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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 GrGLProgramDesc_DEFINED
#define GrGLProgramDesc_DEFINED
#include "GrGLEffect.h"
#include "GrDrawState.h"
#include "GrGpu.h"
class GrGpuGL;
#ifdef SK_DEBUG
// Optionally compile the experimental GS code. Set to SK_DEBUG so that debug build bots will
// execute the code.
#define GR_GL_EXPERIMENTAL_GS 1
#else
#define GR_GL_EXPERIMENTAL_GS 0
#endif
/** This class describes a program to generate. It also serves as a program cache key. Very little
of this is GL-specific. The GL-specific parts could be factored out into a subclass. */
class GrGLProgramDesc {
public:
GrGLProgramDesc() {}
GrGLProgramDesc(const GrGLProgramDesc& desc) { *this = desc; }
// Returns this as a uint32_t array to be used as a key in the program cache.
const uint32_t* asKey() const {
return reinterpret_cast<const uint32_t*>(fKey.begin());
}
// Gets the number of bytes in asKey(). It will be a 4-byte aligned value. When comparing two
// keys the size of either key can be used with memcmp() since the lengths themselves begin the
// keys and thus the memcmp will exit early if the keys are of different lengths.
uint32_t keyLength() const { return *this->atOffset<uint32_t, kLengthOffset>(); }
// Gets the a checksum of the key. Can be used as a hash value for a fast lookup in a cache.
uint32_t getChecksum() const { return *this->atOffset<uint32_t, kChecksumOffset>(); }
// For unit testing.
bool setRandom(SkRandom*,
const GrGpuGL* gpu,
const GrRenderTarget* dummyDstRenderTarget,
const GrTexture* dummyDstCopyTexture,
const GrEffectStage* stages[],
int numColorStages,
int numCoverageStages,
int currAttribIndex);
/**
* Builds a program descriptor from a GrDrawState. Whether the primitive type is points, the
* output of GrDrawState::getBlendOpts, and the caps of the GrGpuGL are also inputs. It also
* outputs the color and coverage stages referenced by the generated descriptor. This may
* not contain all stages from the draw state and coverage stages from the drawState may
* be treated as color stages in the output.
*/
static bool Build(const GrDrawState&,
GrGpu::DrawType drawType,
GrDrawState::BlendOptFlags,
GrBlendCoeff srcCoeff,
GrBlendCoeff dstCoeff,
const GrGpuGL* gpu,
const GrDeviceCoordTexture* dstCopy,
SkTArray<const GrEffectStage*, true>* outColorStages,
SkTArray<const GrEffectStage*, true>* outCoverageStages,
GrGLProgramDesc* outDesc);
int numColorEffects() const {
return this->getHeader().fColorEffectCnt;
}
int numCoverageEffects() const {
return this->getHeader().fCoverageEffectCnt;
}
int numTotalEffects() const { return this->numColorEffects() + this->numCoverageEffects(); }
GrGLProgramDesc& operator= (const GrGLProgramDesc& other);
bool operator== (const GrGLProgramDesc& other) const {
// The length is masked as a hint to the compiler that the address will be 4 byte aligned.
return 0 == memcmp(this->asKey(), other.asKey(), this->keyLength() & ~0x3);
}
bool operator!= (const GrGLProgramDesc& other) const {
return !(*this == other);
}
static bool Less(const GrGLProgramDesc& a, const GrGLProgramDesc& b) {
return memcmp(a.asKey(), b.asKey(), a.keyLength() & ~0x3) < 0;
}
private:
// Specifies where the initial color comes from before the stages are applied.
enum ColorInput {
kSolidWhite_ColorInput,
kAttribute_ColorInput,
kUniform_ColorInput,
kColorInputCnt
};
enum CoverageOutput {
// modulate color and coverage, write result as the color output.
kModulate_CoverageOutput,
// Writes color*coverage as the primary color output and also writes coverage as the
// secondary output. Only set if dual source blending is supported.
kSecondaryCoverage_CoverageOutput,
// Writes color*coverage as the primary color output and also writes coverage * (1 - colorA)
// as the secondary output. Only set if dual source blending is supported.
kSecondaryCoverageISA_CoverageOutput,
// Writes color*coverage as the primary color output and also writes coverage *
// (1 - colorRGB) as the secondary output. Only set if dual source blending is supported.
kSecondaryCoverageISC_CoverageOutput,
// Combines the coverage, dst, and color as coverage * color + (1 - coverage) * dst. This
// can only be set if fDstReadKey is non-zero.
kCombineWithDst_CoverageOutput,
kCoverageOutputCnt
};
static bool CoverageOutputUsesSecondaryOutput(CoverageOutput co) {
switch (co) {
case kSecondaryCoverage_CoverageOutput: // fallthru
case kSecondaryCoverageISA_CoverageOutput:
case kSecondaryCoverageISC_CoverageOutput:
return true;
default:
return false;
}
}
struct KeyHeader {
uint8_t fDstReadKey; // set by GrGLShaderBuilder if there
// are effects that must read the dst.
