mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-09-21 05:42:18 +02:00
64 lines
1.9 KiB
Go
64 lines
1.9 KiB
Go
// Copyright 2013 Hajime Hoshi
|
|
//
|
|
// Permission is hereby granted, free of charge, to any person obtaining a copy
|
|
// of this software and associated documentation files (the "Software"), to deal
|
|
// in the Software without restriction, including without limitation the rights
|
|
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
|
|
// copies of the Software, and to permit persons to whom the Software is
|
|
// furnished to do so, subject to the following conditions:
|
|
//
|
|
// The above copyright notice and this permission notice shall be included in
|
|
// all copies or substantial portions of the Software.
|
|
//
|
|
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
|
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
|
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
|
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
|
|
// SOFTWARE.
|
|
|
|
package matrix
|
|
|
|
type Affine interface {
|
|
Dim() int
|
|
element(i, j int) float64
|
|
setElement(i, j int, element float64)
|
|
}
|
|
|
|
func isIdentity(matrix Affine) bool {
|
|
dim := matrix.Dim()
|
|
for i := 0; i < dim-1; i++ {
|
|
for j := 0; j < dim; j++ {
|
|
element := matrix.element(i, j)
|
|
if i == j && element != 1 {
|
|
return false
|
|
} else if i != j && element != 0 {
|
|
return false
|
|
}
|
|
}
|
|
}
|
|
return true
|
|
}
|
|
|
|
func mul(lhs, rhs, result Affine) {
|
|
dim := lhs.Dim()
|
|
if dim != rhs.Dim() {
|
|
panic("diffrent-sized matrices can't be multiplied")
|
|
}
|
|
|
|
for i := 0; i < dim-1; i++ {
|
|
for j := 0; j < dim; j++ {
|
|
element := float64(0)
|
|
for k := 0; k < dim-1; k++ {
|
|
element += lhs.element(i, k) *
|
|
rhs.element(k, j)
|
|
}
|
|
if j == dim-1 {
|
|
element += lhs.element(i, j)
|
|
}
|
|
result.setElement(i, j, element)
|
|
}
|
|
}
|
|
}
|