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/*
* Copyright 2016 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SKSL_SWIZZLE
#define SKSL_SWIZZLE
#include "SkSLConstructor.h"
#include "SkSLContext.h"
#include "SkSLExpression.h"
#include "SkSLIRGenerator.h"
#include "SkSLUtil.h"
namespace SkSL {
/**
* Given a type and a swizzle component count, returns the type that will result from swizzling. For
* instance, swizzling a float3with two components will result in a float2 It is possible to swizzle
* with more components than the source vector, as in 'float21).xxxx'.
*/
static const Type& get_type(const Context& context, Expression& value, size_t count) {
const Type& base = value.fType.componentType();
if (count == 1) {
return base;
}
if (base == *context.fFloat_Type) {
switch (count) {
case 2: return *context.fFloat2_Type;
case 3: return *context.fFloat3_Type;
case 4: return *context.fFloat4_Type;
}
} else if (base == *context.fHalf_Type) {
switch (count) {
case 2: return *context.fHalf2_Type;
case 3: return *context.fHalf3_Type;
case 4: return *context.fHalf4_Type;
}
} else if (base == *context.fDouble_Type) {
switch (count) {
case 2: return *context.fDouble2_Type;
case 3: return *context.fDouble3_Type;
case 4: return *context.fDouble4_Type;
}
} else if (base == *context.fInt_Type) {
switch (count) {
case 2: return *context.fInt2_Type;
case 3: return *context.fInt3_Type;
case 4: return *context.fInt4_Type;
}
} else if (base == *context.fShort_Type) {
switch (count) {
case 2: return *context.fShort2_Type;
case 3: return *context.fShort3_Type;
case 4: return *context.fShort4_Type;
}
} else if (base == *context.fByte_Type) {
switch (count) {
case 2: return *context.fByte2_Type;
case 3: return *context.fByte3_Type;
case 4: return *context.fByte4_Type;
}
} else if (base == *context.fUInt_Type) {
switch (count) {
case 2: return *context.fUInt2_Type;
case 3: return *context.fUInt3_Type;
case 4: return *context.fUInt4_Type;
}
} else if (base == *context.fUShort_Type) {
switch (count) {
case 2: return *context.fUShort2_Type;
case 3: return *context.fUShort3_Type;
case 4: return *context.fUShort4_Type;
}
} else if (base == *context.fUByte_Type) {
switch (count) {
case 2: return *context.fUByte2_Type;
case 3: return *context.fUByte3_Type;
case 4: return *context.fUByte4_Type;
}
} else if (base == *context.fBool_Type) {
switch (count) {
case 2: return *context.fBool2_Type;
case 3: return *context.fBool3_Type;
case 4: return *context.fBool4_Type;
}
}
ABORT("cannot swizzle %s\n", value.description().c_str());
}
/**
* Represents a vector swizzle operation such as 'float2(1, 2, 3).zyx'.
*/
struct Swizzle : public Expression {
Swizzle(const Context& context, std::unique_ptr<Expression> base, std::vector<int> components)
: INHERITED(base->fOffset, kSwizzle_Kind, get_type(context, *base, components.size()))
, fBase(std::move(base))
, fComponents(std::move(components)) {
SkASSERT(fComponents.size() >= 1 && fComponents.size() <= 4);
}
std::unique_ptr<Expression> constantPropagate(const IRGenerator& irGenerator,
const DefinitionMap& definitions) override {
if (fBase->fKind == Expression::kConstructor_Kind && fBase->isConstant()) {
// we're swizzling a constant vector, e.g. float4(1).x. Simplify it.
SkASSERT(fBase->fKind == Expression::kConstructor_Kind);
if (fType == *irGenerator.fContext.fInt_Type) {
SkASSERT(fComponents.size() == 1);
int64_t value = ((Constructor&) *fBase).getIVecComponent(fComponents[0]);
return std::unique_ptr<Expression>(new IntLiteral(irGenerator.fContext,
-1,
value));
} else if (fType == *irGenerator.fContext.fFloat_Type) {
SkASSERT(fComponents.size() == 1);
double value = ((Constructor&) *fBase).getFVecComponent(fComponents[0]);
return std::unique_ptr<Expression>(new FloatLiteral(irGenerator.fContext,
-1,
value));
}
}
return nullptr;
}
bool hasSideEffects() const override {
return fBase->hasSideEffects();
}
std::unique_ptr<Expression> clone() const override {
return std::unique_ptr<Expression>(new Swizzle(fType, fBase->clone(), fComponents));
}
String description() const override {
String result = fBase->description() + ".";
for (int x : fComponents) {
result += "xyzw"[x];
}
return result;
}
std::unique_ptr<Expression> fBase;
const std::vector<int> fComponents;
typedef Expression INHERITED;
private:
Swizzle(const Type& type, std::unique_ptr<Expression> base, std::vector<int> components)
: INHERITED(base->fOffset, kSwizzle_Kind, type)
, fBase(std::move(base))
, fComponents(std::move(components)) {
SkASSERT(fComponents.size() >= 1 && fComponents.size() <= 4);
}
};
} // namespace
#endif
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