318538484f
This replaces GrXferProcessor::getOptimizations with a new function on GrXPFactory. The results are made available via FragmentProcessorAnalysis. Bug: skia: Change-Id: I535985458c9d13ad858cac94e957e2fdbe332036 Reviewed-on: https://skia-review.googlesource.com/10218 Reviewed-by: Greg Daniel <egdaniel@google.com> Commit-Queue: Brian Salomon <bsalomon@google.com>
233 lines
8.3 KiB
C++
233 lines
8.3 KiB
C++
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/*
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* Copyright 2013 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#ifndef GrBlend_DEFINED
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#define GrBlend_DEFINED
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#include "GrColor.h"
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#include "../private/SkTLogic.h"
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/**
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* Equations for alpha-blending.
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*/
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enum GrBlendEquation {
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// Basic blend equations.
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kAdd_GrBlendEquation, //<! Cs*S + Cd*D
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kSubtract_GrBlendEquation, //<! Cs*S - Cd*D
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kReverseSubtract_GrBlendEquation, //<! Cd*D - Cs*S
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// Advanced blend equations. These are described in the SVG and PDF specs.
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kScreen_GrBlendEquation,
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kOverlay_GrBlendEquation,
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kDarken_GrBlendEquation,
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kLighten_GrBlendEquation,
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kColorDodge_GrBlendEquation,
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kColorBurn_GrBlendEquation,
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kHardLight_GrBlendEquation,
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kSoftLight_GrBlendEquation,
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kDifference_GrBlendEquation,
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kExclusion_GrBlendEquation,
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kMultiply_GrBlendEquation,
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kHSLHue_GrBlendEquation,
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kHSLSaturation_GrBlendEquation,
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kHSLColor_GrBlendEquation,
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kHSLLuminosity_GrBlendEquation,
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kFirstAdvancedGrBlendEquation = kScreen_GrBlendEquation,
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kLast_GrBlendEquation = kHSLLuminosity_GrBlendEquation
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};
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static const int kGrBlendEquationCnt = kLast_GrBlendEquation + 1;
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/**
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* Coefficients for alpha-blending.
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*/
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enum GrBlendCoeff {
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kZero_GrBlendCoeff, //<! 0
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kOne_GrBlendCoeff, //<! 1
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kSC_GrBlendCoeff, //<! src color
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kISC_GrBlendCoeff, //<! one minus src color
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kDC_GrBlendCoeff, //<! dst color
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kIDC_GrBlendCoeff, //<! one minus dst color
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kSA_GrBlendCoeff, //<! src alpha
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kISA_GrBlendCoeff, //<! one minus src alpha
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kDA_GrBlendCoeff, //<! dst alpha
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kIDA_GrBlendCoeff, //<! one minus dst alpha
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kConstC_GrBlendCoeff, //<! constant color
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kIConstC_GrBlendCoeff, //<! one minus constant color
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kConstA_GrBlendCoeff, //<! constant color alpha
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kIConstA_GrBlendCoeff, //<! one minus constant color alpha
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kS2C_GrBlendCoeff,
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kIS2C_GrBlendCoeff,
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kS2A_GrBlendCoeff,
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kIS2A_GrBlendCoeff,
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kLast_GrBlendCoeff = kIS2A_GrBlendCoeff
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};
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static const int kGrBlendCoeffCnt = kLast_GrBlendCoeff + 1;
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/**
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* Given a known blend equation in the form of srcCoeff * srcColor + dstCoeff * dstColor where
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* there may be partial knowledge of the srcColor and dstColor component values, determine what
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* components of the blended output color are known. Coeffs must not refer to the constant or
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* secondary src color.
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*/
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void GrGetCoeffBlendKnownComponents(GrBlendCoeff srcCoeff, GrBlendCoeff dstCoeff,
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GrColor srcColor,
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GrColorComponentFlags srcColorFlags,
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GrColor dstColor,
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GrColorComponentFlags dstColorFlags,
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GrColor* outColor,
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GrColorComponentFlags* outFlags);
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template<GrBlendCoeff Coeff>
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struct GrTBlendCoeffRefsSrc : skstd::bool_constant<kSC_GrBlendCoeff == Coeff ||
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kISC_GrBlendCoeff == Coeff ||
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kSA_GrBlendCoeff == Coeff ||
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kISA_GrBlendCoeff == Coeff> {};
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#define GR_BLEND_COEFF_REFS_SRC(COEFF) \
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GrTBlendCoeffRefsSrc<COEFF>::value
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inline bool GrBlendCoeffRefsSrc(GrBlendCoeff coeff) {
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switch (coeff) {
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case kSC_GrBlendCoeff:
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case kISC_GrBlendCoeff:
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case kSA_GrBlendCoeff:
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case kISA_GrBlendCoeff:
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return true;
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default:
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return false;
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}
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}
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template<GrBlendCoeff Coeff>
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struct GrTBlendCoeffRefsDst : skstd::bool_constant<kDC_GrBlendCoeff == Coeff ||
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kIDC_GrBlendCoeff == Coeff ||
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kDA_GrBlendCoeff == Coeff ||
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kIDA_GrBlendCoeff == Coeff> {};
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#define GR_BLEND_COEFF_REFS_DST(COEFF) \
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GrTBlendCoeffRefsDst<COEFF>::value
