libs/hwui/SkiaShader.cpp - platform/frameworks/base - Gitiles

 /*
  * Copyright (C) 2010 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #define LOG_TAG "OpenGLRenderer"

 #include <utils/Log.h>

 #include <SkMatrix.h>

 #include "Caches.h"
 #include "Layer.h"
 #include "Matrix.h"
 #include "SkiaShader.h"
 #include "Texture.h"

 namespace android {
 namespace uirenderer {

 ///////////////////////////////////////////////////////////////////////////////
 // Support
 ///////////////////////////////////////////////////////////////////////////////

 static const GLint gTileModes[] = {
         GL_CLAMP_TO_EDGE,   // == SkShader::kClamp_TileMode
         GL_REPEAT,          // == SkShader::kRepeat_Mode
         GL_MIRRORED_REPEAT  // == SkShader::kMirror_TileMode
 };

 /**
  * This function does not work for n == 0.
  */
 static inline bool isPowerOfTwo(unsigned int n) {
     return !(n & (n - 1));
 }

 static inline void bindUniformColor(int slot, uint32_t color) {
     const float a = ((color >> 24) & 0xff) / 255.0f;
     glUniform4f(slot,
             a * ((color >> 16) & 0xff) / 255.0f,
             a * ((color >>  8) & 0xff) / 255.0f,
             a * ((color      ) & 0xff) / 255.0f,
             a);
 }

 static inline void bindTexture(Caches* caches, Texture* texture, GLenum wrapS, GLenum wrapT) {
     caches->bindTexture(texture->id);
     texture->setWrapST(wrapS, wrapT);
 }

 /**
  * Compute the matrix to transform to screen space.
  * @param screenSpace Output param for the computed matrix.
  * @param unitMatrix The unit matrix for gradient shaders, as returned by SkShader::asAGradient,
  *      or identity.
  * @param localMatrix Local matrix, as returned by SkShader::getLocalMatrix().
  * @param modelViewMatrix Model view matrix, as supplied by the OpenGLRenderer.
  */
 static void computeScreenSpaceMatrix(mat4& screenSpace, const SkMatrix& unitMatrix,
         const SkMatrix& localMatrix, const mat4& modelViewMatrix) {
     mat4 shaderMatrix;
     // uses implicit construction
     shaderMatrix.loadInverse(localMatrix);
     // again, uses implicit construction
     screenSpace.loadMultiply(unitMatrix, shaderMatrix);
     screenSpace.multiply(modelViewMatrix);
 }

 // Returns true if one is a bitmap and the other is a gradient
 static bool bitmapAndGradient(SkiaShaderType type1, SkiaShaderType type2) {
     return (type1 == kBitmap_SkiaShaderType && type2 == kGradient_SkiaShaderType)
             || (type2 == kBitmap_SkiaShaderType && type1 == kGradient_SkiaShaderType);
 }

 SkiaShaderType SkiaShader::getType(const SkShader& shader) {
     // First check for a gradient shader.
     switch (shader.asAGradient(NULL)) {
         case SkShader::kNone_GradientType:
             // Not a gradient shader. Fall through to check for other types.
             break;
         case SkShader::kLinear_GradientType:
         case SkShader::kRadial_GradientType:
         case SkShader::kSweep_GradientType:
             return kGradient_SkiaShaderType;
         default:
             // This is a Skia gradient that has no SkiaShader equivalent. Return None to skip.
             return kNone_SkiaShaderType;
     }

     // The shader is not a gradient. Check for a bitmap shader.
     if (shader.asABitmap(NULL, NULL, NULL) == SkShader::kDefault_BitmapType) {
         return kBitmap_SkiaShaderType;
     }

     // Check for a ComposeShader.
     SkShader::ComposeRec rec;
     if (shader.asACompose(&rec)) {
         const SkiaShaderType shaderAType = getType(*rec.fShaderA);
         const SkiaShaderType shaderBType = getType(*rec.fShaderB);

         // Compose is only supported if one is a bitmap and the other is a
         // gradient. Otherwise, return None to skip.
         if (!bitmapAndGradient(shaderAType, shaderBType)) {
             return kNone_SkiaShaderType;
         }
         return kCompose_SkiaShaderType;
     }

     if (shader.asACustomShader(NULL)) {
         return kLayer_SkiaShaderType;
     }

     return kNone_SkiaShaderType;
 }

 typedef void (*describeProc)(Caches* caches, ProgramDescription& description,
         const Extensions& extensions, const SkShader& shader);

 describeProc gDescribeProc[] = {
     InvalidSkiaShader::describe,
     SkiaBitmapShader::describe,
     SkiaGradientShader::describe,
     SkiaComposeShader::describe,
     SkiaLayerShader::describe,
 };

