include/gpu/GrShaderCaps.h - 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.
  */


 #ifndef GrShaderCaps_DEFINED
 #define GrShaderCaps_DEFINED

 #include "../private/GrSwizzle.h"
 #include "../private/GrGLSL.h"

 namespace SkSL {
     class ShaderCapsFactory;
 }
 struct GrContextOptions;
 class SkJSONWriter;

 class GrShaderCaps : public SkRefCnt {
 public:
     /**
     * Indicates how GLSL must interact with advanced blend equations. The KHR extension requires
     * special layout qualifiers in the fragment shader.
     */
     enum AdvBlendEqInteraction {
         kNotSupported_AdvBlendEqInteraction,     //<! No _blend_equation_advanced extension
         kAutomatic_AdvBlendEqInteraction,        //<! No interaction required
         kGeneralEnable_AdvBlendEqInteraction,    //<! layout(blend_support_all_equations) out
         kSpecificEnables_AdvBlendEqInteraction,  //<! Specific layout qualifiers per equation

         kLast_AdvBlendEqInteraction = kSpecificEnables_AdvBlendEqInteraction
     };

     GrShaderCaps(const GrContextOptions&);

     void dumpJSON(SkJSONWriter*) const;

     bool shaderDerivativeSupport() const { return fShaderDerivativeSupport; }
     bool geometryShaderSupport() const { return fGeometryShaderSupport; }
     bool gsInvocationsSupport() const { return fGSInvocationsSupport; }
     bool pathRenderingSupport() const { return fPathRenderingSupport; }
     bool dstReadInShaderSupport() const { return fDstReadInShaderSupport; }
     bool dualSourceBlendingSupport() const { return fDualSourceBlendingSupport; }
     bool integerSupport() const { return fIntegerSupport; }
     bool texelBufferSupport() const { return fTexelBufferSupport; }
     int imageLoadStoreSupport() const { return fImageLoadStoreSupport; }

     /**
      * Some helper functions for encapsulating various extensions to read FB Buffer on openglES
      *
      * TODO(joshualitt) On desktop opengl 4.2+ we can achieve something similar to this effect
      */
     bool fbFetchSupport() const { return fFBFetchSupport; }

     bool fbFetchNeedsCustomOutput() const { return fFBFetchNeedsCustomOutput; }

     const char* versionDeclString() const { return fVersionDeclString; }

     const char* fbFetchColorName() const { return fFBFetchColorName; }

     const char* fbFetchExtensionString() const { return fFBFetchExtensionString; }

     bool dropsTileOnZeroDivide() const { return fDropsTileOnZeroDivide; }

     bool flatInterpolationSupport() const { return fFlatInterpolationSupport; }

     bool preferFlatInterpolation() const { return fPreferFlatInterpolation; }

     bool noperspectiveInterpolationSupport() const { return fNoPerspectiveInterpolationSupport; }

     bool externalTextureSupport() const { return fExternalTextureSupport; }

     bool texelFetchSupport() const { return fTexelFetchSupport; }

     bool vertexIDSupport() const { return fVertexIDSupport; }

     bool floatIs32Bits() const { return fFloatIs32Bits; }

     bool halfIs32Bits() const { return fHalfIs32Bits; }

     AdvBlendEqInteraction advBlendEqInteraction() const { return fAdvBlendEqInteraction; }

     bool mustEnableAdvBlendEqs() const {
         return fAdvBlendEqInteraction >= kGeneralEnable_AdvBlendEqInteraction;
     }

     bool mustEnableSpecificAdvBlendEqs() const {
         return fAdvBlendEqInteraction == kSpecificEnables_AdvBlendEqInteraction;
     }

     bool mustDeclareFragmentShaderOutput() const {
         return fGLSLGeneration > k110_GrGLSLGeneration;
     }

     bool usesPrecisionModifiers() const { return fUsesPrecisionModifiers; }

     // Returns whether we can use the glsl function any() in our shader code.
     bool canUseAnyFunctionInShader() const { return fCanUseAnyFunctionInShader; }

     bool canUseMinAndAbsTogether() const { return fCanUseMinAndAbsTogether; }

     bool canUseFractForNegativeValues() const { return fCanUseFractForNegativeValues; }

     bool mustForceNegatedAtanParamToFloat() const { return fMustForceNegatedAtanParamToFloat; }

