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graphicscommand: Move OrthoProjectionMatrix to opengl package

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This commit is contained in:
Hajime Hoshi 2018-10-28 23:54:30 +09:00
parent ce1c616f69
commit 6b02f0ae9e
2 changed files with 33 additions and 18 deletions
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19
internal/graphicscommand/framebuffer.go
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@ -18,23 +18,6 @@ import (
"github.com/hajimehoshi/ebiten/internal/opengl"
)
// orthoProjectionMatrix returns an orthogonal projection matrix for OpenGL.
//
// The matrix converts the coodinates (left, bottom) - (right, top) to the normalized device coodinates (-1, -1) - (1, 1).
func orthoProjectionMatrix(left, right, bottom, top int) []float32 {
e11 := 2 / float32(right-left)
e22 := 2 / float32(top-bottom)
e14 := -1 * float32(right+left) / float32(right-left)
e24 := -1 * float32(top+bottom) / float32(top-bottom)
return []float32{
e11, 0, 0, 0,
0, e22, 0, 0,
0, 0, 1, 0,
e14, e24, 0, 1,
}
}
// framebuffer is a wrapper of OpenGL's framebuffer.
type framebuffer struct {
native opengl.Framebuffer
@ -89,6 +72,6 @@ func (f *framebuffer) projectionMatrix() []float32 {
return f.proMatrix
}
w, h := f.viewportSize()
f.proMatrix = orthoProjectionMatrix(0, w, 0, h)
f.proMatrix = opengl.OrthoProjectionMatrix(0, w, 0, h)
return f.proMatrix
}

32
internal/opengl/matrix.go Normal file
View File

@ -0,0 +1,32 @@
// Copyright 2018 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.
package opengl
// OrthoProjectionMatrix returns an orthogonal projection matrix for OpenGL.
//
// The matrix converts the coodinates (left, bottom) - (right, top) to the normalized device coodinates (-1, -1) - (1, 1).
func OrthoProjectionMatrix(left, right, bottom, top int) []float32 {
e11 := 2 / float32(right-left)
e22 := 2 / float32(top-bottom)
e14 := -1 * float32(right+left) / float32(right-left)
e24 := -1 * float32(top+bottom) / float32(top-bottom)
return []float32{
e11, 0, 0, 0,
0, e22, 0, 0,
0, 0, 1, 0,
e14, e24, 0, 1,
}
}