 typedef void (*setupProgramProc)(Caches* caches, const mat4& modelViewMatrix,
         GLuint* textureUnit, const Extensions& extensions, const SkShader& shader);

 setupProgramProc gSetupProgramProc[] = {
     InvalidSkiaShader::setupProgram,
     SkiaBitmapShader::setupProgram,
     SkiaGradientShader::setupProgram,
     SkiaComposeShader::setupProgram,
     SkiaLayerShader::setupProgram,
 };

 void SkiaShader::describe(Caches* caches, ProgramDescription& description,
         const Extensions& extensions, const SkShader& shader) {
     gDescribeProc[getType(shader)](caches, description, extensions, shader);
 }

 void SkiaShader::setupProgram(Caches* caches, const mat4& modelViewMatrix,
         GLuint* textureUnit, const Extensions& extensions, const SkShader& shader) {

     gSetupProgramProc[getType(shader)](caches, modelViewMatrix, textureUnit, extensions, shader);
 }

 ///////////////////////////////////////////////////////////////////////////////
 // Layer shader
 ///////////////////////////////////////////////////////////////////////////////

 void SkiaLayerShader::describe(Caches*, ProgramDescription& description,
         const Extensions&, const SkShader& /* shader */) {
     description.hasBitmap = true;
 }

 void SkiaLayerShader::setupProgram(Caches* caches, const mat4& modelViewMatrix,
         GLuint* textureUnit, const Extensions&, const SkShader& shader) {
     Layer* layer;
     if (!shader.asACustomShader(reinterpret_cast<void**>(&layer))) {
         LOG_ALWAYS_FATAL("SkiaLayerShader::setupProgram called on the wrong type of shader!");
     }

     GLuint textureSlot = (*textureUnit)++;
     caches->activeTexture(textureSlot);

     const float width = layer->getWidth();
     const float height = layer->getHeight();

     mat4 textureTransform;
     computeScreenSpaceMatrix(textureTransform, SkMatrix::I(), shader.getLocalMatrix(),
             modelViewMatrix);


     // Uniforms
     layer->bindTexture();
     layer->setWrap(GL_CLAMP_TO_EDGE);
     layer->setFilter(GL_LINEAR);

     Program* program = caches->currentProgram;
     glUniform1i(program->getUniform("bitmapSampler"), textureSlot);
     glUniformMatrix4fv(program->getUniform("textureTransform"), 1,
             GL_FALSE, &textureTransform.data[0]);
     glUniform2f(program->getUniform("textureDimension"), 1.0f / width, 1.0f / height);
 }

 ///////////////////////////////////////////////////////////////////////////////
 // Bitmap shader
 ///////////////////////////////////////////////////////////////////////////////

 struct BitmapShaderInfo {
     float width;
     float height;
     GLenum wrapS;
     GLenum wrapT;
     Texture* texture;
 };

 static bool bitmapShaderHelper(Caches* caches, ProgramDescription* description,
         BitmapShaderInfo* shaderInfo,
         const Extensions& extensions,
         const SkBitmap& bitmap, SkShader::TileMode tileModes[2]) {
     Texture* texture = caches->textureCache.get(&bitmap);
     if (!texture) return false;

     const float width = texture->width;
     const float height = texture->height;
     GLenum wrapS, wrapT;

     if (description) {
         description->hasBitmap = true;
     }
     // The driver does not support non-power of two mirrored/repeated
     // textures, so do it ourselves
     if (!extensions.hasNPot() && (!isPowerOfTwo(width) || !isPowerOfTwo(height)) &&
             (tileModes[0] != SkShader::kClamp_TileMode ||
              tileModes[1] != SkShader::kClamp_TileMode)) {
         if (description) {
             description->isBitmapNpot = true;
             description->bitmapWrapS = gTileModes[tileModes[0]];
             description->bitmapWrapT = gTileModes[tileModes[1]];
         }
         wrapS = GL_CLAMP_TO_EDGE;
         wrapT = GL_CLAMP_TO_EDGE;
     } else {
         wrapS = gTileModes[tileModes[0]];
         wrapT = gTileModes[tileModes[1]];
     }

     if (shaderInfo) {
         shaderInfo->width = width;
         shaderInfo->height = height;
         shaderInfo->wrapS = wrapS;
         shaderInfo->wrapT = wrapT;
         shaderInfo->texture = texture;
     }
     return true;
 }

 void SkiaBitmapShader::describe(Caches* caches, ProgramDescription& description,
         const Extensions& extensions, const SkShader& shader) {
     SkBitmap bitmap;
     SkShader::TileMode xy[2];
     if (shader.asABitmap(&bitmap, NULL, xy) != SkShader::kDefault_BitmapType) {
         LOG_ALWAYS_FATAL("SkiaBitmapShader::describe called with a different kind of shader!");
     }
     bitmapShaderHelper(caches, &description, NULL, extensions, bitmap, xy);
 }

 void SkiaBitmapShader::setupProgram(Caches* caches, const mat4& modelViewMatrix,
         GLuint* textureUnit, const Extensions& extensions, const SkShader& shader) {
     SkBitmap bitmap;
     SkShader::TileMode xy[2];
     if (shader.asABitmap(&bitmap, NULL, xy) != SkShader::kDefault_BitmapType) {
         LOG_ALWAYS_FATAL("SkiaBitmapShader::setupProgram called with a different kind of shader!");
     }

