src/gpu/GrProcessor.h - skia - Git at Google

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

 #ifndef GrProcessor_DEFINED
 #define GrProcessor_DEFINED

 #include "GrColor.h"
 #include "GrBuffer.h"
 #include "GrGpuResourceRef.h"
 #include "GrProcessorUnitTest.h"
 #include "GrProgramElement.h"
 #include "GrSamplerParams.h"
 #include "GrShaderVar.h"
 #include "GrSurfaceProxyPriv.h"
 #include "SkMath.h"
 #include "SkString.h"
 #include "../private/SkAtomics.h"

 class GrContext;
 class GrCoordTransform;
 class GrInvariantOutput;
 class GrResourceProvider;
 class GrTextureProxy;

 /**
  * Used by processors to build their keys. It incorporates each per-processor key into a larger
  * shader key.
  */
 class GrProcessorKeyBuilder {
 public:
     GrProcessorKeyBuilder(SkTArray<unsigned char, true>* data) : fData(data), fCount(0) {
         SkASSERT(0 == fData->count() % sizeof(uint32_t));
     }

     void add32(uint32_t v) {
         ++fCount;
         fData->push_back_n(4, reinterpret_cast<uint8_t*>(&v));
     }

     /** Inserts count uint32_ts into the key. The returned pointer is only valid until the next
         add*() call. */
     uint32_t* SK_WARN_UNUSED_RESULT add32n(int count) {
         SkASSERT(count > 0);
         fCount += count;
         return reinterpret_cast<uint32_t*>(fData->push_back_n(4 * count));
     }

     size_t size() const { return sizeof(uint32_t) * fCount; }

 private:
     SkTArray<uint8_t, true>* fData; // unowned ptr to the larger key.
     int fCount;                     // number of uint32_ts added to fData by the processor.
 };

 /** Provides custom shader code to the Ganesh shading pipeline. GrProcessor objects *must* be
     immutable: after being constructed, their fields may not change.

     Dynamically allocated GrProcessors are managed by a per-thread memory pool. The ref count of an
     processor must reach 0 before the thread terminates and the pool is destroyed.
  */
 class GrProcessor {
 public:
     virtual ~GrProcessor() = default;

     /** Human-meaningful string to identify this prcoessor; may be embedded in generated shader
         code. */
     virtual const char* name() const = 0;

     /** Human-readable dump of all information */
     virtual SkString dumpInfo() const {
         SkString str;
         str.appendf("Missing data");
         return str;
     }

     /**
      * Platform specific built-in features that a processor can request for the fragment shader.
      */
     enum RequiredFeatures {
         kNone_RequiredFeatures             = 0,
         kSampleLocations_RequiredFeature   = 1 << 0
     };

     GR_DECL_BITFIELD_OPS_FRIENDS(RequiredFeatures);

     RequiredFeatures requiredFeatures() const { return fRequiredFeatures; }

     void* operator new(size_t size);
     void operator delete(void* target);

     void* operator new(size_t size, void* placement) {
         return ::operator new(size, placement);
     }
     void operator delete(void* target, void* placement) {
         ::operator delete(target, placement);
     }

     /** Helper for down-casting to a GrProcessor subclass */
     template <typename T> const T& cast() const { return *static_cast<const T*>(this); }

     uint32_t classID() const { SkASSERT(kIllegalProcessorClassID != fClassID); return fClassID; }

 protected:
     GrProcessor() : fClassID(kIllegalProcessorClassID), fRequiredFeatures(kNone_RequiredFeatures) {}

