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Diffstat (limited to 'src/deps/skia/include/effects/SkPerlinNoiseShader.h')
-rw-r--r-- | src/deps/skia/include/effects/SkPerlinNoiseShader.h | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/src/deps/skia/include/effects/SkPerlinNoiseShader.h b/src/deps/skia/include/effects/SkPerlinNoiseShader.h new file mode 100644 index 000000000..f94b3420f --- /dev/null +++ b/src/deps/skia/include/effects/SkPerlinNoiseShader.h @@ -0,0 +1,54 @@ +/* + * 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 SkPerlinNoiseShader_DEFINED +#define SkPerlinNoiseShader_DEFINED + +#include "include/core/SkShader.h" + +/** \class SkPerlinNoiseShader + + SkPerlinNoiseShader 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 SkPerlinNoiseShader { +public: + /** + * 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) and must be non-negative. + * + * The number of octaves provided should be fairly small, with a limit of 255 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 sk_sp<SkShader> MakeFractalNoise(SkScalar baseFrequencyX, SkScalar baseFrequencyY, + int numOctaves, SkScalar seed, + const SkISize* tileSize = nullptr); + static sk_sp<SkShader> MakeTurbulence(SkScalar baseFrequencyX, SkScalar baseFrequencyY, + int numOctaves, SkScalar seed, + const SkISize* tileSize = nullptr); + + static void RegisterFlattenables(); + +private: + SkPerlinNoiseShader() = delete; +}; + +#endif |