1 /*
2 * Copyright 2012 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 SkGradientShaderPriv_DEFINED
9 #define SkGradientShaderPriv_DEFINED
10
11 #include "SkGradientBitmapCache.h"
12 #include "SkGradientShader.h"
13 #include "SkClampRange.h"
14 #include "SkColorPriv.h"
15 #include "SkReadBuffer.h"
16 #include "SkWriteBuffer.h"
17 #include "SkMallocPixelRef.h"
18 #include "SkUtils.h"
19 #include "SkTemplates.h"
20 #include "SkShader.h"
21 #include "SkOnce.h"
22
sk_memset32_dither(uint32_t dst[],uint32_t v0,uint32_t v1,int count)23 static inline void sk_memset32_dither(uint32_t dst[], uint32_t v0, uint32_t v1,
24 int count) {
25 if (count > 0) {
26 if (v0 == v1) {
27 sk_memset32(dst, v0, count);
28 } else {
29 int pairs = count >> 1;
30 for (int i = 0; i < pairs; i++) {
31 *dst++ = v0;
32 *dst++ = v1;
33 }
34 if (count & 1) {
35 *dst = v0;
36 }
37 }
38 }
39 }
40
41 // Clamp
42
clamp_tileproc(SkFixed x)43 static inline SkFixed clamp_tileproc(SkFixed x) {
44 return SkClampMax(x, 0xFFFF);
45 }
46
47 // Repeat
48
repeat_tileproc(SkFixed x)49 static inline SkFixed repeat_tileproc(SkFixed x) {
50 return x & 0xFFFF;
51 }
52
53 // Mirror
54
55 // Visual Studio 2010 (MSC_VER=1600) optimizes bit-shift code incorrectly.
56 // See http://code.google.com/p/skia/issues/detail?id=472
57 #if defined(_MSC_VER) && (_MSC_VER >= 1600)
58 #pragma optimize("", off)
59 #endif
60
mirror_tileproc(SkFixed x)61 static inline SkFixed mirror_tileproc(SkFixed x) {
62 int s = x << 15 >> 31;
63 return (x ^ s) & 0xFFFF;
64 }
65
66 #if defined(_MSC_VER) && (_MSC_VER >= 1600)
67 #pragma optimize("", on)
68 #endif
69
70 ///////////////////////////////////////////////////////////////////////////////
71
72 typedef SkFixed (*TileProc)(SkFixed);
73
74 ///////////////////////////////////////////////////////////////////////////////
75
76 static const TileProc gTileProcs[] = {
77 clamp_tileproc,
78 repeat_tileproc,
79 mirror_tileproc
80 };
81
82 ///////////////////////////////////////////////////////////////////////////////
83
84 class SkGradientShaderBase : public SkShader {
85 public:
86 struct Descriptor {
DescriptorDescriptor87 Descriptor() {
88 sk_bzero(this, sizeof(*this));
89 fTileMode = SkShader::kClamp_TileMode;
90 }
91
92 const SkMatrix* fLocalMatrix;
93 const SkColor* fColors;
94 const SkScalar* fPos;
95 int fCount;
96 SkShader::TileMode fTileMode;
97 uint32_t fGradFlags;
98
99 void flatten(SkWriteBuffer&) const;
100 };
101
102 class DescriptorScope : public Descriptor {
103 public:
DescriptorScope()104 DescriptorScope() {}
105
106 bool unflatten(SkReadBuffer&);
107
108 // fColors and fPos always point into local memory, so they can be safely mutated
109 //
mutableColors()110 SkColor* mutableColors() { return const_cast<SkColor*>(fColors); }
mutablePos()111 SkScalar* mutablePos() { return const_cast<SkScalar*>(fPos); }
112
113 private:
114 enum {
115 kStorageCount = 16
116 };
117 SkColor fColorStorage[kStorageCount];
118 SkScalar fPosStorage[kStorageCount];
119 SkMatrix fLocalMatrixStorage;
120 SkAutoMalloc fDynamicStorage;
121 };
122
123 public:
124 SkGradientShaderBase(const Descriptor& desc);
125 virtual ~SkGradientShaderBase();
126
127 // The cache is initialized on-demand when getCache16/32 is called.
128 class GradientShaderCache : public SkRefCnt {
129 public:
130 GradientShaderCache(U8CPU alpha, const SkGradientShaderBase& shader);
131 ~GradientShaderCache();
132
133 const uint16_t* getCache16();
134 const SkPMColor* getCache32();
135
getCache32PixelRef()136 SkMallocPixelRef* getCache32PixelRef() const { return fCache32PixelRef; }
137
getAlpha()138 unsigned getAlpha() const { return fCacheAlpha; }
139
140 private:
141 // Working pointers. If either is NULL, we need to recompute the corresponding cache values.