     GLuint textureSlot = (*textureUnit)++;
     Caches::getInstance().activeTexture(textureSlot);

     BitmapShaderInfo shaderInfo;
     if (!bitmapShaderHelper(caches, NULL, &shaderInfo, extensions, bitmap, xy)) {
         return;
     }

     Program* program = caches->currentProgram;
     Texture* texture = shaderInfo.texture;

     const AutoTexture autoCleanup(texture);

     mat4 textureTransform;
     computeScreenSpaceMatrix(textureTransform, SkMatrix::I(), shader.getLocalMatrix(),
             modelViewMatrix);

     // Uniforms
     bindTexture(caches, texture, shaderInfo.wrapS, shaderInfo.wrapT);
     texture->setFilter(GL_LINEAR);

     glUniform1i(program->getUniform("bitmapSampler"), textureSlot);
     glUniformMatrix4fv(program->getUniform("textureTransform"), 1,
             GL_FALSE, &textureTransform.data[0]);
     glUniform2f(program->getUniform("textureDimension"), 1.0f / shaderInfo.width,
             1.0f / shaderInfo.height);
 }

 ///////////////////////////////////////////////////////////////////////////////
 // Linear gradient shader
 ///////////////////////////////////////////////////////////////////////////////

 static void toUnitMatrix(const SkPoint pts[2], SkMatrix* matrix) {
     SkVector vec = pts[1] - pts[0];
     const float mag = vec.length();
     const float inv = mag ? 1.0f / mag : 0;

     vec.scale(inv);
     matrix->setSinCos(-vec.fY, vec.fX, pts[0].fX, pts[0].fY);
     matrix->postTranslate(-pts[0].fX, -pts[0].fY);
     matrix->postScale(inv, inv);
 }

 ///////////////////////////////////////////////////////////////////////////////
 // Circular gradient shader
 ///////////////////////////////////////////////////////////////////////////////

 static void toCircularUnitMatrix(const float x, const float y, const float radius,
         SkMatrix* matrix) {
     const float inv = 1.0f / radius;
     matrix->setTranslate(-x, -y);
     matrix->postScale(inv, inv);
 }

 ///////////////////////////////////////////////////////////////////////////////
 // Sweep gradient shader
 ///////////////////////////////////////////////////////////////////////////////

 static void toSweepUnitMatrix(const float x, const float y, SkMatrix* matrix) {
     matrix->setTranslate(-x, -y);
 }

 ///////////////////////////////////////////////////////////////////////////////
 // Common gradient code
 ///////////////////////////////////////////////////////////////////////////////

 static bool isSimpleGradient(const SkShader::GradientInfo& gradInfo) {
     return gradInfo.fColorCount == 2 && gradInfo.fTileMode == SkShader::kClamp_TileMode;
 }

 void SkiaGradientShader::describe(Caches*, ProgramDescription& description,
         const Extensions& /* extensions */, const SkShader& shader) {
     SkShader::GradientInfo gradInfo;
     gradInfo.fColorCount = 0;
     gradInfo.fColors = NULL;
     gradInfo.fColorOffsets = NULL;

     switch (shader.asAGradient(&gradInfo)) {
         case SkShader::kLinear_GradientType:
             description.gradientType = ProgramDescription::kGradientLinear;
             break;
         case SkShader::kRadial_GradientType:
             description.gradientType = ProgramDescription::kGradientCircular;
             break;
         case SkShader::kSweep_GradientType:
             description.gradientType = ProgramDescription::kGradientSweep;
             break;
         default:
             // Do nothing. This shader is unsupported.
             return;
     }
     description.hasGradient = true;
     description.isSimpleGradient = isSimpleGradient(gradInfo);
 }

 void SkiaGradientShader::setupProgram(Caches* caches, const mat4& modelViewMatrix,
         GLuint* textureUnit, const Extensions&, const SkShader& shader) {
     // SkShader::GradientInfo.fColorCount is an in/out parameter. As input, it tells asAGradient
     // how much space has been allocated for fColors and fColorOffsets.  10 was chosen
     // arbitrarily, but should be >= 2.
     // As output, it tells the number of actual colors/offsets in the gradient.
     const int COLOR_COUNT = 10;
     SkAutoSTMalloc<COLOR_COUNT, SkColor> colorStorage(COLOR_COUNT);
     SkAutoSTMalloc<COLOR_COUNT, SkScalar> positionStorage(COLOR_COUNT);