     // Returns whether a device incorrectly implements atan(y,x) as atan(y/x)
     bool atan2ImplementedAsAtanYOverX() const { return fAtan2ImplementedAsAtanYOverX; }

     // If this returns true some operation (could be a no op) must be called between floor and abs
     // to make sure the driver compiler doesn't inline them together which can cause a driver bug in
     // the shader.
     bool mustDoOpBetweenFloorAndAbs() const { return fMustDoOpBetweenFloorAndAbs; }

     // If false, SkSL uses a workaround so that sk_FragCoord doesn't actually query gl_FragCoord
     bool canUseFragCoord() const { return fCanUseFragCoord; }

     // If true interpolated vertex shader outputs are inaccurate.
     bool interpolantsAreInaccurate() const { return fInterpolantsAreInaccurate; }

     bool requiresLocalOutputColorForFBFetch() const { return fRequiresLocalOutputColorForFBFetch; }

     bool mustObfuscateUniformColor() const { return fMustObfuscateUniformColor; }

     // The D3D shader compiler, when targeting PS 3.0 (ie within ANGLE) fails to compile certain
     // constructs. See detailed comments in GrGLCaps.cpp.
     bool mustGuardDivisionEvenAfterExplicitZeroCheck() const {
         return fMustGuardDivisionEvenAfterExplicitZeroCheck;
     }

     // Returns the string of an extension that must be enabled in the shader to support
     // derivatives. If nullptr is returned then no extension needs to be enabled. Before calling
     // this function, the caller should check that shaderDerivativeSupport exists.
     const char* shaderDerivativeExtensionString() const {
         SkASSERT(this->shaderDerivativeSupport());
         return fShaderDerivativeExtensionString;
     }

     // Returns the string of an extension that must be enabled in the shader to support geometry
     // shaders. If nullptr is returned then no extension needs to be enabled. Before calling this
     // function, the caller must verify that geometryShaderSupport exists.
     const char* geometryShaderExtensionString() const {
         SkASSERT(this->geometryShaderSupport());
         return fGeometryShaderExtensionString;
     }

     // Returns the string of an extension that must be enabled in the shader to support
     // geometry shader invocations. If nullptr is returned then no extension needs to be enabled.
     // Before calling this function, the caller must verify that gsInvocationsSupport exists.
     const char* gsInvocationsExtensionString() const {
         SkASSERT(this->gsInvocationsSupport());
         return fGSInvocationsExtensionString;
     }

     // Returns the string of an extension that will do all necessary coord transfomations needed
     // when reading the fragment position. If such an extension does not exisits, this function
     // returns a nullptr, and all transforms of the frag position must be done manually in the
     // shader.
     const char* fragCoordConventionsExtensionString() const {
         return fFragCoordConventionsExtensionString;
     }

     // This returns the name of an extension that must be enabled in the shader, if such a thing is
     // required in order to use a secondary output in the shader. This returns a nullptr if no such
     // extension is required. However, the return value of this function does not say whether dual
     // source blending is supported.
     const char* secondaryOutputExtensionString() const {
         return fSecondaryOutputExtensionString;
     }

     const char* externalTextureExtensionString() const {
         SkASSERT(this->externalTextureSupport());
         return fExternalTextureExtensionString;
     }

     const char* texelBufferExtensionString() const {
         SkASSERT(this->texelBufferSupport());
         return fTexelBufferExtensionString;
     }

     const char* noperspectiveInterpolationExtensionString() const {
         SkASSERT(this->noperspectiveInterpolationSupport());
         return fNoPerspectiveInterpolationExtensionString;
     }

     const char* imageLoadStoreExtensionString() const {
         SkASSERT(this->imageLoadStoreSupport());
         return fImageLoadStoreExtensionString;
     }

     int maxVertexSamplers() const { return fMaxVertexSamplers; }

     int maxGeometrySamplers() const { return fMaxGeometrySamplers; }

     int maxFragmentSamplers() const { return fMaxFragmentSamplers; }

     int maxCombinedSamplers() const { return fMaxCombinedSamplers; }

     /**
      * In general using multiple texture units for image rendering seems to be a win at smaller
      * sizes of dst rects and a loss at larger sizes. Dst rects above this pixel area threshold will
      * not use multitexturing.
      */
     size_t disableImageMultitexturingDstRectAreaThreshold() const {
         return fDisableImageMultitexturingDstRectAreaThreshold;
     }

