SkSLIndexExpression.h revision 9df16b5e85ef37c44e02257e49eb996efca0e173
1/* 2 * Copyright 2016 Google Inc. 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8#ifndef SKSL_INDEX 9#define SKSL_INDEX 10 11#include "SkSLExpression.h" 12#include "SkSLUtil.h" 13 14namespace SkSL { 15 16/** 17 * Given a type, returns the type that will result from extracting an array value from it. 18 */ 19static const Type& index_type(const Context& context, const Type& type) { 20 if (type.kind() == Type::kMatrix_Kind) { 21 if (type.componentType() == *context.fFloat_Type) { 22 switch (type.columns()) { 23 case 2: return *context.fVec2_Type; 24 case 3: return *context.fVec3_Type; 25 case 4: return *context.fVec4_Type; 26 default: ASSERT(false); 27 } 28 } else { 29 ASSERT(type.componentType() == *context.fDouble_Type); 30 switch (type.columns()) { 31 case 2: return *context.fDVec2_Type; 32 case 3: return *context.fDVec3_Type; 33 case 4: return *context.fDVec4_Type; 34 default: ASSERT(false); 35 } 36 } 37 } 38 return type.componentType(); 39} 40 41/** 42 * An expression which extracts a value from an array or matrix, as in 'm[2]'. 43 */ 44struct IndexExpression : public Expression { 45 IndexExpression(const Context& context, std::unique_ptr<Expression> base, 46 std::unique_ptr<Expression> index) 47 : INHERITED(base->fPosition, kIndex_Kind, index_type(context, base->fType)) 48 , fBase(std::move(base)) 49 , fIndex(std::move(index)) { 50 ASSERT(fIndex->fType == *context.fInt_Type); 51 } 52 53 std::string description() const override { 54 return fBase->description() + "[" + fIndex->description() + "]"; 55 } 56 57 const std::unique_ptr<Expression> fBase; 58 const std::unique_ptr<Expression> fIndex; 59 60 typedef Expression INHERITED; 61}; 62 63} // namespace 64 65#endif 66