/*
* Copyright 2016 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SKSL_UTIL
#define SKSL_UTIL
#include "include/core/SkTypes.h"
#include "include/sksl/SkSLVersion.h"
#include "src/sksl/SkSLGLSL.h"
#include <memory>
enum class SkSLType :
char;
namespace SkSL {
class Context;
class OutputStream;
class StringStream;
class Type;
struct ShaderCaps {
/**
* 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
kLast_AdvBlendEqInteraction = kGeneralEnable_AdvBlendEqInteraction
};
bool mustEnableAdvBlendEqs()
const {
return fAdvBlendEqInteraction >= kGeneralEnable_AdvBlendEqInteraction;
}
bool mustDeclareFragmentShaderOutput()
const {
return fGLSLGeneration > SkSL::GLSLGeneration::k110;
}
// 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->fShaderDerivativeSupport);
return fShaderDerivativeExtensionString;
}
// This returns the name of an extension that must be enabled in the shader to support external
// textures. In some cases, two extensions must be enabled - the second extension is returned
// by secondExternalTextureExtensionString(). If that function returns nullptr, then only one
// extension is required.
const char* externalTextureExtensionString()
const {
SkASSERT(this->fExternalTextureSupport);
return fExternalTextureExtensionString;
}
const char* secondExternalTextureExtensionString()
const {
SkASSERT(this->fExternalTextureSupport);
return fSecondExternalTextureExtensionString;
}
/**
* SkSL 300 requires support for derivatives, nonsquare matrices and bitwise integer operations.
*/
SkSL::Version supportedSkSLVerion()
const {
if (fShaderDerivativeSupport && fNonsquareMatrixSupport && fIntegerSupport &&
fGLSLGeneration >= SkSL::GLSLGeneration::k330) {
return SkSL::Version::k300;
}
return SkSL::Version::k100;
}
bool supportsDistanceFieldText()
const {
return fShaderDerivativeSupport; }
SkSL::GLSLGeneration fGLSLGeneration = SkSL::GLSLGeneration::k330;
bool fDualSourceBlendingSupport =
false;
bool fShaderDerivativeSupport =
false;
/** Enables sampleGrad and sampleLod functions that don't rely on implicit derivatives */
bool fExplicitTextureLodSupport =
false;
/** Indicates true 32-bit integer support, with unsigned types and bitwise operations */
bool fIntegerSupport =
false;
bool fNonsquareMatrixSupport =
false;
/** asinh(), acosh(), atanh() */
bool fInverseHyperbolicSupport =
false;
bool fFBFetchSupport =
false;
bool fFBFetchNeedsCustomOutput =
false;
bool fUsesPrecisionModifiers =
false;
bool fFlatInterpolationSupport =
false;
bool fNoPerspectiveInterpolationSupport =
false;
bool fSampleMaskSupport =
false;
bool fExternalTextureSupport =
false;
bool fFloatIs32Bits =
true;
// isinf() is defined, and floating point infinities are handled according to IEEE standards.
bool fInfinitySupport =
false;
// Used by SkSL to know when to generate polyfills.
bool fBuiltinFMASupport =
true;
bool fBuiltinDeterminantSupport =
true;
// Used for specific driver bug work arounds
bool fCanUseVoidInSequenceExpressions =
true;
bool fCanUseMinAndAbsTogether =
true;
bool fCanUseFractForNegativeValues =
true;
bool fMustForceNegatedAtanParamToFloat =
false;
bool fMustForceNegatedLdexpParamToMultiply =
false;
// http://skbug.com/12076
// Returns whether a device incorrectly implements atan(y,x) as atan(y/x)
bool fAtan2ImplementedAsAtanYOverX =
false;
// 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 fMustDoOpBetweenFloorAndAbs =
false;
// The D3D shader compiler, when targeting PS 3.0 (ie within ANGLE) fails to compile certain
// constructs. See detailed comments in GrGLCaps.cpp.
bool fMustGuardDivisionEvenAfterExplicitZeroCheck =
false;
// If false, SkSL uses a workaround so that sk_FragCoord doesn't actually query gl_FragCoord
bool fCanUseFragCoord =
true;
// If true, then conditions in for loops need "&& true" to work around driver bugs.
bool fAddAndTrueToLoopCondition =
false;
// If true, then expressions such as "x && y" or "x || y" are rewritten as ternary to work
// around driver bugs.
bool fUnfoldShortCircuitAsTernary =
false;
bool fEmulateAbsIntFunction =
false;
bool fRewriteDoWhileLoops =
false;
bool fRewriteSwitchStatements =
false;
bool fRemovePowWithConstantExponent =
false;
// The Android emulator claims samplerExternalOES is an unknown type if a default precision
// statement is made for the type.
bool fNoDefaultPrecisionForExternalSamplers =
false;
// ARM GPUs calculate `matrix * vector` in SPIR-V at full precision, even when the inputs are
// RelaxedPrecision. Rewriting the multiply as a sum of vector*scalar fixes this. (skia:11769)
bool fRewriteMatrixVectorMultiply =
false;
// Rewrites matrix equality comparisons to avoid an Adreno driver bug. (skia:11308)
bool fRewriteMatrixComparisons =
false;
// Strips const from function parameters in the GLSL code generator. (skia:13858)
bool fRemoveConstFromFunctionParameters =
false;
// On some Android devices colors aren't accurate enough for the double lookup in the
// Perlin noise shader. This workaround aggressively snaps colors to multiples of 1/255.
bool fPerlinNoiseRoundingFix =
false;
// Vulkan requires certain builtin variables be present, even if they're unused. At one time,
// validation errors would result if sk_Clockwise was missing. Now, it's just (Adreno) driver
// bugs that drop or corrupt draws if they're missing.
bool fMustDeclareFragmentFrontFacing =
false;
// SPIR-V currently doesn't handle different array strides being passed in to a fixed sized
// array function parameter, so fForceStd430ArrayLayout will make all array strides conform
// to std430 stride alignment rules.
bool fForceStd430ArrayLayout =
false;
const char* fVersionDeclString =
"";
const char* fShaderDerivativeExtensionString = nullptr;
const char* fExternalTextureExtensionString = nullptr;
const char* fSecondExternalTextureExtensionString = nullptr;
const char* fFBFetchColorName = nullptr;
AdvBlendEqInteraction fAdvBlendEqInteraction = kNotSupported_AdvBlendEqInteraction;
};
// Various sets of caps for use in tests
class ShaderCapsFactory {
public:
static const ShaderCaps*
Default() {
static const SkSL::ShaderCaps* sCaps = [] {
std::unique_ptr<ShaderCaps> caps = MakeShaderCaps();
caps->fVersionDeclString =
"#version 400";
caps->fShaderDerivativeSupport =
true;
return caps.release();
}();
return sCaps;
}
static const ShaderCaps* Standalone() {
static const SkSL::ShaderCaps* sCaps = MakeShaderCaps().release();
return sCaps;
}
protected:
static std::unique_ptr<ShaderCaps> MakeShaderCaps();
};
bool type_to_sksltype(
const Context& context,
const Type& type, SkSLType* outTyp
e);
void write_stringstream(const StringStream& d, OutputStream& out);
} // namespace SkSL
#endif // SKSL_UTIL