     SkShader::GradientInfo gradInfo;
     gradInfo.fColorCount = COLOR_COUNT;
     gradInfo.fColors = colorStorage.get();
     gradInfo.fColorOffsets = positionStorage.get();

     SkShader::GradientType gradType = shader.asAGradient(&gradInfo);

     Program* program = caches->currentProgram;
     if (CC_UNLIKELY(!isSimpleGradient(gradInfo))) {
         if (gradInfo.fColorCount > COLOR_COUNT) {
             // There was not enough room in our arrays for all the colors and offsets. Try again,
             // now that we know the true number of colors.
             gradInfo.fColors = colorStorage.reset(gradInfo.fColorCount);
             gradInfo.fColorOffsets = positionStorage.reset(gradInfo.fColorCount);

             shader.asAGradient(&gradInfo);
         }
         GLuint textureSlot = (*textureUnit)++;
         caches->activeTexture(textureSlot);

 #ifndef SK_SCALAR_IS_FLOAT
     #error Need to convert gradInfo.fColorOffsets to float!
 #endif
         Texture* texture = caches->gradientCache.get(gradInfo.fColors, gradInfo.fColorOffsets,
                 gradInfo.fColorCount);

         // Uniforms
         bindTexture(caches, texture, gTileModes[gradInfo.fTileMode], gTileModes[gradInfo.fTileMode]);
         glUniform1i(program->getUniform("gradientSampler"), textureSlot);
     } else {
         bindUniformColor(program->getUniform("startColor"), gradInfo.fColors[0]);
         bindUniformColor(program->getUniform("endColor"), gradInfo.fColors[1]);
     }

     caches->dither.setupProgram(program, textureUnit);

     SkMatrix unitMatrix;
     switch (gradType) {
         case SkShader::kLinear_GradientType:
             toUnitMatrix(gradInfo.fPoint, &unitMatrix);
             break;
         case SkShader::kRadial_GradientType:
             toCircularUnitMatrix(gradInfo.fPoint[0].fX, gradInfo.fPoint[0].fY,
                     gradInfo.fRadius[0], &unitMatrix);
             break;
         case SkShader::kSweep_GradientType:
             toSweepUnitMatrix(gradInfo.fPoint[0].fX, gradInfo.fPoint[0].fY, &unitMatrix);
             break;
         default:
             LOG_ALWAYS_FATAL("Invalid SkShader gradient type %d", gradType);
     }

     mat4 screenSpace;
     computeScreenSpaceMatrix(screenSpace, unitMatrix, shader.getLocalMatrix(), modelViewMatrix);
     glUniformMatrix4fv(program->getUniform("screenSpace"), 1, GL_FALSE, &screenSpace.data[0]);
 }

 ///////////////////////////////////////////////////////////////////////////////
 // Compose shader
 ///////////////////////////////////////////////////////////////////////////////

 void SkiaComposeShader::describe(Caches* caches, ProgramDescription& description,
         const Extensions& extensions, const SkShader& shader) {
     SkShader::ComposeRec rec;
     if (!shader.asACompose(&rec)) {
         LOG_ALWAYS_FATAL("SkiaComposeShader::describe called on the wrong shader type!");
     }
     SkiaShader::describe(caches, description, extensions, *rec.fShaderA);
     SkiaShader::describe(caches, description, extensions, *rec.fShaderB);
     if (SkiaShader::getType(*rec.fShaderA) == kBitmap_SkiaShaderType) {
         description.isBitmapFirst = true;
     }
     if (!SkXfermode::AsMode(rec.fMode, &description.shadersMode)) {
         // TODO: Support other modes.
         description.shadersMode = SkXfermode::kSrcOver_Mode;
     }
 }

 void SkiaComposeShader::setupProgram(Caches* caches, const mat4& modelViewMatrix,
         GLuint* textureUnit, const Extensions& extensions, const SkShader& shader) {
     SkShader::ComposeRec rec;
     if (!shader.asACompose(&rec)) {
         LOG_ALWAYS_FATAL("SkiaComposeShader::setupProgram called on the wrong shader type!");
     }

     // Apply this compose shader's local transform and pass it down to
     // the child shaders. They will in turn apply their local transform
     // to this matrix.
     mat4 transform;
     computeScreenSpaceMatrix(transform, SkMatrix::I(), shader.getLocalMatrix(),
             modelViewMatrix);

     SkiaShader::setupProgram(caches, transform, textureUnit, extensions, *rec.fShaderA);
     SkiaShader::setupProgram(caches, transform, textureUnit, extensions, *rec.fShaderB);
 }

