ebiten/internal/affine/affine.go
2017-01-19 10:59:07 +09:00

91 lines
2.0 KiB
Go

// Copyright 2014 Hajime Hoshi
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package affine
import (
"github.com/hajimehoshi/ebiten/internal/endian"
)
var identityValues = map[int]string{
ColorMDim: colorMValueString([ColorMDim - 1][ColorMDim]float64{
{1, 0, 0, 0, 0},
{0, 1, 0, 0, 0},
{0, 0, 1, 0, 0},
{0, 0, 0, 1, 0},
}),
GeoMDim: geoMValueString([GeoMDim - 1][GeoMDim]float64{
{1, 0, 0},
{0, 1, 0},
}),
}
func uint64ToBytes(value uint64) []uint8 {
result := make([]uint8, 8)
if endian.IsLittle() {
for i := 0; i < 8; i++ {
result[i] = uint8(value)
value >>= 8
}
} else {
for i := 7; 0 <= i; i-- {
result[i] = uint8(value)
value >>= 8
}
}
return result
}
type affine interface {
dim() int
Element(i, j int) float64
SetElement(i, j int, element float64)
}
// add is deprecated
func add(lhs, rhs, result affine) {
dim := lhs.dim()
if dim != rhs.dim() {
panic("ebiten: different-sized matrices can't be multiplied")
}
for i := 0; i < dim-1; i++ {
for j := 0; j < dim; j++ {
v := lhs.Element(i, j) + rhs.Element(i, j)
result.SetElement(i, j, v)
}
}
}
func mul(lhs, rhs, result affine) {
dim := lhs.dim()
if dim != rhs.dim() {
panic("ebiten: different-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)
}
}
}