     /**
      * Given a texture's config, this determines what swizzle must be appended to accesses to the
      * texture in generated shader code. Swizzling may be implemented in texture parameters or a
      * sampler rather than in the shader. In this case the returned swizzle will always be "rgba".
      */
     const GrSwizzle& configTextureSwizzle(GrPixelConfig config) const {
         return fConfigTextureSwizzle[config];
     }

     /** Swizzle that should occur on the fragment shader outputs for a given config. */
     const GrSwizzle& configOutputSwizzle(GrPixelConfig config) const {
         return fConfigOutputSwizzle[config];
     }

     GrGLSLGeneration generation() const { return fGLSLGeneration; }

 private:
     void applyOptionsOverrides(const GrContextOptions& options);

     GrGLSLGeneration fGLSLGeneration;

     bool fShaderDerivativeSupport   : 1;
     bool fGeometryShaderSupport     : 1;
     bool fGSInvocationsSupport      : 1;
     bool fPathRenderingSupport      : 1;
     bool fDstReadInShaderSupport    : 1;
     bool fDualSourceBlendingSupport : 1;
     bool fIntegerSupport            : 1;
     bool fTexelBufferSupport        : 1;
     bool fImageLoadStoreSupport     : 1;
     bool fDropsTileOnZeroDivide : 1;
     bool fFBFetchSupport : 1;
     bool fFBFetchNeedsCustomOutput : 1;
     bool fUsesPrecisionModifiers : 1;
     bool fFlatInterpolationSupport : 1;
     bool fPreferFlatInterpolation : 1;
     bool fNoPerspectiveInterpolationSupport : 1;
     bool fExternalTextureSupport : 1;
     bool fTexelFetchSupport : 1;
     bool fVertexIDSupport : 1;
     bool fFloatIs32Bits : 1;
     bool fHalfIs32Bits : 1;

     // Used for specific driver bug work arounds
     bool fCanUseAnyFunctionInShader : 1;
     bool fCanUseMinAndAbsTogether : 1;
     bool fCanUseFractForNegativeValues : 1;
     bool fMustForceNegatedAtanParamToFloat : 1;
     bool fAtan2ImplementedAsAtanYOverX : 1;
     bool fMustDoOpBetweenFloorAndAbs : 1;
     bool fRequiresLocalOutputColorForFBFetch : 1;
     bool fMustObfuscateUniformColor : 1;
     bool fMustGuardDivisionEvenAfterExplicitZeroCheck : 1;
     bool fCanUseFragCoord : 1;
     bool fInterpolantsAreInaccurate : 1;

     const char* fVersionDeclString;

     const char* fShaderDerivativeExtensionString;
     const char* fGeometryShaderExtensionString;
     const char* fGSInvocationsExtensionString;
     const char* fFragCoordConventionsExtensionString;
     const char* fSecondaryOutputExtensionString;
     const char* fExternalTextureExtensionString;
     const char* fTexelBufferExtensionString;
     const char* fNoPerspectiveInterpolationExtensionString;
     const char* fImageLoadStoreExtensionString;

     const char* fFBFetchColorName;
     const char* fFBFetchExtensionString;

     int fMaxVertexSamplers;
     int fMaxGeometrySamplers;
     int fMaxFragmentSamplers;
     int fMaxCombinedSamplers;

     size_t fDisableImageMultitexturingDstRectAreaThreshold;

     AdvBlendEqInteraction fAdvBlendEqInteraction;

     GrSwizzle fConfigTextureSwizzle[kGrPixelConfigCnt];
     GrSwizzle fConfigOutputSwizzle[kGrPixelConfigCnt];

     friend class GrCaps;  // For initialization.
     friend class GrGLCaps;
     friend class GrMockCaps;
     friend class GrMtlCaps;
     friend class GrVkCaps;
     friend class SkSL::ShaderCapsFactory;
 };