 }; // namespace uirenderer
 }; // namespace android
	/*
	* Copyright (C) 2010 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#define LOG_TAG "OpenGLRenderer"

	#include <utils/Log.h>

	#include <SkMatrix.h>

	#include "Caches.h"
	#include "Layer.h"
	#include "Matrix.h"
	#include "SkiaShader.h"
	#include "Texture.h"

	namespace android {
	namespace uirenderer {

	///////////////////////////////////////////////////////////////////////////////
	// Support
	///////////////////////////////////////////////////////////////////////////////

	static const GLint gTileModes[] = {
	GL_CLAMP_TO_EDGE, // == SkShader::kClamp_TileMode
	GL_REPEAT, // == SkShader::kRepeat_Mode
	GL_MIRRORED_REPEAT // == SkShader::kMirror_TileMode
	};

	/**
	* This function does not work for n == 0.
	*/
	static inline bool isPowerOfTwo(unsigned int n) {
	return !(n & (n - 1));
	}

	static inline void bindUniformColor(int slot, uint32_t color) {
	const float a = ((color >> 24) & 0xff) / 255.0f;
	glUniform4f(slot,
	a * ((color >> 16) & 0xff) / 255.0f,
	a * ((color >> 8) & 0xff) / 255.0f,
	a * ((color ) & 0xff) / 255.0f,
	a);
	}

	static inline void bindTexture(Caches* caches, Texture* texture, GLenum wrapS, GLenum wrapT) {
	caches->bindTexture(texture->id);
	texture->setWrapST(wrapS, wrapT);
	}

	/**
	* Compute the matrix to transform to screen space.
	* @param screenSpace Output param for the computed matrix.
	* @param unitMatrix The unit matrix for gradient shaders, as returned by SkShader::asAGradient,
	* or identity.
	* @param localMatrix Local matrix, as returned by SkShader::getLocalMatrix().
	* @param modelViewMatrix Model view matrix, as supplied by the OpenGLRenderer.
	*/
	static void computeScreenSpaceMatrix(mat4& screenSpace, const SkMatrix& unitMatrix,
	const SkMatrix& localMatrix, const mat4& modelViewMatrix) {
	mat4 shaderMatrix;
	// uses implicit construction
	shaderMatrix.loadInverse(localMatrix);
	// again, uses implicit construction
	screenSpace.loadMultiply(unitMatrix, shaderMatrix);
	screenSpace.multiply(modelViewMatrix);
	}

	// Returns true if one is a bitmap and the other is a gradient
	static bool bitmapAndGradient(SkiaShaderType type1, SkiaShaderType type2) {
	return (type1 == kBitmap_SkiaShaderType && type2 == kGradient_SkiaShaderType)
	\|\| (type2 == kBitmap_SkiaShaderType && type1 == kGradient_SkiaShaderType);
	}

	SkiaShaderType SkiaShader::getType(const SkShader& shader) {
	// First check for a gradient shader.
	switch (shader.asAGradient(NULL)) {
	case SkShader::kNone_GradientType:
	// Not a gradient shader. Fall through to check for other types.
	break;
	case SkShader::kLinear_GradientType:
	case SkShader::kRadial_GradientType:
	case SkShader::kSweep_GradientType:
	return kGradient_SkiaShaderType;
	default:
	// This is a Skia gradient that has no SkiaShader equivalent. Return None to skip.
	return kNone_SkiaShaderType;
	}

	// The shader is not a gradient. Check for a bitmap shader.
	if (shader.asABitmap(NULL, NULL, NULL) == SkShader::kDefault_BitmapType) {
	return kBitmap_SkiaShaderType;
	}

	// Check for a ComposeShader.
	SkShader::ComposeRec rec;
	if (shader.asACompose(&rec)) {
	const SkiaShaderType shaderAType = getType(*rec.fShaderA);
	const SkiaShaderType shaderBType = getType(*rec.fShaderB);

	// Compose is only supported if one is a bitmap and the other is a
	// gradient. Otherwise, return None to skip.
	if (!bitmapAndGradient(shaderAType, shaderBType)) {
	return kNone_SkiaShaderType;
	}
	return kCompose_SkiaShaderType;
	}

	if (shader.asACustomShader(NULL)) {
	return kLayer_SkiaShaderType;
	}

	return kNone_SkiaShaderType;
	}

	typedef void (describeProc)(Caches caches, ProgramDescription& description,
	const Extensions& extensions, const SkShader& shader);

	describeProc gDescribeProc[] = {
	InvalidSkiaShader::describe,
	SkiaBitmapShader::describe,
	SkiaGradientShader::describe,
	SkiaComposeShader::describe,
	SkiaLayerShader::describe,
	};

