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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 "SkSLExpression.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 vec3 with two components will result in a vec2. It is possible to swizzle
* with more components than the source vector, as in 'vec2(1).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.fVec2_Type;
case 3: return *context.fVec3_Type;
case 4: return *context.fVec4_Type;
}
} else if (base == *context.fDouble_Type) {
switch (count) {
case 2: return *context.fDVec2_Type;
case 3: return *context.fDVec3_Type;
case 4: return *context.fDVec4_Type;
}
} else if (base == *context.fInt_Type) {
switch (count) {
case 2: return *context.fIVec2_Type;
case 3: return *context.fIVec3_Type;
case 4: return *context.fIVec4_Type;
}
} else if (base == *context.fUInt_Type) {
switch (count) {
case 2: return *context.fUVec2_Type;
case 3: return *context.fUVec3_Type;
case 4: return *context.fUVec4_Type;
}
} else if (base == *context.fBool_Type) {
switch (count) {
case 2: return *context.fBVec2_Type;
case 3: return *context.fBVec3_Type;
case 4: return *context.fBVec4_Type;
}
}
ABORT("cannot swizzle %s\n", value.description().c_str());
}
/**
* Represents a vector swizzle operation such as 'vec2(1, 2, 3).zyx'.
*/
struct Swizzle : public Expression {
Swizzle(const Context& context, std::unique_ptr<Expression> base, std::vector<int> components)
: INHERITED(base->fPosition, kSwizzle_Kind, get_type(context, *base, components.size()))
, fBase(std::move(base))
, fComponents(std::move(components)) {
ASSERT(fComponents.size() >= 1 && fComponents.size() <= 4);
}
std::string description() const override {
std::string result = fBase->description() + ".";
for (int x : fComponents) {
result += "xyzw"[x];
}
return result;
}
const std::unique_ptr<Expression> fBase;
const std::vector<int> fComponents;
typedef Expression INHERITED;
};
} // namespace
#endif
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