ebiten/internal/affine/colorm_notjs.go

58 lines
1.4 KiB
Go
Raw Normal View History

2017-01-17 18:23:52 +01:00
// Copyright 2017 The Ebiten Authors
//
// 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.
// +build !js
package affine
import (
"math"
"github.com/hajimehoshi/ebiten/internal/endian"
)
// Element returns a value of a matrix at (i, j).
func (c *ColorM) Element(i, j int) float64 {
if c.values == "" {
if i == j {
return 1
}
return 0
}
offset := 8 * (i*ColorMDim + j)
v := uint64(0)
if endian.IsLittle() {
for k := 7; 0 <= k; k-- {
v <<= 8
v += uint64(c.values[offset+k])
}
} else {
for k := 0; k < 8; k++ {
v <<= 8
v += uint64(c.values[offset+k])
}
}
return math.Float64frombits(v)
}
// SetElement sets an element at (i, j).
func (c *ColorM) SetElement(i, j int, value float64) {
if c.values == "" {
c.values = colorMIdentityValue
}
b := uint64ToBytes(math.Float64bits(value))
offset := 8 * (i*ColorMDim + j)
c.values = c.values[:offset] + string(b) + c.values[offset+8:]
}