	typedef void (setupProgramProc)(Caches caches, const mat4& modelViewMatrix,
	GLuint* textureUnit, const Extensions& extensions, const SkShader& shader);

	setupProgramProc gSetupProgramProc[] = {
	InvalidSkiaShader::setupProgram,
	SkiaBitmapShader::setupProgram,
	SkiaGradientShader::setupProgram,
	SkiaComposeShader::setupProgram,
	SkiaLayerShader::setupProgram,
	};

	void SkiaShader::describe(Caches* caches, ProgramDescription& description,
	const Extensions& extensions, const SkShader& shader) {
	gDescribeProc[getType(shader)](caches, description, extensions, shader);
	}

	void SkiaShader::setupProgram(Caches* caches, const mat4& modelViewMatrix,
	GLuint* textureUnit, const Extensions& extensions, const SkShader& shader) {

	gSetupProgramProc[getType(shader)](caches, modelViewMatrix, textureUnit, extensions, shader);
	}

	///////////////////////////////////////////////////////////////////////////////
	// Layer shader
	///////////////////////////////////////////////////////////////////////////////

	void SkiaLayerShader::describe(Caches*, ProgramDescription& description,
	const Extensions&, const SkShader& /* shader */) {
	description.hasBitmap = true;
	}

	void SkiaLayerShader::setupProgram(Caches* caches, const mat4& modelViewMatrix,
	GLuint* textureUnit, const Extensions&, const SkShader& shader) {
	Layer* layer;
	if (!shader.asACustomShader(reinterpret_cast<void**>(&layer))) {
	LOG_ALWAYS_FATAL("SkiaLayerShader::setupProgram called on the wrong type of shader!");
	}

	GLuint textureSlot = (*textureUnit)++;
	caches->activeTexture(textureSlot);

	const float width = layer->getWidth();
	const float height = layer->getHeight();

	mat4 textureTransform;
	computeScreenSpaceMatrix(textureTransform, SkMatrix::I(), shader.getLocalMatrix(),
	modelViewMatrix);


	// Uniforms
	layer->bindTexture();
	layer->setWrap(GL_CLAMP_TO_EDGE);
	layer->setFilter(GL_LINEAR);

	Program* program = caches->currentProgram;
	glUniform1i(program->getUniform("bitmapSampler"), textureSlot);
	glUniformMatrix4fv(program->getUniform("textureTransform"), 1,
	GL_FALSE, &textureTransform.data[0]);
	glUniform2f(program->getUniform("textureDimension"), 1.0f / width, 1.0f / height);
	}

	///////////////////////////////////////////////////////////////////////////////
	// Bitmap shader
	///////////////////////////////////////////////////////////////////////////////

	struct BitmapShaderInfo {
	float width;
	float height;
	GLenum wrapS;
	GLenum wrapT;
	Texture* texture;
	};

	static bool bitmapShaderHelper(Caches* caches, ProgramDescription* description,
	BitmapShaderInfo* shaderInfo,
	const Extensions& extensions,
	const SkBitmap& bitmap, SkShader::TileMode tileModes[2]) {
	Texture* texture = caches->textureCache.get(&bitmap);
	if (!texture) return false;

	const float width = texture->width;
	const float height = texture->height;
	GLenum wrapS, wrapT;

	if (description) {
	description->hasBitmap = true;
	}
	// The driver does not support non-power of two mirrored/repeated
	// textures, so do it ourselves
	if (!extensions.hasNPot() && (!isPowerOfTwo(width) \|\| !isPowerOfTwo(height)) &&
	(tileModes[0] != SkShader::kClamp_TileMode \|\|
	tileModes[1] != SkShader::kClamp_TileMode)) {
	if (description) {
	description->isBitmapNpot = true;
	description->bitmapWrapS = gTileModes[tileModes[0]];
	description->bitmapWrapT = gTileModes[tileModes[1]];
	}
	wrapS = GL_CLAMP_TO_EDGE;
	wrapT = GL_CLAMP_TO_EDGE;
	} else {
	wrapS = gTileModes[tileModes[0]];
	wrapT = gTileModes[tileModes[1]];
	}

	if (shaderInfo) {
	shaderInfo->width = width;
	shaderInfo->height = height;
	shaderInfo->wrapS = wrapS;
	shaderInfo->wrapT = wrapT;
	shaderInfo->texture = texture;
	}
	return true;
	}

	void SkiaBitmapShader::describe(Caches* caches, ProgramDescription& description,
	const Extensions& extensions, const SkShader& shader) {
	SkBitmap bitmap;
	SkShader::TileMode xy[2];
	if (shader.asABitmap(&bitmap, NULL, xy) != SkShader::kDefault_BitmapType) {
	LOG_ALWAYS_FATAL("SkiaBitmapShader::describe called with a different kind of shader!");
	}
	bitmapShaderHelper(caches, &description, NULL, extensions, bitmap, xy);
	}

	void SkiaBitmapShader::setupProgram(Caches* caches, const mat4& modelViewMatrix,
	GLuint* textureUnit, const Extensions& extensions, const SkShader& shader) {
	SkBitmap bitmap;
	SkShader::TileMode xy[2];
	if (shader.asABitmap(&bitmap, NULL, xy) != SkShader::kDefault_BitmapType) {
	LOG_ALWAYS_FATAL("SkiaBitmapShader::setupProgram called with a different kind of shader!");
	}