142 uint16_t* fCache16;
143 SkPMColor* fCache32;
144
145 uint16_t* fCache16Storage; // Storage for fCache16, allocated on demand.
146 SkMallocPixelRef* fCache32PixelRef;
147 const unsigned fCacheAlpha; // The alpha value we used when we computed the cache.
148 // Larger than 8bits so we can store uninitialized
149 // value.
150
151 const SkGradientShaderBase& fShader;
152
153 // Make sure we only initialize the caches once.
154 bool fCache16Inited, fCache32Inited;
155 SkMutex fCache16Mutex, fCache32Mutex;
156
157 static void initCache16(GradientShaderCache* cache);
158 static void initCache32(GradientShaderCache* cache);
159
160 static void Build16bitCache(uint16_t[], SkColor c0, SkColor c1, int count);
161 static void Build32bitCache(SkPMColor[], SkColor c0, SkColor c1, int count,
162 U8CPU alpha, uint32_t gradFlags);
163 };
164
165 class GradientShaderBaseContext : public SkShader::Context {
166 public:
167 GradientShaderBaseContext(const SkGradientShaderBase& shader, const ContextRec&);
168
getFlags()169 virtual uint32_t getFlags() const SK_OVERRIDE { return fFlags; }
170
171 protected:
172 SkMatrix fDstToIndex;
173 SkMatrix::MapXYProc fDstToIndexProc;
174 uint8_t fDstToIndexClass;
175 uint8_t fFlags;
176
177 SkAutoTUnref<GradientShaderCache> fCache;
178
179 private:
180 typedef SkShader::Context INHERITED;
181 };
182
183 virtual bool isOpaque() const SK_OVERRIDE;
184
185 void getGradientTableBitmap(SkBitmap*) const;
186
187 enum {
188 /// Seems like enough for visual accuracy. TODO: if pos[] deserves
189 /// it, use a larger cache.
190 kCache16Bits = 8,
191 kCache16Count = (1 << kCache16Bits),
192 kCache16Shift = 16 - kCache16Bits,
193 kSqrt16Shift = 8 - kCache16Bits,
194
195 /// Seems like enough for visual accuracy. TODO: if pos[] deserves
196 /// it, use a larger cache.
197 kCache32Bits = 8,
198 kCache32Count = (1 << kCache32Bits),
199 kCache32Shift = 16 - kCache32Bits,
200 kSqrt32Shift = 8 - kCache32Bits,
201
202 /// This value is used to *read* the dither cache; it may be 0
203 /// if dithering is disabled.
204 kDitherStride32 = kCache32Count,
205 kDitherStride16 = kCache16Count,
206 };
207
208 enum GpuColorType {
209 kTwo_GpuColorType,
210 kThree_GpuColorType, // Symmetric three color
211 kTexture_GpuColorType
212 };
213
214 // Determines and returns the gradient is a two color gradient, symmetric three color gradient
215 // or other (texture gradient). If it is two or symmetric three color, the colors array will
216 // also be filled with the gradient colors
217 GpuColorType getGpuColorType(SkColor colors[3]) const;
218
getGradFlags()219 uint32_t getGradFlags() const { return fGradFlags; }
220
221 protected:
222 SkGradientShaderBase(SkReadBuffer& );
223 virtual void flatten(SkWriteBuffer&) const SK_OVERRIDE;
224 SK_TO_STRING_OVERRIDE()
225
226 SkMatrix fPtsToUnit; // set by subclass
227 TileMode fTileMode;
228 TileProc fTileProc;
229 int fColorCount;
230 uint8_t fGradFlags;
231
232 struct Rec {
233 SkFixed fPos; // 0...1
234 uint32_t fScale; // (1 << 24) / range
235 };
236 Rec* fRecs;
237
238 void commonAsAGradient(GradientInfo*, bool flipGrad = false) const;
239
240 virtual bool onAsLuminanceColor(SkColor*) const SK_OVERRIDE;
241
242 /*
243 * Takes in pointers to gradient color and Rec info as colorSrc and recSrc respectively.
244 * Count is the number of colors in the gradient
245 * It will then flip all the color and rec information and return in their respective Dst
246 * pointers. It is assumed that space has already been allocated for the Dst pointers.
