mirror of
https://github.com/hajimehoshi/ebiten.git
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64 lines
1.9 KiB
Go
64 lines
1.9 KiB
Go
// Copyright 2013 Hajime Hoshi
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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// SOFTWARE.
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package matrix
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type Affine interface {
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Dim() int
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element(i, j int) float64
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setElement(i, j int, element float64)
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}
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func isIdentity(matrix Affine) bool {
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dim := matrix.Dim()
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for i := 0; i < dim-1; i++ {
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for j := 0; j < dim; j++ {
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element := matrix.element(i, j)
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if i == j && element != 1 {
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return false
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} else if i != j && element != 0 {
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return false
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}
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}
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}
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return true
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}
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func mul(lhs, rhs, result Affine) {
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dim := lhs.Dim()
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if dim != rhs.Dim() {
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panic("diffrent-sized matrices can't be multiplied")
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}
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for i := 0; i < dim-1; i++ {
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for j := 0; j < dim; j++ {
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element := float64(0)
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for k := 0; k < dim-1; k++ {
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element += lhs.element(i, k) *
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rhs.element(k, j)
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}
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if j == dim-1 {
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element += lhs.element(i, j)
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}
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result.setElement(i, j, element)
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}
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}
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}
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