	GLuint textureSlot = (*textureUnit)++;
	Caches::getInstance().activeTexture(textureSlot);

	BitmapShaderInfo shaderInfo;
	if (!bitmapShaderHelper(caches, NULL, &shaderInfo, extensions, bitmap, xy)) {
	return;
	}

	Program* program = caches->currentProgram;
	Texture* texture = shaderInfo.texture;

	const AutoTexture autoCleanup(texture);

	mat4 textureTransform;
	computeScreenSpaceMatrix(textureTransform, SkMatrix::I(), shader.getLocalMatrix(),
	modelViewMatrix);

	// Uniforms
	bindTexture(caches, texture, shaderInfo.wrapS, shaderInfo.wrapT);
	texture->setFilter(GL_LINEAR);

	glUniform1i(program->getUniform("bitmapSampler"), textureSlot);
	glUniformMatrix4fv(program->getUniform("textureTransform"), 1,
	GL_FALSE, &textureTransform.data[0]);
	glUniform2f(program->getUniform("textureDimension"), 1.0f / shaderInfo.width,
	1.0f / shaderInfo.height);
	}

	///////////////////////////////////////////////////////////////////////////////
	// Linear gradient shader
	///////////////////////////////////////////////////////////////////////////////

	static void toUnitMatrix(const SkPoint pts[2], SkMatrix* matrix) {
	SkVector vec = pts[1] - pts[0];
	const float mag = vec.length();
	const float inv = mag ? 1.0f / mag : 0;

	vec.scale(inv);
	matrix->setSinCos(-vec.fY, vec.fX, pts[0].fX, pts[0].fY);
	matrix->postTranslate(-pts[0].fX, -pts[0].fY);
	matrix->postScale(inv, inv);
	}

	///////////////////////////////////////////////////////////////////////////////
	// Circular gradient shader
	///////////////////////////////////////////////////////////////////////////////

	static void toCircularUnitMatrix(const float x, const float y, const float radius,
	SkMatrix* matrix) {
	const float inv = 1.0f / radius;
	matrix->setTranslate(-x, -y);
	matrix->postScale(inv, inv);
	}

	///////////////////////////////////////////////////////////////////////////////
	// Sweep gradient shader
	///////////////////////////////////////////////////////////////////////////////

	static void toSweepUnitMatrix(const float x, const float y, SkMatrix* matrix) {
	matrix->setTranslate(-x, -y);
	}

	///////////////////////////////////////////////////////////////////////////////
	// Common gradient code
	///////////////////////////////////////////////////////////////////////////////

	static bool isSimpleGradient(const SkShader::GradientInfo& gradInfo) {
	return gradInfo.fColorCount == 2 && gradInfo.fTileMode == SkShader::kClamp_TileMode;
	}

	void SkiaGradientShader::describe(Caches*, ProgramDescription& description,
	const Extensions& /* extensions */, const SkShader& shader) {
	SkShader::GradientInfo gradInfo;
	gradInfo.fColorCount = 0;
	gradInfo.fColors = NULL;
	gradInfo.fColorOffsets = NULL;

	switch (shader.asAGradient(&gradInfo)) {
	case SkShader::kLinear_GradientType:
	description.gradientType = ProgramDescription::kGradientLinear;
	break;
	case SkShader::kRadial_GradientType:
	description.gradientType = ProgramDescription::kGradientCircular;
	break;
	case SkShader::kSweep_GradientType:
	description.gradientType = ProgramDescription::kGradientSweep;
	break;
	default:
	// Do nothing. This shader is unsupported.
	return;
	}
	description.hasGradient = true;
	description.isSimpleGradient = isSimpleGradient(gradInfo);
	}

	void SkiaGradientShader::setupProgram(Caches* caches, const mat4& modelViewMatrix,
	GLuint* textureUnit, const Extensions&, const SkShader& shader) {
	// SkShader::GradientInfo.fColorCount is an in/out parameter. As input, it tells asAGradient
	// how much space has been allocated for fColors and fColorOffsets. 10 was chosen
	// arbitrarily, but should be >= 2.
	// As output, it tells the number of actual colors/offsets in the gradient.
	const int COLOR_COUNT = 10;
	SkAutoSTMalloc<COLOR_COUNT, SkColor> colorStorage(COLOR_COUNT);
	SkAutoSTMalloc<COLOR_COUNT, SkScalar> positionStorage(COLOR_COUNT);