     /**
      * If the prcoessor will generate code that uses platform specific built-in features, then it
      * must call these methods from its constructor. Otherwise, requests to use these features will
      * be denied.
      */
     void setWillUseSampleLocations() { fRequiredFeatures |= kSampleLocations_RequiredFeature; }

     void combineRequiredFeatures(const GrProcessor& other) {
         fRequiredFeatures |= other.fRequiredFeatures;
     }

     template <typename PROC_SUBCLASS> void initClassID() {
          static uint32_t kClassID = GenClassID();
          fClassID = kClassID;
     }

 private:
     GrProcessor(const GrProcessor&) = delete;
     GrProcessor& operator=(const GrProcessor&) = delete;

     static uint32_t GenClassID() {
         // fCurrProcessorClassID has been initialized to kIllegalProcessorClassID. The
         // atomic inc returns the old value not the incremented value. So we add
         // 1 to the returned value.
         uint32_t id = static_cast<uint32_t>(sk_atomic_inc(&gCurrProcessorClassID)) + 1;
         if (!id) {
             SkFAIL("This should never wrap as it should only be called once for each GrProcessor "
                    "subclass.");
         }
         return id;
     }

     enum {
         kIllegalProcessorClassID = 0,
     };
     static int32_t gCurrProcessorClassID;

     uint32_t                                        fClassID;
     RequiredFeatures                                fRequiredFeatures;
 };

 GR_MAKE_BITFIELD_OPS(GrProcessor::RequiredFeatures);

 /** A GrProcessor with the ability to access textures, buffers, and image storages. */
 class GrResourceIOProcessor : public GrProcessor {
 public:
     class TextureSampler;
     class BufferAccess;
     class ImageStorageAccess;

     int numTextureSamplers() const { return fTextureSamplers.count(); }

     /** Returns the access pattern for the texture at index. index must be valid according to
         numTextureSamplers(). */
     const TextureSampler& textureSampler(int index) const { return *fTextureSamplers[index]; }

     int numBuffers() const { return fBufferAccesses.count(); }

     /** Returns the access pattern for the buffer at index. index must be valid according to
         numBuffers(). */
     const BufferAccess& bufferAccess(int index) const { return *fBufferAccesses[index]; }

     int numImageStorages() const { return fImageStorageAccesses.count(); }

     /** Returns the access object for the image at index. index must be valid according to
         numImages(). */
     const ImageStorageAccess& imageStorageAccess(int index) const {
         return *fImageStorageAccesses[index];
     }

     bool isBad() const { return fIsBad; }

 protected:
     GrResourceIOProcessor() : fIsBad(false) {}

     /**
      * Subclasses call these from their constructor to register sampler/image sources. The processor
      * subclass manages the lifetime of the objects (these functions only store pointers). The
      * TextureSampler and/or BufferAccess instances are typically member fields of the GrProcessor
      * subclass. These must only be called from the constructor because GrProcessors are immutable.
      */
     void addTextureSampler(const TextureSampler*);
     void addBufferAccess(const BufferAccess*);
     void addImageStorageAccess(GrResourceProvider* resourceProvider, const ImageStorageAccess*);

     bool hasSameSamplersAndAccesses(const GrResourceIOProcessor&) const;

     // These methods can be used by derived classes that also derive from GrProgramElement.
     void addPendingIOs() const;
     void removeRefs() const;
     void pendingIOComplete() const;

     void markAsBad() { fIsBad = true; }

 private:
     SkSTArray<4, const TextureSampler*, true> fTextureSamplers;
     SkSTArray<1, const BufferAccess*, true> fBufferAccesses;
     SkSTArray<1, const ImageStorageAccess*, true> fImageStorageAccesses;
     bool fIsBad;

     typedef GrProcessor INHERITED;
 };

 /**
  * Used to represent a texture that is required by a GrResourceIOProcessor. It holds a GrTexture
  * along with an associated GrSamplerParams. TextureSamplers don't perform any coord manipulation to
  * account for texture origin.
  */
 class GrResourceIOProcessor::TextureSampler : public SkNoncopyable {
 public:
     /**
      * Must be initialized before adding to a GrProcessor's texture access list.
      */
     TextureSampler();

