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* Copyright 2019 Google LLC
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
#ifndef SkRuntimeEffect_DEFINED
#define SkRuntimeEffect_DEFINED
#include "include/core/SkData.h"
#include "include/core/SkImageInfo.h"
#include "include/core/SkMatrix.h"
#include "include/core/SkShader.h"
#include "include/core/SkString.h"
#include "include/private/SkOnce.h"
#include "include/private/SkSLSampleUsage.h"
#include <vector>
class GrFragmentProcessor;
class GrRecordingContext;
class SkColorFilter;
class SkImage;
class SkShader;
namespace SkSL {
class FunctionDefinition;
struct Program;
enum class ProgramKind : int8_t;
} // namespace SkSL
namespace skvm {
class Program;
} // namespace skvm
* SkRuntimeEffect supports creating custom SkShader and SkColorFilter objects using Skia's SkSL
* shading language.
* NOTE: This API is experimental and subject to change.
class SK_API SkRuntimeEffect : public SkRefCnt {
struct Uniform {
enum class Type {
enum Flags {
kArray_Flag = 0x1,
kSRGBUnpremul_Flag = 0x2,
SkString name;
size_t offset;
Type type;
int count;
uint32_t flags;
bool isArray() const { return SkToBool(this->flags & kArray_Flag); }
size_t sizeInBytes() const;
struct Options {
// For testing purposes, completely disable the inliner. (Normally, Runtime Effects don't
// run the inliner directly, but they still get an inlining pass once they are painted.)
bool forceNoInline = false;
// If the effect is compiled successfully, `effect` will be non-null.
// Otherwise, `errorText` will contain the reason for failure.
struct Result {
sk_sp<SkRuntimeEffect> effect;
SkString errorText;
// MakeForColorFilter and MakeForShader verify that the SkSL code is valid for those stages of
// the Skia pipeline. In all of the signatures described below, color parameters and return
// values are flexible. They are listed as being 'vec4', but they can also be 'half4' or
// 'float4'. ('vec4' is an alias for 'float4').
// Color filter SkSL requires an entry point that looks like:
// vec4 main(vec4 inColor) { ... }
static Result MakeForColorFilter(SkString sksl, const Options&);
// Shader SkSL requires an entry point that looks like:
// vec4 main(vec2 inCoords) { ... }
// -or-
// vec4 main(vec2 inCoords, vec4 inColor) { ... }
// Most shaders don't use the input color, so that parameter is optional.
static Result MakeForShader(SkString sksl, const Options&);
// [DEPRECATED] Make supports SkSL that is legal as either an SkShader or SkColorFilter.
// makeColorFilter might return nullptr, if the effect is dependent on position in any way.
static Result Make(SkString sksl, const Options&);
// We can't use a default argument for `options` due to a bug in Clang.
static Result MakeForColorFilter(SkString sksl) {
return MakeForColorFilter(std::move(sksl), Options{});
static Result MakeForShader(SkString sksl) {
return MakeForShader(std::move(sksl), Options{});
static Result Make(SkString sksl) {
return Make(std::move(sksl), Options{});
static Result MakeForColorFilter(std::unique_ptr<SkSL::Program> program);
static Result MakeForShader(std::unique_ptr<SkSL::Program> program);
sk_sp<SkShader> makeShader(sk_sp<SkData> uniforms,
sk_sp<SkShader> children[],
size_t childCount,
const SkMatrix* localMatrix,
bool isOpaque) const;
sk_sp<SkImage> makeImage(GrRecordingContext*,
sk_sp<SkData> uniforms,
sk_sp<SkShader> children[],
size_t childCount,
const SkMatrix* localMatrix,
SkImageInfo resultInfo,
bool mipmapped) const;
sk_sp<SkColorFilter> makeColorFilter(sk_sp<SkData> uniforms) const;
sk_sp<SkColorFilter> makeColorFilter(sk_sp<SkData> uniforms,
sk_sp<SkColorFilter> children[],
size_t childCount) const;
const SkString& source() const { return fSkSL; }
template <typename T>
class ConstIterable {
ConstIterable(const std::vector<T>& vec) : fVec(vec) {}
using const_iterator = typename std::vector<T>::const_iterator;
const_iterator begin() const { return fVec.begin(); }
const_iterator end() const { return fVec.end(); }
size_t count() const { return fVec.size(); }
const std::vector<T>& fVec;
// Combined size of all 'uniform' variables. When calling makeColorFilter or makeShader,
// provide an SkData of this size, containing values for all of those variables.