	SkShader::GradientInfo gradInfo;
	gradInfo.fColorCount = COLOR_COUNT;
	gradInfo.fColors = colorStorage.get();
	gradInfo.fColorOffsets = positionStorage.get();

	SkShader::GradientType gradType = shader.asAGradient(&gradInfo);

	Program* program = caches->currentProgram;
	if (CC_UNLIKELY(!isSimpleGradient(gradInfo))) {
	if (gradInfo.fColorCount > COLOR_COUNT) {
	// There was not enough room in our arrays for all the colors and offsets. Try again,
	// now that we know the true number of colors.
	gradInfo.fColors = colorStorage.reset(gradInfo.fColorCount);
	gradInfo.fColorOffsets = positionStorage.reset(gradInfo.fColorCount);

	shader.asAGradient(&gradInfo);
	}
	GLuint textureSlot = (*textureUnit)++;
	caches->activeTexture(textureSlot);

	#ifndef SK_SCALAR_IS_FLOAT
	#error Need to convert gradInfo.fColorOffsets to float!
	#endif
	Texture* texture = caches->gradientCache.get(gradInfo.fColors, gradInfo.fColorOffsets,
	gradInfo.fColorCount);

	// Uniforms
	bindTexture(caches, texture, gTileModes[gradInfo.fTileMode], gTileModes[gradInfo.fTileMode]);
	glUniform1i(program->getUniform("gradientSampler"), textureSlot);
	} else {
	bindUniformColor(program->getUniform("startColor"), gradInfo.fColors[0]);
	bindUniformColor(program->getUniform("endColor"), gradInfo.fColors[1]);
	}

	caches->dither.setupProgram(program, textureUnit);

	SkMatrix unitMatrix;
	switch (gradType) {
	case SkShader::kLinear_GradientType:
	toUnitMatrix(gradInfo.fPoint, &unitMatrix);
	break;
	case SkShader::kRadial_GradientType:
	toCircularUnitMatrix(gradInfo.fPoint[0].fX, gradInfo.fPoint[0].fY,
	gradInfo.fRadius[0], &unitMatrix);
	break;
	case SkShader::kSweep_GradientType:
	toSweepUnitMatrix(gradInfo.fPoint[0].fX, gradInfo.fPoint[0].fY, &unitMatrix);
	break;
	default:
	LOG_ALWAYS_FATAL("Invalid SkShader gradient type %d", gradType);
	}

	mat4 screenSpace;
	computeScreenSpaceMatrix(screenSpace, unitMatrix, shader.getLocalMatrix(), modelViewMatrix);
	glUniformMatrix4fv(program->getUniform("screenSpace"), 1, GL_FALSE, &screenSpace.data[0]);
	}

	///////////////////////////////////////////////////////////////////////////////
	// Compose shader
	///////////////////////////////////////////////////////////////////////////////

	void SkiaComposeShader::describe(Caches* caches, ProgramDescription& description,
	const Extensions& extensions, const SkShader& shader) {
	SkShader::ComposeRec rec;
	if (!shader.asACompose(&rec)) {
	LOG_ALWAYS_FATAL("SkiaComposeShader::describe called on the wrong shader type!");
	}
	SkiaShader::describe(caches, description, extensions, *rec.fShaderA);
	SkiaShader::describe(caches, description, extensions, *rec.fShaderB);
	if (SkiaShader::getType(*rec.fShaderA) == kBitmap_SkiaShaderType) {
	description.isBitmapFirst = true;
	}
	if (!SkXfermode::AsMode(rec.fMode, &description.shadersMode)) {
	// TODO: Support other modes.
	description.shadersMode = SkXfermode::kSrcOver_Mode;
	}
	}

	void SkiaComposeShader::setupProgram(Caches* caches, const mat4& modelViewMatrix,
	GLuint* textureUnit, const Extensions& extensions, const SkShader& shader) {
	SkShader::ComposeRec rec;
	if (!shader.asACompose(&rec)) {
	LOG_ALWAYS_FATAL("SkiaComposeShader::setupProgram called on the wrong shader type!");
	}

	// Apply this compose shader's local transform and pass it down to
	// the child shaders. They will in turn apply their local transform
	// to this matrix.
	mat4 transform;
	computeScreenSpaceMatrix(transform, SkMatrix::I(), shader.getLocalMatrix(),
	modelViewMatrix);

	SkiaShader::setupProgram(caches, transform, textureUnit, extensions, *rec.fShaderA);
	SkiaShader::setupProgram(caches, transform, textureUnit, extensions, *rec.fShaderB);
	}

	}; // namespace uirenderer
	}; // namespace android