 #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 GrShaderCaps_DEFINED
	#define GrShaderCaps_DEFINED

	#include "../private/GrSwizzle.h"
	#include "../private/GrGLSL.h"

	namespace SkSL {
	class ShaderCapsFactory;
	}
	struct GrContextOptions;
	class SkJSONWriter;

	class GrShaderCaps : public SkRefCnt {
	public:
	/**
	* Indicates how GLSL must interact with advanced blend equations. The KHR extension requires
	* special layout qualifiers in the fragment shader.
	*/
	enum AdvBlendEqInteraction {
	kNotSupported_AdvBlendEqInteraction, //<! No _blend_equation_advanced extension
	kAutomatic_AdvBlendEqInteraction, //<! No interaction required
	kGeneralEnable_AdvBlendEqInteraction, //<! layout(blend_support_all_equations) out
	kSpecificEnables_AdvBlendEqInteraction, //<! Specific layout qualifiers per equation

	kLast_AdvBlendEqInteraction = kSpecificEnables_AdvBlendEqInteraction
	};

	GrShaderCaps(const GrContextOptions&);

	void dumpJSON(SkJSONWriter*) const;

	bool shaderDerivativeSupport() const { return fShaderDerivativeSupport; }
	bool geometryShaderSupport() const { return fGeometryShaderSupport; }
	bool gsInvocationsSupport() const { return fGSInvocationsSupport; }
	bool pathRenderingSupport() const { return fPathRenderingSupport; }
	bool dstReadInShaderSupport() const { return fDstReadInShaderSupport; }
	bool dualSourceBlendingSupport() const { return fDualSourceBlendingSupport; }
	bool integerSupport() const { return fIntegerSupport; }
	bool texelBufferSupport() const { return fTexelBufferSupport; }
	int imageLoadStoreSupport() const { return fImageLoadStoreSupport; }

	/**
	* Some helper functions for encapsulating various extensions to read FB Buffer on openglES
	*
	* TODO(joshualitt) On desktop opengl 4.2+ we can achieve something similar to this effect
	*/
	bool fbFetchSupport() const { return fFBFetchSupport; }

	bool fbFetchNeedsCustomOutput() const { return fFBFetchNeedsCustomOutput; }

	const char* versionDeclString() const { return fVersionDeclString; }

	const char* fbFetchColorName() const { return fFBFetchColorName; }

	const char* fbFetchExtensionString() const { return fFBFetchExtensionString; }

	bool dropsTileOnZeroDivide() const { return fDropsTileOnZeroDivide; }

	bool flatInterpolationSupport() const { return fFlatInterpolationSupport; }

	bool preferFlatInterpolation() const { return fPreferFlatInterpolation; }

	bool noperspectiveInterpolationSupport() const { return fNoPerspectiveInterpolationSupport; }

	bool externalTextureSupport() const { return fExternalTextureSupport; }

	bool texelFetchSupport() const { return fTexelFetchSupport; }

	bool vertexIDSupport() const { return fVertexIDSupport; }

	bool floatIs32Bits() const { return fFloatIs32Bits; }

	bool halfIs32Bits() const { return fHalfIs32Bits; }

	AdvBlendEqInteraction advBlendEqInteraction() const { return fAdvBlendEqInteraction; }

	bool mustEnableAdvBlendEqs() const {
	return fAdvBlendEqInteraction >= kGeneralEnable_AdvBlendEqInteraction;
	}

	bool mustEnableSpecificAdvBlendEqs() const {
	return fAdvBlendEqInteraction == kSpecificEnables_AdvBlendEqInteraction;
	}

	bool mustDeclareFragmentShaderOutput() const {
	return fGLSLGeneration > k110_GrGLSLGeneration;
	}

	bool usesPrecisionModifiers() const { return fUsesPrecisionModifiers; }

	// Returns whether we can use the glsl function any() in our shader code.
	bool canUseAnyFunctionInShader() const { return fCanUseAnyFunctionInShader; }

	bool canUseMinAndAbsTogether() const { return fCanUseMinAndAbsTogether; }

	bool canUseFractForNegativeValues() const { return fCanUseFractForNegativeValues; }

	bool mustForceNegatedAtanParamToFloat() const { return fMustForceNegatedAtanParamToFloat; }

