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/*
* Copyright 2015 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkLightingShader_DEFINED
#define SkLightingShader_DEFINED
#include "SkFlattenable.h"
#include "SkLight.h"
#include "SkShader.h"
#include "SkTDArray.h"
class SkBitmap;
class SkMatrix;
class SK_API SkLightingShader {
public:
class Lights : public SkRefCnt {
public:
class Builder {
public:
Builder(const SkLight lights[], int numLights)
: fLights(new Lights(lights, numLights)) {}
Builder() : fLights(new Lights) {}
// TODO: limit the number of lights here or just ignore those
// above some maximum?
void add(const SkLight& light) {
if (fLights) {
*fLights->fLights.push() = light;
}
}
const Lights* finish() {
return fLights.release();
}
private:
SkAutoTUnref<Lights> fLights;
};
int numLights() const {
return fLights.count();
}
const SkLight& light(int index) const {
return fLights[index];
}
private:
Lights() {}
Lights(const SkLight lights[], int numLights) : fLights(lights, numLights) {}
SkTDArray<SkLight> fLights;
typedef SkRefCnt INHERITED;
};
/** Returns a shader that lights the diffuse and normal maps with a single light.
It returns a shader with a reference count of 1.
The caller should decrement the shader's reference count when done with the shader.
It is an error for count to be < 2.
@param diffuse the diffuse bitmap
@param normal the normal map
@param light the light applied to the normal map
@param ambient the linear (unpremul) ambient light color. Range is 0..1/channel.
@param localMatrix the matrix mapping the textures to the dest rect
nullptr will be returned if:
either 'diffuse' or 'normal' are empty
either 'diffuse' or 'normal' are too big (> 65535 on a side)
'diffuse' and 'normal' aren't the same size
The lighting equation is currently:
result = LightColor * DiffuseColor * (Normal * LightDir) + AmbientColor
The normal map is currently assumed to be an 8888 image where the normal at a texel
is retrieved by:
N.x = R-127;
N.y = G-127;
N.z = B-127;
N.normalize();
The +Z axis is thus encoded in RGB as (127, 127, 255) while the -Z axis is
(127, 127, 0).
*/
static sk_sp<SkShader> Make(const SkBitmap& diffuse, const SkBitmap& normal,
const Lights* lights, const SkVector& invNormRotation,
const SkMatrix* diffLocalMatrix, const SkMatrix* normLocalMatrix);
SK_DECLARE_FLATTENABLE_REGISTRAR_GROUP()
};
#endif
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