aeaf58cekrajcevski } 653b8ccc2f6d258a8466f79fc418e9e0a55aeaf58cekrajcevski 654b8ccc2f6d258a8466f79fc418e9e0a55aeaf58cekrajcevski return allocator->createT< 65545a0bf505914adf0ee8c69e2647230618bbb3a63krajcevski SkTCompressedAlphaBlitter<4, 8, CompressorR11EAC>, int, int, void*> 656d5e46c7893afdd5976c1581a2ae81168252f5deckrajcevski (width, height, outputBuffer); 6576c354881b63935626a0700366937530d38b8b1e8krajcevski} 6586c354881b63935626a0700366937530d38b8b1e8krajcevski 6594ad76e35111585f4da662d54943f23792dd1e0aekrajcevskivoid DecompressR11EAC(uint8_t* dst, int dstRowBytes, const uint8_t* src, int width, int height) { 6604ad76e35111585f4da662d54943f23792dd1e0aekrajcevski for (int j = 0; j < height; j += 4) { 6614ad76e35111585f4da662d54943f23792dd1e0aekrajcevski for (int i = 0; i < width; i += 4) { 6624ad76e35111585f4da662d54943f23792dd1e0aekrajcevski decompress_r11_eac_block(dst + i, dstRowBytes, src); 6634ad76e35111585f4da662d54943f23792dd1e0aekrajcevski src += 8; 6644ad76e35111585f4da662d54943f23792dd1e0aekrajcevski } 6654ad76e35111585f4da662d54943f23792dd1e0aekrajcevski dst += 4 * dstRowBytes; 6664ad76e35111585f4da662d54943f23792dd1e0aekrajcevski } 6674ad76e35111585f4da662d54943f23792dd1e0aekrajcevski} 6684ad76e35111585f4da662d54943f23792dd1e0aekrajcevski 6696c354881b63935626a0700366937530d38b8b1e8krajcevski} // namespace SkTextureCompressor 670