247 * The rec src and dst are only assumed to be valid if count > 2
248 */
249 static void FlipGradientColors(SkColor* colorDst, Rec* recDst,
250 SkColor* colorSrc, Rec* recSrc,
251 int count);
252
253 // V23_COMPATIBILITY_CODE
254 // Used for 2-pt conical gradients since we sort start/end cirlces by radius
255 // Assumes space has already been allocated for fOrigColors
256 void flipGradientColors();
257
258 private:
259 enum {
260 kColorStorageCount = 4, // more than this many colors, and we'll use sk_malloc for the space
261
262 kStorageSize = kColorStorageCount * (sizeof(SkColor) + sizeof(SkScalar) + sizeof(Rec))
263 };
264 SkColor fStorage[(kStorageSize + 3) >> 2];
265 SkColor* fOrigColors; // original colors, before modulation by paint in context.
266 SkScalar* fOrigPos; // original positions
267 bool fColorsAreOpaque;
268
269 GradientShaderCache* refCache(U8CPU alpha) const;
270 mutable SkMutex fCacheMutex;
271 mutable SkAutoTUnref<GradientShaderCache> fCache;
272
273 void initCommon();
274
275 typedef SkShader INHERITED;
276 };
277
init_dither_toggle(int x,int y)278 static inline int init_dither_toggle(int x, int y) {
279 x &= 1;
280 y = (y & 1) << 1;
281 return (x | y) * SkGradientShaderBase::kDitherStride32;
282 }
283
next_dither_toggle(int toggle)284 static inline int next_dither_toggle(int toggle) {
285 return toggle ^ SkGradientShaderBase::kDitherStride32;
286 }
287
init_dither_toggle16(int x,int y)288 static inline int init_dither_toggle16(int x, int y) {
289 return ((x ^ y) & 1) * SkGradientShaderBase::kDitherStride16;
290 }
291
next_dither_toggle16(int toggle)292 static inline int next_dither_toggle16(int toggle) {
293 return toggle ^ SkGradientShaderBase::kDitherStride16;
294 }
295
296 ///////////////////////////////////////////////////////////////////////////////
297
298 #if SK_SUPPORT_GPU
299
300 #include "GrCoordTransform.h"
301 #include "gl/GrGLProcessor.h"
302
303 class GrProcessorStage;
304 class GrBackendProcessorFactory;
305
306 /*
307 * The interpretation of the texture matrix depends on the sample mode. The
308 * texture matrix is applied both when the texture coordinates are explicit
309 * and when vertex positions are used as texture coordinates. In the latter
310 * case the texture matrix is applied to the pre-view-matrix position
311 * values.
312 *
313 * Normal SampleMode
314 * The post-matrix texture coordinates are in normalize space with (0,0) at
315 * the top-left and (1,1) at the bottom right.
316 * RadialGradient
317 * The matrix specifies the radial gradient parameters.
318 * (0,0) in the post-matrix space is center of the radial gradient.
319 * Radial2Gradient
320 * Matrix transforms to space where first circle is centered at the
321 * origin. The second circle will be centered (x, 0) where x may be
322 * 0 and is provided by setRadial2Params. The post-matrix space is
323 * normalized such that 1 is the second radius - first radius.
324 * SweepGradient
325 * The angle from the origin of texture coordinates in post-matrix space
326 * determines the gradient value.
327 */
328
329 class GrTextureStripAtlas;
330
331 // Base class for Gr gradient effects
332 class GrGradientEffect : public GrFragmentProcessor {
333 public:
334
335 GrGradientEffect(GrContext* ctx,
336 const SkGradientShaderBase& shader,
337 const SkMatrix& matrix,
338 SkShader::TileMode tileMode);
339
340 virtual ~GrGradientEffect();
341
useAtlas()342 bool useAtlas() const { return SkToBool(-1 != fRow); }
getYCoord()343 SkScalar getYCoord() const { return fYCoord; };
344
345 virtual void getConstantColorComponents(GrColor* color, uint32_t* validFlags) const SK_OVERRIDE;
346
getColorType()347 SkGradientShaderBase::GpuColorType getColorType() const { return fColorType; }
348
349 enum PremulType {
350 kBeforeInterp_PremulType,
351 kAfterInterp_PremulType,
352 };
353
getPremulType()354 PremulType getPremulType() const { return fPremulType; }
355
getColors(int pos)356 const SkColor* getColors(int pos) const {
357 SkASSERT(fColorType != SkGradientShaderBase::kTexture_GpuColorType);
358 SkASSERT((pos-1) <= fColorType);
359 return &fColors[pos];
360 }
361
362 protected:
363
364 /** Populates a pair of arrays with colors and stop info to construct a random gradient.
365 The function decides whether stop values should be used or not. The return value indicates
366 the number of colors, which will be capped by kMaxRandomGradientColors. colors should be
367 sized to be at least kMaxRandomGradientColors. stops is a pointer to an array of at least
368 size kMaxRandomGradientColors. It may be updated to NULL, indicating that NULL should be
369 passed to the gradient factory rather than the array.