	// Returns whether a device incorrectly implements atan(y,x) as atan(y/x)
	bool atan2ImplementedAsAtanYOverX() const { return fAtan2ImplementedAsAtanYOverX; }

	// If this returns true some operation (could be a no op) must be called between floor and abs
	// to make sure the driver compiler doesn't inline them together which can cause a driver bug in
	// the shader.
	bool mustDoOpBetweenFloorAndAbs() const { return fMustDoOpBetweenFloorAndAbs; }

	// If false, SkSL uses a workaround so that sk_FragCoord doesn't actually query gl_FragCoord
	bool canUseFragCoord() const { return fCanUseFragCoord; }

	// If true interpolated vertex shader outputs are inaccurate.
	bool interpolantsAreInaccurate() const { return fInterpolantsAreInaccurate; }

	bool requiresLocalOutputColorForFBFetch() const { return fRequiresLocalOutputColorForFBFetch; }

	bool mustObfuscateUniformColor() const { return fMustObfuscateUniformColor; }

	// The D3D shader compiler, when targeting PS 3.0 (ie within ANGLE) fails to compile certain
	// constructs. See detailed comments in GrGLCaps.cpp.
	bool mustGuardDivisionEvenAfterExplicitZeroCheck() const {
	return fMustGuardDivisionEvenAfterExplicitZeroCheck;
	}

	// Returns the string of an extension that must be enabled in the shader to support
	// derivatives. If nullptr is returned then no extension needs to be enabled. Before calling
	// this function, the caller should check that shaderDerivativeSupport exists.
	const char* shaderDerivativeExtensionString() const {
	SkASSERT(this->shaderDerivativeSupport());
	return fShaderDerivativeExtensionString;
	}

	// Returns the string of an extension that must be enabled in the shader to support geometry
	// shaders. If nullptr is returned then no extension needs to be enabled. Before calling this
	// function, the caller must verify that geometryShaderSupport exists.
	const char* geometryShaderExtensionString() const {
	SkASSERT(this->geometryShaderSupport());
	return fGeometryShaderExtensionString;
	}

	// Returns the string of an extension that must be enabled in the shader to support
	// geometry shader invocations. If nullptr is returned then no extension needs to be enabled.
	// Before calling this function, the caller must verify that gsInvocationsSupport exists.
	const char* gsInvocationsExtensionString() const {
	SkASSERT(this->gsInvocationsSupport());
	return fGSInvocationsExtensionString;
	}

	// Returns the string of an extension that will do all necessary coord transfomations needed
	// when reading the fragment position. If such an extension does not exisits, this function
	// returns a nullptr, and all transforms of the frag position must be done manually in the
	// shader.
	const char* fragCoordConventionsExtensionString() const {
	return fFragCoordConventionsExtensionString;
	}

	// This returns the name of an extension that must be enabled in the shader, if such a thing is
	// required in order to use a secondary output in the shader. This returns a nullptr if no such
	// extension is required. However, the return value of this function does not say whether dual
	// source blending is supported.
	const char* secondaryOutputExtensionString() const {
	return fSecondaryOutputExtensionString;
	}

	const char* externalTextureExtensionString() const {
	SkASSERT(this->externalTextureSupport());
	return fExternalTextureExtensionString;
	}

	const char* texelBufferExtensionString() const {
	SkASSERT(this->texelBufferSupport());
	return fTexelBufferExtensionString;
	}

	const char* noperspectiveInterpolationExtensionString() const {
	SkASSERT(this->noperspectiveInterpolationSupport());
	return fNoPerspectiveInterpolationExtensionString;
	}

	const char* imageLoadStoreExtensionString() const {
	SkASSERT(this->imageLoadStoreSupport());
	return fImageLoadStoreExtensionString;
	}

	int maxVertexSamplers() const { return fMaxVertexSamplers; }

	int maxGeometrySamplers() const { return fMaxGeometrySamplers; }

	int maxFragmentSamplers() const { return fMaxFragmentSamplers; }

	int maxCombinedSamplers() const { return fMaxCombinedSamplers; }

	/**
	* In general using multiple texture units for image rendering seems to be a win at smaller
	* sizes of dst rects and a loss at larger sizes. Dst rects above this pixel area threshold will
	* not use multitexturing.
	*/
	size_t disableImageMultitexturingDstRectAreaThreshold() const {
	return fDisableImageMultitexturingDstRectAreaThreshold;
	}

