| /* |
| * Copyright 2021 Google LLC |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include "src/sksl/ir/SkSLConstructorMatrixResize.h" |
| |
| #include "src/sksl/ir/SkSLConstructor.h" |
| #include "src/sksl/ir/SkSLType.h" |
| |
| namespace SkSL { |
| |
| std::unique_ptr<Expression> ConstructorMatrixResize::Make(const Context& context, |
| int offset, |
| const Type& type, |
| std::unique_ptr<Expression> arg) { |
| SkASSERT(type.isMatrix()); |
| SkASSERT(arg->type().componentType() == type.componentType()); |
| |
| // If the matrix isn't actually changing size, return it as-is. |
| if (type.rows() == arg->type().rows() && type.columns() == arg->type().columns()) { |
| return arg; |
| } |
| |
| return std::make_unique<ConstructorMatrixResize>(offset, type, std::move(arg)); |
| } |
| |
| const Expression* ConstructorMatrixResize::getConstantSubexpression(int n) const { |
| int rows = this->type().rows(); |
| int row = n % rows; |
| int col = n / rows; |
| |
| SkASSERT(col >= 0); |
| SkASSERT(row >= 0); |
| SkASSERT(col < this->type().columns()); |
| SkASSERT(row < this->type().rows()); |
| |
| // GLSL resize matrices are of the form: |
| // |m m 0| |
| // |m m 0| |
| // |0 0 1| |
| // Where `m` is the matrix being wrapped, and other cells contain the identity matrix. |
| |
| // Forward `getConstantSubexpression` to the wrapped matrix if the position is in its bounds. |
| if (col < this->argument()->type().columns() && row < this->argument()->type().rows()) { |
| // Recalculate `n` in terms of the inner matrix's dimensions. |
| n = row + (col * this->argument()->type().rows()); |
| return this->argument()->getConstantSubexpression(n); |
| } |
| |
| // Synthesize an identity matrix for out-of-bounds positions. |
| return (col == row) ? &fOneLiteral : &fZeroLiteral; |
| } |
| |
| } // namespace SkSL |