370 */
371 static const int kMaxRandomGradientColors = 4;
372 static int RandomGradientParams(SkRandom* r,
373 SkColor colors[kMaxRandomGradientColors],
374 SkScalar** stops,
375 SkShader::TileMode* tm);
376
377 virtual bool onIsEqual(const GrProcessor&) const SK_OVERRIDE;
378
getCoordTransform()379 const GrCoordTransform& getCoordTransform() const { return fCoordTransform; }
380
381 private:
382 static const GrCoordSet kCoordSet = kLocal_GrCoordSet;
383
384 GrCoordTransform fCoordTransform;
385 GrTextureAccess fTextureAccess;
386 SkScalar fYCoord;
387 GrTextureStripAtlas* fAtlas;
388 int fRow;
389 bool fIsOpaque;
390 SkGradientShaderBase::GpuColorType fColorType;
391 SkColor fColors[3]; // More than 3 colors we use texture
392 PremulType fPremulType; // This only changes behavior for two and three color special cases.
393 // It is already baked into to the table for texture gradients.
394 typedef GrFragmentProcessor INHERITED;
395
396 };
397
398 ///////////////////////////////////////////////////////////////////////////////
399
400 // Base class for GL gradient effects
401 class GrGLGradientEffect : public GrGLFragmentProcessor {
402 public:
403 GrGLGradientEffect(const GrBackendProcessorFactory& factory);
404 virtual ~GrGLGradientEffect();
405
406 virtual void setData(const GrGLProgramDataManager&, const GrProcessor&) SK_OVERRIDE;
407
408 protected:
409 /**
410 * Subclasses must call this. It will return a key for the part of the shader code controlled
411 * by the base class. The subclasses must stick it in their key and then pass it to the below
412 * emit* functions from their emitCode function.
413 */
414 static uint32_t GenBaseGradientKey(const GrProcessor&);
415
416 // Emits the uniform used as the y-coord to texture samples in derived classes. Subclasses
417 // should call this method from their emitCode().
418 void emitUniforms(GrGLProgramBuilder* builder, uint32_t baseKey);
419
420
421 // emit code that gets a fragment's color from an expression for t; Has branches for 3 separate
422 // control flows inside -- 2 color gradients, 3 color symmetric gradients (both using
423 // native GLSL mix), and 4+ color gradients that use the traditional texture lookup.
424 void emitColor(GrGLProgramBuilder* builder,
425 const char* gradientTValue,
426 uint32_t baseKey,
427 const char* outputColor,
428 const char* inputColor,
429 const TextureSamplerArray& samplers);
430
431 private:
432 enum {
433 kPremulTypeKeyBitCnt = 1,
434 kPremulTypeMask = 1,
435 kPremulBeforeInterpKey = kPremulTypeMask,
436
437 kTwoColorKey = 2 << kPremulTypeKeyBitCnt,
438 kThreeColorKey = 3 << kPremulTypeKeyBitCnt,
439 kColorKeyMask = kTwoColorKey | kThreeColorKey,
440 kColorKeyBitCnt = 2,
441
442 // Subclasses must shift any key bits they produce up by this amount
443 // and combine with the result of GenBaseGradientKey.
444 kBaseKeyBitCnt = (kPremulTypeKeyBitCnt + kColorKeyBitCnt)
445 };
446 GR_STATIC_ASSERT(kBaseKeyBitCnt <= 32);
447
ColorTypeFromKey(uint32_t baseKey)448 static SkGradientShaderBase::GpuColorType ColorTypeFromKey(uint32_t baseKey){
449 if (kTwoColorKey == (baseKey & kColorKeyMask)) {
450 return SkGradientShaderBase::kTwo_GpuColorType;
451 } else if (kThreeColorKey == (baseKey & kColorKeyMask)) {
452 return SkGradientShaderBase::kThree_GpuColorType;
453 } else {return SkGradientShaderBase::kTexture_GpuColorType;}
454 }
455
PremulTypeFromKey(uint32_t baseKey)456 static GrGradientEffect::PremulType PremulTypeFromKey(uint32_t baseKey){
457 if (kPremulBeforeInterpKey == (baseKey & kPremulTypeMask)) {
458 return GrGradientEffect::kBeforeInterp_PremulType;
459 } else {
460 return GrGradientEffect::kAfterInterp_PremulType;
461 }
462 }
463
464 SkScalar fCachedYCoord;
465 GrGLProgramDataManager::UniformHandle fFSYUni;
466 GrGLProgramDataManager::UniformHandle fColorStartUni;
467 GrGLProgramDataManager::UniformHandle fColorMidUni;
468 GrGLProgramDataManager::UniformHandle fColorEndUni;
469
470 typedef GrGLFragmentProcessor INHERITED;
471 };
472
473 #endif
474
475 #endif
476