958788ab46
BUG=skia: GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=3785 Change-Id: I187e50e09ed7a3316719fae51af770259928fdf9 Reviewed-on: https://skia-review.googlesource.com/3785 Reviewed-by: Florin Malita <fmalita@chromium.org> Commit-Queue: Mike Reed <reed@google.com>
116 lines
4.6 KiB
C++
116 lines
4.6 KiB
C++
/*
|
|
* 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 "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 SkShader {
|
|
public:
|
|
struct StitchData;
|
|
struct PaintingData;
|
|
|
|
/**
|
|
* About the noise types : the difference between the 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.
|
|
*/
|
|
enum Type {
|
|
kFractalNoise_Type,
|
|
kTurbulence_Type,
|
|
kFirstType = kFractalNoise_Type,
|
|
kLastType = kTurbulence_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 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);
|
|
|
|
class PerlinNoiseShaderContext : public SkShader::Context {
|
|
public:
|
|
PerlinNoiseShaderContext(const SkPerlinNoiseShader& shader, const ContextRec&);
|
|
virtual ~PerlinNoiseShaderContext();
|
|
|
|
void shadeSpan(int x, int y, SkPMColor[], int count) override;
|
|
|
|
private:
|
|
SkPMColor shade(const SkPoint& point, StitchData& stitchData) const;
|
|
SkScalar calculateTurbulenceValueForPoint(
|
|
int channel,
|
|
StitchData& stitchData, 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
|
|
sk_sp<GrFragmentProcessor> asFragmentProcessor(const AsFPArgs&) const override;
|
|
#endif
|
|
|
|
SK_TO_STRING_OVERRIDE()
|
|
SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkPerlinNoiseShader)
|
|
|
|
protected:
|
|
void flatten(SkWriteBuffer&) const override;
|
|
Context* onCreateContext(const ContextRec&, void* storage) const override;
|
|
size_t onContextSize(const ContextRec&) const override;
|
|
|
|
private:
|
|
SkPerlinNoiseShader(SkPerlinNoiseShader::Type type, SkScalar baseFrequencyX,
|
|
SkScalar baseFrequencyY, int numOctaves, SkScalar seed,
|
|
const SkISize* tileSize);
|
|
virtual ~SkPerlinNoiseShader();
|
|
|
|
const SkPerlinNoiseShader::Type fType;
|
|
const SkScalar fBaseFrequencyX;
|
|
const SkScalar fBaseFrequencyY;
|
|
const int fNumOctaves;
|
|
const SkScalar fSeed;
|
|
const SkISize fTileSize;
|
|
const bool fStitchTiles;
|
|
|
|
typedef SkShader INHERITED;
|
|
};
|
|
|
|
#endif
|