src/gpu/effects/GrGradientEffects.cpp - platform/external/skia - Gitiles

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */

 #include "GrGradientEffects.h"
 #include "gl/GrGLProgramStage.h"
 #include "GrProgramStageFactory.h"

 /////////////////////////////////////////////////////////////////////

 class GrGLRadialGradient : public GrGLProgramStage {

 public:

     GrGLRadialGradient(const GrProgramStageFactory& factory,
                        const GrCustomStage&) : INHERITED (factory) { }
     virtual ~GrGLRadialGradient() { }

     virtual void emitVS(GrGLShaderBuilder* state,
                         const char* vertexCoords) SK_OVERRIDE { }
     virtual void emitFS(GrGLShaderBuilder* state,
                         const char* outputColor,
                         const char* inputColor,
                         const char* samplerName) SK_OVERRIDE;

     static StageKey GenKey(const GrCustomStage& s) { return 0; }

 private:

     typedef GrGLProgramStage INHERITED;

 };

 void GrGLRadialGradient::emitFS(GrGLShaderBuilder* state,
                         const char* outputColor,
                         const char* inputColor,
                         const char* samplerName) {
     state->fSampleCoords.printf("vec2(length(%s.xy), 0.5)",
                                 state->fSampleCoords.c_str());
     state->fComplexCoord = true;

     state->emitDefaultFetch(outputColor, samplerName);
 }


 /////////////////////////////////////////////////////////////////////


 GrRadialGradient::GrRadialGradient() {

 }

 GrRadialGradient::~GrRadialGradient() {

 }


 const GrProgramStageFactory& GrRadialGradient::getFactory() const {
     return GrTProgramStageFactory<GrRadialGradient>::getInstance();
 }

 bool GrRadialGradient::isEqual(const GrCustomStage& sBase) const {
     return true;
 }

 /////////////////////////////////////////////////////////////////////

 class GrGLRadial2Gradient : public GrGLProgramStage {

 public:

     GrGLRadial2Gradient(const GrProgramStageFactory& factory,
                         const GrCustomStage&);
     virtual ~GrGLRadial2Gradient() { }

     virtual void setupVariables(GrGLShaderBuilder* state,
                                 int stage) SK_OVERRIDE;
     virtual void emitVS(GrGLShaderBuilder* state,
                         const char* vertexCoords) SK_OVERRIDE;
     virtual void emitFS(GrGLShaderBuilder* state,
                         const char* outputColor,
                         const char* inputColor,
                         const char* samplerName) SK_OVERRIDE;
     virtual void initUniforms(const GrGLInterface*, int programID) SK_OVERRIDE;
     virtual void setData(const GrGLInterface*,
                          const GrGLTexture&,
                          const GrCustomStage&,
                          int stageNum) SK_OVERRIDE;

     static StageKey GenKey(const GrCustomStage& s) {
         return (static_cast<const GrRadial2Gradient&>(s).isDegenerate());
     }

 protected:

     const GrGLShaderVar* fParamVar;
     GrGLint fParamLocation;

     const char* fVSVaryingName;
     const char* fFSVaryingName;

     bool fIsDegenerate;

     // @{
     /// Values last uploaded as uniforms

     GrScalar fCachedCenter;
     GrScalar fCachedRadius;
     bool     fCachedPosRoot;

     // @}

 private:

     typedef GrGLProgramStage INHERITED;

 };

 GrGLRadial2Gradient::GrGLRadial2Gradient(
         const GrProgramStageFactory& factory,
         const GrCustomStage& baseData)
     : INHERITED(factory)
     , fParamVar(NULL)
     , fVSVaryingName(NULL)
     , fFSVaryingName(NULL)
     , fCachedCenter(GR_ScalarMax)
     , fCachedRadius(-GR_ScalarMax)
     , fCachedPosRoot(0) {

     const GrRadial2Gradient& data =
         static_cast<const GrRadial2Gradient&>(baseData);
     fIsDegenerate = data.isDegenerate();
 }

 void GrGLRadial2Gradient::setupVariables(GrGLShaderBuilder* state, int stage) {
     fParamVar = &state->addUniform(
         GrGLShaderBuilder::kBoth_VariableLifetime,
         kFloat_GrSLType, "uRadial2Params", stage, 6);

     fParamLocation = GrGLProgramStage::kUseUniform;