     // MDB TODO: this is the last GrTexture-based reset call!
     void reset(GrTexture*,
                GrSamplerParams::FilterMode = GrSamplerParams::kNone_FilterMode,
                SkShader::TileMode tileXAndY = SkShader::kClamp_TileMode,
                GrShaderFlags visibility = kFragment_GrShaderFlag);

     // MDB TODO: ultimately we shouldn't need the resource provider parameter
     TextureSampler(GrResourceProvider*, sk_sp<GrTextureProxy>, const GrSamplerParams&);
     explicit TextureSampler(GrResourceProvider*, sk_sp<GrTextureProxy>,
                             GrSamplerParams::FilterMode = GrSamplerParams::kNone_FilterMode,
                             SkShader::TileMode tileXAndY = SkShader::kClamp_TileMode,
                             GrShaderFlags visibility = kFragment_GrShaderFlag);
     void reset(GrResourceProvider*, sk_sp<GrTextureProxy>, const GrSamplerParams&,
                GrShaderFlags visibility = kFragment_GrShaderFlag);
     void reset(GrResourceProvider*, sk_sp<GrTextureProxy>,
                GrSamplerParams::FilterMode = GrSamplerParams::kNone_FilterMode,
                SkShader::TileMode tileXAndY = SkShader::kClamp_TileMode,
                GrShaderFlags visibility = kFragment_GrShaderFlag);

     bool operator==(const TextureSampler& that) const {
         return this->texture() == that.texture() &&
                fParams == that.fParams &&
                fVisibility == that.fVisibility;
     }

     bool operator!=(const TextureSampler& other) const { return !(*this == other); }

     GrTexture* texture() const { return fTexture.get(); }
     GrShaderFlags visibility() const { return fVisibility; }
     const GrSamplerParams& params() const { return fParams; }

     /**
      * For internal use by GrProcessor.
      */
     const GrGpuResourceRef* programTexture() const { return &fTexture; }

     bool isBad() const { return !fTexture.get(); }

 private:

     typedef GrTGpuResourceRef<GrTexture> ProgramTexture;

     ProgramTexture                  fTexture;
     GrSamplerParams                 fParams;
     GrShaderFlags                   fVisibility;

     typedef SkNoncopyable INHERITED;
 };

 /**
  * Used to represent a texel buffer that will be read in a GrResourceIOProcessor. It holds a
  * GrBuffer along with an associated offset and texel config.
  */
 class GrResourceIOProcessor::BufferAccess : public SkNoncopyable {
 public:
     BufferAccess() = default;
     BufferAccess(GrPixelConfig texelConfig, GrBuffer* buffer,
                  GrShaderFlags visibility = kFragment_GrShaderFlag) {
         this->reset(texelConfig, buffer, visibility);
     }
     /**
      * Must be initialized before adding to a GrProcessor's buffer access list.
      */
     void reset(GrPixelConfig texelConfig, GrBuffer* buffer,
                GrShaderFlags visibility = kFragment_GrShaderFlag) {
         fTexelConfig = texelConfig;
         fBuffer.set(SkRef(buffer), kRead_GrIOType);
         fVisibility = visibility;
     }

     bool operator==(const BufferAccess& that) const {
         return fTexelConfig == that.fTexelConfig &&
                this->buffer() == that.buffer() &&
                fVisibility == that.fVisibility;
     }

     bool operator!=(const BufferAccess& that) const { return !(*this == that); }

     GrPixelConfig texelConfig() const { return fTexelConfig; }
     GrBuffer* buffer() const { return fBuffer.get(); }
     GrShaderFlags visibility() const { return fVisibility; }

     /**
      * For internal use by GrProcessor.
      */
     const GrGpuResourceRef* programBuffer() const { return &fBuffer;}

 private:
     GrPixelConfig fTexelConfig;
     GrTGpuResourceRef<GrBuffer> fBuffer;
     GrShaderFlags fVisibility;

     typedef SkNoncopyable INHERITED;
 };

