1/*
2 * Copyright 2013 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#include "SkDither.h"
9#include "SkPerlinNoiseShader.h"
10#include "SkColorFilter.h"
11#include "SkFlattenableBuffers.h"
12#include "SkShader.h"
13#include "SkUnPreMultiply.h"
14#include "SkString.h"
15
16#if SK_SUPPORT_GPU
17#include "GrContext.h"
18#include "GrCoordTransform.h"
19#include "gl/GrGLEffect.h"
20#include "GrTBackendEffectFactory.h"
21#include "SkGr.h"
22#endif
23
24static const int kBlockSize = 256;
25static const int kBlockMask = kBlockSize - 1;
26static const int kPerlinNoise = 4096;
27static const int kRandMaximum = SK_MaxS32; // 2**31 - 1
28
29namespace {
30
31// noiseValue is the color component's value (or color)
32// limitValue is the maximum perlin noise array index value allowed
33// newValue is the current noise dimension (either width or height)
34inline int checkNoise(int noiseValue, int limitValue, int newValue) {
35    // If the noise value would bring us out of bounds of the current noise array while we are
36    // stiching noise tiles together, wrap the noise around the current dimension of the noise to
37    // stay within the array bounds in a continuous fashion (so that tiling lines are not visible)
38    if (noiseValue >= limitValue) {
39        noiseValue -= newValue;
40    }
41    if (noiseValue >= limitValue - 1) {
42        noiseValue -= newValue - 1;
43    }
44    return noiseValue;
45}
46
47inline SkScalar smoothCurve(SkScalar t) {
48    static const SkScalar SK_Scalar3 = 3.0f;
49
50    // returns t * t * (3 - 2 * t)
51    return SkScalarMul(SkScalarSquare(t), SK_Scalar3 - 2 * t);
52}
53
54bool perlin_noise_type_is_valid(SkPerlinNoiseShader::Type type) {
55    return (SkPerlinNoiseShader::kFractalNoise_Type == type) ||
56           (SkPerlinNoiseShader::kTurbulence_Type == type);
57}
58
59} // end namespace
60
61struct SkPerlinNoiseShader::StitchData {
62    StitchData()
63      : fWidth(0)
64      , fWrapX(0)
65      , fHeight(0)
66      , fWrapY(0)
67    {}
68
69    bool operator==(const StitchData& other) const {
70        return fWidth == other.fWidth &&
71               fWrapX == other.fWrapX &&
72               fHeight == other.fHeight &&
73               fWrapY == other.fWrapY;
74    }
75
76    int fWidth; // How much to subtract to wrap for stitching.
77    int fWrapX; // Minimum value to wrap.
78    int fHeight;
79    int fWrapY;
80};
81
82struct SkPerlinNoiseShader::PaintingData {
83    PaintingData(const SkISize& tileSize)
84      : fSeed(0)
85      , fTileSize(tileSize)
86      , fPermutationsBitmap(NULL)
87      , fNoiseBitmap(NULL)
88    {}
89
90    ~PaintingData()
91    {
92        SkDELETE(fPermutationsBitmap);
93        SkDELETE(fNoiseBitmap);
94    }
95
96    int         fSeed;
97    uint8_t     fLatticeSelector[kBlockSize];
98    uint16_t    fNoise[4][kBlockSize][2];
99    SkPoint     fGradient[4][kBlockSize];
100    SkISize     fTileSize;
101    SkVector    fBaseFrequency;
102    StitchData  fStitchDataInit;
103
104private:
105
106    SkBitmap*    fPermutationsBitmap;
107    SkBitmap*    fNoiseBitmap;
108
109public:
110
111    inline int random()  {
112        static const int gRandAmplitude = 16807; // 7**5; primitive root of m
113        static const int gRandQ = 127773; // m / a
114        static const int gRandR = 2836; // m % a
115
116        int result = gRandAmplitude * (fSeed % gRandQ) - gRandR * (fSeed / gRandQ);
117        if (result <= 0)
118            result += kRandMaximum;
119        fSeed = result;
120        return result;
121    }
122
123    void init(SkScalar seed)
124    {
125        static const SkScalar gInvBlockSizef = SkScalarInvert(SkIntToScalar(kBlockSize));
126
127        // The seed value clamp to the range [1, kRandMaximum - 1].
128        fSeed = SkScalarRoundToInt(seed);
129        if (fSeed <= 0) {
130            fSeed = -(fSeed % (kRandMaximum - 1)) + 1;
131        }
132        if (fSeed > kRandMaximum - 1) {
133            fSeed = kRandMaximum - 1;
134        }
135        for (int channel = 0; channel < 4; ++channel) {
136            for (int i = 0; i < kBlockSize; ++i) {
137                fLatticeSelector[i] = i;
138                fNoise[channel][i][0] = (random() % (2 * kBlockSize));
139                fNoise[channel][i][1] = (random() % (2 * kBlockSize));
140            }
141        }
142        for (int i = kBlockSize - 1; i > 0; --i) {
143            int k = fLatticeSelector[i];
144            int j = random() % kBlockSize;
145            SkASSERT(j >= 0);
146            SkASSERT(j < kBlockSize);
147            fLatticeSelector[i] = fLatticeSelector[j];
148            fLatticeSelector[j] = k;
149        }
150
151        // Perform the permutations now
152        {
153            // Copy noise data
154            uint16_t noise[4][kBlockSize][2];
155            for (int i = 0; i < kBlockSize; ++i) {
156                for (int channel = 0; channel < 4; ++channel) {
157                    for (int j = 0; j < 2; ++j) {
158                        noise[channel][i][j] = fNoise[channel][i][j];
159                    }
160                }
161            }
162            // Do permutations on noise data
163            for (int i = 0; i < kBlockSize; ++i) {
164                for (int channel = 0; channel < 4; ++channel) {
165                    for (int j = 0; j < 2; ++j) {
166                        fNoise[channel][i][j] = noise[channel][fLatticeSelector[i]][j];
167                    }
168                }
169            }
170        }
171
172        // Half of the largest possible value for 16 bit unsigned int
173        static const SkScalar gHalfMax16bits = 32767.5f;
174
175        // Compute gradients from permutated noise data
176        for (int channel = 0; channel < 4; ++channel) {
177            for (int i = 0; i < kBlockSize; ++i) {
178                fGradient[channel][i] = SkPoint::Make(
179                    SkScalarMul(SkIntToScalar(fNoise[channel][i][0] - kBlockSize),
180                                gInvBlockSizef),
181                    SkScalarMul(SkIntToScalar(fNoise[channel][i][1] - kBlockSize),
182                                gInvBlockSizef));
183                fGradient[channel][i].normalize();
184                // Put the normalized gradient back into the noise data
185                fNoise[channel][i][0] = SkScalarRoundToInt(SkScalarMul(
186                    fGradient[channel][i].fX + SK_Scalar1, gHalfMax16bits));
187                fNoise[channel][i][1] = SkScalarRoundToInt(SkScalarMul(
188                    fGradient[channel][i].fY + SK_Scalar1, gHalfMax16bits));
189            }
190        }
191
192        // Invalidate bitmaps
193        SkDELETE(fPermutationsBitmap);
194        fPermutationsBitmap = NULL;
195        SkDELETE(fNoiseBitmap);
196        fNoiseBitmap = NULL;
197    }
198
199    void stitch() {
200        SkScalar tileWidth  = SkIntToScalar(fTileSize.width());
201        SkScalar tileHeight = SkIntToScalar(fTileSize.height());
202        SkASSERT(tileWidth > 0 && tileHeight > 0);
203        // When stitching tiled turbulence, the frequencies must be adjusted
204        // so that the tile borders will be continuous.
205        if (fBaseFrequency.fX) {
206            SkScalar lowFrequencx = SkScalarDiv(
207                SkScalarMulFloor(tileWidth, fBaseFrequency.fX), tileWidth);
208            SkScalar highFrequencx = SkScalarDiv(
209                SkScalarMulCeil(tileWidth, fBaseFrequency.fX), tileWidth);
210            // BaseFrequency should be non-negative according to the standard.
211            if (SkScalarDiv(fBaseFrequency.fX, lowFrequencx) <
212                SkScalarDiv(highFrequencx, fBaseFrequency.fX)) {
213                fBaseFrequency.fX = lowFrequencx;
214            } else {
215                fBaseFrequency.fX = highFrequencx;
216            }
217        }
218        if (fBaseFrequency.fY) {
219            SkScalar lowFrequency = SkScalarDiv(
220                SkScalarMulFloor(tileHeight, fBaseFrequency.fY), tileHeight);
221            SkScalar highFrequency = SkScalarDiv(
222                SkScalarMulCeil(tileHeight, fBaseFrequency.fY), tileHeight);
223            if (SkScalarDiv(fBaseFrequency.fY, lowFrequency) <
224                SkScalarDiv(highFrequency, fBaseFrequency.fY)) {
225                fBaseFrequency.fY = lowFrequency;
226            } else {
227                fBaseFrequency.fY = highFrequency;
228            }
229        }
230        // Set up TurbulenceInitial stitch values.
