diff options
Diffstat (limited to 'experimental/SkPerlinNoiseShader2/SkPerlinNoiseShader2.h')
| -rw-r--r-- | experimental/SkPerlinNoiseShader2/SkPerlinNoiseShader2.h | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/experimental/SkPerlinNoiseShader2/SkPerlinNoiseShader2.h b/experimental/SkPerlinNoiseShader2/SkPerlinNoiseShader2.h new file mode 100644 index 0000000000..3c02c5de24 --- /dev/null +++ b/experimental/SkPerlinNoiseShader2/SkPerlinNoiseShader2.h @@ -0,0 +1,141 @@ +/* + * Copyright 2013 Google Inc. + * + * Use of this source code is governed by a BSD-style license that can be + * found in the LICENSE file. + */ + +#ifndef SkPerlinNoiseShader2_DEFINED +#define SkPerlinNoiseShader2_DEFINED + +#include "SkShader.h" + +/** \class SkPerlinNoiseShader2 + + SkPerlinNoiseShader2 creates an image using the Perlin turbulence function. + + It can produce tileable noise if asked to stitch tiles and provided a tile size. + In order to fill a large area with repeating noise, set the stitchTiles flag to + true, and render exactly a single tile of noise. Without this flag, the result + will contain visible seams between tiles. + + The algorithm used is described here : + http://www.w3.org/TR/SVG/filters.html#feTurbulenceElement +*/ +class SK_API SkPerlinNoiseShader2 : public SkShader { +public: + struct StitchData; + struct PaintingData; + + /** + * About the noise types : the difference between the first 2 is just minor tweaks to the + * algorithm, they're not 2 entirely different noises. The output looks different, but once the + * noise is generated in the [1, -1] range, the output is brought back in the [0, 1] range by + * doing : + * kFractalNoise_Type : noise * 0.5 + 0.5 + * kTurbulence_Type : abs(noise) + * Very little differences between the 2 types, although you can tell the difference visually. + * "Improved" is based on the Improved Perlin Noise algorithm described at + * http://mrl.nyu.edu/~perlin/noise/. It is quite distinct from the other two, and the noise is + * a 2D slice of a 3D noise texture. Minor changes to the Z coordinate will result in minor + * changes to the noise, making it suitable for animated noise. + */ + enum Type { + kFractalNoise_Type, + kTurbulence_Type, + kImprovedNoise_Type, + kFirstType = kFractalNoise_Type, + kLastType = kImprovedNoise_Type + }; + /** + * This will construct Perlin noise of the given type (Fractal Noise or Turbulence). + * + * Both base frequencies (X and Y) have a usual range of (0..1). + * + * The number of octaves provided should be fairly small, although no limit is enforced. + * Each octave doubles the frequency, so 10 octaves would produce noise from + * baseFrequency * 1, * 2, * 4, ..., * 512, which quickly yields insignificantly small + * periods and resembles regular unstructured noise rather than Perlin noise. + * + * If tileSize isn't NULL or an empty size, the tileSize parameter will be used to modify + * the frequencies so that the noise will be tileable for the given tile size. If tileSize + * is NULL or an empty size, the frequencies will be used as is without modification. + */ + static SkShader* CreateFractalNoise(SkScalar baseFrequencyX, SkScalar baseFrequencyY, + int numOctaves, SkScalar seed, + const SkISize* tileSize = NULL); + static SkShader* CreateTurbulence(SkScalar baseFrequencyX, SkScalar baseFrequencyY, + int numOctaves, SkScalar seed, + const SkISize* tileSize = NULL); + /** + * Creates an Improved Perlin Noise shader. The z value is roughly equivalent to the seed of the + * other two types, but minor variations to z will only slightly change the noise. + */ + static SkShader* CreateImprovedNoise(SkScalar baseFrequencyX, SkScalar baseFrequencyY, + int numOctaves, SkScalar z); + /** + * Create alias for CreateTurbulunce until all Skia users changed + * its code to use the new naming + */ + static SkShader* CreateTubulence(SkScalar baseFrequencyX, SkScalar baseFrequencyY, + int numOctaves, SkScalar seed, + const SkISize* tileSize = NULL) { + return CreateTurbulence(baseFrequencyX, baseFrequencyY, numOctaves, seed, tileSize); + } + + + size_t contextSize() const override; + + class PerlinNoiseShaderContext : public SkShader::Context { + public: + PerlinNoiseShaderContext(const SkPerlinNoiseShader2& shader, const ContextRec&); + virtual ~PerlinNoiseShaderContext(); + + void shadeSpan(int x, int y, SkPMColor[], int count) override; + void shadeSpan16(int x, int y, uint16_t[], int count) override; + + private: + SkPMColor shade(const SkPoint& point, StitchData& stitchData) const; + SkScalar calculateTurbulenceValueForPoint( + int channel, + StitchData& stitchData, const SkPoint& point) const; + SkScalar calculateImprovedNoiseValueForPoint(int channel, const SkPoint& point) const; + SkScalar noise2D(int channel, + const StitchData& stitchData, const SkPoint& noiseVector) const; + + SkMatrix fMatrix; + PaintingData* fPaintingData; + + typedef SkShader::Context INHERITED; + }; + +#if SK_SUPPORT_GPU + const GrFragmentProcessor* asFragmentProcessor(GrContext* context, const SkMatrix& viewM, + const SkMatrix*, SkFilterQuality) const override; +#endif + + SK_TO_STRING_OVERRIDE() + SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkPerlinNoiseShader2) + +protected: + void flatten(SkWriteBuffer&) const override; + Context* onCreateContext(const ContextRec&, void* storage) const override; + +private: + SkPerlinNoiseShader2(SkPerlinNoiseShader2::Type type, SkScalar baseFrequencyX, + SkScalar baseFrequencyY, int numOctaves, SkScalar seed, + const SkISize* tileSize); + virtual ~SkPerlinNoiseShader2(); + + const SkPerlinNoiseShader2::Type fType; + const SkScalar fBaseFrequencyX; + const SkScalar fBaseFrequencyY; + const int fNumOctaves; + const SkScalar fSeed; + const SkISize fTileSize; + const bool fStitchTiles; + + typedef SkShader INHERITED; +}; + +#endif |