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1 /* | 1 /* |
2 * Copyright 2014 Google Inc. | 2 * Copyright 2014 Google Inc. |
3 * | 3 * |
4 * Use of this source code is governed by a BSD-style license that can be | 4 * Use of this source code is governed by a BSD-style license that can be |
5 * found in the LICENSE file. | 5 * found in the LICENSE file. |
6 */ | 6 */ |
7 | 7 |
8 #ifndef SkTextureCompressor_DEFINED | 8 #ifndef SkTextureCompressor_DEFINED |
9 #define SkTextureCompressor_DEFINED | 9 #define SkTextureCompressor_DEFINED |
10 | 10 |
11 #include "SkImageInfo.h" | 11 #include "SkImageInfo.h" |
| 12 #include "SkBlitter.h" |
12 | 13 |
13 class SkBitmap; | 14 class SkBitmap; |
14 class SkData; | 15 class SkData; |
15 | 16 |
16 namespace SkTextureCompressor { | 17 namespace SkTextureCompressor { |
17 // Various texture compression formats that we support. | 18 // Various texture compression formats that we support. |
18 enum Format { | 19 enum Format { |
19 // Alpha only formats. | 20 // Alpha only formats. |
20 kLATC_Format, | 21 kLATC_Format, |
21 kR11_EAC_Format, | 22 kR11_EAC_Format, |
(...skipping 13 matching lines...) Expand all Loading... |
35 // be large enough to hold the compressed data according to the format. | 36 // be large enough to hold the compressed data according to the format. |
36 bool CompressBufferToFormat(uint8_t* dst, const uint8_t* src, SkColorType sr
cColorType, | 37 bool CompressBufferToFormat(uint8_t* dst, const uint8_t* src, SkColorType sr
cColorType, |
37 int width, int height, int rowBytes, Format form
at, | 38 int width, int height, int rowBytes, Format form
at, |
38 bool opt = true /* Use optimization if available
*/); | 39 bool opt = true /* Use optimization if available
*/); |
39 | 40 |
40 // This typedef defines what the nominal aspects of a compression function | 41 // This typedef defines what the nominal aspects of a compression function |
41 // are. The typedef is not meant to be used by clients of the API, but rathe
r | 42 // are. The typedef is not meant to be used by clients of the API, but rathe
r |
42 // allows SIMD optimized compression functions to be implemented. | 43 // allows SIMD optimized compression functions to be implemented. |
43 typedef bool (*CompressionProc)(uint8_t* dst, const uint8_t* src, | 44 typedef bool (*CompressionProc)(uint8_t* dst, const uint8_t* src, |
44 int width, int height, int rowBytes); | 45 int width, int height, int rowBytes); |
| 46 |
| 47 // This class implements a blitter that blits directly into a buffer that wi
ll |
| 48 // be used as an R11 EAC compressed texture. We compute this buffer by |
| 49 // buffering four scan lines and then outputting them all at once. This blit
ter |
| 50 // is only expected to be used with alpha masks, i.e. kAlpha8_SkColorType. |
| 51 class R11_EACBlitter : public SkBlitter { |
| 52 public: |
| 53 R11_EACBlitter(int width, int height, void *compressedBuffer); |
| 54 virtual ~R11_EACBlitter() { this->flushRuns(); } |
| 55 |
| 56 // Blit a horizontal run of one or more pixels. |
| 57 virtual void blitH(int x, int y, int width) SK_OVERRIDE { |
| 58 // This function is intended to be called from any standard RGB |
| 59 // buffer, so we should never encounter it. However, if some code |
| 60 // path does end up here, then this needs to be investigated. |
| 61 SkFAIL("Not implemented!"); |
| 62 } |
| 63 |
| 64 /// Blit a horizontal run of antialiased pixels; runs[] is a *sparse* |
| 65 /// zero-terminated run-length encoding of spans of constant alpha value
s. |
| 66 virtual void blitAntiH(int x, int y, |
| 67 const SkAlpha antialias[], |
| 68 const int16_t runs[]) SK_OVERRIDE; |
| 69 |
| 70 // Blit a vertical run of pixels with a constant alpha value. |
| 71 virtual void blitV(int x, int y, int height, SkAlpha alpha) SK_OVERRIDE
{ |
| 72 // This function is currently not implemented. It is not explicitly |
| 73 // required by the contract, but if at some time a code path runs in
to |
| 74 // this function (which is entirely possible), it needs to be implem
ented. |
| 75 // |
| 76 // TODO (krajcevski): |
| 77 // This function will be most easily implemented in one of two ways: |
| 78 // 1. Buffer each vertical column value and then construct a list |
| 79 // of alpha values and output all of the blocks at once. This onl
y |
| 80 // requires a write to the compressed buffer |
| 81 // 2. Replace the indices of each block with the proper indices base
d |
| 82 // on the alpha value. This requires a read and write of the comp
ressed |
| 83 // buffer, but much less overhead. |
| 84 SkFAIL("Not implemented!"); |
| 85 } |
| 86 |
| 87 // Blit a solid rectangle one or more pixels wide. |
| 88 virtual void blitRect(int x, int y, int width, int height) SK_OVERRIDE { |
| 89 // Analogous to blitRow, this function is intended for RGB targets |
| 90 // and should never be called by this blitter. Any calls to this fun
ction |
| 91 // are probably a bug and should be investigated. |
| 92 SkFAIL("Not implemented!"); |
| 93 } |
| 94 |
| 95 // Blit a rectangle with one alpha-blended column on the left, |
| 96 // width (zero or more) opaque pixels, and one alpha-blended column |