231        fStitchDataInit.fWidth  =
232            SkScalarMulRound(tileWidth, fBaseFrequency.fX);
233        fStitchDataInit.fWrapX  = kPerlinNoise + fStitchDataInit.fWidth;
234        fStitchDataInit.fHeight =
235            SkScalarMulRound(tileHeight, fBaseFrequency.fY);
236        fStitchDataInit.fWrapY  = kPerlinNoise + fStitchDataInit.fHeight;
237    }
238
239    SkBitmap* getPermutationsBitmap()
240    {
241        if (!fPermutationsBitmap) {
242            fPermutationsBitmap = SkNEW(SkBitmap);
243            fPermutationsBitmap->setConfig(SkBitmap::kA8_Config, kBlockSize, 1);
244            fPermutationsBitmap->allocPixels();
245            uint8_t* bitmapPixels = fPermutationsBitmap->getAddr8(0, 0);
246            memcpy(bitmapPixels, fLatticeSelector, sizeof(uint8_t) * kBlockSize);
247        }
248        return fPermutationsBitmap;
249    }
250
251    SkBitmap* getNoiseBitmap()
252    {
253        if (!fNoiseBitmap) {
254            fNoiseBitmap = SkNEW(SkBitmap);
255            fNoiseBitmap->setConfig(SkBitmap::kARGB_8888_Config, kBlockSize, 4);
256            fNoiseBitmap->allocPixels();
257            uint32_t* bitmapPixels = fNoiseBitmap->getAddr32(0, 0);
258            memcpy(bitmapPixels, fNoise[0][0], sizeof(uint16_t) * kBlockSize * 4 * 2);
259        }
260        return fNoiseBitmap;
261    }
262};
263
264SkShader* SkPerlinNoiseShader::CreateFractalNoise(SkScalar baseFrequencyX, SkScalar baseFrequencyY,
265                                                  int numOctaves, SkScalar seed,
266                                                  const SkISize* tileSize) {
267    return SkNEW_ARGS(SkPerlinNoiseShader, (kFractalNoise_Type, baseFrequencyX, baseFrequencyY,
268                                            numOctaves, seed, tileSize));
269}
270
271SkShader* SkPerlinNoiseShader::CreateTubulence(SkScalar baseFrequencyX, SkScalar baseFrequencyY,
272                                              int numOctaves, SkScalar seed,
273                                              const SkISize* tileSize) {
274    return SkNEW_ARGS(SkPerlinNoiseShader, (kTurbulence_Type, baseFrequencyX, baseFrequencyY,
275                                            numOctaves, seed, tileSize));
276}
277
278SkPerlinNoiseShader::SkPerlinNoiseShader(SkPerlinNoiseShader::Type type,
279                                         SkScalar baseFrequencyX,
280                                         SkScalar baseFrequencyY,
281                                         int numOctaves,
282                                         SkScalar seed,
283                                         const SkISize* tileSize)
284  : fType(type)
285  , fBaseFrequencyX(baseFrequencyX)
286  , fBaseFrequencyY(baseFrequencyY)
287  , fNumOctaves(numOctaves > 255 ? 255 : numOctaves/*[0,255] octaves allowed*/)
288  , fSeed(seed)
289  , fStitchTiles((tileSize != NULL) && !tileSize->isEmpty())
290  , fPaintingData(NULL)
291{
292    SkASSERT(numOctaves >= 0 && numOctaves < 256);
293    setTileSize(fStitchTiles ? *tileSize : SkISize::Make(0,0));
294    fMatrix.reset();
295}
296
297SkPerlinNoiseShader::SkPerlinNoiseShader(SkFlattenableReadBuffer& buffer) :
298        INHERITED(buffer), fPaintingData(NULL) {
299    fType           = (SkPerlinNoiseShader::Type) buffer.readInt();
300    fBaseFrequencyX = buffer.readScalar();
301    fBaseFrequencyY = buffer.readScalar();
302    fNumOctaves     = buffer.readInt();
303    fSeed           = buffer.readScalar();
304    fStitchTiles    = buffer.readBool();
305    fTileSize.fWidth  = buffer.readInt();
306    fTileSize.fHeight = buffer.readInt();
307    setTileSize(fTileSize);
308    fMatrix.reset();
309    buffer.validate(perlin_noise_type_is_valid(fType) &&
310                    (fNumOctaves >= 0) && (fNumOctaves <= 255));
311}
312
313SkPerlinNoiseShader::~SkPerlinNoiseShader() {
314    // Safety, should have been done in endContext()
315    SkDELETE(fPaintingData);
316}
317
318void SkPerlinNoiseShader::flatten(SkFlattenableWriteBuffer& buffer) const {
319    this->INHERITED::flatten(buffer);
320    buffer.writeInt((int) fType);
321    buffer.writeScalar(fBaseFrequencyX);
322    buffer.writeScalar(fBaseFrequencyY);
323    buffer.writeInt(fNumOctaves);
324    buffer.writeScalar(fSeed);
325    buffer.writeBool(fStitchTiles);
326    buffer.writeInt(fTileSize.fWidth);
327    buffer.writeInt(fTileSize.fHeight);
328}
329
330void SkPerlinNoiseShader::initPaint(PaintingData& paintingData)
331{
332    paintingData.init(fSeed);
333
334    // Set frequencies to original values
335    paintingData.fBaseFrequency.set(fBaseFrequencyX, fBaseFrequencyY);
336    // Adjust frequecies based on size if stitching is enabled
337    if (fStitchTiles) {
338        paintingData.stitch();
339    }
340}
341
342void SkPerlinNoiseShader::setTileSize(const SkISize& tileSize) {
343    fTileSize = tileSize;
344
345    if (NULL == fPaintingData) {
346        fPaintingData = SkNEW_ARGS(PaintingData, (fTileSize));
347        initPaint(*fPaintingData);
348    } else {
349        // Set Size
350        fPaintingData->fTileSize = fTileSize;
351        // Set frequencies to original values
352        fPaintingData->fBaseFrequency.set(fBaseFrequencyX, fBaseFrequencyY);
353        // Adjust frequecies based on size if stitching is enabled
354        if (fStitchTiles) {
355            fPaintingData->stitch();
356        }
357    }
358}
359
360SkScalar SkPerlinNoiseShader::noise2D(int channel, const PaintingData& paintingData,
361                                     const StitchData& stitchData, const SkPoint& noiseVector)
362{
363    struct Noise {
364        int noisePositionIntegerValue;
365        SkScalar noisePositionFractionValue;
366        Noise(SkScalar component)
367        {
368            SkScalar position = component + kPerlinNoise;
369            noisePositionIntegerValue = SkScalarFloorToInt(position);
370            noisePositionFractionValue = position - SkIntToScalar(noisePositionIntegerValue);
371        }
372    };
373    Noise noiseX(noiseVector.x());
374    Noise noiseY(noiseVector.y());
375    SkScalar u, v;
376    // If stitching, adjust lattice points accordingly.