     // For radial gradients without perspective we can pass the linear
     // part of the quadratic as a varying.
     if (state->fVaryingDims == state->fCoordDims) {
         state->addVarying(kFloat_GrSLType, "Radial2BCoeff", stage,
                           &fVSVaryingName, &fFSVaryingName);
     }
 }

 void GrGLRadial2Gradient::emitVS(GrGLShaderBuilder* state,
                         const char* vertexCoords) {
     GrStringBuilder* code = &state->fVSCode;
     GrStringBuilder p2;
     GrStringBuilder p3;
     fParamVar->appendArrayAccess(2, &p2);
     fParamVar->appendArrayAccess(3, &p3);

     // For radial gradients without perspective we can pass the linear
     // part of the quadratic as a varying.
     if (state->fVaryingDims == state->fCoordDims) {
         // r2Var = 2 * (r2Parm[2] * varCoord.x - r2Param[3])
         code->appendf("\t%s = 2.0 *(%s * %s.x - %s);\n",
                       fVSVaryingName, p2.c_str(),
                       vertexCoords, p3.c_str());
     }
 }

 void GrGLRadial2Gradient::emitFS(GrGLShaderBuilder* state,
                         const char* outputColor,
                         const char* inputColor,
                         const char* samplerName) {
     GrStringBuilder* code = &state->fFSCode;
     GrStringBuilder cName("c");
     GrStringBuilder ac4Name("ac4");
     GrStringBuilder rootName("root");
     GrStringBuilder p0;
     GrStringBuilder p1;
     GrStringBuilder p2;
     GrStringBuilder p3;
     GrStringBuilder p4;
     GrStringBuilder p5;
     fParamVar->appendArrayAccess(0, &p0);
     fParamVar->appendArrayAccess(1, &p1);
     fParamVar->appendArrayAccess(2, &p2);
     fParamVar->appendArrayAccess(3, &p3);
     fParamVar->appendArrayAccess(4, &p4);
     fParamVar->appendArrayAccess(5, &p5);

     // If we we're able to interpolate the linear component,
     // bVar is the varying; otherwise compute it
     GrStringBuilder bVar;
     if (state->fCoordDims == state->fVaryingDims) {
         bVar = fFSVaryingName;
         GrAssert(2 == state->fVaryingDims);
     } else {
         GrAssert(3 == state->fVaryingDims);
         bVar = "b";
         //bVar.appendS32(stageNum);
         code->appendf("\tfloat %s = 2.0 * (%s * %s.x - %s);\n",
                       bVar.c_str(), p2.c_str(),
                       state->fSampleCoords.c_str(), p3.c_str());
     }

     // c = (x^2)+(y^2) - params[4]
     code->appendf("\tfloat %s = dot(%s, %s) - %s;\n",
                   cName.c_str(), state->fSampleCoords.c_str(),
                   state->fSampleCoords.c_str(),
                   p4.c_str());

     // If we aren't degenerate, emit some extra code, and accept a slightly
     // more complex coord.
     if (fIsDegenerate) {

         // ac4 = 4.0 * params[0] * c
         code->appendf("\tfloat %s = %s * 4.0 * %s;\n",
                       ac4Name.c_str(), p0.c_str(),
                       cName.c_str());

         // root = sqrt(b^2-4ac)
         // (abs to avoid exception due to fp precision)
         code->appendf("\tfloat %s = sqrt(abs(%s*%s - %s));\n",
                       rootName.c_str(), bVar.c_str(), bVar.c_str(),
                       ac4Name.c_str());

