4dc5a45405
Preparation for generating bookmaker files for all remaining interfaces Standardize enum and enum classes by including a comma after the last entry. Replace flatten-related #define in public interfaces with their equivalent. The motivation is to give documentation something to refer to. An alternative would be to move part or all of this out of the public interface; something I can work on in a follow-up CL. R=reed@google.com,bsalomon@google.com Bug: skia:6898 Change-Id: I4b865f6ec3d8f5d31e50448fef7d2714510302f0 Reviewed-on: https://skia-review.googlesource.com/129312 Reviewed-by: Brian Salomon <bsalomon@google.com> Commit-Queue: Cary Clark <caryclark@skia.org>
61 lines
2.6 KiB
C++
61 lines
2.6 KiB
C++
/*
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* Copyright 2013 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#ifndef SkPerlinNoiseShader_DEFINED
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#define SkPerlinNoiseShader_DEFINED
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#include "SkShader.h"
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/** \class SkPerlinNoiseShader
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SkPerlinNoiseShader creates an image using the Perlin turbulence function.
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It can produce tileable noise if asked to stitch tiles and provided a tile size.
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In order to fill a large area with repeating noise, set the stitchTiles flag to
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true, and render exactly a single tile of noise. Without this flag, the result
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will contain visible seams between tiles.
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The algorithm used is described here :
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http://www.w3.org/TR/SVG/filters.html#feTurbulenceElement
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*/
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class SK_API SkPerlinNoiseShader {
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public:
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/**
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* This will construct Perlin noise of the given type (Fractal Noise or Turbulence).
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*
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* Both base frequencies (X and Y) have a usual range of (0..1) and must be non-negative.
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*
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* The number of octaves provided should be fairly small, with a limit of 255 enforced.
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* Each octave doubles the frequency, so 10 octaves would produce noise from
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* baseFrequency * 1, * 2, * 4, ..., * 512, which quickly yields insignificantly small
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* periods and resembles regular unstructured noise rather than Perlin noise.
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*
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* If tileSize isn't NULL or an empty size, the tileSize parameter will be used to modify
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* the frequencies so that the noise will be tileable for the given tile size. If tileSize
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* is NULL or an empty size, the frequencies will be used as is without modification.
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*/
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static sk_sp<SkShader> MakeFractalNoise(SkScalar baseFrequencyX, SkScalar baseFrequencyY,
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int numOctaves, SkScalar seed,
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const SkISize* tileSize = nullptr);
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static sk_sp<SkShader> MakeTurbulence(SkScalar baseFrequencyX, SkScalar baseFrequencyY,
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int numOctaves, SkScalar seed,
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const SkISize* tileSize = nullptr);
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/**
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* Creates an Improved Perlin Noise shader. The z value is roughly equivalent to the seed of the
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* other two types, but minor variations to z will only slightly change the noise.
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*/
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static sk_sp<SkShader> MakeImprovedNoise(SkScalar baseFrequencyX, SkScalar baseFrequencyY,
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int numOctaves, SkScalar z);
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static void InitializeFlattenables();
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private:
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SkPerlinNoiseShader() = delete;
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};
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#endif
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