377    if (fStitchTiles) {
378        noiseX.noisePositionIntegerValue =
379            checkNoise(noiseX.noisePositionIntegerValue, stitchData.fWrapX, stitchData.fWidth);
380        noiseY.noisePositionIntegerValue =
381            checkNoise(noiseY.noisePositionIntegerValue, stitchData.fWrapY, stitchData.fHeight);
382    }
383    noiseX.noisePositionIntegerValue &= kBlockMask;
384    noiseY.noisePositionIntegerValue &= kBlockMask;
385    int latticeIndex =
386        paintingData.fLatticeSelector[noiseX.noisePositionIntegerValue] +
387        noiseY.noisePositionIntegerValue;
388    int nextLatticeIndex =
389        paintingData.fLatticeSelector[(noiseX.noisePositionIntegerValue + 1) & kBlockMask] +
390        noiseY.noisePositionIntegerValue;
391    SkScalar sx = smoothCurve(noiseX.noisePositionFractionValue);
392    SkScalar sy = smoothCurve(noiseY.noisePositionFractionValue);
393    // This is taken 1:1 from SVG spec: http://www.w3.org/TR/SVG11/filters.html#feTurbulenceElement
394    SkPoint fractionValue = SkPoint::Make(noiseX.noisePositionFractionValue,
395                                          noiseY.noisePositionFractionValue); // Offset (0,0)
396    u = paintingData.fGradient[channel][latticeIndex & kBlockMask].dot(fractionValue);
397    fractionValue.fX -= SK_Scalar1; // Offset (-1,0)
398    v = paintingData.fGradient[channel][nextLatticeIndex & kBlockMask].dot(fractionValue);
399    SkScalar a = SkScalarInterp(u, v, sx);
400    fractionValue.fY -= SK_Scalar1; // Offset (-1,-1)
401    v = paintingData.fGradient[channel][(nextLatticeIndex + 1) & kBlockMask].dot(fractionValue);
402    fractionValue.fX = noiseX.noisePositionFractionValue; // Offset (0,-1)
403    u = paintingData.fGradient[channel][(latticeIndex + 1) & kBlockMask].dot(fractionValue);
404    SkScalar b = SkScalarInterp(u, v, sx);
405    return SkScalarInterp(a, b, sy);
406}
407
408SkScalar SkPerlinNoiseShader::calculateTurbulenceValueForPoint(
409    int channel, const PaintingData& paintingData, StitchData& stitchData, const SkPoint& point)
410{
411    if (fStitchTiles) {
412        // Set up TurbulenceInitial stitch values.
413        stitchData = paintingData.fStitchDataInit;
414    }
415    SkScalar turbulenceFunctionResult = 0;
416    SkPoint noiseVector(SkPoint::Make(SkScalarMul(point.x(), paintingData.fBaseFrequency.fX),
417                                      SkScalarMul(point.y(), paintingData.fBaseFrequency.fY)));
418    SkScalar ratio = SK_Scalar1;
419    for (int octave = 0; octave < fNumOctaves; ++octave) {
420        SkScalar noise = noise2D(channel, paintingData, stitchData, noiseVector);
421        turbulenceFunctionResult += SkScalarDiv(
422            (fType == kFractalNoise_Type) ? noise : SkScalarAbs(noise), ratio);
423        noiseVector.fX *= 2;
424        noiseVector.fY *= 2;
425        ratio *= 2;
426        if (fStitchTiles) {
427            // Update stitch values
428            stitchData.fWidth  *= 2;
429            stitchData.fWrapX   = stitchData.fWidth + kPerlinNoise;
430            stitchData.fHeight *= 2;
431            stitchData.fWrapY   = stitchData.fHeight + kPerlinNoise;
432        }
433    }
434
435    // The value of turbulenceFunctionResult comes from ((turbulenceFunctionResult) + 1) / 2
436    // by fractalNoise and (turbulenceFunctionResult) by turbulence.
437    if (fType == kFractalNoise_Type) {
438        turbulenceFunctionResult =
439            SkScalarMul(turbulenceFunctionResult, SK_ScalarHalf) + SK_ScalarHalf;
440    }
441
442    if (channel == 3) { // Scale alpha by paint value
443        turbulenceFunctionResult = SkScalarMul(turbulenceFunctionResult,
444            SkScalarDiv(SkIntToScalar(getPaintAlpha()), SkIntToScalar(255)));
445    }
446
447    // Clamp result
448    return SkScalarPin(turbulenceFunctionResult, 0, SK_Scalar1);
449}
450
451SkPMColor SkPerlinNoiseShader::shade(const SkPoint& point, StitchData& stitchData) {
452    SkMatrix matrix = fMatrix;
453    SkMatrix invMatrix;
454    if (!matrix.invert(&invMatrix)) {
455        invMatrix.reset();
456    } else {
457        invMatrix.postConcat(invMatrix); // Square the matrix
458    }
459    // This (1,1) translation is due to WebKit's 1 based coordinates for the noise
460    // (as opposed to 0 based, usually). The same adjustment is in the setData() function.
461    matrix.postTranslate(SK_Scalar1, SK_Scalar1);
462    SkPoint newPoint;
463    matrix.mapPoints(&newPoint, &point, 1);
464    invMatrix.mapPoints(&newPoint, &newPoint, 1);
465    newPoint.fX = SkScalarRoundToScalar(newPoint.fX);
466    newPoint.fY = SkScalarRoundToScalar(newPoint.fY);
467
468    U8CPU rgba[4];
469    for (int channel = 3; channel >= 0; --channel) {
470        rgba[channel] = SkScalarFloorToInt(255 *
471            calculateTurbulenceValueForPoint(channel, *fPaintingData, stitchData, newPoint));
472    }
473    return SkPreMultiplyARGB(rgba[3], rgba[0], rgba[1], rgba[2]);
474}
475
476bool SkPerlinNoiseShader::setContext(const SkBitmap& device, const SkPaint& paint,
477                                     const SkMatrix& matrix) {
478    fMatrix = matrix;
479    return INHERITED::setContext(device, paint, matrix);
480}
481
482void SkPerlinNoiseShader::shadeSpan(int x, int y, SkPMColor result[], int count) {
483    SkPoint point = SkPoint::Make(SkIntToScalar(x), SkIntToScalar(y));
484    StitchData stitchData;
485    for (int i = 0; i < count; ++i) {
486        result[i] = shade(point, stitchData);
487        point.fX += SK_Scalar1;
488    }
489}
490
491void SkPerlinNoiseShader::shadeSpan16(int x, int y, uint16_t result[], int count) {
492    SkPoint point = SkPoint::Make(SkIntToScalar(x), SkIntToScalar(y));
493    StitchData stitchData;
494    DITHER_565_SCAN(y);
495    for (int i = 0; i < count; ++i) {
496        unsigned dither = DITHER_VALUE(x);
497        result[i] = SkDitherRGB32To565(shade(point, stitchData), dither);
498        DITHER_INC_X(x);
499        point.fX += SK_Scalar1;
500    }
501}
502
503/////////////////////////////////////////////////////////////////////
504
505#if SK_SUPPORT_GPU
506
507#include "GrTBackendEffectFactory.h"
508
509class GrGLNoise : public GrGLEffect {
510public:
511    GrGLNoise(const GrBackendEffectFactory& factory,
512              const GrDrawEffect& drawEffect);
513    virtual ~GrGLNoise() {}
514
515    static inline EffectKey GenKey(const GrDrawEffect&, const GrGLCaps&);
516
517    virtual void setData(const GrGLUniformManager&, const GrDrawEffect&) SK_OVERRIDE;
518
519protected:
520    SkPerlinNoiseShader::Type           fType;
521    bool                                fStitchTiles;
522    int                                 fNumOctaves;
523    GrGLUniformManager::UniformHandle   fBaseFrequencyUni;
524    GrGLUniformManager::UniformHandle   fAlphaUni;
525    GrGLUniformManager::UniformHandle   fInvMatrixUni;
526
527private:
528    typedef GrGLEffect INHERITED;
529};
530
531class GrGLPerlinNoise : public GrGLNoise {
532public:
533    GrGLPerlinNoise(const GrBackendEffectFactory& factory,
534                    const GrDrawEffect& drawEffect)
535      : GrGLNoise(factory, drawEffect) {}
536    virtual ~GrGLPerlinNoise() {}
537
538    virtual void emitCode(GrGLShaderBuilder*,
539                          const GrDrawEffect&,
540                          EffectKey,
541                          const char* outputColor,
542                          const char* inputColor,
543                          const TransformedCoordsArray&,
544                          const TextureSamplerArray&) SK_OVERRIDE;
545
546    virtual void setData(const GrGLUniformManager&, const GrDrawEffect&) SK_OVERRIDE;
547
548private:
549    GrGLUniformManager::UniformHandle fStitchDataUni;
550
551    typedef GrGLNoise INHERITED;
552};
553
554class GrGLSimplexNoise : public GrGLNoise {
555    // Note : This is for reference only. GrGLPerlinNoise is used for processing.
556public:
557    GrGLSimplexNoise(const GrBackendEffectFactory& factory,
558                     const GrDrawEffect& drawEffect)
559      : GrGLNoise(factory, drawEffect) {}
560
561    virtual ~GrGLSimplexNoise() {}
562
563    virtual void emitCode(GrGLShaderBuilder*,
564                          const GrDrawEffect&,
565                          EffectKey,
566                          const char* outputColor,
567                          const char* inputColor,
568                          const TransformedCoordsArray&,
569                          const TextureSamplerArray&) SK_OVERRIDE;
570
571    virtual void setData(const GrGLUniformManager&, const GrDrawEffect&) SK_OVERRIDE;
572
573private:
574    GrGLUniformManager::UniformHandle fSeedUni;
575
576    typedef GrGLNoise INHERITED;
577};
578
579/////////////////////////////////////////////////////////////////////
580
581class GrNoiseEffect : public GrEffect {
582public:
583    virtual ~GrNoiseEffect() { }
584
585    SkPerlinNoiseShader::Type type() const { return fType; }
586    bool stitchTiles() const { return fStitchTiles; }
587    const SkVector& baseFrequency() const { return fBaseFrequency; }
588    int numOctaves() const { return fNumOctaves; }
589    const SkMatrix& matrix() const { return fCoordTransform.getMatrix(); }
590    uint8_t alpha() const { return fAlpha; }
591
592    void getConstantColorComponents(GrColor*, uint32_t* validFlags) const SK_OVERRIDE {
593        *validFlags = 0; // This is noise. Nothing is constant.
