mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-09-20 13:22:19 +02:00
125 lines
3.0 KiB
Go
125 lines
3.0 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 opengl
|
|
|
|
import (
|
|
"errors"
|
|
"fmt"
|
|
"github.com/go-gl/gl"
|
|
)
|
|
|
|
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 RenderTarget struct {
|
|
framebuffer gl.Framebuffer
|
|
width int
|
|
height int
|
|
flipY bool
|
|
}
|
|
|
|
func NewRenderTarget(width, height int, flipY bool) *RenderTarget {
|
|
return &RenderTarget{
|
|
width: width,
|
|
height: height,
|
|
flipY: flipY,
|
|
}
|
|
}
|
|
|
|
func NewRenderTargetFromTexture(texture *Texture) (*RenderTarget, error) {
|
|
framebuffer, err := createFramebuffer(texture.Native())
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return &RenderTarget{
|
|
framebuffer: framebuffer,
|
|
width: texture.Width(),
|
|
height: texture.Height(),
|
|
}, nil
|
|
}
|
|
|
|
func (r *RenderTarget) Width() int {
|
|
return r.width
|
|
}
|
|
|
|
func (r *RenderTarget) Height() int {
|
|
return r.height
|
|
}
|
|
|
|
func (r *RenderTarget) FlipY() bool {
|
|
return r.flipY
|
|
}
|
|
|
|
func (r *RenderTarget) Dispose() {
|
|
r.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")
|
|
}
|
|
|
|
// Set this framebuffer opaque because alpha values on a target might be
|
|
// confusing.
|
|
gl.ClearColor(0, 0, 0, 1)
|
|
gl.Clear(gl.COLOR_BUFFER_BIT)
|
|
|
|
return framebuffer, nil
|
|
}
|
|
|
|
func (r *RenderTarget) SetAsViewport() error {
|
|
gl.Flush()
|
|
r.framebuffer.Bind()
|
|
err := gl.CheckFramebufferStatus(gl.FRAMEBUFFER)
|
|
if err != gl.FRAMEBUFFER_COMPLETE {
|
|
return errors.New(fmt.Sprintf("glBindFramebuffer failed: %d", err))
|
|
}
|
|
|
|
gl.BlendFuncSeparate(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA, gl.ZERO, gl.ONE)
|
|
|
|
width := AdjustSizeForTexture(r.width)
|
|
height := AdjustSizeForTexture(r.height)
|
|
gl.Viewport(0, 0, width, height)
|
|
return nil
|
|
}
|
|
|
|
func (r *RenderTarget) ProjectionMatrix() [4][4]float64 {
|
|
width := AdjustSizeForTexture(r.width)
|
|
height := AdjustSizeForTexture(r.height)
|
|
m := orthoProjectionMatrix(0, width, 0, height)
|
|
if r.flipY {
|
|
m[1][1] *= -1
|
|
m[1][3] += float64(r.height) / float64(AdjustSizeForTexture(r.height)) * 2
|
|
}
|
|
return m
|
|
}
|