mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-12-27 04:08:53 +01:00
114 lines
2.9 KiB
Go
114 lines
2.9 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 opengl
|
|
|
|
import (
|
|
"errors"
|
|
"fmt"
|
|
"github.com/go-gl/gl"
|
|
"github.com/hajimehoshi/ebiten/internal"
|
|
)
|
|
|
|
func orthoProjectionMatrix(left, right, bottom, top int) [4][4]float64 {
|
|
e11 := float64(2) / float64(right-left)
|
|
e22 := float64(2) / float64(top-bottom)
|
|
e14 := -1 * float64(right+left) / float64(right-left)
|
|
e24 := -1 * float64(top+bottom) / float64(top-bottom)
|
|
|
|
return [4][4]float64{
|
|
{e11, 0, 0, e14},
|
|
{0, e22, 0, e24},
|
|
{0, 0, 1, 0},
|
|
{0, 0, 0, 1},
|
|
}
|
|
}
|
|
|
|
type Framebuffer struct {
|
|
framebuffer gl.Framebuffer
|
|
width int
|
|
height int
|
|
flipY bool
|
|
}
|
|
|
|
func NewZeroFramebuffer(width, height int) (*Framebuffer, error) {
|
|
r := &Framebuffer{
|
|
width: width,
|
|
height: height,
|
|
flipY: true,
|
|
}
|
|
return r, nil
|
|
}
|
|
|
|
func NewFramebufferFromTexture(texture *Texture) (*Framebuffer, error) {
|
|
framebuffer, err := createFramebuffer(texture.Native())
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
w, h := texture.Size()
|
|
return &Framebuffer{
|
|
framebuffer: framebuffer,
|
|
width: w,
|
|
height: h,
|
|
}, nil
|
|
}
|
|
|
|
func (f *Framebuffer) Size() (width, height int) {
|
|
return f.width, f.height
|
|
}
|
|
|
|
func (f *Framebuffer) Dispose() {
|
|
f.framebuffer.Delete()
|
|
}
|
|
|
|
func createFramebuffer(nativeTexture gl.Texture) (gl.Framebuffer, error) {
|
|
framebuffer := gl.GenFramebuffer()
|
|
framebuffer.Bind()
|
|
|
|
gl.FramebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, nativeTexture, 0)
|
|
if gl.CheckFramebufferStatus(gl.FRAMEBUFFER) != gl.FRAMEBUFFER_COMPLETE {
|
|
return 0, errors.New("creating framebuffer failed")
|
|
}
|
|
|
|
return framebuffer, nil
|
|
}
|
|
|
|
func (f *Framebuffer) SetAsViewport() error {
|
|
gl.Flush()
|
|
f.framebuffer.Bind()
|
|
err := gl.CheckFramebufferStatus(gl.FRAMEBUFFER)
|
|
if err != gl.FRAMEBUFFER_COMPLETE {
|
|
if gl.GetError() != 0 {
|
|
return errors.New(fmt.Sprintf("glBindFramebuffer failed: %d", gl.GetError()))
|
|
}
|
|
return errors.New("glBindFramebuffer failed: the context is different?")
|
|
}
|
|
|
|
width := internal.NextPowerOf2Int(f.width)
|
|
height := internal.NextPowerOf2Int(f.height)
|
|
gl.Viewport(0, 0, width, height)
|
|
return nil
|
|
}
|
|
|
|
func (f *Framebuffer) ProjectionMatrix() [4][4]float64 {
|
|
width := internal.NextPowerOf2Int(f.width)
|
|
height := internal.NextPowerOf2Int(f.height)
|
|
m := orthoProjectionMatrix(0, width, 0, height)
|
|
if f.flipY {
|
|
m[1][1] *= -1
|
|
m[1][3] += float64(f.height) / float64(internal.NextPowerOf2Int(f.height)) * 2
|
|
}
|
|
return m
|
|
}
|