ethannicholas | 417011c | 2015-11-09 06:35:12 -0800 | [diff] [blame] | 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 | #ifndef SkPerlinNoiseShader2_DEFINED |
| 9 | #define SkPerlinNoiseShader2_DEFINED |
| 10 | |
| 11 | #include "SkShader.h" |
| 12 | |
| 13 | /** \class SkPerlinNoiseShader2 |
| 14 | |
| 15 | SkPerlinNoiseShader2 creates an image using the Perlin turbulence function. |
| 16 | |
| 17 | It can produce tileable noise if asked to stitch tiles and provided a tile size. |
| 18 | In order to fill a large area with repeating noise, set the stitchTiles flag to |
| 19 | true, and render exactly a single tile of noise. Without this flag, the result |
| 20 | will contain visible seams between tiles. |
| 21 | |
| 22 | The algorithm used is described here : |
| 23 | http://www.w3.org/TR/SVG/filters.html#feTurbulenceElement |
| 24 | */ |
| 25 | class SK_API SkPerlinNoiseShader2 : public SkShader { |
| 26 | public: |
| 27 | struct StitchData; |
| 28 | struct PaintingData; |
| 29 | |
| 30 | /** |
| 31 | * About the noise types : the difference between the first 2 is just minor tweaks to the |
| 32 | * algorithm, they're not 2 entirely different noises. The output looks different, but once the |
| 33 | * noise is generated in the [1, -1] range, the output is brought back in the [0, 1] range by |
| 34 | * doing : |
| 35 | * kFractalNoise_Type : noise * 0.5 + 0.5 |
| 36 | * kTurbulence_Type : abs(noise) |
| 37 | * Very little differences between the 2 types, although you can tell the difference visually. |
| 38 | * "Improved" is based on the Improved Perlin Noise algorithm described at |
| 39 | * http://mrl.nyu.edu/~perlin/noise/. It is quite distinct from the other two, and the noise is |
| 40 | * a 2D slice of a 3D noise texture. Minor changes to the Z coordinate will result in minor |
| 41 | * changes to the noise, making it suitable for animated noise. |
| 42 | */ |
| 43 | enum Type { |
| 44 | kFractalNoise_Type, |
| 45 | kTurbulence_Type, |
| 46 | kImprovedNoise_Type, |
| 47 | kFirstType = kFractalNoise_Type, |
| 48 | kLastType = kImprovedNoise_Type |
| 49 | }; |
| 50 | /** |
| 51 | * This will construct Perlin noise of the given type (Fractal Noise or Turbulence). |
| 52 | * |
| 53 | * Both base frequencies (X and Y) have a usual range of (0..1). |
| 54 | * |
| 55 | * The number of octaves provided should be fairly small, although no limit is enforced. |
| 56 | * Each octave doubles the frequency, so 10 octaves would produce noise from |
| 57 | * baseFrequency * 1, * 2, * 4, ..., * 512, which quickly yields insignificantly small |
| 58 | * periods and resembles regular unstructured noise rather than Perlin noise. |
| 59 | * |
| 60 | * If tileSize isn't NULL or an empty size, the tileSize parameter will be used to modify |
| 61 | * the frequencies so that the noise will be tileable for the given tile size. If tileSize |
| 62 | * is NULL or an empty size, the frequencies will be used as is without modification. |
| 63 | */ |
reed | 8a21c9f | 2016-03-08 18:50:00 -0800 | [diff] [blame] | 64 | static sk_sp<SkShader> MakeFractalNoise(SkScalar baseFrequencyX, SkScalar baseFrequencyY, |
| 65 | int numOctaves, SkScalar seed, |
| 66 | const SkISize* tileSize = NULL); |
| 67 | static sk_sp<SkShader> MakeTurbulence(SkScalar baseFrequencyX, SkScalar baseFrequencyY, |
| 68 | int numOctaves, SkScalar seed, |
| 69 | const SkISize* tileSize = NULL); |
ethannicholas | 417011c | 2015-11-09 06:35:12 -0800 | [diff] [blame] | 70 | /** |