594    }
595
596protected:
597    virtual bool onIsEqual(const GrEffect& sBase) const SK_OVERRIDE {
598        const GrNoiseEffect& s = CastEffect<GrNoiseEffect>(sBase);
599        return fType == s.fType &&
600               fBaseFrequency == s.fBaseFrequency &&
601               fNumOctaves == s.fNumOctaves &&
602               fStitchTiles == s.fStitchTiles &&
603               fCoordTransform.getMatrix() == s.fCoordTransform.getMatrix() &&
604               fAlpha == s.fAlpha;
605    }
606
607    GrNoiseEffect(SkPerlinNoiseShader::Type type, const SkVector& baseFrequency, int numOctaves,
608                  bool stitchTiles, const SkMatrix& matrix, uint8_t alpha)
609      : fType(type)
610      , fBaseFrequency(baseFrequency)
611      , fNumOctaves(numOctaves)
612      , fStitchTiles(stitchTiles)
613      , fMatrix(matrix)
614      , fAlpha(alpha) {
615        // This (1,1) translation is due to WebKit's 1 based coordinates for the noise
616        // (as opposed to 0 based, usually). The same adjustment is in the shadeSpan() functions.
617        SkMatrix m = matrix;
618        m.postTranslate(SK_Scalar1, SK_Scalar1);
619        fCoordTransform.reset(kLocal_GrCoordSet, m);
620        this->addCoordTransform(&fCoordTransform);
621        this->setWillNotUseInputColor();
622    }
623
624    SkPerlinNoiseShader::Type       fType;
625    GrCoordTransform                fCoordTransform;
626    SkVector                        fBaseFrequency;
627    int                             fNumOctaves;
628    bool                            fStitchTiles;
629    SkMatrix                        fMatrix;
630    uint8_t                         fAlpha;
631
632private:
633    typedef GrEffect INHERITED;
634};
635
636class GrPerlinNoiseEffect : public GrNoiseEffect {
637public:
638    static GrEffectRef* Create(SkPerlinNoiseShader::Type type, const SkVector& baseFrequency,
639                               int numOctaves, bool stitchTiles,
640                               const SkPerlinNoiseShader::StitchData& stitchData,
641                               GrTexture* permutationsTexture, GrTexture* noiseTexture,
642                               const SkMatrix& matrix, uint8_t alpha) {
643        AutoEffectUnref effect(SkNEW_ARGS(GrPerlinNoiseEffect, (type, baseFrequency, numOctaves,
644            stitchTiles, stitchData, permutationsTexture, noiseTexture, matrix, alpha)));
645        return CreateEffectRef(effect);
646    }
647
648    virtual ~GrPerlinNoiseEffect() { }
649
650    static const char* Name() { return "PerlinNoise"; }
651    virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE {
652        return GrTBackendEffectFactory<GrPerlinNoiseEffect>::getInstance();
653    }
654    const SkPerlinNoiseShader::StitchData& stitchData() const { return fStitchData; }
655
656    typedef GrGLPerlinNoise GLEffect;
657
658private:
659    virtual bool onIsEqual(const GrEffect& sBase) const SK_OVERRIDE {
660        const GrPerlinNoiseEffect& s = CastEffect<GrPerlinNoiseEffect>(sBase);
661        return INHERITED::onIsEqual(sBase) &&
662               fPermutationsAccess.getTexture() == s.fPermutationsAccess.getTexture() &&
663               fNoiseAccess.getTexture() == s.fNoiseAccess.getTexture() &&
664               fStitchData == s.fStitchData;
665    }
666
667    GrPerlinNoiseEffect(SkPerlinNoiseShader::Type type, const SkVector& baseFrequency,
668                        int numOctaves, bool stitchTiles,
669                        const SkPerlinNoiseShader::StitchData& stitchData,
670                        GrTexture* permutationsTexture, GrTexture* noiseTexture,
671                        const SkMatrix& matrix, uint8_t alpha)
672      : GrNoiseEffect(type, baseFrequency, numOctaves, stitchTiles, matrix, alpha)
673      , fPermutationsAccess(permutationsTexture)
674      , fNoiseAccess(noiseTexture)
675      , fStitchData(stitchData) {
676        this->addTextureAccess(&fPermutationsAccess);
677        this->addTextureAccess(&fNoiseAccess);
678    }
679
680    GR_DECLARE_EFFECT_TEST;
681
682    GrTextureAccess                 fPermutationsAccess;
683    GrTextureAccess                 fNoiseAccess;
684    SkPerlinNoiseShader::StitchData fStitchData;
685
686    typedef GrNoiseEffect INHERITED;
687};
688
689class GrSimplexNoiseEffect : public GrNoiseEffect {
690    // Note : This is for reference only. GrPerlinNoiseEffect is used for processing.
691public:
692    static GrEffectRef* Create(SkPerlinNoiseShader::Type type, const SkVector& baseFrequency,
693                               int numOctaves, bool stitchTiles, const SkScalar seed,
694                               const SkMatrix& matrix, uint8_t alpha) {
695        AutoEffectUnref effect(SkNEW_ARGS(GrSimplexNoiseEffect, (type, baseFrequency, numOctaves,
696            stitchTiles, seed, matrix, alpha)));
697        return CreateEffectRef(effect);
698    }
699
700    virtual ~GrSimplexNoiseEffect() { }
701
702    static const char* Name() { return "SimplexNoise"; }
703    virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE {
704        return GrTBackendEffectFactory<GrSimplexNoiseEffect>::getInstance();
705    }
706    const SkScalar& seed() const { return fSeed; }
707
708    typedef GrGLSimplexNoise GLEffect;
709
710private:
711    virtual bool onIsEqual(const GrEffect& sBase) const SK_OVERRIDE {
712        const GrSimplexNoiseEffect& s = CastEffect<GrSimplexNoiseEffect>(sBase);
713        return INHERITED::onIsEqual(sBase) && fSeed == s.fSeed;
714    }
715
716    GrSimplexNoiseEffect(SkPerlinNoiseShader::Type type, const SkVector& baseFrequency,
717                         int numOctaves, bool stitchTiles, const SkScalar seed,
718                         const SkMatrix& matrix, uint8_t alpha)
719      : GrNoiseEffect(type, baseFrequency, numOctaves, stitchTiles, matrix, alpha)
720      , fSeed(seed) {
721    }
722
723    SkScalar fSeed;
724
725    typedef GrNoiseEffect INHERITED;
726};
727
728/////////////////////////////////////////////////////////////////////
729GR_DEFINE_EFFECT_TEST(GrPerlinNoiseEffect);
730
731GrEffectRef* GrPerlinNoiseEffect::TestCreate(SkRandom* random,
732                                             GrContext* context,
733                                             const GrDrawTargetCaps&,
734                                             GrTexture**) {
735    int      numOctaves = random->nextRangeU(2, 10);
736    bool     stitchTiles = random->nextBool();
737    SkScalar seed = SkIntToScalar(random->nextU());
738    SkISize  tileSize = SkISize::Make(random->nextRangeU(4, 4096), random->nextRangeU(4, 4096));
739    SkScalar baseFrequencyX = random->nextRangeScalar(0.01f,
740                                                      0.99f);
741    SkScalar baseFrequencyY = random->nextRangeScalar(0.01f,
742                                                      0.99f);
