/*
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* Copyright 2016 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 SkNormalSource_DEFINED
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#define SkNormalSource_DEFINED
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#include "SkFlattenable.h"
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#include "SkShaderBase.h"
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class SkMatrix;
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struct SkPoint3;
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#if SK_SUPPORT_GPU
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class GrFragmentProcessor;
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#endif
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/** Abstract class that generates or reads in normals for use by SkLightingShader.
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*/
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class SK_API SkNormalSource : public SkFlattenable {
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public:
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virtual ~SkNormalSource() override;
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#if SK_SUPPORT_GPU
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/** Returns a fragment processor that takes no input and outputs a normal (already rotated)
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as its output color. To be used as a child fragment processor.
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*/
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virtual std::unique_ptr<GrFragmentProcessor> asFragmentProcessor(const GrFPArgs&) const = 0;
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#endif
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class Provider {
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public:
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virtual ~Provider() {}
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/** Called for each span of the object being drawn on the CPU. Your subclass should set
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the appropriate normals that correspond to the specified device coordinates.
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*/
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virtual void fillScanLine(int x, int y, SkPoint3 output[], int count) const = 0;
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};
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/** Returns an instance of 'Provider' that provides normals for the CPU pipeline. The
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necessary data will be initialized in place at 'storage'.
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*/
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virtual Provider* asProvider(const SkShaderBase::ContextRec&, SkArenaAlloc*) const = 0;
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/** Returns a normal source that provides normals sourced from the the normal map argument.
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@param map a shader that outputs the normal map
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@param ctm the current canvas' total matrix, used to rotate normals when necessary.
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nullptr will be returned if 'map' is null
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The normal map is currently assumed to be an 8888 image where the normal at a texel
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is retrieved by:
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N.x = R-127;
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N.y = G-127;
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N.z = B-127;
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N.normalize();
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The +Z axis is thus encoded in RGB as (127, 127, 255) while the -Z axis is
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(127, 127, 0).
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*/
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static sk_sp<SkNormalSource> MakeFromNormalMap(sk_sp<SkShader> map, const SkMatrix& ctm);
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/** Returns a normal source that provides straight-up normals only <0, 0, 1>.
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*/
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static sk_sp<SkNormalSource> MakeFlat();
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static Type GetFlattenableType() { return kSkNormalSource_Type; }
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Type getFlattenableType() const override { return GetFlattenableType(); }
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static sk_sp<SkNormalSource> Deserialize(const void* data, size_t size,
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const SkDeserialProcs* procs = nullptr) {
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return sk_sp<SkNormalSource>(static_cast<SkNormalSource*>(
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SkFlattenable::Deserialize(GetFlattenableType(), data, size, procs).release()));
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}
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static void RegisterFlattenables();
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};
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#endif
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