size_t uniformSize() const;
ConstIterable<Uniform> uniforms() const { return ConstIterable<Uniform>(fUniforms); }
ConstIterable<SkString> children() const { return ConstIterable<SkString>(fChildren); }
// Returns pointer to the named uniform variable's description, or nullptr if not found
const Uniform* findUniform(const char* name) const;
// Returns index of the named child, or -1 if not found
int findChild(const char* name) const;
static void RegisterFlattenables();
~SkRuntimeEffect() override;
// For internal use.
std::unique_ptr<GrFragmentProcessor> makeFP(sk_sp<SkData> uniforms,
std::unique_ptr<GrFragmentProcessor> children[],
size_t childCount) const;
enum Flags {
kUsesSampleCoords_Flag = 0x1,
kAllowColorFilter_Flag = 0x2,
kAllowShader_Flag = 0x4,
SkRuntimeEffect(SkString sksl,
std::unique_ptr<SkSL::Program> baseProgram,
const Options& options,
const SkSL::FunctionDefinition& main,
std::vector<Uniform>&& uniforms,
std::vector<SkString>&& children,
std::vector<SkSL::SampleUsage>&& sampleUsages,
uint32_t flags);
static Result Make(std::unique_ptr<SkSL::Program> program, SkSL::ProgramKind kind);
static Result Make(SkString sksl, const Options& options, SkSL::ProgramKind kind);
static Result Make(SkString sksl, std::unique_ptr<SkSL::Program> program,
const Options& options, SkSL::ProgramKind kind);
uint32_t hash() const { return fHash; }
bool usesSampleCoords() const { return (fFlags & kUsesSampleCoords_Flag); }
bool allowShader() const { return (fFlags & kAllowShader_Flag); }
bool allowColorFilter() const { return (fFlags & kAllowColorFilter_Flag); }
struct FilterColorInfo {
const skvm::Program& program;
bool alphaUnchanged;
FilterColorInfo getFilterColorInfo();
friend class GrSkSLFP; // fBaseProgram, fSampleUsages
friend class GrGLSLSkSLFP; //
friend class SkRTShader; // fBaseProgram, fMain
friend class SkRuntimeColorFilter; //
uint32_t fHash;
SkString fSkSL;
std::unique_ptr<SkSL::Program> fBaseProgram;
const SkSL::FunctionDefinition& fMain;
std::vector<Uniform> fUniforms;
std::vector<SkString> fChildren;
std::vector<SkSL::SampleUsage> fSampleUsages;
SkOnce fColorFilterProgramOnce;
std::unique_ptr<skvm::Program> fColorFilterProgram;
bool fColorFilterProgramLeavesAlphaUnchanged;
uint32_t fFlags; // Flags
/** Base class for SkRuntimeShaderBuilder, defined below. */
template <typename Child> class SkRuntimeEffectBuilder {
struct BuilderUniform {
// Copy 'val' to this variable. No type conversion is performed - 'val' must be same
// size as expected by the effect. Information about the variable can be queried by
// looking at fVar. If the size is incorrect, no copy will be performed, and debug
// builds will abort. If this is the result of querying a missing variable, fVar will
// be nullptr, and assigning will also do nothing (and abort in debug builds).