         // x coord is: (-b + params[5] * sqrt(b^2-4ac)) * params[1]
         // y coord is 0.5 (texture is effectively 1D)
         state->fSampleCoords.printf("vec2((-%s + %s * %s) * %s, 0.5)",
                             bVar.c_str(), p5.c_str(),
                             rootName.c_str(), p1.c_str());
     } else {
         // x coord is: -c/b
         // y coord is 0.5 (texture is effectively 1D)
         state->fSampleCoords.printf("vec2((-%s / %s), 0.5)",
                             cName.c_str(), bVar.c_str());
     }
     state->fComplexCoord = true;

     state->emitDefaultFetch(outputColor, samplerName);
 }

 void GrGLRadial2Gradient::initUniforms(const GrGLInterface* gl, int programID) {
     GR_GL_CALL_RET(gl, fParamLocation,
         GetUniformLocation(programID, fParamVar->getName().c_str()));
 }

 void GrGLRadial2Gradient::setData(const GrGLInterface* gl,
                                  const GrGLTexture& texture,
                                  const GrCustomStage& baseData,
                                  int stageNum) {
     const GrRadial2Gradient& data =
         static_cast<const GrRadial2Gradient&>(baseData);
     GrAssert(data.isDegenerate() == fIsDegenerate);
     GrScalar centerX1 = data.center();
     GrScalar radius0 = data.radius();
     if (fCachedCenter != centerX1 ||
         fCachedRadius != radius0 ||
         fCachedPosRoot != data.isPosRoot()) {

         GrScalar a = GrMul(centerX1, centerX1) - GR_Scalar1;

         // When we're in the degenerate (linear) case, the second
         // value will be INF but the program doesn't read it. (We
         // use the same 6 uniforms even though we don't need them
         // all in the linear case just to keep the code complexity
         // down).
         float values[6] = {
             GrScalarToFloat(a),
             1 / (2.f * GrScalarToFloat(a)),
             GrScalarToFloat(centerX1),
             GrScalarToFloat(radius0),
             GrScalarToFloat(GrMul(radius0, radius0)),
             data.isPosRoot() ? 1.f : -1.f
         };

         GR_GL_CALL(gl, Uniform1fv(fParamLocation, 6, values));
         fCachedCenter = centerX1;
         fCachedRadius = radius0;
         fCachedPosRoot = data.isPosRoot();
     }
 }


 /////////////////////////////////////////////////////////////////////

 GrRadial2Gradient::GrRadial2Gradient(GrScalar center,
                                      GrScalar radius,
                                      bool posRoot)
     : fCenterX1 (center)
     , fRadius0 (radius)
     , fPosRoot (posRoot) {

 }

 GrRadial2Gradient::~GrRadial2Gradient() {

 }


 const GrProgramStageFactory& GrRadial2Gradient::getFactory() const {
     return GrTProgramStageFactory<GrRadial2Gradient>::getInstance();
 }

 bool GrRadial2Gradient::isEqual(const GrCustomStage& sBase) const {
     const GrRadial2Gradient& s = static_cast<const GrRadial2Gradient&>(sBase);
     return (this->isDegenerate() == s.isDegenerate());
 }

 /////////////////////////////////////////////////////////////////////

 class GrGLSweepGradient : public GrGLProgramStage {

 public:

     GrGLSweepGradient(const GrProgramStageFactory& factory,
                       const GrCustomStage&) : INHERITED (factory) { }
     virtual ~GrGLSweepGradient() { }

     virtual void emitVS(GrGLShaderBuilder* state,
                         const char* vertexCoords) SK_OVERRIDE { }
     virtual void emitFS(GrGLShaderBuilder* state,
                         const char* outputColor,
                         const char* inputColor,
                         const char* samplerName) SK_OVERRIDE;

     static StageKey GenKey(const GrCustomStage& s) { return 0; }

 private:

     typedef GrGLProgramStage INHERITED;

 };

 void GrGLSweepGradient::emitFS(GrGLShaderBuilder* state,
                               const char* outputColor,
                               const char* inputColor,
                               const char* samplerName) {
     state->fSampleCoords.printf(
         "vec2(atan(- %s.y, - %s.x) * 0.1591549430918 + 0.5, 0.5)",
         state->fSampleCoords.c_str(), state->fSampleCoords.c_str());
     state->fComplexCoord = true;

     state->emitDefaultFetch(outputColor, samplerName);
 }

 /////////////////////////////////////////////////////////////////////

 GrSweepGradient::GrSweepGradient() {

 }

 GrSweepGradient::~GrSweepGradient() {

 }

 const GrProgramStageFactory& GrSweepGradient::getFactory() const {
     return GrTProgramStageFactory<GrSweepGradient>::getInstance();
 }

 bool GrSweepGradient::isEqual(const GrCustomStage& sBase) const {
     return true;
 }
	/*
	* Copyright 2012 Google Inc.
	*
	* Use of this source code is governed by a BSD-style license that can be
	* found in the LICENSE file.
	*/