 /**
  * This is used by a GrProcessor to access a texture using image load/store in its shader code.
  * ImageStorageAccesses don't perform any coord manipulation to account for texture origin.
  * Currently the format of the load/store data in the shader is inferred from the texture config,
  * though it could be made explicit.
  */
 class GrResourceIOProcessor::ImageStorageAccess : public SkNoncopyable {
 public:
     ImageStorageAccess(sk_sp<GrTextureProxy>, GrIOType, GrSLMemoryModel, GrSLRestrict,
                        GrShaderFlags visibility = kFragment_GrShaderFlag);

     bool operator==(const ImageStorageAccess& that) const {
         return this->proxy() == that.proxy() && fVisibility == that.fVisibility;
     }

     bool operator!=(const ImageStorageAccess& that) const { return !(*this == that); }

     GrTexture* texture() const { return fProxyRef.getProxy()->priv().peekTexture(); }
     GrTextureProxy* proxy() const { return fProxyRef.getProxy()->asTextureProxy(); }
     GrShaderFlags visibility() const { return fVisibility; }
     GrIOType ioType() const { return fProxyRef.ioType(); }
     GrImageStorageFormat format() const { return fFormat; }
     GrSLMemoryModel memoryModel() const { return fMemoryModel; }
     GrSLRestrict restrict() const { return fRestrict; }

     // MDB: In the future this should be renamed instantiate
     bool isBad(GrResourceProvider* resourceProvider) const {
         return SkToBool(!fProxyRef.getProxy()->instantiate(resourceProvider));
     }

     /**
      * For internal use by GrProcessor.
      */
     const GrSurfaceProxyRef* programProxy() const { return &fProxyRef; }

 private:
     GrSurfaceProxyRef    fProxyRef;
     GrShaderFlags        fVisibility;
     GrImageStorageFormat fFormat;
     GrSLMemoryModel      fMemoryModel;
     GrSLRestrict         fRestrict;
     typedef SkNoncopyable INHERITED;
 };

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

	#ifndef GrProcessor_DEFINED
	#define GrProcessor_DEFINED

	#include "GrColor.h"
	#include "GrBuffer.h"
	#include "GrGpuResourceRef.h"
	#include "GrProcessorUnitTest.h"
	#include "GrProgramElement.h"
	#include "GrSamplerParams.h"
	#include "GrShaderVar.h"
	#include "GrSurfaceProxyPriv.h"
	#include "SkMath.h"
	#include "SkString.h"
	#include "../private/SkAtomics.h"

	class GrContext;
	class GrCoordTransform;
	class GrInvariantOutput;
	class GrResourceProvider;
	class GrTextureProxy;

	/**
	* Used by processors to build their keys. It incorporates each per-processor key into a larger
	* shader key.
	*/
	class GrProcessorKeyBuilder {
	public:
	GrProcessorKeyBuilder(SkTArray<unsigned char, true>* data) : fData(data), fCount(0) {
	SkASSERT(0 == fData->count() % sizeof(uint32_t));
	}

	void add32(uint32_t v) {
	++fCount;
	fData->push_back_n(4, reinterpret_cast<uint8_t*>(&v));
	}

	/** Inserts count uint32_ts into the key. The returned pointer is only valid until the next
	add() call. /
	uint32_t* SK_WARN_UNUSED_RESULT add32n(int count) {
	SkASSERT(count > 0);
	fCount += count;
	return reinterpret_cast<uint32_t>(fData->push_back_n(4 count));
	}

	size_t size() const { return sizeof(uint32_t) * fCount; }

	private:
	SkTArray<uint8_t, true>* fData; // unowned ptr to the larger key.
	int fCount; // number of uint32_ts added to fData by the processor.
	};

	/** Provides custom shader code to the Ganesh shading pipeline. GrProcessor objects must be
	immutable: after being constructed, their fields may not change.