743
744    SkShader* shader = random->nextBool() ?
745        SkPerlinNoiseShader::CreateFractalNoise(baseFrequencyX, baseFrequencyY, numOctaves, seed,
746                                                stitchTiles ? &tileSize : NULL) :
747        SkPerlinNoiseShader::CreateTubulence(baseFrequencyX, baseFrequencyY, numOctaves, seed,
748                                             stitchTiles ? &tileSize : NULL);
749
750    SkPaint paint;
751    GrEffectRef* effect = shader->asNewEffect(context, paint);
752
753    SkDELETE(shader);
754
755    return effect;
756}
757
758/////////////////////////////////////////////////////////////////////
759
760void GrGLSimplexNoise::emitCode(GrGLShaderBuilder* builder,
761                                const GrDrawEffect&,
762                                EffectKey key,
763                                const char* outputColor,
764                                const char* inputColor,
765                                const TransformedCoordsArray& coords,
766                                const TextureSamplerArray&) {
767    sk_ignore_unused_variable(inputColor);
768
769    SkString vCoords = builder->ensureFSCoords2D(coords, 0);
770
771    fSeedUni = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
772                                   kFloat_GrSLType, "seed");
773    const char* seedUni = builder->getUniformCStr(fSeedUni);
774    fInvMatrixUni = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
775                                        kMat33f_GrSLType, "invMatrix");
776    const char* invMatrixUni = builder->getUniformCStr(fInvMatrixUni);
777    fBaseFrequencyUni = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
778                                            kVec2f_GrSLType, "baseFrequency");
779    const char* baseFrequencyUni = builder->getUniformCStr(fBaseFrequencyUni);
780    fAlphaUni = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
781                                    kFloat_GrSLType, "alpha");
782    const char* alphaUni = builder->getUniformCStr(fAlphaUni);
783
784    // Add vec3 modulo 289 function
785    static const GrGLShaderVar gVec3Args[] =  {
786        GrGLShaderVar("x", kVec3f_GrSLType)
787    };
788
789    SkString mod289_3_funcName;
790    builder->fsEmitFunction(kVec3f_GrSLType,
791                            "mod289", SK_ARRAY_COUNT(gVec3Args), gVec3Args,
792                            "const vec2 C = vec2(1.0 / 289.0, 289.0);\n"
793                            "return x - floor(x * C.xxx) * C.yyy;", &mod289_3_funcName);
794
795    // Add vec4 modulo 289 function
796    static const GrGLShaderVar gVec4Args[] =  {
797        GrGLShaderVar("x", kVec4f_GrSLType)
798    };
799
800    SkString mod289_4_funcName;
801    builder->fsEmitFunction(kVec4f_GrSLType,
802                            "mod289", SK_ARRAY_COUNT(gVec4Args), gVec4Args,
803                            "const vec2 C = vec2(1.0 / 289.0, 289.0);\n"
804                            "return x - floor(x * C.xxxx) * C.yyyy;", &mod289_4_funcName);
805
806    // Add vec4 permute function
807    SkString permuteCode;
808    permuteCode.appendf("const vec2 C = vec2(34.0, 1.0);\n"
809                        "return %s(((x * C.xxxx) + C.yyyy) * x);", mod289_4_funcName.c_str());
810    SkString permuteFuncName;
811    builder->fsEmitFunction(kVec4f_GrSLType,
812                            "permute", SK_ARRAY_COUNT(gVec4Args), gVec4Args,
813                            permuteCode.c_str(), &permuteFuncName);
814
815    // Add vec4 taylorInvSqrt function
816    SkString taylorInvSqrtFuncName;
817    builder->fsEmitFunction(kVec4f_GrSLType,
818                            "taylorInvSqrt", SK_ARRAY_COUNT(gVec4Args), gVec4Args,
819                            "const vec2 C = vec2(-0.85373472095314, 1.79284291400159);\n"
820                            "return x * C.xxxx + C.yyyy;", &taylorInvSqrtFuncName);
821
822    // Add vec3 noise function
823    static const GrGLShaderVar gNoiseVec3Args[] =  {
824        GrGLShaderVar("v", kVec3f_GrSLType)
825    };
826
827    SkString noiseCode;
828    noiseCode.append(
829        "const vec2 C = vec2(1.0/6.0, 1.0/3.0);\n"
830        "const vec4 D = vec4(0.0, 0.5, 1.0, 2.0);\n"
831
832        // First corner
833        "vec3 i = floor(v + dot(v, C.yyy));\n"
834        "vec3 x0 = v - i + dot(i, C.xxx);\n"
835
836        // Other corners
837        "vec3 g = step(x0.yzx, x0.xyz);\n"
838        "vec3 l = 1.0 - g;\n"
839        "vec3 i1 = min(g.xyz, l.zxy);\n"
840        "vec3 i2 = max(g.xyz, l.zxy);\n"
841
842        "vec3 x1 = x0 - i1 + C.xxx;\n"
843        "vec3 x2 = x0 - i2 + C.yyy;\n" // 2.0*C.x = 1/3 = C.y
844        "vec3 x3 = x0 - D.yyy;\n" // -1.0+3.0*C.x = -0.5 = -D.y
845    );
846
847    noiseCode.appendf(
848        // Permutations
849        "i = %s(i);\n"
850        "vec4 p = %s(%s(%s(\n"
851        "         i.z + vec4(0.0, i1.z, i2.z, 1.0)) +\n"
852        "         i.y + vec4(0.0, i1.y, i2.y, 1.0)) +\n"
853        "         i.x + vec4(0.0, i1.x, i2.x, 1.0));\n",
854        mod289_3_funcName.c_str(), permuteFuncName.c_str(), permuteFuncName.c_str(),
855        permuteFuncName.c_str());
856
857    noiseCode.append(
858        // Gradients: 7x7 points over a square, mapped onto an octahedron.
859        // The ring size 17*17 = 289 is close to a multiple of 49 (49*6 = 294)
860        "float n_ = 0.142857142857;\n" // 1.0/7.0
861        "vec3  ns = n_ * D.wyz - D.xzx;\n"
862
863        "vec4 j = p - 49.0 * floor(p * ns.z * ns.z);\n" // mod(p,7*7)
864
865        "vec4 x_ = floor(j * ns.z);\n"
866        "vec4 y_ = floor(j - 7.0 * x_);" // mod(j,N)
867
868        "vec4 x = x_ *ns.x + ns.yyyy;\n"
869        "vec4 y = y_ *ns.x + ns.yyyy;\n"
870        "vec4 h = 1.0 - abs(x) - abs(y);\n"
871
872        "vec4 b0 = vec4(x.xy, y.xy);\n"
873        "vec4 b1 = vec4(x.zw, y.zw);\n"
874    );
875
876    noiseCode.append(
877        "vec4 s0 = floor(b0) * 2.0 + 1.0;\n"
878        "vec4 s1 = floor(b1) * 2.0 + 1.0;\n"
879        "vec4 sh = -step(h, vec4(0.0));\n"
880
881        "vec4 a0 = b0.xzyw + s0.xzyw * sh.xxyy;\n"
882        "vec4 a1 = b1.xzyw + s1.xzyw * sh.zzww;\n"
883
884        "vec3 p0 = vec3(a0.xy, h.x);\n"
885        "vec3 p1 = vec3(a0.zw, h.y);\n"
886        "vec3 p2 = vec3(a1.xy, h.z);\n"
887        "vec3 p3 = vec3(a1.zw, h.w);\n"
888    );
889
890    noiseCode.appendf(
891        // Normalise gradients
892        "vec4 norm = %s(vec4(dot(p0,p0), dot(p1,p1), dot(p2, p2), dot(p3,p3)));\n"
893        "p0 *= norm.x;\n"
894        "p1 *= norm.y;\n"
895        "p2 *= norm.z;\n"
896        "p3 *= norm.w;\n"
897
898        // Mix final noise value
899        "vec4 m = max(0.6 - vec4(dot(x0,x0), dot(x1,x1), dot(x2,x2), dot(x3,x3)), 0.0);\n"
900        "m = m * m;\n"
901        "return 42.0 * dot(m*m, vec4(dot(p0,x0), dot(p1,x1), dot(p2,x2), dot(p3,x3)));",
902        taylorInvSqrtFuncName.c_str());
903
904    SkString noiseFuncName;
905    builder->fsEmitFunction(kFloat_GrSLType,
906                            "snoise", SK_ARRAY_COUNT(gNoiseVec3Args), gNoiseVec3Args,
907                            noiseCode.c_str(), &noiseFuncName);
908
909    const char* noiseVecIni = "noiseVecIni";
910    const char* factors     = "factors";
911    const char* sum         = "sum";
912    const char* xOffsets    = "xOffsets";
913    const char* yOffsets    = "yOffsets";
914    const char* channel     = "channel";
915
916    // Fill with some prime numbers
917    builder->fsCodeAppendf("\t\tconst vec4 %s = vec4(13.0, 53.0, 101.0, 151.0);\n", xOffsets);
918    builder->fsCodeAppendf("\t\tconst vec4 %s = vec4(109.0, 167.0, 23.0, 67.0);\n", yOffsets);
919
920    // There are rounding errors if the floor operation is not performed here
921    builder->fsCodeAppendf(
922        "\t\tvec3 %s = vec3(floor((%s*vec3(%s, 1.0)).xy) * vec2(0.66) * %s, 0.0);\n",
923        noiseVecIni, invMatrixUni, vCoords.c_str(), baseFrequencyUni);
924
925    // Perturb the texcoords with three components of noise
926    builder->fsCodeAppendf("\t\t%s += 0.1 * vec3(%s(%s + vec3(  0.0,   0.0, %s)),"
927                                                "%s(%s + vec3( 43.0,  17.0, %s)),"
928                                                "%s(%s + vec3(-17.0, -43.0, %s)));\n",
929                           noiseVecIni, noiseFuncName.c_str(), noiseVecIni, seedUni,
930                                        noiseFuncName.c_str(), noiseVecIni, seedUni,
931                                        noiseFuncName.c_str(), noiseVecIni, seedUni);
932
933    builder->fsCodeAppendf("\t\t%s = vec4(0.0);\n", outputColor);
934
935    builder->fsCodeAppendf("\t\tvec3 %s = vec3(1.0);\n", factors);
936    builder->fsCodeAppendf("\t\tfloat %s = 0.0;\n", sum);
937
938    // Loop over all octaves
939    builder->fsCodeAppendf("\t\tfor (int octave = 0; octave < %d; ++octave) {\n", fNumOctaves);
940
941    // Loop over the 4 channels
942    builder->fsCodeAppendf("\t\t\tfor (int %s = 3; %s >= 0; --%s) {\n", channel, channel, channel);
943
944    builder->fsCodeAppendf(
945        "\t\t\t\t%s[channel] += %s.x * %s(%s * %s.yyy - vec3(%s[%s], %s[%s], %s * %s.z));\n",
946        outputColor, factors, noiseFuncName.c_str(), noiseVecIni, factors, xOffsets, channel,
947        yOffsets, channel, seedUni, factors);
948
949    builder->fsCodeAppend("\t\t\t}\n"); // end of the for loop on channels
950
951    builder->fsCodeAppendf("\t\t\t%s += %s.x;\n", sum, factors);
952    builder->fsCodeAppendf("\t\t\t%s *= vec3(0.5, 2.0, 0.75);\n", factors);
953
954    builder->fsCodeAppend("\t\t}\n"); // end of the for loop on octaves
955
956    if (fType == SkPerlinNoiseShader::kFractalNoise_Type) {
957        // The value of turbulenceFunctionResult comes from ((turbulenceFunctionResult) + 1) / 2
958        // by fractalNoise and (turbulenceFunctionResult) by turbulence.
