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* Copyright 2013 Google Inc.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
#ifndef GrPrimitiveProcessor_DEFINED
#define GrPrimitiveProcessor_DEFINED
#include "GrColor.h"
#include "GrProcessor.h"
#include "GrShaderVar.h"
* The GrPrimitiveProcessor represents some kind of geometric primitive. This includes the shape
* of the primitive and the inherent color of the primitive. The GrPrimitiveProcessor is
* responsible for providing a color and coverage input into the Ganesh rendering pipeline. Through
* optimization, Ganesh may decide a different color, no color, and / or no coverage are required
* from the GrPrimitiveProcessor, so the GrPrimitiveProcessor must be able to support this
* functionality.
* There are two feedback loops between the GrFragmentProcessors, the GrXferProcessor, and the
* GrPrimitiveProcessor. These loops run on the CPU and to determine known properties of the final
* color and coverage inputs to the GrXferProcessor in order to perform optimizations that preserve
* correctness. The GrDrawOp seeds these loops with initial color and coverage, in its
* getProcessorAnalysisInputs implementation. These seed values are processed by the
* subsequent
* stages of the rendering pipeline and the output is then fed back into the GrDrawOp in
* the applyPipelineOptimizations call, where the op can use the information to inform decisions
* about GrPrimitiveProcessor creation.
class GrGLSLPrimitiveProcessor;
* GrPrimitiveProcessor defines an interface which all subclasses must implement. All
* GrPrimitiveProcessors must proivide seed color and coverage for the Ganesh color / coverage
* pipelines, and they must provide some notion of equality
class GrPrimitiveProcessor : public GrResourceIOProcessor, public GrProgramElement {
/** Describes a vertex or instance attribute. */
class Attribute {
constexpr Attribute() = default;
constexpr Attribute(const char* name, GrVertexAttribType type) : fName(name), fType(type) {}
constexpr Attribute(const Attribute&) = default;
Attribute& operator=(const Attribute&) = default;
constexpr bool isInitialized() const { return SkToBool(fName); }
constexpr const char* name() const { return fName; }
constexpr GrVertexAttribType type() const { return fType; }
inline constexpr size_t size() const;
constexpr size_t sizeAlign4() const { return SkAlign4(this->size()); }
GrShaderVar asShaderVar() const {
return {fName, GrVertexAttribTypeToSLType(fType), GrShaderVar::kIn_TypeModifier};
const char* fName = nullptr;
GrVertexAttribType fType = kFloat_GrVertexAttribType;
int numVertexAttributes() const { return fVertexAttributeCnt; }
const Attribute& vertexAttribute(int i) const;
int numInstanceAttributes() const { return fInstanceAttributeCnt; }
const Attribute& instanceAttribute(int i) const;
bool hasVertexAttributes() const { return SkToBool(fVertexAttributeCnt); }
bool hasInstanceAttributes() const { return SkToBool(fInstanceAttributeCnt); }
#ifdef SK_DEBUG
* A common practice is to populate the the vertex/instance's memory using an implicit array of
* structs. In this case, it is best to assert that:
* debugOnly_stride == sizeof(struct) and
* offsetof(struct, field[i]) == debugOnly_AttributeOffset(i)
* In general having Op subclasses assert that attribute offsets and strides agree with their
* tessellation code's expectations is good practice.
* However, these functions walk the attributes to compute offsets and call virtual functions
* to access the attributes. Thus, they are only available in debug builds.
size_t debugOnly_vertexStride() const;
size_t debugOnly_instanceStride() const;
size_t debugOnly_vertexAttributeOffset(int) const;
size_t debugOnly_instanceAttributeOffset(int) const;
// Only the GrGeometryProcessor subclass actually has a geo shader or vertex attributes, but
// we put these calls on the base class to prevent having to cast
virtual bool willUseGeoShader() const = 0;
* Computes a transformKey from an array of coord transforms. Will only look at the first
* <numCoords> transforms in the array.
* TODO: A better name for this function would be "compute" instead of "get".
uint32_t getTransformKey(const SkTArray<const GrCoordTransform*, true>& coords,
int numCoords) const;
* Sets a unique key on the GrProcessorKeyBuilder that is directly associated with this geometry
* processor's GL backend implementation.
* TODO: A better name for this function would be "compute" instead of "get".
virtual void getGLSLProcessorKey(const GrShaderCaps&, GrProcessorKeyBuilder*) const = 0;
/** Returns a new instance of the appropriate *GL* implementation class
for the given GrProcessor; caller is responsible for deleting
the object. */
virtual GrGLSLPrimitiveProcessor* createGLSLInstance(const GrShaderCaps&) const = 0;
virtual bool isPathRendering() const { return false; }
* If non-null, overrides the dest color returned by GrGLSLFragmentShaderBuilder::dstColor().
virtual const char* getDestColorOverride() const { return nullptr; }
virtual float getSampleShading() const { return 0.0; }
void setVertexAttributeCnt(int cnt) { fVertexAttributeCnt = cnt; }
void setInstanceAttributeCnt(int cnt) { fInstanceAttributeCnt = cnt; }
void addPendingIOs() const override { GrResourceIOProcessor::addPendingIOs(); }
void removeRefs() const override { GrResourceIOProcessor::removeRefs(); }
void pendingIOComplete() const override { GrResourceIOProcessor::pendingIOComplete(); }
void notifyRefCntIsZero() const final {}
virtual const Attribute& onVertexAttribute(int) const = 0;
virtual const Attribute& onInstanceAttribute(int) const = 0;
int fVertexAttributeCnt = 0;
int fInstanceAttributeCnt = 0;
typedef GrProcessor INHERITED;
* Returns the size of the attrib type in bytes.
* This was moved from include/private/GrTypesPriv.h in service of Skia dependents that build
* with C++11.
static constexpr inline size_t GrVertexAttribTypeSize(GrVertexAttribType type) {
switch (type) {
case kFloat_GrVertexAttribType:
return sizeof(float);
case kFloat2_GrVertexAttribType:
return 2 * sizeof(float);
case kFloat3_GrVertexAttribType:
return 3 * sizeof(float);
case kFloat4_GrVertexAttribType:
return 4 * sizeof(float);
case kHalf_GrVertexAttribType:
return sizeof(float);
case kHalf2_GrVertexAttribType:
return 2 * sizeof(float);
case kHalf3_GrVertexAttribType:
return 3 * sizeof(float);
case kHalf4_GrVertexAttribType:
return 4 * sizeof(float);
case kInt2_GrVertexAttribType:
return 2 * sizeof(int32_t);
case kInt3_GrVertexAttribType:
return 3 * sizeof(int32_t);
case kInt4_GrVertexAttribType:
return 4 * sizeof(int32_t);
case kUByte_norm_GrVertexAttribType:
return 1 * sizeof(char);
case kUByte4_norm_GrVertexAttribType:
return 4 * sizeof(char);
case kShort2_GrVertexAttribType:
return 2 * sizeof(int16_t);
case kUShort2_GrVertexAttribType: // fall through
case kUShort2_norm_GrVertexAttribType:
return 2 * sizeof(uint16_t);
case kInt_GrVertexAttribType:
return sizeof(int32_t);
case kUint_GrVertexAttribType:
return sizeof(uint32_t);
// GCC fails because SK_ABORT evaluates to non constexpr. clang and cl.exe think this is
// unreachable and don't complain.
#if defined(__clang__) || !defined(__GNUC__)
SK_ABORT("Unsupported type conversion");
return 0;
constexpr size_t GrPrimitiveProcessor::Attribute::size() const {
return GrVertexAttribTypeSize(fType);