	Dynamically allocated GrProcessors are managed by a per-thread memory pool. The ref count of an
	processor must reach 0 before the thread terminates and the pool is destroyed.
	*/
	class GrProcessor {
	public:
	virtual ~GrProcessor() = default;

	/** Human-meaningful string to identify this prcoessor; may be embedded in generated shader
	code. */
	virtual const char* name() const = 0;

	/** Human-readable dump of all information */
	virtual SkString dumpInfo() const {
	SkString str;
	str.appendf("Missing data");
	return str;
	}

	/**
	* Platform specific built-in features that a processor can request for the fragment shader.
	*/
	enum RequiredFeatures {
	kNone_RequiredFeatures = 0,
	kSampleLocations_RequiredFeature = 1 << 0
	};

	GR_DECL_BITFIELD_OPS_FRIENDS(RequiredFeatures);

	RequiredFeatures requiredFeatures() const { return fRequiredFeatures; }

	void* operator new(size_t size);
	void operator delete(void* target);

	void* operator new(size_t size, void* placement) {
	return ::operator new(size, placement);
	}
	void operator delete(void* target, void* placement) {
	::operator delete(target, placement);
	}

	/** Helper for down-casting to a GrProcessor subclass */
	template <typename T> const T& cast() const { return static_cast<const T>(this); }

	uint32_t classID() const { SkASSERT(kIllegalProcessorClassID != fClassID); return fClassID; }

	protected:
	GrProcessor() : fClassID(kIllegalProcessorClassID), fRequiredFeatures(kNone_RequiredFeatures) {}

	/**
	* If the prcoessor will generate code that uses platform specific built-in features, then it
	* must call these methods from its constructor. Otherwise, requests to use these features will
	* be denied.
	*/
	void setWillUseSampleLocations() { fRequiredFeatures \|= kSampleLocations_RequiredFeature; }

	void combineRequiredFeatures(const GrProcessor& other) {
	fRequiredFeatures \|= other.fRequiredFeatures;
	}

	template <typename PROC_SUBCLASS> void initClassID() {
	static uint32_t kClassID = GenClassID();
	fClassID = kClassID;
	}

	private:
	GrProcessor(const GrProcessor&) = delete;
	GrProcessor& operator=(const GrProcessor&) = delete;

	static uint32_t GenClassID() {
	// fCurrProcessorClassID has been initialized to kIllegalProcessorClassID. The
	// atomic inc returns the old value not the incremented value. So we add
	// 1 to the returned value.
	uint32_t id = static_cast<uint32_t>(sk_atomic_inc(&gCurrProcessorClassID)) + 1;
	if (!id) {
	SkFAIL("This should never wrap as it should only be called once for each GrProcessor "
	"subclass.");
	}
	return id;
	}

	enum {
	kIllegalProcessorClassID = 0,
	};
	static int32_t gCurrProcessorClassID;

	uint32_t fClassID;
	RequiredFeatures fRequiredFeatures;
	};

	GR_MAKE_BITFIELD_OPS(GrProcessor::RequiredFeatures);

	/** A GrProcessor with the ability to access textures, buffers, and image storages. */
	class GrResourceIOProcessor : public GrProcessor {
	public:
	class TextureSampler;
	class BufferAccess;
	class ImageStorageAccess;

	int numTextureSamplers() const { return fTextureSamplers.count(); }

	/** Returns the access pattern for the texture at index. index must be valid according to
	numTextureSamplers(). */
	const TextureSampler& textureSampler(int index) const { return *fTextureSamplers[index]; }

	int numBuffers() const { return fBufferAccesses.count(); }

	/** Returns the access pattern for the buffer at index. index must be valid according to
	numBuffers(). */
	const BufferAccess& bufferAccess(int index) const { return *fBufferAccesses[index]; }

	int numImageStorages() const { return fImageStorageAccesses.count(); }

	/** Returns the access object for the image at index. index must be valid according to
	numImages(). */
	const ImageStorageAccess& imageStorageAccess(int index) const {
	return *fImageStorageAccesses[index];
	}