	#include "GrGradientEffects.h"
	#include "gl/GrGLProgramStage.h"
	#include "GrProgramStageFactory.h"

	/////////////////////////////////////////////////////////////////////

	class GrGLRadialGradient : public GrGLProgramStage {

	public:

	GrGLRadialGradient(const GrProgramStageFactory& factory,
	const GrCustomStage&) : INHERITED (factory) { }
	virtual ~GrGLRadialGradient() { }

	virtual void emitVS(GrGLShaderBuilder* state,
	const char* vertexCoords) SK_OVERRIDE { }
	virtual void emitFS(GrGLShaderBuilder* state,
	const char* outputColor,
	const char* inputColor,
	const char* samplerName) SK_OVERRIDE;

	static StageKey GenKey(const GrCustomStage& s) { return 0; }

	private:

	typedef GrGLProgramStage INHERITED;

	};

	void GrGLRadialGradient::emitFS(GrGLShaderBuilder* state,
	const char* outputColor,
	const char* inputColor,
	const char* samplerName) {
	state->fSampleCoords.printf("vec2(length(%s.xy), 0.5)",
	state->fSampleCoords.c_str());
	state->fComplexCoord = true;

	state->emitDefaultFetch(outputColor, samplerName);
	}


	/////////////////////////////////////////////////////////////////////


	GrRadialGradient::GrRadialGradient() {

	}

	GrRadialGradient::~GrRadialGradient() {

	}


	const GrProgramStageFactory& GrRadialGradient::getFactory() const {
	return GrTProgramStageFactory<GrRadialGradient>::getInstance();
	}

	bool GrRadialGradient::isEqual(const GrCustomStage& sBase) const {
	return true;
	}

	/////////////////////////////////////////////////////////////////////

	class GrGLRadial2Gradient : public GrGLProgramStage {

	public:

	GrGLRadial2Gradient(const GrProgramStageFactory& factory,
	const GrCustomStage&);
	virtual ~GrGLRadial2Gradient() { }

	virtual void setupVariables(GrGLShaderBuilder* state,
	int stage) SK_OVERRIDE;
	virtual void emitVS(GrGLShaderBuilder* state,
	const char* vertexCoords) SK_OVERRIDE;
	virtual void emitFS(GrGLShaderBuilder* state,
	const char* outputColor,
	const char* inputColor,
	const char* samplerName) SK_OVERRIDE;
	virtual void initUniforms(const GrGLInterface*, int programID) SK_OVERRIDE;
	virtual void setData(const GrGLInterface*,
	const GrGLTexture&,
	const GrCustomStage&,
	int stageNum) SK_OVERRIDE;

	static StageKey GenKey(const GrCustomStage& s) {
	return (static_cast<const GrRadial2Gradient&>(s).isDegenerate());
	}

	protected:

	const GrGLShaderVar* fParamVar;
	GrGLint fParamLocation;

	const char* fVSVaryingName;
	const char* fFSVaryingName;

	bool fIsDegenerate;

	// @{
	/// Values last uploaded as uniforms

	GrScalar fCachedCenter;
	GrScalar fCachedRadius;
	bool fCachedPosRoot;

	// @}

	private:

	typedef GrGLProgramStage INHERITED;

	};

	GrGLRadial2Gradient::GrGLRadial2Gradient(
	const GrProgramStageFactory& factory,
	const GrCustomStage& baseData)
	: INHERITED(factory)
	, fParamVar(NULL)
	, fVSVaryingName(NULL)
	, fFSVaryingName(NULL)
	, fCachedCenter(GR_ScalarMax)
	, fCachedRadius(-GR_ScalarMax)
	, fCachedPosRoot(0) {

	const GrRadial2Gradient& data =
	static_cast<const GrRadial2Gradient&>(baseData);
	fIsDegenerate = data.isDegenerate();
	}

	void GrGLRadial2Gradient::setupVariables(GrGLShaderBuilder* state, int stage) {
	fParamVar = &state->addUniform(
	GrGLShaderBuilder::kBoth_VariableLifetime,
	kFloat_GrSLType, "uRadial2Params", stage, 6);

	fParamLocation = GrGLProgramStage::kUseUniform;

