skia2/include/gpu/GrShaderCaps.h

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/*
* 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 GrShaderCaps : public SkRefCnt {
public:
/** Info about shader variable precision within a given shader stage. That is, this info
is relevant to a float (or vecNf) variable declared with a GrSLPrecision
in a given GrShaderType. The info here is hoisted from the OpenGL spec. */
struct PrecisionInfo {
PrecisionInfo() {
fLogRangeLow = 0;
fLogRangeHigh = 0;
fBits = 0;
}
/** Is this precision level allowed in the shader stage? */
bool supported() const { return 0 != fBits; }
bool operator==(const PrecisionInfo& that) const {
return fLogRangeLow == that.fLogRangeLow && fLogRangeHigh == that.fLogRangeHigh &&
fBits == that.fBits;
}
bool operator!=(const PrecisionInfo& that) const { return !(*this == that); }
/** floor(log2(|min_value|)) */
int fLogRangeLow;
/** floor(log2(|max_value|)) */
int fLogRangeHigh;
/** Number of bits of precision. As defined in OpenGL (with names modified to reflect this
struct) :
"""
If the smallest representable value greater than 1 is 1 + e, then fBits will
contain floor(log2(e)), and every value in the range [2^fLogRangeLow,
2^fLogRangeHigh] can be represented to at least one part in 2^fBits.
"""
*/
int fBits;
};
/**
* 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&);
SkString dump() const;
bool shaderDerivativeSupport() const { return fShaderDerivativeSupport; }
bool geometryShaderSupport() const { return fGeometryShaderSupport; }
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; }
/**
* Get the precision info for a variable of type kFloat_GrSLType, kVec2f_GrSLType, etc in a
* given shader type. If the shader type is not supported or the precision level is not
* supported in that shader type then the returned struct will report false when supported() is
* called.
*/
const PrecisionInfo& getFloatShaderPrecisionInfo(GrShaderType shaderType,
GrSLPrecision precision) const {
return fFloatPrecisions[shaderType][precision];
}
/**
* Is there any difference between the float shader variable precision types? If this is true
* then unless the shader type is not supported, any call to getFloatShaderPrecisionInfo() would
* report the same info for all precisions in all shader types.
*/
bool floatPrecisionVaries() const { return fShaderPrecisionVaries; }
/**
* PLS storage size in bytes (0 when not supported). The PLS spec defines a minimum size of 16
* bytes whenever PLS is supported.
*/
int pixelLocalStorageSize() const { return fPixelLocalStorageSize; }
/**
* True if this context supports the necessary extensions and features to enable the PLS path
* renderer.
*/
bool plsPathRenderingSupport() const {
#if GR_ENABLE_PLS_PATH_RENDERING
return fPLSPathRenderingSupport;
#else
return false;
#endif
}
/**
* 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; }
bool bindlessTextureSupport() const { return fBindlessTextureSupport; }
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 noperspectiveInterpolationSupport() const { return fNoPerspectiveInterpolationSupport; }
bool multisampleInterpolationSupport() const { return fMultisampleInterpolationSupport; }
bool sampleVariablesSupport() const { return fSampleVariablesSupport; }
bool sampleMaskOverrideCoverageSupport() const { return fSampleMaskOverrideCoverageSupport; }
bool externalTextureSupport() const { return fExternalTextureSupport; }
bool texelFetchSupport() const { return fTexelFetchSupport; }
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 mustForceNegatedAtanParamToFloat() const { return fMustForceNegatedAtanParamToFloat; }
// Returns whether a device incorrectly implements atan(y,x) as atan(y/x)