	bool isBad() const { return fIsBad; }

	protected:
	GrResourceIOProcessor() : fIsBad(false) {}

	/**
	* Subclasses call these from their constructor to register sampler/image sources. The processor
	* subclass manages the lifetime of the objects (these functions only store pointers). The
	* TextureSampler and/or BufferAccess instances are typically member fields of the GrProcessor
	* subclass. These must only be called from the constructor because GrProcessors are immutable.
	*/
	void addTextureSampler(const TextureSampler*);
	void addBufferAccess(const BufferAccess*);
	void addImageStorageAccess(GrResourceProvider* resourceProvider, const ImageStorageAccess*);

	bool hasSameSamplersAndAccesses(const GrResourceIOProcessor&) const;

	// These methods can be used by derived classes that also derive from GrProgramElement.
	void addPendingIOs() const;
	void removeRefs() const;
	void pendingIOComplete() const;

	void markAsBad() { fIsBad = true; }

	private:
	SkSTArray<4, const TextureSampler*, true> fTextureSamplers;
	SkSTArray<1, const BufferAccess*, true> fBufferAccesses;
	SkSTArray<1, const ImageStorageAccess*, true> fImageStorageAccesses;
	bool fIsBad;

	typedef GrProcessor INHERITED;
	};

	/**
	* Used to represent a texture that is required by a GrResourceIOProcessor. It holds a GrTexture
	* along with an associated GrSamplerParams. TextureSamplers don't perform any coord manipulation to
	* account for texture origin.
	*/
	class GrResourceIOProcessor::TextureSampler : public SkNoncopyable {
	public:
	/**
	* Must be initialized before adding to a GrProcessor's texture access list.
	*/
	TextureSampler();

	// MDB TODO: this is the last GrTexture-based reset call!
	void reset(GrTexture*,
	GrSamplerParams::FilterMode = GrSamplerParams::kNone_FilterMode,
	SkShader::TileMode tileXAndY = SkShader::kClamp_TileMode,
	GrShaderFlags visibility = kFragment_GrShaderFlag);

	// MDB TODO: ultimately we shouldn't need the resource provider parameter
	TextureSampler(GrResourceProvider*, sk_sp<GrTextureProxy>, const GrSamplerParams&);
	explicit TextureSampler(GrResourceProvider*, sk_sp<GrTextureProxy>,
	GrSamplerParams::FilterMode = GrSamplerParams::kNone_FilterMode,
	SkShader::TileMode tileXAndY = SkShader::kClamp_TileMode,
	GrShaderFlags visibility = kFragment_GrShaderFlag);
	void reset(GrResourceProvider*, sk_sp<GrTextureProxy>, const GrSamplerParams&,
	GrShaderFlags visibility = kFragment_GrShaderFlag);
	void reset(GrResourceProvider*, sk_sp<GrTextureProxy>,
	GrSamplerParams::FilterMode = GrSamplerParams::kNone_FilterMode,
	SkShader::TileMode tileXAndY = SkShader::kClamp_TileMode,
	GrShaderFlags visibility = kFragment_GrShaderFlag);

	bool operator==(const TextureSampler& that) const {
	return this->texture() == that.texture() &&
	fParams == that.fParams &&
	fVisibility == that.fVisibility;
	}

	bool operator!=(const TextureSampler& other) const { return !(*this == other); }

	GrTexture* texture() const { return fTexture.get(); }
	GrShaderFlags visibility() const { return fVisibility; }
	const GrSamplerParams& params() const { return fParams; }

	/**
	* For internal use by GrProcessor.
	*/
	const GrGpuResourceRef* programTexture() const { return &fTexture; }

	bool isBad() const { return !fTexture.get(); }

	private:

	typedef GrTGpuResourceRef<GrTexture> ProgramTexture;