959        builder->fsCodeAppendf("\t\t%s = %s * vec4(0.5 / %s) + vec4(0.5);\n",
960                               outputColor, outputColor, sum);
961    } else {
962        builder->fsCodeAppendf("\t\t%s = abs(%s / vec4(%s));\n",
963                               outputColor, outputColor, sum);
964    }
965
966    builder->fsCodeAppendf("\t\t%s.a *= %s;\n", outputColor, alphaUni);
967
968    // Clamp values
969    builder->fsCodeAppendf("\t\t%s = clamp(%s, 0.0, 1.0);\n", outputColor, outputColor);
970
971    // Pre-multiply the result
972    builder->fsCodeAppendf("\t\t%s = vec4(%s.rgb * %s.aaa, %s.a);\n",
973                           outputColor, outputColor, outputColor, outputColor);
974}
975
976void GrGLPerlinNoise::emitCode(GrGLShaderBuilder* builder,
977                               const GrDrawEffect&,
978                               EffectKey key,
979                               const char* outputColor,
980                               const char* inputColor,
981                               const TransformedCoordsArray& coords,
982                               const TextureSamplerArray& samplers) {
983    sk_ignore_unused_variable(inputColor);
984
985    SkString vCoords = builder->ensureFSCoords2D(coords, 0);
986
987    fInvMatrixUni = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
988                                        kMat33f_GrSLType, "invMatrix");
989    const char* invMatrixUni = builder->getUniformCStr(fInvMatrixUni);
990    fBaseFrequencyUni = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
991                                            kVec2f_GrSLType, "baseFrequency");
992    const char* baseFrequencyUni = builder->getUniformCStr(fBaseFrequencyUni);
993    fAlphaUni = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
994                                    kFloat_GrSLType, "alpha");
995    const char* alphaUni = builder->getUniformCStr(fAlphaUni);
996
997    const char* stitchDataUni = NULL;
998    if (fStitchTiles) {
999        fStitchDataUni = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
1000                                             kVec2f_GrSLType, "stitchData");
1001        stitchDataUni = builder->getUniformCStr(fStitchDataUni);
1002    }
1003
1004    // There are 4 lines, so the center of each line is 1/8, 3/8, 5/8 and 7/8
1005    const char* chanCoordR  = "0.125";
1006    const char* chanCoordG  = "0.375";
1007    const char* chanCoordB  = "0.625";
1008    const char* chanCoordA  = "0.875";
1009    const char* chanCoord   = "chanCoord";
1010    const char* stitchData  = "stitchData";
1011    const char* ratio       = "ratio";
1012    const char* noiseXY     = "noiseXY";
1013    const char* noiseVec    = "noiseVec";
1014    const char* noiseSmooth = "noiseSmooth";
1015    const char* fractVal    = "fractVal";
1016    const char* uv          = "uv";
1017    const char* ab          = "ab";
1018    const char* latticeIdx  = "latticeIdx";
1019    const char* lattice     = "lattice";
1020    const char* inc8bit     = "0.00390625";  // 1.0 / 256.0
1021    // This is the math to convert the two 16bit integer packed into rgba 8 bit input into a
1022    // [-1,1] vector and perform a dot product between that vector and the provided vector.
1023    const char* dotLattice  = "dot(((%s.ga + %s.rb * vec2(%s)) * vec2(2.0) - vec2(1.0)), %s);";
1024
1025    // Add noise function
1026    static const GrGLShaderVar gPerlinNoiseArgs[] =  {
1027        GrGLShaderVar(chanCoord, kFloat_GrSLType),
1028        GrGLShaderVar(noiseVec, kVec2f_GrSLType)
1029    };
1030
1031    static const GrGLShaderVar gPerlinNoiseStitchArgs[] =  {
1032        GrGLShaderVar(chanCoord, kFloat_GrSLType),
1033        GrGLShaderVar(noiseVec, kVec2f_GrSLType),
1034        GrGLShaderVar(stitchData, kVec2f_GrSLType)
1035    };
1036
1037    SkString noiseCode;
1038
1039    noiseCode.appendf("\tvec4 %s = vec4(floor(%s), fract(%s));", noiseXY, noiseVec, noiseVec);
1040
1041    // smooth curve : t * t * (3 - 2 * t)
1042    noiseCode.appendf("\n\tvec2 %s = %s.zw * %s.zw * (vec2(3.0) - vec2(2.0) * %s.zw);",
1043        noiseSmooth, noiseXY, noiseXY, noiseXY);
1044
1045    // Adjust frequencies if we're stitching tiles
1046    if (fStitchTiles) {
1047        noiseCode.appendf("\n\tif(%s.x >= %s.x) { %s.x -= %s.x; }",
1048            noiseXY, stitchData, noiseXY, stitchData);
1049        noiseCode.appendf("\n\tif(%s.x >= (%s.x - 1.0)) { %s.x -= (%s.x - 1.0); }",
1050            noiseXY, stitchData, noiseXY, stitchData);
1051        noiseCode.appendf("\n\tif(%s.y >= %s.y) { %s.y -= %s.y; }",
1052            noiseXY, stitchData, noiseXY, stitchData);
1053        noiseCode.appendf("\n\tif(%s.y >= (%s.y - 1.0)) { %s.y -= (%s.y - 1.0); }",
1054            noiseXY, stitchData, noiseXY, stitchData);
1055    }
1056
1057    // Get texture coordinates and normalize
1058    noiseCode.appendf("\n\t%s.xy = fract(floor(mod(%s.xy, 256.0)) / vec2(256.0));\n",
1059        noiseXY, noiseXY);
1060
1061    // Get permutation for x
1062    {
1063        SkString xCoords("");
1064        xCoords.appendf("vec2(%s.x, 0.5)", noiseXY);
1065
1066        noiseCode.appendf("\n\tvec2 %s;\n\t%s.x = ", latticeIdx, latticeIdx);
1067        builder->appendTextureLookup(&noiseCode, samplers[0], xCoords.c_str(), kVec2f_GrSLType);
1068        noiseCode.append(".r;");
1069    }
1070
1071    // Get permutation for x + 1
1072    {
1073        SkString xCoords("");
1074        xCoords.appendf("vec2(fract(%s.x + %s), 0.5)", noiseXY, inc8bit);
1075
1076        noiseCode.appendf("\n\t%s.y = ", latticeIdx);
1077        builder->appendTextureLookup(&noiseCode, samplers[0], xCoords.c_str(), kVec2f_GrSLType);
1078        noiseCode.append(".r;");
1079    }
1080
1081#if defined(SK_BUILD_FOR_ANDROID)
1082    // Android rounding for Tegra devices, like, for example: Xoom (Tegra 2), Nexus 7 (Tegra 3).
