mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-11-10 04:57:26 +01:00
71 lines
1.8 KiB
Go
71 lines
1.8 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 graphics
|
|
|
|
import (
|
|
"github.com/hajimehoshi/ebiten/internal/opengl"
|
|
)
|
|
|
|
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,
|
|
}
|
|
}
|
|
|
|
type framebuffer struct {
|
|
native opengl.Framebuffer
|
|
flipY bool
|
|
proMatrix []float32
|
|
}
|
|
|
|
func newFramebufferFromTexture(context *opengl.Context, texture *texture) (*framebuffer, error) {
|
|
native, err := context.NewFramebuffer(opengl.Texture(texture.native))
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return &framebuffer{
|
|
native: native,
|
|
}, nil
|
|
}
|
|
|
|
const viewportSize = 4096
|
|
|
|
func (f *framebuffer) setAsViewport(context *opengl.Context) error {
|
|
width := viewportSize
|
|
height := viewportSize
|
|
return context.SetViewport(f.native, width, height)
|
|
}
|
|
|
|
func (f *framebuffer) projectionMatrix(height int) []float32 {
|
|
if f.proMatrix != nil {
|
|
return f.proMatrix
|
|
}
|
|
m := orthoProjectionMatrix(0, viewportSize, 0, viewportSize)
|
|
if f.flipY {
|
|
m[4*1+1] *= -1
|
|
m[4*3+1] += float32(height) / float32(viewportSize) * 2
|
|
}
|
|
f.proMatrix = m
|
|
return f.proMatrix
|
|
}
|