	// For radial gradients without perspective we can pass the linear
	// part of the quadratic as a varying.
	if (state->fVaryingDims == state->fCoordDims) {
	state->addVarying(kFloat_GrSLType, "Radial2BCoeff", stage,
	&fVSVaryingName, &fFSVaryingName);
	}
	}

	void GrGLRadial2Gradient::emitVS(GrGLShaderBuilder* state,
	const char* vertexCoords) {
	GrStringBuilder* code = &state->fVSCode;
	GrStringBuilder p2;
	GrStringBuilder p3;
	fParamVar->appendArrayAccess(2, &p2);
	fParamVar->appendArrayAccess(3, &p3);

	// For radial gradients without perspective we can pass the linear
	// part of the quadratic as a varying.
	if (state->fVaryingDims == state->fCoordDims) {
	// r2Var = 2 * (r2Parm[2] * varCoord.x - r2Param[3])
	code->appendf("\t%s = 2.0 (%s %s.x - %s);\n",
	fVSVaryingName, p2.c_str(),
	vertexCoords, p3.c_str());
	}
	}

	void GrGLRadial2Gradient::emitFS(GrGLShaderBuilder* state,
	const char* outputColor,
	const char* inputColor,
	const char* samplerName) {
	GrStringBuilder* code = &state->fFSCode;
	GrStringBuilder cName("c");
	GrStringBuilder ac4Name("ac4");
	GrStringBuilder rootName("root");
	GrStringBuilder p0;
	GrStringBuilder p1;
	GrStringBuilder p2;
	GrStringBuilder p3;
	GrStringBuilder p4;
	GrStringBuilder p5;
	fParamVar->appendArrayAccess(0, &p0);
	fParamVar->appendArrayAccess(1, &p1);
	fParamVar->appendArrayAccess(2, &p2);
	fParamVar->appendArrayAccess(3, &p3);
	fParamVar->appendArrayAccess(4, &p4);
	fParamVar->appendArrayAccess(5, &p5);

	// If we we're able to interpolate the linear component,
	// bVar is the varying; otherwise compute it
	GrStringBuilder bVar;
	if (state->fCoordDims == state->fVaryingDims) {
	bVar = fFSVaryingName;
	GrAssert(2 == state->fVaryingDims);
	} else {
	GrAssert(3 == state->fVaryingDims);
	bVar = "b";
	//bVar.appendS32(stageNum);
	code->appendf("\tfloat %s = 2.0 * (%s * %s.x - %s);\n",
	bVar.c_str(), p2.c_str(),
	state->fSampleCoords.c_str(), p3.c_str());
	}

	// c = (x^2)+(y^2) - params[4]
	code->appendf("\tfloat %s = dot(%s, %s) - %s;\n",
	cName.c_str(), state->fSampleCoords.c_str(),
	state->fSampleCoords.c_str(),
	p4.c_str());

	// If we aren't degenerate, emit some extra code, and accept a slightly
	// more complex coord.
	if (fIsDegenerate) {

	// ac4 = 4.0 * params[0] * c
	code->appendf("\tfloat %s = %s * 4.0 * %s;\n",
	ac4Name.c_str(), p0.c_str(),
	cName.c_str());

	// root = sqrt(b^2-4ac)
	// (abs to avoid exception due to fp precision)
	code->appendf("\tfloat %s = sqrt(abs(%s*%s - %s));\n",
	rootName.c_str(), bVar.c_str(), bVar.c_str(),
	ac4Name.c_str());