	/**
	* Given a texture's config, this determines what swizzle must be appended to accesses to the
	* texture in generated shader code. Swizzling may be implemented in texture parameters or a
	* sampler rather than in the shader. In this case the returned swizzle will always be "rgba".
	*/
	const GrSwizzle& configTextureSwizzle(GrPixelConfig config) const {
	return fConfigTextureSwizzle[config];
	}

	/** Swizzle that should occur on the fragment shader outputs for a given config. */
	const GrSwizzle& configOutputSwizzle(GrPixelConfig config) const {
	return fConfigOutputSwizzle[config];
	}

	GrGLSLGeneration generation() const { return fGLSLGeneration; }

	private:
	void applyOptionsOverrides(const GrContextOptions& options);

	GrGLSLGeneration fGLSLGeneration;

	bool fShaderDerivativeSupport : 1;
	bool fGeometryShaderSupport : 1;
	bool fGSInvocationsSupport : 1;
	bool fPathRenderingSupport : 1;
	bool fDstReadInShaderSupport : 1;
	bool fDualSourceBlendingSupport : 1;
	bool fIntegerSupport : 1;
	bool fTexelBufferSupport : 1;
	bool fImageLoadStoreSupport : 1;
	bool fDropsTileOnZeroDivide : 1;
	bool fFBFetchSupport : 1;
	bool fFBFetchNeedsCustomOutput : 1;
	bool fUsesPrecisionModifiers : 1;
	bool fFlatInterpolationSupport : 1;
	bool fPreferFlatInterpolation : 1;
	bool fNoPerspectiveInterpolationSupport : 1;
	bool fExternalTextureSupport : 1;
	bool fTexelFetchSupport : 1;
	bool fVertexIDSupport : 1;
	bool fFloatIs32Bits : 1;
	bool fHalfIs32Bits : 1;

	// Used for specific driver bug work arounds
	bool fCanUseAnyFunctionInShader : 1;
	bool fCanUseMinAndAbsTogether : 1;
	bool fCanUseFractForNegativeValues : 1;
	bool fMustForceNegatedAtanParamToFloat : 1;
	bool fAtan2ImplementedAsAtanYOverX : 1;
	bool fMustDoOpBetweenFloorAndAbs : 1;
	bool fRequiresLocalOutputColorForFBFetch : 1;
	bool fMustObfuscateUniformColor : 1;
	bool fMustGuardDivisionEvenAfterExplicitZeroCheck : 1;
	bool fCanUseFragCoord : 1;
	bool fInterpolantsAreInaccurate : 1;

	const char* fVersionDeclString;

	const char* fShaderDerivativeExtensionString;
	const char* fGeometryShaderExtensionString;
	const char* fGSInvocationsExtensionString;
	const char* fFragCoordConventionsExtensionString;
	const char* fSecondaryOutputExtensionString;
	const char* fExternalTextureExtensionString;
	const char* fTexelBufferExtensionString;
	const char* fNoPerspectiveInterpolationExtensionString;
	const char* fImageLoadStoreExtensionString;

	const char* fFBFetchColorName;
	const char* fFBFetchExtensionString;

	int fMaxVertexSamplers;
	int fMaxGeometrySamplers;
	int fMaxFragmentSamplers;
	int fMaxCombinedSamplers;

	size_t fDisableImageMultitexturingDstRectAreaThreshold;

	AdvBlendEqInteraction fAdvBlendEqInteraction;

	GrSwizzle fConfigTextureSwizzle[kGrPixelConfigCnt];
	GrSwizzle fConfigOutputSwizzle[kGrPixelConfigCnt];

	friend class GrCaps; // For initialization.
	friend class GrGLCaps;
	friend class GrMockCaps;
	friend class GrMtlCaps;
	friend class GrVkCaps;
	friend class SkSL::ShaderCapsFactory;
	};

	#endif