// Otherwise, 0.
uint8_t fFragPosKey; // set by GrGLShaderBuilder if there are
// effects that read the fragment position.
// Otherwise, 0.
ColorInput fColorInput : 8;
ColorInput fCoverageInput : 8;
CoverageOutput fCoverageOutput : 8;
SkBool8 fHasVertexCode;
SkBool8 fEmitsPointSize;
// To enable experimental geometry shader code (not for use in
// production)
#if GR_GL_EXPERIMENTAL_GS
SkBool8 fExperimentalGS;
#endif
int8_t fPositionAttributeIndex;
int8_t fLocalCoordAttributeIndex;
int8_t fColorAttributeIndex;
int8_t fCoverageAttributeIndex;
int8_t fColorEffectCnt;
int8_t fCoverageEffectCnt;
};
// The key, stored in fKey, is composed of five parts:
// 1. uint32_t for total key length.
// 2. uint32_t for a checksum.
// 3. Header struct defined above.
// 4. An array of offsets to effect keys and their sizes (see 5). uint16_t for each
// offset and size.
// 5. per-effect keys. Each effect's key is a variable length array of uint32_t.
enum {
// Part 1.
kLengthOffset = 0,
// Part 2.
kChecksumOffset = kLengthOffset + sizeof(uint32_t),
// Part 3.
kHeaderOffset = kChecksumOffset + sizeof(uint32_t),
kHeaderSize = SkAlign4(sizeof(KeyHeader)),
// Part 4.
// This is the offset in the overall key to the array of per-effect offset,length pairs.
kEffectKeyOffsetsAndLengthOffset = kHeaderOffset + kHeaderSize,
};
template<typename T, size_t OFFSET> T* atOffset() {
return reinterpret_cast<T*>(reinterpret_cast<intptr_t>(fKey.begin()) + OFFSET);
}
template<typename T, size_t OFFSET> const T* atOffset() const {
return reinterpret_cast<const T*>(reinterpret_cast<intptr_t>(fKey.begin()) + OFFSET);
}
KeyHeader* header() { return this->atOffset<KeyHeader, kHeaderOffset>(); }
// Shared code between setRandom() and Build().
static bool GetEffectKeyAndUpdateStats(const GrEffectStage& stage,
const GrGLCaps& caps,
bool useExplicitLocalCoords,
GrEffectKeyBuilder* b,
uint16_t* effectKeySize,
bool* setTrueIfReadsDst,
bool* setTrueIfReadsPos,
bool* setTrueIfHasVertexCode);
void finalize();
const KeyHeader& getHeader() const { return *this->atOffset<KeyHeader, kHeaderOffset>(); }
/** Used to provide effects' keys to their emitCode() function. */
class EffectKeyProvider {
public:
enum EffectType {
kColor_EffectType,
kCoverage_EffectType,
};
EffectKeyProvider(const GrGLProgramDesc* desc, EffectType type) : fDesc(desc) {
// Coverage effect key offsets begin immediately after those of the color effects.
fBaseIndex = kColor_EffectType == type ? 0 : desc->numColorEffects();
}
GrEffectKey get(int index) const {
const uint16_t* offsetsAndLengths = reinterpret_cast<const uint16_t*>(
fDesc->fKey.begin() + kEffectKeyOffsetsAndLengthOffset);
// We store two uint16_ts per effect, one for the offset to the effect's key and one for
// its length. Here we just need the offset.
uint16_t offset = offsetsAndLengths[2 * (fBaseIndex + index) + 0];
uint16_t length = offsetsAndLengths[2 * (fBaseIndex + index) + 1];
// Currently effects must add to the key in units of uint32_t.
SkASSERT(0 == (length % sizeof(uint32_t)));
return GrEffectKey(reinterpret_cast<const uint32_t*>(fDesc->fKey.begin() + offset),
length / sizeof(uint32_t));
}
private:
const GrGLProgramDesc* fDesc;
int fBaseIndex;
};
enum {
kMaxPreallocEffects = 8,
kIntsPerEffect = 4, // This is an overestimate of the average effect key size.
kPreAllocSize = kEffectKeyOffsetsAndLengthOffset +
kMaxPreallocEffects * sizeof(uint32_t) * kIntsPerEffect,
};
SkSTArray<kPreAllocSize, uint8_t, true> fKey;
// GrGLProgram and GrGLShaderBuilder read the private fields to generate code. TODO: Split out
// part of GrGLShaderBuilder that is used by effects so that this header doesn't need to be
// visible to GrGLEffects. Then make public accessors as necessary and remove friends.
friend class GrGLProgram;
friend class GrGLShaderBuilder;
friend class GrGLFullShaderBuilder;
friend class GrGLFragmentOnlyShaderBuilder;
};
#endif