skia2/include/gpu/GrProcessor.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 GrProcessor_DEFINED
#define GrProcessor_DEFINED
#include "GrColor.h"
#include "GrProcessorUnitTest.h"
#include "GrProgramElement.h"
#include "GrTextureAccess.h"
#include "GrBufferAccess.h"
#include "SkMath.h"
#include "SkString.h"
#include "../private/SkAtomics.h"
class GrContext;
class GrCoordTransform;
class GrInvariantOutput;
/**
* Used by processors to build their keys. It incorporates each per-processor key into a larger
* shader key.
*/
class GrProcessorKeyBuilder {
public:
GrProcessorKeyBuilder(SkTArray<unsigned char, true>* data) : fData(data), fCount(0) {
SkASSERT(0 == fData->count() % sizeof(uint32_t));
}
void add32(uint32_t v) {
++fCount;
fData->push_back_n(4, reinterpret_cast<uint8_t*>(&v));
}
/** Inserts count uint32_ts into the key. The returned pointer is only valid until the next
add*() call. */
uint32_t* SK_WARN_UNUSED_RESULT add32n(int count) {
SkASSERT(count > 0);
fCount += count;
return reinterpret_cast<uint32_t*>(fData->push_back_n(4 * count));
}
size_t size() const { return sizeof(uint32_t) * fCount; }
private:
SkTArray<uint8_t, true>* fData; // unowned ptr to the larger key.
int fCount; // number of uint32_ts added to fData by the processor.
};
/** Provides custom shader code to the Ganesh shading pipeline. GrProcessor objects *must* be
immutable: after being constructed, their fields may not change.
Dynamically allocated GrProcessors are managed by a per-thread memory pool. The ref count of an
processor must reach 0 before the thread terminates and the pool is destroyed.
*/
class GrProcessor : public GrProgramElement {
public:
virtual ~GrProcessor();
/** Human-meaningful string to identify this prcoessor; may be embedded
in generated shader code. */
virtual const char* name() const = 0;
// Human-readable dump of all information
virtual SkString dumpInfo() const {
SkString str;
str.appendf("Missing data");
return str;
}
int numTextures() const { return fTextureAccesses.count(); }
/** Returns the access pattern for the texture at index. index must be valid according to
numTextures(). */
const GrTextureAccess& textureAccess(int index) const { return *fTextureAccesses[index]; }
/** Shortcut for textureAccess(index).texture(); */
GrTexture* texture(int index) const { return this->textureAccess(index).getTexture(); }
int numBuffers() const { return fBufferAccesses.count(); }
/** Returns the access pattern for the buffer at index. index must be valid according to
numBuffers(). */
const GrBufferAccess& bufferAccess(int index) const {
return *fBufferAccesses[index];
}
/**
* Platform specific built-in features that a processor can request for the fragment shader.
*/
enum RequiredFeatures {
kNone_RequiredFeatures = 0,
kFragmentPosition_RequiredFeature = 1 << 0,
kSampleLocations_RequiredFeature = 1 << 1
};
GR_DECL_BITFIELD_OPS_FRIENDS(RequiredFeatures);
RequiredFeatures requiredFeatures() const { return fRequiredFeatures; }
void* operator new(size_t size);
void operator delete(void* target);
void* operator new(size_t size, void* placement) {
return ::operator new(size, placement);
}
void operator delete(void* target, void* placement) {
::operator delete(target, placement);
}
/**
* Helper for down-casting to a GrProcessor subclass
*/
template <typename T> const T& cast() const { return *static_cast<const T*>(this); }
uint32_t classID() const { SkASSERT(kIllegalProcessorClassID != fClassID); return fClassID; }
protected:
GrProcessor() : fClassID(kIllegalProcessorClassID), fRequiredFeatures(kNone_RequiredFeatures) {}
/**
* Subclasses call these from their constructor to register sampler sources. The processor
* subclass manages the lifetime of the objects (these functions only store pointers). The
* GrTextureAccess and/or GrBufferAccess instances are typically member fields of the
* GrProcessor subclass. These must only be called from the constructor because GrProcessors
* are immutable.
*/
void addTextureAccess(const GrTextureAccess* textureAccess);
void addBufferAccess(const GrBufferAccess* bufferAccess);
bool hasSameSamplers(const GrProcessor&) const;
/**
* If the prcoessor will generate code that uses platform specific built-in features, then it
* must call these methods from its constructor. Otherwise, requests to use these features will
* be denied.
*/
void setWillReadFragmentPosition() { fRequiredFeatures |= kFragmentPosition_RequiredFeature; }
void setWillUseSampleLocations() { fRequiredFeatures |= kSampleLocations_RequiredFeature; }
void combineRequiredFeatures(const GrProcessor& other) {
fRequiredFeatures |= other.fRequiredFeatures;
}
template <typename PROC_SUBCLASS> void initClassID() {
static uint32_t kClassID = GenClassID();
fClassID = kClassID;
}
uint32_t fClassID;
private:
static uint32_t GenClassID() {
// fCurrProcessorClassID has been initialized to kIllegalProcessorClassID. The
// atomic inc returns the old value not the incremented value. So we add
// 1 to the returned value.
uint32_t id = static_cast<uint32_t>(sk_atomic_inc(&gCurrProcessorClassID)) + 1;
if (!id) {
SkFAIL("This should never wrap as it should only be called once for each GrProcessor "
"subclass.");
}
return id;
}
enum {
kIllegalProcessorClassID = 0,
};
static int32_t gCurrProcessorClassID;
RequiredFeatures fRequiredFeatures;
SkSTArray<4, const GrTextureAccess*, true> fTextureAccesses;
SkSTArray<2, const GrBufferAccess*, true> fBufferAccesses;
typedef GrProgramElement INHERITED;
};
GR_MAKE_BITFIELD_OPS(GrProcessor::RequiredFeatures);
#endif