1083    // The issue is that colors aren't accurate enough on Tegra devices. For example, if an 8 bit
1084    // value of 124 (or 0.486275 here) is entered, we can get a texture value of 123.513725
1085    // (or 0.484368 here). The following rounding operation prevents these precision issues from
1086    // affecting the result of the noise by making sure that we only have multiples of 1/255.
1087    // (Note that 1/255 is about 0.003921569, which is the value used here).
1088    noiseCode.appendf("\n\t%s = floor(%s * vec2(255.0) + vec2(0.5)) * vec2(0.003921569);",
1089                      latticeIdx, latticeIdx);
1090#endif
1091
1092    // Get (x,y) coordinates with the permutated x
1093    noiseCode.appendf("\n\t%s = fract(%s + %s.yy);", latticeIdx, latticeIdx, noiseXY);
1094
1095    noiseCode.appendf("\n\tvec2 %s = %s.zw;", fractVal, noiseXY);
1096
1097    noiseCode.appendf("\n\n\tvec2 %s;", uv);
1098    // Compute u, at offset (0,0)
1099    {
1100        SkString latticeCoords("");
1101        latticeCoords.appendf("vec2(%s.x, %s)", latticeIdx, chanCoord);
1102        noiseCode.appendf("\n\tvec4 %s = ", lattice);
1103        builder->appendTextureLookup(&noiseCode, samplers[1], latticeCoords.c_str(),
1104            kVec2f_GrSLType);
1105        noiseCode.appendf(".bgra;\n\t%s.x = ", uv);
1106        noiseCode.appendf(dotLattice, lattice, lattice, inc8bit, fractVal);
1107    }
1108
1109    noiseCode.appendf("\n\t%s.x -= 1.0;", fractVal);
1110    // Compute v, at offset (-1,0)
1111    {
1112        SkString latticeCoords("");
1113        latticeCoords.appendf("vec2(%s.y, %s)", latticeIdx, chanCoord);
1114        noiseCode.append("\n\tlattice = ");
1115        builder->appendTextureLookup(&noiseCode, samplers[1], latticeCoords.c_str(),
1116            kVec2f_GrSLType);
1117        noiseCode.appendf(".bgra;\n\t%s.y = ", uv);
1118        noiseCode.appendf(dotLattice, lattice, lattice, inc8bit, fractVal);
1119    }
1120
1121    // Compute 'a' as a linear interpolation of 'u' and 'v'
1122    noiseCode.appendf("\n\tvec2 %s;", ab);
1123    noiseCode.appendf("\n\t%s.x = mix(%s.x, %s.y, %s.x);", ab, uv, uv, noiseSmooth);
1124
1125    noiseCode.appendf("\n\t%s.y -= 1.0;", fractVal);
1126    // Compute v, at offset (-1,-1)
1127    {
1128        SkString latticeCoords("");
1129        latticeCoords.appendf("vec2(fract(%s.y + %s), %s)", latticeIdx, inc8bit, chanCoord);
1130        noiseCode.append("\n\tlattice = ");
1131        builder->appendTextureLookup(&noiseCode, samplers[1], latticeCoords.c_str(),
1132            kVec2f_GrSLType);
1133        noiseCode.appendf(".bgra;\n\t%s.y = ", uv);
1134        noiseCode.appendf(dotLattice, lattice, lattice, inc8bit, fractVal);
1135    }
1136
1137    noiseCode.appendf("\n\t%s.x += 1.0;", fractVal);
1138    // Compute u, at offset (0,-1)
1139    {
1140        SkString latticeCoords("");
1141        latticeCoords.appendf("vec2(fract(%s.x + %s), %s)", latticeIdx, inc8bit, chanCoord);
1142        noiseCode.append("\n\tlattice = ");
1143        builder->appendTextureLookup(&noiseCode, samplers[1], latticeCoords.c_str(),
1144            kVec2f_GrSLType);
1145        noiseCode.appendf(".bgra;\n\t%s.x = ", uv);
1146        noiseCode.appendf(dotLattice, lattice, lattice, inc8bit, fractVal);
1147    }
1148
1149    // Compute 'b' as a linear interpolation of 'u' and 'v'
1150    noiseCode.appendf("\n\t%s.y = mix(%s.x, %s.y, %s.x);", ab, uv, uv, noiseSmooth);
1151    // Compute the noise as a linear interpolation of 'a' and 'b'
1152    noiseCode.appendf("\n\treturn mix(%s.x, %s.y, %s.y);\n", ab, ab, noiseSmooth);
1153
1154    SkString noiseFuncName;
1155    if (fStitchTiles) {
1156        builder->fsEmitFunction(kFloat_GrSLType,
1157                                "perlinnoise", SK_ARRAY_COUNT(gPerlinNoiseStitchArgs),
1158                                gPerlinNoiseStitchArgs, noiseCode.c_str(), &noiseFuncName);
1159    } else {
1160        builder->fsEmitFunction(kFloat_GrSLType,
1161                                "perlinnoise", SK_ARRAY_COUNT(gPerlinNoiseArgs),
1162                                gPerlinNoiseArgs, noiseCode.c_str(), &noiseFuncName);
1163    }
1164
1165    // There are rounding errors if the floor operation is not performed here
1166    builder->fsCodeAppendf("\n\t\tvec2 %s = floor((%s * vec3(%s, 1.0)).xy) * %s;",
1167                           noiseVec, invMatrixUni, vCoords.c_str(), baseFrequencyUni);
1168
1169    // Clear the color accumulator
1170    builder->fsCodeAppendf("\n\t\t%s = vec4(0.0);", outputColor);
1171
1172    if (fStitchTiles) {
1173        // Set up TurbulenceInitial stitch values.
1174        builder->fsCodeAppendf("\n\t\tvec2 %s = %s;", stitchData, stitchDataUni);
1175    }
1176
1177    builder->fsCodeAppendf("\n\t\tfloat %s = 1.0;", ratio);
1178
1179    // Loop over all octaves
1180    builder->fsCodeAppendf("\n\t\tfor (int octave = 0; octave < %d; ++octave) {", fNumOctaves);
1181
1182    builder->fsCodeAppendf("\n\t\t\t%s += ", outputColor);
1183    if (fType != SkPerlinNoiseShader::kFractalNoise_Type) {
1184        builder->fsCodeAppend("abs(");
1185    }
1186    if (fStitchTiles) {
1187        builder->fsCodeAppendf(
1188            "vec4(\n\t\t\t\t%s(%s, %s, %s),\n\t\t\t\t%s(%s, %s, %s),"
1189                 "\n\t\t\t\t%s(%s, %s, %s),\n\t\t\t\t%s(%s, %s, %s))",
1190            noiseFuncName.c_str(), chanCoordR, noiseVec, stitchData,
1191            noiseFuncName.c_str(), chanCoordG, noiseVec, stitchData,
1192            noiseFuncName.c_str(), chanCoordB, noiseVec, stitchData,
1193            noiseFuncName.c_str(), chanCoordA, noiseVec, stitchData);
1194    } else {
1195        builder->fsCodeAppendf(
1196            "vec4(\n\t\t\t\t%s(%s, %s),\n\t\t\t\t%s(%s, %s),"
1197                 "\n\t\t\t\t%s(%s, %s),\n\t\t\t\t%s(%s, %s))",
1198            noiseFuncName.c_str(), chanCoordR, noiseVec,
1199            noiseFuncName.c_str(), chanCoordG, noiseVec,
1200            noiseFuncName.c_str(), chanCoordB, noiseVec,
1201            noiseFuncName.c_str(), chanCoordA, noiseVec);
1202    }
1203    if (fType != SkPerlinNoiseShader::kFractalNoise_Type) {
1204        builder->fsCodeAppendf(")"); // end of "abs("
1205    }
1206    builder->fsCodeAppendf(" * %s;", ratio);
1207
1208    builder->fsCodeAppendf("\n\t\t\t%s *= vec2(2.0);", noiseVec);
1209    builder->fsCodeAppendf("\n\t\t\t%s *= 0.5;", ratio);
1210
1211    if (fStitchTiles) {
1212        builder->fsCodeAppendf("\n\t\t\t%s *= vec2(2.0);", stitchData);
1213    }
1214    builder->fsCodeAppend("\n\t\t}"); // end of the for loop on octaves
1215
1216    if (fType == SkPerlinNoiseShader::kFractalNoise_Type) {
1217        // The value of turbulenceFunctionResult comes from ((turbulenceFunctionResult) + 1) / 2
1218        // by fractalNoise and (turbulenceFunctionResult) by turbulence.