| 71 | * Creates an Improved Perlin Noise shader. The z value is roughly equivalent to the seed of the |
| 72 | * other two types, but minor variations to z will only slightly change the noise. |
| 73 | */ |
reed | 8a21c9f | 2016-03-08 18:50:00 -0800 | [diff] [blame] | 74 | static sk_sp<SkShader> MakeImprovedNoise(SkScalar baseFrequencyX, SkScalar baseFrequencyY, |
| 75 | int numOctaves, SkScalar z); |
ethannicholas | 417011c | 2015-11-09 06:35:12 -0800 | [diff] [blame] | 76 | /** |
| 77 | * Create alias for CreateTurbulunce until all Skia users changed |
| 78 | * its code to use the new naming |
| 79 | */ |
reed | 8a21c9f | 2016-03-08 18:50:00 -0800 | [diff] [blame] | 80 | static sk_sp<SkShader> MakeTubulence(SkScalar baseFrequencyX, SkScalar baseFrequencyY, |
| 81 | int numOctaves, SkScalar seed, |
| 82 | const SkISize* tileSize = NULL) { |
| 83 | return MakeTurbulence(baseFrequencyX, baseFrequencyY, numOctaves, seed, tileSize); |
ethannicholas | 417011c | 2015-11-09 06:35:12 -0800 | [diff] [blame] | 84 | } |
| 85 | |
ethannicholas | 417011c | 2015-11-09 06:35:12 -0800 | [diff] [blame] | 86 | class PerlinNoiseShaderContext : public SkShader::Context { |
| 87 | public: |
| 88 | PerlinNoiseShaderContext(const SkPerlinNoiseShader2& shader, const ContextRec&); |
| 89 | virtual ~PerlinNoiseShaderContext(); |
| 90 | |
| 91 | void shadeSpan(int x, int y, SkPMColor[], int count) override; |
ethannicholas | 417011c | 2015-11-09 06:35:12 -0800 | [diff] [blame] | 92 | |
| 93 | private: |
| 94 | SkPMColor shade(const SkPoint& point, StitchData& stitchData) const; |
| 95 | SkScalar calculateTurbulenceValueForPoint( |
| 96 | int channel, |
| 97 | StitchData& stitchData, const SkPoint& point) const; |
| 98 | SkScalar calculateImprovedNoiseValueForPoint(int channel, const SkPoint& point) const; |
| 99 | SkScalar noise2D(int channel, |
| 100 | const StitchData& stitchData, const SkPoint& noiseVector) const; |
| 101 | |
| 102 | SkMatrix fMatrix; |
| 103 | PaintingData* fPaintingData; |
| 104 | |
| 105 | typedef SkShader::Context INHERITED; |
| 106 | }; |
| 107 | |
| 108 | #if SK_SUPPORT_GPU |
brianosman | 839345d | 2016-07-22 11:04:53 -0700 | [diff] [blame] | 109 | sk_sp<GrFragmentProcessor> asFragmentProcessor(const AsFPArgs&) const override; |
ethannicholas | 417011c | 2015-11-09 06:35:12 -0800 | [diff] [blame] | 110 | #endif |
| 111 | |
| 112 | SK_TO_STRING_OVERRIDE() |
| 113 | SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkPerlinNoiseShader2) |
| 114 | |
| 115 | protected: |
| 116 | void flatten(SkWriteBuffer&) const override; |
reed | 773ceda | 2016-03-03 18:18:25 -0800 | [diff] [blame] | 117 | size_t onContextSize(const ContextRec&) const override; |
ethannicholas | 417011c | 2015-11-09 06:35:12 -0800 | [diff] [blame] | 118 | Context* onCreateContext(const ContextRec&, void* storage) const override; |
| 119 | |
| 120 | private: |
| 121 | SkPerlinNoiseShader2(SkPerlinNoiseShader2::Type type, SkScalar baseFrequencyX, |
| 122 | SkScalar baseFrequencyY, int numOctaves, SkScalar seed, |
| 123 | const SkISize* tileSize); |
| 124 | virtual ~SkPerlinNoiseShader2(); |
| 125 | |
| 126 | const SkPerlinNoiseShader2::Type fType; |
| 127 | const SkScalar fBaseFrequencyX; |
| 128 | const SkScalar fBaseFrequencyY; |
| 129 | const int fNumOctaves; |
| 130 | const SkScalar fSeed; |
| 131 | const SkISize fTileSize; |
| 132 | const bool fStitchTiles; |
| 133 | |
| 134 | typedef SkShader INHERITED; |
| 135 | }; |
| 136 | |
| 137 | #endif |