1 /* 2 * Copyright 2014 Google Inc. 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8 #ifndef SkTextureCompressor_DEFINED 9 #define SkTextureCompressor_DEFINED 10 11 #include "SkBitmapProcShader.h" 12 #include "SkImageInfo.h" 13 14 class SkBitmap; 15 class SkBlitter; 16 class SkData; 17 18 namespace SkTextureCompressor { 19 // Various texture compression formats that we support. 20 enum Format { 21 // Alpha only formats. 22 kLATC_Format, // 4x4 blocks, (de)compresses A8 23 kR11_EAC_Format, // 4x4 blocks, (de)compresses A8 24 25 // RGB only formats 26 kETC1_Format, // 4x4 blocks, compresses RGB 565, decompresses 8-bit RGB 27 // NOTE: ETC1 supports 8-bit RGB compression, but we 28 // currently don't have any RGB8 SkColorTypes. We could 29 // support 8-bit RGBA but we would have to preprocess the 30 // bitmap to insert alphas. 31 32 // Multi-purpose formats 33 kASTC_4x4_Format, // 4x4 blocks, no compression, decompresses RGBA 34 kASTC_5x4_Format, // 5x4 blocks, no compression, decompresses RGBA 35 kASTC_5x5_Format, // 5x5 blocks, no compression, decompresses RGBA 36 kASTC_6x5_Format, // 6x5 blocks, no compression, decompresses RGBA 37 kASTC_6x6_Format, // 6x6 blocks, no compression, decompresses RGBA 38 kASTC_8x5_Format, // 8x5 blocks, no compression, decompresses RGBA 39 kASTC_8x6_Format, // 8x6 blocks, no compression, decompresses RGBA 40 kASTC_8x8_Format, // 8x8 blocks, no compression, decompresses RGBA 41 kASTC_10x5_Format, // 10x5 blocks, no compression, decompresses RGBA 42 kASTC_10x6_Format, // 10x6 blocks, no compression, decompresses RGBA 43 kASTC_10x8_Format, // 10x8 blocks, no compression, decompresses RGBA 44 kASTC_10x10_Format, // 10x10 blocks, no compression, decompresses RGBA 45 kASTC_12x10_Format, // 12x10 blocks, no compression, decompresses RGBA 46 kASTC_12x12_Format, // 12x12 blocks, compresses A8, decompresses RGBA 47 48 kLast_Format = kASTC_12x12_Format 49 }; 50 static const int kFormatCnt = kLast_Format + 1; 51 52 // Returns the size of the compressed data given the width, height, and 53 // desired compression format. If the width and height are not an appropriate 54 // multiple of the block size, then this function returns an error (-1). 55 int GetCompressedDataSize(Format fmt, int width, int height); 56 57 // Returns an SkData holding a blob of compressed data that corresponds 58 // to the bitmap. If the bitmap colorType cannot be compressed using the 59 // associated format, then we return NULL. The caller is responsible for 60 // calling unref() on the returned data. 61 SkData* CompressBitmapToFormat(const SkBitmap& bitmap, Format format); 62 63 // Compresses the given src data into dst. The src data is assumed to be 64 // large enough to hold width*height pixels. The dst data is expected to 65 // be large enough to hold the compressed data according to the format. 66 bool CompressBufferToFormat(uint8_t* dst, const uint8_t* src, SkColorType srcColorType, 67 int width, int height, size_t rowBytes, Format format, 68 bool opt = true /* Use optimization if available */); 69 70 // Decompresses the given src data from the format specified into the 71 // destination buffer. The width and height of the data passed corresponds 72 // to the width and height of the uncompressed image. The destination buffer (dst) 73 // is assumed to be large enough to hold the entire decompressed image. The 74 // decompressed image colors are determined based on the passed format. 75 // 76 // Note, CompressBufferToFormat compresses A8 data into ASTC. However, 77 // general ASTC data encodes RGBA data, so that is what the decompressor 78 // operates on. 79 // 80 // Returns true if successfully decompresses the src data. 81 bool DecompressBufferFromFormat(uint8_t* dst, int dstRowBytes, const uint8_t* src, 82 int width, int height, Format format); 83 84 // This typedef defines what the nominal aspects of a compression function 85 // are. The typedef is not meant to be used by clients of the API, but rather 86 // allows SIMD optimized compression functions to be implemented. 87 typedef bool (*CompressionProc)(uint8_t* dst, const uint8_t* src, 88 int width, int height, size_t rowBytes); 89 90 // Returns true if there exists a blitter for the specified format. ExistsBlitterForFormat(Format format)91 inline bool ExistsBlitterForFormat(Format format) { 92 switch (format) { 93 case kLATC_Format: 94 case kR11_EAC_Format: 95 case kASTC_12x12_Format: 96 return true; 97 98 default: 99 return false; 100 } 101 } 102 103 // Returns the blitter for the given compression format. Note, the blitter 104 // is intended to be used with the proper input. I.e. if you try to blit 105 // RGB source data into an R11 EAC texture, you're gonna have a bad time. 106 SkBlitter* CreateBlitterForFormat(int width, int height, void* compressedBuffer, 107 SkTBlitterAllocator *allocator, Format format); 108 109 // Returns the desired dimensions of the block size for the given format. These dimensions 110 // don't necessarily correspond to the specification's dimensions, since there may 111 // be specialized algorithms that operate on multiple blocks at once. If the 112 // flag 'matchSpec' is true, then the actual dimensions from the specification are 113 // returned. If the flag is false, then these dimensions reflect the appropriate operable 114 // dimensions of the compression functions. 115 void GetBlockDimensions(Format format, int* dimX, int* dimY, bool matchSpec = false); 116 } 117 118 #endif 119