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/*
* Copyright 2014 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkTextureCompressor_DEFINED
#define SkTextureCompressor_DEFINED
#include "SkBitmapProcShader.h"
#include "SkImageInfo.h"
class SkBitmap;
class SkBlitter;
class SkData;
namespace SkTextureCompressor {
// Various texture compression formats that we support.
enum Format {
// Alpha only formats.
kLATC_Format, // 4x4 blocks, (de)compresses A8
kR11_EAC_Format, // 4x4 blocks, (de)compresses A8
// RGB only formats
kETC1_Format, // 4x4 blocks, compresses RGB 565, decompresses 8-bit RGB
// NOTE: ETC1 supports 8-bit RGB compression, but we
// currently don't have any RGB8 SkColorTypes. We could
// support 8-bit RGBA but we would have to preprocess the
// bitmap to insert alphas.
// Multi-purpose formats
kASTC_4x4_Format, // 4x4 blocks, no compression, decompresses RGBA
kASTC_5x4_Format, // 5x4 blocks, no compression, decompresses RGBA
kASTC_5x5_Format, // 5x5 blocks, no compression, decompresses RGBA
kASTC_6x5_Format, // 6x5 blocks, no compression, decompresses RGBA
kASTC_6x6_Format, // 6x6 blocks, no compression, decompresses RGBA
kASTC_8x5_Format, // 8x5 blocks, no compression, decompresses RGBA
kASTC_8x6_Format, // 8x6 blocks, no compression, decompresses RGBA
kASTC_8x8_Format, // 8x8 blocks, no compression, decompresses RGBA
kASTC_10x5_Format, // 10x5 blocks, no compression, decompresses RGBA
kASTC_10x6_Format, // 10x6 blocks, no compression, decompresses RGBA
kASTC_10x8_Format, // 10x8 blocks, no compression, decompresses RGBA
kASTC_10x10_Format, // 10x10 blocks, no compression, decompresses RGBA
kASTC_12x10_Format, // 12x10 blocks, no compression, decompresses RGBA
kASTC_12x12_Format, // 12x12 blocks, compresses A8, decompresses RGBA
kLast_Format = kASTC_12x12_Format
};
static const int kFormatCnt = kLast_Format + 1;
// Returns the size of the compressed data given the width, height, and
// desired compression format. If the width and height are not an appropriate
// multiple of the block size, then this function returns an error (-1).
int GetCompressedDataSize(Format fmt, int width, int height);
// Returns an SkData holding a blob of compressed data that corresponds
// to the pixmap. If the pixmap colorType cannot be compressed using the
// associated format, then we return nullptr. The caller is responsible for
// calling unref() on the returned data.
SkData* CompressBitmapToFormat(const SkPixmap&, Format format);
// Compresses the given src data into dst. The src data is assumed to be
// large enough to hold width*height pixels. The dst data is expected to
// be large enough to hold the compressed data according to the format.
bool CompressBufferToFormat(uint8_t* dst, const uint8_t* src, SkColorType srcColorType,
int width, int height, size_t rowBytes, Format format);
// Decompresses the given src data from the format specified into the
// destination buffer. The width and height of the data passed corresponds
// to the width and height of the uncompressed image. The destination buffer (dst)
// is assumed to be large enough to hold the entire decompressed image. The
// decompressed image colors are determined based on the passed format.
//
// Note, CompressBufferToFormat compresses A8 data into ASTC. However,
// general ASTC data encodes RGBA data, so that is what the decompressor
// operates on.
//
// Returns true if successfully decompresses the src data.
bool DecompressBufferFromFormat(uint8_t* dst, int dstRowBytes, const uint8_t* src,
int width, int height, Format format);
// Returns true if there exists a blitter for the specified format.
inline bool ExistsBlitterForFormat(Format format) {
switch (format) {
case kLATC_Format:
case kR11_EAC_Format:
case kASTC_12x12_Format:
return true;
default:
return false;
}
}
// Returns the blitter for the given compression format. Note, the blitter
// is intended to be used with the proper input. I.e. if you try to blit
// RGB source data into an R11 EAC texture, you're gonna have a bad time.
SkBlitter* CreateBlitterForFormat(int width, int height, void* compressedBuffer,
SkTBlitterAllocator *allocator, Format format);
// Returns the desired dimensions of the block size for the given format. These dimensions
// don't necessarily correspond to the specification's dimensions, since there may
// be specialized algorithms that operate on multiple blocks at once. If the
// flag 'matchSpec' is true, then the actual dimensions from the specification are
// returned. If the flag is false, then these dimensions reflect the appropriate operable
// dimensions of the compression functions.
void GetBlockDimensions(Format format, int* dimX, int* dimY, bool matchSpec = false);
}
#endif
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