bool atan2ImplementedAsAtanYOverX() const { return fAtan2ImplementedAsAtanYOverX; }
bool requiresLocalOutputColorForFBFetch() const { return fRequiresLocalOutputColorForFBFetch; }
// 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 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* multisampleInterpolationExtensionString() const {
SkASSERT(this->multisampleInterpolationSupport());
return fMultisampleInterpolationExtensionString;
}
const char* sampleVariablesExtensionString() const {
SkASSERT(this->sampleVariablesSupport());
return fSampleVariablesExtensionString;
}
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; }
int maxVertexImageStorages() const { return fMaxVertexImageStorages; }
int maxGeometryImageStorages() const { return fMaxGeometryImageStorages; }
int maxFragmentImageStorages() const { return fMaxFragmentImageStorages; }
int maxCombinedImageStorages() const { return fMaxCombinedImageStorages; }
/**
* 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];
}
/** Precision qualifier that should be used with a sampler, given its config and visibility. */
GrSLPrecision samplerPrecision(GrPixelConfig config, GrShaderFlags visibility) const {
return static_cast<GrSLPrecision>(fSamplerPrecisions[visibility][config]);
}
GrGLSLGeneration generation() const { return fGLSLGeneration; }
private:
/** GrCaps subclasses must call this after filling in the shader precision table. */
void initSamplerPrecisionTable();
void applyOptionsOverrides(const GrContextOptions& options);
GrGLSLGeneration fGLSLGeneration;
bool fShaderDerivativeSupport : 1;
bool fGeometryShaderSupport : 1;
bool fPathRenderingSupport : 1;
bool fDstReadInShaderSupport : 1;
bool fDualSourceBlendingSupport : 1;
bool fIntegerSupport : 1;
bool fTexelBufferSupport : 1;
bool fImageLoadStoreSupport : 1;
bool fPLSPathRenderingSupport : 1;
bool fShaderPrecisionVaries : 1;
bool fDropsTileOnZeroDivide : 1;
bool fFBFetchSupport : 1;
bool fFBFetchNeedsCustomOutput : 1;
bool fBindlessTextureSupport : 1;
bool fUsesPrecisionModifiers : 1;
bool fCanUseAnyFunctionInShader : 1;
bool fFlatInterpolationSupport : 1;
bool fNoPerspectiveInterpolationSupport : 1;
bool fMultisampleInterpolationSupport : 1;
bool fSampleVariablesSupport : 1;
bool fSampleMaskOverrideCoverageSupport : 1;
bool fExternalTextureSupport : 1;
bool fTexelFetchSupport : 1;
// Used for specific driver bug work arounds
bool fCanUseMinAndAbsTogether : 1;
bool fMustForceNegatedAtanParamToFloat : 1;
bool fAtan2ImplementedAsAtanYOverX : 1;
bool fRequiresLocalOutputColorForFBFetch : 1;
PrecisionInfo fFloatPrecisions[kGrShaderTypeCount][kGrSLPrecisionCount];
int fPixelLocalStorageSize;
const char* fVersionDeclString;
const char* fShaderDerivativeExtensionString;
const char* fFragCoordConventionsExtensionString;
const char* fSecondaryOutputExtensionString;
const char* fExternalTextureExtensionString;
const char* fTexelBufferExtensionString;
const char* fNoPerspectiveInterpolationExtensionString;
const char* fMultisampleInterpolationExtensionString;
const char* fSampleVariablesExtensionString;
const char* fImageLoadStoreExtensionString;
const char* fFBFetchColorName;
const char* fFBFetchExtensionString;
int fMaxVertexSamplers;
int fMaxGeometrySamplers;
int fMaxFragmentSamplers;
int fMaxCombinedSamplers;
int fMaxVertexImageStorages;
int fMaxGeometryImageStorages;
int fMaxFragmentImageStorages;
int fMaxCombinedImageStorages;
AdvBlendEqInteraction fAdvBlendEqInteraction;
GrSwizzle fConfigTextureSwizzle[kGrPixelConfigCnt];
GrSwizzle fConfigOutputSwizzle[kGrPixelConfigCnt];
uint8_t fSamplerPrecisions[(1 << kGrShaderTypeCount)][kGrPixelConfigCnt];
friend class GrGLCaps; // For initialization.
friend class GrVkCaps;
friend class SkSL::ShaderCapsFactory;
};
#endif