1219        builder->fsCodeAppendf("\n\t\t%s = %s * vec4(0.5) + vec4(0.5);", outputColor, outputColor);
1220    }
1221
1222    builder->fsCodeAppendf("\n\t\t%s.a *= %s;", outputColor, alphaUni);
1223
1224    // Clamp values
1225    builder->fsCodeAppendf("\n\t\t%s = clamp(%s, 0.0, 1.0);", outputColor, outputColor);
1226
1227    // Pre-multiply the result
1228    builder->fsCodeAppendf("\n\t\t%s = vec4(%s.rgb * %s.aaa, %s.a);\n",
1229                  outputColor, outputColor, outputColor, outputColor);
1230}
1231
1232GrGLNoise::GrGLNoise(const GrBackendEffectFactory& factory, const GrDrawEffect& drawEffect)
1233  : INHERITED (factory)
1234  , fType(drawEffect.castEffect<GrPerlinNoiseEffect>().type())
1235  , fStitchTiles(drawEffect.castEffect<GrPerlinNoiseEffect>().stitchTiles())
1236  , fNumOctaves(drawEffect.castEffect<GrPerlinNoiseEffect>().numOctaves()) {
1237}
1238
1239GrGLEffect::EffectKey GrGLNoise::GenKey(const GrDrawEffect& drawEffect, const GrGLCaps&) {
1240    const GrPerlinNoiseEffect& turbulence = drawEffect.castEffect<GrPerlinNoiseEffect>();
1241
1242    EffectKey key = turbulence.numOctaves();
1243
1244    key = key << 3; // Make room for next 3 bits
1245
1246    switch (turbulence.type()) {
1247        case SkPerlinNoiseShader::kFractalNoise_Type:
1248            key |= 0x1;
1249            break;
1250        case SkPerlinNoiseShader::kTurbulence_Type:
1251            key |= 0x2;
1252            break;
1253        default:
1254            // leave key at 0
1255            break;
1256    }
1257
1258    if (turbulence.stitchTiles()) {
1259        key |= 0x4; // Flip the 3rd bit if tile stitching is on
1260    }
1261
1262    return key;
1263}
1264
1265void GrGLNoise::setData(const GrGLUniformManager& uman, const GrDrawEffect& drawEffect) {
1266    const GrPerlinNoiseEffect& turbulence = drawEffect.castEffect<GrPerlinNoiseEffect>();
1267
1268    const SkVector& baseFrequency = turbulence.baseFrequency();
1269    uman.set2f(fBaseFrequencyUni, baseFrequency.fX, baseFrequency.fY);
1270    uman.set1f(fAlphaUni, SkScalarDiv(SkIntToScalar(turbulence.alpha()), SkIntToScalar(255)));
1271
1272    SkMatrix m = turbulence.matrix();
1273    m.postTranslate(-SK_Scalar1, -SK_Scalar1);
1274    SkMatrix invM;
1275    if (!m.invert(&invM)) {
1276        invM.reset();
1277    } else {
1278        invM.postConcat(invM); // Square the matrix
1279    }
1280    uman.setSkMatrix(fInvMatrixUni, invM);
1281}
1282
1283void GrGLPerlinNoise::setData(const GrGLUniformManager& uman, const GrDrawEffect& drawEffect) {
1284    INHERITED::setData(uman, drawEffect);
1285
1286    const GrPerlinNoiseEffect& turbulence = drawEffect.castEffect<GrPerlinNoiseEffect>();
1287    if (turbulence.stitchTiles()) {
1288        const SkPerlinNoiseShader::StitchData& stitchData = turbulence.stitchData();
1289        uman.set2f(fStitchDataUni, SkIntToScalar(stitchData.fWidth),
1290                                   SkIntToScalar(stitchData.fHeight));
1291    }
1292}
1293
1294void GrGLSimplexNoise::setData(const GrGLUniformManager& uman, const GrDrawEffect& drawEffect) {
1295    INHERITED::setData(uman, drawEffect);
1296
1297    const GrSimplexNoiseEffect& turbulence = drawEffect.castEffect<GrSimplexNoiseEffect>();
1298    uman.set1f(fSeedUni, turbulence.seed());
1299}
1300
1301/////////////////////////////////////////////////////////////////////
1302
1303GrEffectRef* SkPerlinNoiseShader::asNewEffect(GrContext* context, const SkPaint& paint) const {
1304    SkASSERT(NULL != context);
1305
1306    if (0 == fNumOctaves) {
1307        SkColor clearColor = 0;
1308        if (kFractalNoise_Type == fType) {
1309            clearColor = SkColorSetARGB(paint.getAlpha() / 2, 127, 127, 127);
1310        }
1311        SkAutoTUnref<SkColorFilter> cf(SkColorFilter::CreateModeFilter(
1312                                                clearColor, SkXfermode::kSrc_Mode));
1313        return cf->asNewEffect(context);
1314    }
1315
1316    // Either we don't stitch tiles, either we have a valid tile size
1317    SkASSERT(!fStitchTiles || !fTileSize.isEmpty());
1318
1319#ifdef SK_USE_SIMPLEX_NOISE
1320    // Simplex noise is currently disabled but can be enabled by defining SK_USE_SIMPLEX_NOISE
1321    sk_ignore_unused_variable(context);
1322    GrEffectRef* effect =
1323        GrSimplexNoiseEffect::Create(fType, fPaintingData->fBaseFrequency,
1324                                     fNumOctaves, fStitchTiles, fSeed,
1325                                     this->getLocalMatrix(), paint.getAlpha());
1326#else
1327    GrTexture* permutationsTexture = GrLockAndRefCachedBitmapTexture(
1328        context, *fPaintingData->getPermutationsBitmap(), NULL);
1329    GrTexture* noiseTexture = GrLockAndRefCachedBitmapTexture(
1330        context, *fPaintingData->getNoiseBitmap(), NULL);
1331
1332    GrEffectRef* effect = (NULL != permutationsTexture) && (NULL != noiseTexture) ?
1333        GrPerlinNoiseEffect::Create(fType, fPaintingData->fBaseFrequency,
1334                                    fNumOctaves, fStitchTiles,
1335                                    fPaintingData->fStitchDataInit,
1336                                    permutationsTexture, noiseTexture,
1337                                    this->getLocalMatrix(), paint.getAlpha()) :
1338        NULL;
1339
1340    // Unlock immediately, this is not great, but we don't have a way of
1341    // knowing when else to unlock it currently. TODO: Remove this when
1342    // unref becomes the unlock replacement for all types of textures.
1343    if (NULL != permutationsTexture) {
1344        GrUnlockAndUnrefCachedBitmapTexture(permutationsTexture);
1345    }
1346    if (NULL != noiseTexture) {
1347        GrUnlockAndUnrefCachedBitmapTexture(noiseTexture);
1348    }
1349#endif
1350
1351    return effect;
1352}
1353
1354#else
1355
1356GrEffectRef* SkPerlinNoiseShader::asNewEffect(GrContext*, const SkPaint&) const {
1357    SkDEBUGFAIL("Should not call in GPU-less build");
1358    return NULL;
1359}
1360
1361#endif
1362
1363#ifdef SK_DEVELOPER
1364void SkPerlinNoiseShader::toString(SkString* str) const {
1365    str->append("SkPerlinNoiseShader: (");
1366
1367    str->append("type: ");
1368    switch (fType) {
1369        case kFractalNoise_Type:
1370            str->append("\"fractal noise\"");
1371            break;
1372        case kTurbulence_Type:
1373            str->append("\"turbulence\"");
1374            break;
1375        default:
1376            str->append("\"unknown\"");
1377            break;
1378    }
1379    str->append(" base frequency: (");
1380    str->appendScalar(fBaseFrequencyX);
1381    str->append(", ");
1382    str->appendScalar(fBaseFrequencyY);
1383    str->append(") number of octaves: ");
1384    str->appendS32(fNumOctaves);
1385    str->append(" seed: ");
1386    str->appendScalar(fSeed);
1387    str->append(" stitch tiles: ");
1388    str->append(fStitchTiles ? "true " : "false ");
1389
1390    this->INHERITED::toString(str);
1391
1392    str->append(")");
1393}
1394#endif
1395