mirror of
https://github.com/hajimehoshi/ebiten.git
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64 lines
1.6 KiB
Go
64 lines
1.6 KiB
Go
package opengl
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import (
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"fmt"
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"github.com/go-gl/gl"
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"github.com/hajimehoshi/ebiten/graphics"
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)
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type RenderTarget struct {
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framebuffer gl.Framebuffer
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width int
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height int
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flipY bool
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}
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func createFramebuffer(nativeTexture gl.Texture) gl.Framebuffer {
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framebuffer := gl.GenFramebuffer()
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framebuffer.Bind()
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gl.FramebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0,
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gl.TEXTURE_2D, nativeTexture, 0)
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if gl.CheckFramebufferStatus(gl.FRAMEBUFFER) != gl.FRAMEBUFFER_COMPLETE {
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panic("creating framebuffer failed")
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}
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// Set this framebuffer opaque because alpha values on a target might be
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// confusing.
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gl.ClearColor(0, 0, 0, 1)
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gl.Clear(gl.COLOR_BUFFER_BIT)
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return framebuffer
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}
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func (r *RenderTarget) setAsViewport() {
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gl.Flush()
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r.framebuffer.Bind()
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err := gl.CheckFramebufferStatus(gl.FRAMEBUFFER)
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if err != gl.FRAMEBUFFER_COMPLETE {
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panic(fmt.Sprintf("glBindFramebuffer failed: %d", err))
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}
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gl.BlendFuncSeparate(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA, gl.ZERO, gl.ONE)
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width := graphics.AdjustSizeForTexture(r.width)
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height := graphics.AdjustSizeForTexture(r.height)
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gl.Viewport(0, 0, width, height)
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}
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func (r *RenderTarget) projectionMatrix() [4][4]float64 {
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width := graphics.AdjustSizeForTexture(r.width)
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height := graphics.AdjustSizeForTexture(r.height)
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matrix := graphics.OrthoProjectionMatrix(0, width, 0, height)
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if r.flipY {
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matrix[1][1] *= -1
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matrix[1][3] += float64(r.height) /
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float64(graphics.AdjustSizeForTexture(r.height)) * 2
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}
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return matrix
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}
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func (r *RenderTarget) dispose() {
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r.framebuffer.Delete()
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}
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