	ProgramTexture fTexture;
	GrSamplerParams fParams;
	GrShaderFlags fVisibility;

	typedef SkNoncopyable INHERITED;
	};

	/**
	* Used to represent a texel buffer that will be read in a GrResourceIOProcessor. It holds a
	* GrBuffer along with an associated offset and texel config.
	*/
	class GrResourceIOProcessor::BufferAccess : public SkNoncopyable {
	public:
	BufferAccess() = default;
	BufferAccess(GrPixelConfig texelConfig, GrBuffer* buffer,
	GrShaderFlags visibility = kFragment_GrShaderFlag) {
	this->reset(texelConfig, buffer, visibility);
	}
	/**
	* Must be initialized before adding to a GrProcessor's buffer access list.
	*/
	void reset(GrPixelConfig texelConfig, GrBuffer* buffer,
	GrShaderFlags visibility = kFragment_GrShaderFlag) {
	fTexelConfig = texelConfig;
	fBuffer.set(SkRef(buffer), kRead_GrIOType);
	fVisibility = visibility;
	}

	bool operator==(const BufferAccess& that) const {
	return fTexelConfig == that.fTexelConfig &&
	this->buffer() == that.buffer() &&
	fVisibility == that.fVisibility;
	}

	bool operator!=(const BufferAccess& that) const { return !(*this == that); }

	GrPixelConfig texelConfig() const { return fTexelConfig; }
	GrBuffer* buffer() const { return fBuffer.get(); }
	GrShaderFlags visibility() const { return fVisibility; }

	/**
	* For internal use by GrProcessor.
	*/
	const GrGpuResourceRef* programBuffer() const { return &fBuffer;}

	private:
	GrPixelConfig fTexelConfig;
	GrTGpuResourceRef<GrBuffer> fBuffer;
	GrShaderFlags fVisibility;

	typedef SkNoncopyable INHERITED;
	};

	/**
	* This is used by a GrProcessor to access a texture using image load/store in its shader code.
	* ImageStorageAccesses don't perform any coord manipulation to account for texture origin.
	* Currently the format of the load/store data in the shader is inferred from the texture config,
	* though it could be made explicit.
	*/
	class GrResourceIOProcessor::ImageStorageAccess : public SkNoncopyable {
	public:
	ImageStorageAccess(sk_sp<GrTextureProxy>, GrIOType, GrSLMemoryModel, GrSLRestrict,
	GrShaderFlags visibility = kFragment_GrShaderFlag);

	bool operator==(const ImageStorageAccess& that) const {
	return this->proxy() == that.proxy() && fVisibility == that.fVisibility;
	}

	bool operator!=(const ImageStorageAccess& that) const { return !(*this == that); }

	GrTexture* texture() const { return fProxyRef.getProxy()->priv().peekTexture(); }
	GrTextureProxy* proxy() const { return fProxyRef.getProxy()->asTextureProxy(); }
	GrShaderFlags visibility() const { return fVisibility; }
	GrIOType ioType() const { return fProxyRef.ioType(); }
	GrImageStorageFormat format() const { return fFormat; }
	GrSLMemoryModel memoryModel() const { return fMemoryModel; }
	GrSLRestrict restrict() const { return fRestrict; }

	// MDB: In the future this should be renamed instantiate
	bool isBad(GrResourceProvider* resourceProvider) const {
	return SkToBool(!fProxyRef.getProxy()->instantiate(resourceProvider));
	}

	/**
	* For internal use by GrProcessor.
	*/
	const GrSurfaceProxyRef* programProxy() const { return &fProxyRef; }

	private:
	GrSurfaceProxyRef fProxyRef;
	GrShaderFlags fVisibility;
	GrImageStorageFormat fFormat;
	GrSLMemoryModel fMemoryModel;
	GrSLRestrict fRestrict;
	typedef SkNoncopyable INHERITED;
	};

	#endif