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inline bool GrBlendCoeffRefsDst(GrBlendCoeff coeff) {
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switch (coeff) {
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case kDC_GrBlendCoeff:
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case kIDC_GrBlendCoeff:
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case kDA_GrBlendCoeff:
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case kIDA_GrBlendCoeff:
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return true;
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default:
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return false;
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}
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}
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template<GrBlendCoeff Coeff>
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struct GrTBlendCoeffRefsSrc2 : skstd::bool_constant<kS2C_GrBlendCoeff == Coeff ||
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kIS2C_GrBlendCoeff == Coeff ||
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kS2A_GrBlendCoeff == Coeff ||
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kIS2A_GrBlendCoeff == Coeff> {};
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#define GR_BLEND_COEFF_REFS_SRC2(COEFF) \
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GrTBlendCoeffRefsSrc2<COEFF>::value
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inline bool GrBlendCoeffRefsSrc2(GrBlendCoeff coeff) {
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switch (coeff) {
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case kS2C_GrBlendCoeff:
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case kIS2C_GrBlendCoeff:
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case kS2A_GrBlendCoeff:
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case kIS2A_GrBlendCoeff:
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return true;
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default:
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return false;
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}
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}
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template<GrBlendCoeff SrcCoeff, GrBlendCoeff DstCoeff>
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struct GrTBlendCoeffsUseSrcColor : skstd::bool_constant<kZero_GrBlendCoeff != SrcCoeff ||
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GR_BLEND_COEFF_REFS_SRC(DstCoeff)> {};
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#define GR_BLEND_COEFFS_USE_SRC_COLOR(SRC_COEFF, DST_COEFF) \
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GrTBlendCoeffsUseSrcColor<SRC_COEFF, DST_COEFF>::value
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template<GrBlendCoeff SrcCoeff, GrBlendCoeff DstCoeff>
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struct GrTBlendCoeffsUseDstColor : skstd::bool_constant<GR_BLEND_COEFF_REFS_DST(SrcCoeff) ||
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kZero_GrBlendCoeff != DstCoeff> {};
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#define GR_BLEND_COEFFS_USE_DST_COLOR(SRC_COEFF, DST_COEFF) \
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GrTBlendCoeffsUseDstColor<SRC_COEFF, DST_COEFF>::value
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template<GrBlendEquation Equation>
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struct GrTBlendEquationIsAdvanced : skstd::bool_constant<Equation >= kFirstAdvancedGrBlendEquation> {};
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#define GR_BLEND_EQUATION_IS_ADVANCED(EQUATION) \
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GrTBlendEquationIsAdvanced<EQUATION>::value
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inline bool GrBlendEquationIsAdvanced(GrBlendEquation equation) {
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return equation >= kFirstAdvancedGrBlendEquation;
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}
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template<GrBlendEquation BlendEquation, GrBlendCoeff SrcCoeff, GrBlendCoeff DstCoeff>
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struct GrTBlendModifiesDst : skstd::bool_constant<
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(kAdd_GrBlendEquation != BlendEquation && kReverseSubtract_GrBlendEquation != BlendEquation) ||
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kZero_GrBlendCoeff != SrcCoeff ||
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kOne_GrBlendCoeff != DstCoeff> {};
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#define GR_BLEND_MODIFIES_DST(EQUATION, SRC_COEFF, DST_COEFF) \
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GrTBlendModifiesDst<EQUATION, SRC_COEFF, DST_COEFF>::value
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/**
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* Advanced blend equations can always tweak alpha for coverage. (See GrCustomXfermode.cpp)
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*
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* For "add" and "reverse subtract" the blend equation with f=coverage is:
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*
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* D' = f * (S * srcCoeff + D * dstCoeff) + (1-f) * D
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* = f * S * srcCoeff + D * (f * dstCoeff + (1 - f))
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*
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* (Let srcCoeff be negative for reverse subtract.) We can tweak alpha for coverage when the
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* following relationship holds:
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*
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* (f*S) * srcCoeff' + D * dstCoeff' == f * S * srcCoeff + D * (f * dstCoeff + (1 - f))
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*
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* (Where srcCoeff' and dstCoeff' have any reference to S pre-multiplied by f.)
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*
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* It's easy to see this works for the src term as long as srcCoeff' == srcCoeff (meaning srcCoeff
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* does not reference S). For the dst term, this will work as long as the following is true:
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*|
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* dstCoeff' == f * dstCoeff + (1 - f)
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* dstCoeff' == 1 - f * (1 - dstCoeff)
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*
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* By inspection we can see this will work as long as dstCoeff has a 1, and any other term in
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* dstCoeff references S.
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*
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* Moreover, if the blend doesn't modify the dst at all then it is ok to arbitrarily modify the src
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* color so folding in coverage is allowed.
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*/
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template<GrBlendEquation Equation, GrBlendCoeff SrcCoeff, GrBlendCoeff DstCoeff>
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struct GrTBlendCanTweakAlphaForCoverage : skstd::bool_constant<
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GR_BLEND_EQUATION_IS_ADVANCED(Equation) ||
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((kAdd_GrBlendEquation == Equation || kReverseSubtract_GrBlendEquation == Equation) &&
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!GR_BLEND_COEFF_REFS_SRC(SrcCoeff) &&
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(kOne_GrBlendCoeff == DstCoeff ||
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kISC_GrBlendCoeff == DstCoeff ||
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kISA_GrBlendCoeff == DstCoeff)) ||
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!GrTBlendModifiesDst<Equation, SrcCoeff, DstCoeff>::value> {};
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#define GR_BLEND_CAN_TWEAK_ALPHA_FOR_COVERAGE(EQUATION, SRC_COEFF, DST_COEFF) \
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GrTBlendCanTweakAlphaForCoverage<EQUATION, SRC_COEFF, DST_COEFF>::value
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#endif
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