	// x coord is: (-b + params[5] * sqrt(b^2-4ac)) * params[1]
	// y coord is 0.5 (texture is effectively 1D)
	state->fSampleCoords.printf("vec2((-%s + %s * %s) * %s, 0.5)",
	bVar.c_str(), p5.c_str(),
	rootName.c_str(), p1.c_str());
	} else {
	// x coord is: -c/b
	// y coord is 0.5 (texture is effectively 1D)
	state->fSampleCoords.printf("vec2((-%s / %s), 0.5)",
	cName.c_str(), bVar.c_str());
	}
	state->fComplexCoord = true;

	state->emitDefaultFetch(outputColor, samplerName);
	}

	void GrGLRadial2Gradient::initUniforms(const GrGLInterface* gl, int programID) {
	GR_GL_CALL_RET(gl, fParamLocation,
	GetUniformLocation(programID, fParamVar->getName().c_str()));
	}

	void GrGLRadial2Gradient::setData(const GrGLInterface* gl,
	const GrGLTexture& texture,
	const GrCustomStage& baseData,
	int stageNum) {
	const GrRadial2Gradient& data =
	static_cast<const GrRadial2Gradient&>(baseData);
	GrAssert(data.isDegenerate() == fIsDegenerate);
	GrScalar centerX1 = data.center();
	GrScalar radius0 = data.radius();
	if (fCachedCenter != centerX1 \|\|
	fCachedRadius != radius0 \|\|
	fCachedPosRoot != data.isPosRoot()) {

	GrScalar a = GrMul(centerX1, centerX1) - GR_Scalar1;

	// When we're in the degenerate (linear) case, the second
	// value will be INF but the program doesn't read it. (We
	// use the same 6 uniforms even though we don't need them
	// all in the linear case just to keep the code complexity
	// down).
	float values[6] = {
	GrScalarToFloat(a),
	1 / (2.f * GrScalarToFloat(a)),
	GrScalarToFloat(centerX1),
	GrScalarToFloat(radius0),
	GrScalarToFloat(GrMul(radius0, radius0)),
	data.isPosRoot() ? 1.f : -1.f
	};

	GR_GL_CALL(gl, Uniform1fv(fParamLocation, 6, values));
	fCachedCenter = centerX1;
	fCachedRadius = radius0;
	fCachedPosRoot = data.isPosRoot();
	}
	}


	/////////////////////////////////////////////////////////////////////

	GrRadial2Gradient::GrRadial2Gradient(GrScalar center,
	GrScalar radius,
	bool posRoot)
	: fCenterX1 (center)
	, fRadius0 (radius)
	, fPosRoot (posRoot) {

	}

	GrRadial2Gradient::~GrRadial2Gradient() {

	}


	const GrProgramStageFactory& GrRadial2Gradient::getFactory() const {
	return GrTProgramStageFactory<GrRadial2Gradient>::getInstance();
	}

	bool GrRadial2Gradient::isEqual(const GrCustomStage& sBase) const {
	const GrRadial2Gradient& s = static_cast<const GrRadial2Gradient&>(sBase);
	return (this->isDegenerate() == s.isDegenerate());
	}

	/////////////////////////////////////////////////////////////////////

	class GrGLSweepGradient : public GrGLProgramStage {

	public:

	GrGLSweepGradient(const GrProgramStageFactory& factory,
	const GrCustomStage&) : INHERITED (factory) { }
	virtual ~GrGLSweepGradient() { }

	virtual void emitVS(GrGLShaderBuilder* state,
	const char* vertexCoords) SK_OVERRIDE { }
	virtual void emitFS(GrGLShaderBuilder* state,
	const char* outputColor,
	const char* inputColor,
	const char* samplerName) SK_OVERRIDE;

	static StageKey GenKey(const GrCustomStage& s) { return 0; }

	private:

	typedef GrGLProgramStage INHERITED;

	};

	void GrGLSweepGradient::emitFS(GrGLShaderBuilder* state,
	const char* outputColor,
	const char* inputColor,
	const char* samplerName) {
	state->fSampleCoords.printf(
	"vec2(atan(- %s.y, - %s.x) * 0.1591549430918 + 0.5, 0.5)",
	state->fSampleCoords.c_str(), state->fSampleCoords.c_str());
	state->fComplexCoord = true;

	state->emitDefaultFetch(outputColor, samplerName);
	}

	/////////////////////////////////////////////////////////////////////

	GrSweepGradient::GrSweepGradient() {

	}

	GrSweepGradient::~GrSweepGradient() {

	}

	const GrProgramStageFactory& GrSweepGradient::getFactory() const {
	return GrTProgramStageFactory<GrSweepGradient>::getInstance();
	}

	bool GrSweepGradient::isEqual(const GrCustomStage& sBase) const {
	return true;
	}