template <typename T>
std::enable_if_t<std::is_trivially_copyable<T>::value, BuilderUniform&> operator=(
const T& val) {
if (!fVar) {
SkDEBUGFAIL("Assigning to missing variable");
} else if (sizeof(val) != fVar->sizeInBytes()) {
SkDEBUGFAIL("Incorrect value size");
} else {
memcpy(SkTAddOffset<void>(fOwner->writableUniformData(), fVar->offset),
&val, sizeof(val));
return *this;
BuilderUniform& operator=(const SkMatrix& val) {
if (!fVar) {
SkDEBUGFAIL("Assigning to missing variable");
} else if (fVar->sizeInBytes() != 9 * sizeof(float)) {
SkDEBUGFAIL("Incorrect value size");
} else {
float* data = SkTAddOffset<float>(fOwner->writableUniformData(), fVar->offset);
data[0] = val.get(0); data[1] = val.get(3); data[2] = val.get(6);
data[3] = val.get(1); data[4] = val.get(4); data[5] = val.get(7);
data[6] = val.get(2); data[7] = val.get(5); data[8] = val.get(8);
return *this;
template <typename T>
bool set(const T val[], const int count) {
static_assert(std::is_trivially_copyable<T>::value, "Value must be trivial copyable");
if (!fVar) {
SkDEBUGFAIL("Assigning to missing variable");
return false;
} else if (sizeof(T) * count != fVar->sizeInBytes()) {
SkDEBUGFAIL("Incorrect value size");
return false;
} else {
memcpy(SkTAddOffset<void>(fOwner->writableUniformData(), fVar->offset),
val, sizeof(T) * count);
return true;
SkRuntimeEffectBuilder* fOwner;
const SkRuntimeEffect::Uniform* fVar; // nullptr if the variable was not found
struct BuilderChild {
template <typename C> BuilderChild& operator=(C&& val) {
if (fIndex < 0) {
SkDEBUGFAIL("Assigning to missing child");
} else {
fOwner->fChildren[fIndex] = std::forward<C>(val);
return *this;
SkRuntimeEffectBuilder* fOwner;
int fIndex; // -1 if the child was not found
const SkRuntimeEffect* effect() const { return fEffect.get(); }
BuilderUniform uniform(const char* name) { return { this, fEffect->findUniform(name) }; }
BuilderChild child(const char* name) { return { this, fEffect->findChild(name) }; }
SkRuntimeEffectBuilder() = delete;
explicit SkRuntimeEffectBuilder(sk_sp<SkRuntimeEffect> effect)
: fEffect(std::move(effect))
, fUniforms(SkData::MakeUninitialized(fEffect->uniformSize()))
, fChildren(fEffect->children().count()) {}
SkRuntimeEffectBuilder(SkRuntimeEffectBuilder&&) = default;
SkRuntimeEffectBuilder(const SkRuntimeEffectBuilder&) = default;
SkRuntimeEffectBuilder& operator=(SkRuntimeEffectBuilder&&) = delete;
SkRuntimeEffectBuilder& operator=(const SkRuntimeEffectBuilder&) = delete;
sk_sp<SkData> uniforms() { return fUniforms; }
Child* children() { return; }
size_t numChildren() { return fChildren.size(); }
void* writableUniformData() {
if (!fUniforms->unique()) {
fUniforms = SkData::MakeWithCopy(fUniforms->data(), fUniforms->size());
return fUniforms->writable_data();
sk_sp<SkRuntimeEffect> fEffect;
sk_sp<SkData> fUniforms;
std::vector<Child> fChildren;
* SkRuntimeShaderBuilder is a utility to simplify creating SkShader objects from SkRuntimeEffects.
* NOTE: Like SkRuntimeEffect, this API is experimental and subject to change!
* Given an SkRuntimeEffect, the SkRuntimeShaderBuilder manages creating an input data block and
* provides named access to the 'uniform' variables in that block, as well as named access
* to a list of child shader slots. Usage:
* sk_sp<SkRuntimeEffect> effect = ...;
* SkRuntimeShaderBuilder builder(effect);
* builder.uniform("some_uniform_float") = 3.14f;
* builder.uniform("some_uniform_matrix") = SkM44::Rotate(...);
* builder.child("some_child_effect") = mySkImage->makeShader(...);
* ...
* sk_sp<SkShader> shader = builder.makeShader(nullptr, false);
* Note that SkRuntimeShaderBuilder is built entirely on the public API of SkRuntimeEffect,
* so can be used as-is or serve as inspiration for other interfaces or binding techniques.
class SK_API SkRuntimeShaderBuilder : public SkRuntimeEffectBuilder<sk_sp<SkShader>> {
explicit SkRuntimeShaderBuilder(sk_sp<SkRuntimeEffect>);
// This is currently required by Android Framework but may go away if that dependency
// can be removed.
SkRuntimeShaderBuilder(const SkRuntimeShaderBuilder&) = default;
sk_sp<SkShader> makeShader(const SkMatrix* localMatrix, bool isOpaque);
sk_sp<SkImage> makeImage(GrRecordingContext*,
const SkMatrix* localMatrix,
SkImageInfo resultInfo,
bool mipmapped);
using INHERITED = SkRuntimeEffectBuilder<sk_sp<SkShader>>;