| 97 // on the right. The result will always be at least two pixels wide. |
| 98 virtual void blitAntiRect(int x, int y, int width, int height, |
| 99 SkAlpha leftAlpha, SkAlpha rightAlpha) SK_OVER
RIDE { |
| 100 // This function is currently not implemented. It is not explicitly |
| 101 // required by the contract, but if at some time a code path runs in
to |
| 102 // this function (which is entirely possible), it needs to be implem
ented. |
| 103 // |
| 104 // TODO (krajcevski): |
| 105 // This function will be most easily implemented as follows: |
| 106 // 1. If width/height are smaller than a block, then update the |
| 107 // indices of the affected blocks. |
| 108 // 2. If width/height are larger than a block, then construct a 9-pa
tch |
| 109 // of block encodings that represent the rectangle, and write the
m |
| 110 // to the compressed buffer as necessary. Whether or not the bloc
ks |
| 111 // are overwritten by zeros or just their indices are updated is
up |
| 112 // to debate. |
| 113 SkFAIL("Not implemented!"); |
| 114 } |
| 115 |
| 116 // Blit a pattern of pixels defined by a rectangle-clipped mask; |
| 117 // typically used for text. |
| 118 virtual void blitMask(const SkMask&, const SkIRect& clip) SK_OVERRIDE { |
| 119 // This function is currently not implemented. It is not explicitly |
| 120 // required by the contract, but if at some time a code path runs in
to |
| 121 // this function (which is entirely possible), it needs to be implem
ented. |
| 122 // |
| 123 // TODO (krajcevski): |
| 124 // This function will be most easily implemented in the same way as |
| 125 // blitAntiRect above. |
| 126 SkFAIL("Not implemented!"); |
| 127 } |
| 128 |
| 129 // If the blitter just sets a single value for each pixel, return the |
| 130 // bitmap it draws into, and assign value. If not, return NULL and ignor
e |
| 131 // the value parameter. |
| 132 virtual const SkBitmap* justAnOpaqueColor(uint32_t* value) SK_OVERRIDE { |
| 133 return NULL; |
| 134 } |
| 135 |
| 136 /** |
| 137 * Compressed texture blitters only really work correctly if they get |
| 138 * four blocks at a time. That being said, this blitter tries it's best |
| 139 * to preserve semantics if blitAntiH doesn't get called in too many |
| 140 * weird ways... |
| 141 */ |
| 142 virtual int requestRowsPreserved() const { return kR11_EACBlockSz; } |
| 143 |
| 144 protected: |
| 145 virtual void onNotifyFinished() { this->flushRuns(); } |
| 146 |
| 147 private: |
| 148 static const int kR11_EACBlockSz = 4; |
| 149 static const int kPixelsPerBlock = kR11_EACBlockSz * kR11_EACBlockSz; |
| 150 |
| 151 // The longest possible run of pixels that this blitter will receive. |
| 152 // This is initialized in the constructor to 0x7FFE, which is one less |
| 153 // than the largest positive 16-bit integer. We make sure that it's one |
| 154 // less for debugging purposes. We also don't make this variable static |
| 155 // in order to make sure that we can construct a valid pointer to it. |
| 156 const int16_t kLongestRun; |
| 157 |
| 158 // Usually used in conjunction with kLongestRun. This is initialized to |
| 159 // zero. |
| 160 const SkAlpha kZeroAlpha; |
| 161 |
| 162 // This is the information that we buffer whenever we're asked to blit |
| 163 // a row with this blitter. |
| 164 struct BufferedRun { |
| 165 const SkAlpha* fAlphas; |
| 166 const int16_t* fRuns; |
| 167 int fX, fY; |
| 168 } fBufferedRuns[kR11_EACBlockSz]; |
| 169 |
| 170 // The next row (0-3) that we need to blit. This value should never exce
ed |
| 171 // the number of rows that we have (kR11_EACBlockSz) |
| 172 int fNextRun; |
| 173 |
| 174 // The width and height of the image that we're blitting |
| 175 const int fWidth; |
| 176 const int fHeight; |
| 177 |
| 178 // The R11 EAC buffer that we're blitting into. It is assumed that the b
uffer |
| 179 // is large enough to store a compressed image of size fWidth*fHeight. |
| 180 uint64_t* const fBuffer; |
| 181 |
| 182 // Various utility functions |
| 183 int blocksWide() const { return fWidth / kR11_EACBlockSz; } |
| 184 int blocksTall() const { return fHeight / kR11_EACBlockSz; } |
| 185 int totalBlocks() const { return (fWidth * fHeight) / kPixelsPerBlock; } |
| 186 |
| 187 // Returns the block index for the block containing pixel (x, y). Block |
| 188 // indices start at zero and proceed in raster order. |
| 189 int getBlockOffset(int x, int y) const { |
| 190 SkASSERT(x < fWidth); |
| 191 SkASSERT(y < fHeight); |
| 192 const int blockCol = x / kR11_EACBlockSz; |
| 193 const int blockRow = y / kR11_EACBlockSz; |
| 194 return blockRow * this->blocksWide() + blockCol; |
| 195 } |
| 196 |
| 197 // Returns a pointer to the block containing pixel (x, y) |
| 198 uint64_t *getBlock(int x, int y) const { |
| 199 return fBuffer + this->getBlockOffset(x, y); |
| 200 } |
| 201 |
| 202 // The following function writes the buffered runs to compressed blocks. |
| 203 // If fNextRun < 4, then we fill the runs that we haven't buffered with |
| 204 // the constant zero buffer. |
| 205 void flushRuns(); |
| 206 }; |
45 } | 207 } |
46 | 208 |
47 #endif | 209 #endif |
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