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/*
* Copyright 2014 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef GrProcOptInfo_DEFINED
#define GrProcOptInfo_DEFINED
#include "GrColor.h"
#include "GrInvariantOutput.h"
class GrFragmentStage;
class GrFragmentProcessor;
class GrPrimitiveProcessor;
class GrProcessor;
/**
* GrProcOptInfo gathers invariant data from a set of processor stages.It is used to recognize
* optimizations related to eliminating stages and vertex attributes that aren't necessary for a
* draw.
*/
class GrProcOptInfo {
public:
GrProcOptInfo()
: fInOut(0, static_cast<GrColorComponentFlags>(0), false)
, fFirstEffectStageIndex(0)
, fInputColorIsUsed(true)
, fInputColor(0)
, fReadsFragPosition(false) {}
void calcWithInitialValues(const GrFragmentStage*, int stageCount, GrColor startColor,
GrColorComponentFlags flags, bool areCoverageStages);
void calcColorWithPrimProc(const GrPrimitiveProcessor*, const GrFragmentStage*, int stagecount);
void calcCoverageWithPrimProc(const GrPrimitiveProcessor*, const GrFragmentStage*,
int stagecount);
bool isSolidWhite() const { return fInOut.isSolidWhite(); }
bool isOpaque() const { return fInOut.isOpaque(); }
bool isSingleComponent() const { return fInOut.isSingleComponent(); }
// TODO: Once texture pixel configs quaries are updated, we no longer need this function.
// For now this function will correctly tell us if we are using LCD text or not and should only
// be called when looking at the coverage output.
bool isFourChannelOutput() const { return !fInOut.isSingleComponent() &&
fInOut.isLCDCoverage(); }
GrColor color() const { return fInOut.color(); }
uint8_t validFlags() const { return fInOut.validFlags(); }
/**
* Returns the index of the first effective color stage. If an intermediate stage doesn't read
* its input or has a known output, then we can ignore all earlier stages since they will not
* affect the final output. Thus the first effective stage index is the index to the first stage
* that will have an effect on the final output.
*
* If stages before the firstEffectiveStageIndex are removed, corresponding values from
* inputColorIsUsed(), inputColorToEffectiveStage(), removeVertexAttribs(), and readsDst() must
* be used when setting up the draw to ensure correct drawing.
*/
int firstEffectiveStageIndex() const { return fFirstEffectStageIndex; }
/**
* True if the first effective stage reads its input, false otherwise.
*/
bool inputColorIsUsed() const { return fInputColorIsUsed; }
/**
* If input color is used and per-vertex colors are not used, this is the input color to the
* first effective stage.
*/
GrColor inputColorToEffectiveStage() const { return fInputColor; }
/**
* Returns true if any of the stages preserved by GrProcOptInfo read the frag position.
*/
bool readsFragPosition() const { return fReadsFragPosition; }
private:
void internalCalc(const GrFragmentStage*, int stagecount, bool initWillReadFragPosition);
GrInvariantOutput fInOut;
int fFirstEffectStageIndex;
bool fInputColorIsUsed;
GrColor fInputColor;
bool fReadsFragPosition;
};
#endif