mirror of
https://github.com/hajimehoshi/ebiten.git
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116 lines
3.2 KiB
Go
116 lines
3.2 KiB
Go
package offscreen
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// #cgo LDFLAGS: -framework OpenGL
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//
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// #include <stdlib.h>
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// #include <OpenGL/gl.h>
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import "C"
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import (
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"fmt"
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"github.com/hajimehoshi/go-ebiten/graphics"
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"github.com/hajimehoshi/go-ebiten/graphics/matrix"
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"github.com/hajimehoshi/go-ebiten/graphics/opengl/rendertarget"
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"github.com/hajimehoshi/go-ebiten/graphics/opengl/shader"
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"github.com/hajimehoshi/go-ebiten/graphics/opengl/texture"
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grendertarget "github.com/hajimehoshi/go-ebiten/graphics/rendertarget"
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gtexture "github.com/hajimehoshi/go-ebiten/graphics/texture"
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)
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type Offscreen struct {
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screenHeight int
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screenScale int
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mainFramebufferTexture *grendertarget.RenderTarget
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projectionMatrix [16]float32
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}
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func New(screenWidth, screenHeight, screenScale int) *Offscreen {
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offscreen := &Offscreen{
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screenHeight: screenHeight,
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screenScale: screenScale,
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}
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// The main framebuffer should be created sooner than any other
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// framebuffers!
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mainFramebuffer := C.GLint(0)
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C.glGetIntegerv(C.GL_FRAMEBUFFER_BINDING, &mainFramebuffer)
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var err error
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offscreen.mainFramebufferTexture, err = rendertarget.NewWithFramebuffer(
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screenWidth*screenScale,
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screenHeight*screenScale,
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rendertarget.Framebuffer(mainFramebuffer))
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if err != nil {
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panic("creating main framebuffer failed: " + err.Error())
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}
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return offscreen
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}
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func (o *Offscreen) Set(rt *grendertarget.RenderTarget) {
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C.glFlush()
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rt.SetAsOffscreen(&setter{o, rt == o.mainFramebufferTexture})
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}
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func (o *Offscreen) SetMainFramebuffer() {
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o.Set(o.mainFramebufferTexture)
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}
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func (o *Offscreen) DrawTexture(texture *gtexture.Texture,
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geometryMatrix matrix.Geometry, colorMatrix matrix.Color) {
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d := &drawable{o, geometryMatrix, colorMatrix}
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texture.Draw(d.Draw)
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}
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func (o *Offscreen) DrawTextureParts(texture *gtexture.Texture,
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parts []graphics.TexturePart,
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geometryMatrix matrix.Geometry, colorMatrix matrix.Color) {
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d := &drawable{o, geometryMatrix, colorMatrix}
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texture.DrawParts(parts, d.Draw)
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}
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type setter struct {
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offscreen *Offscreen
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usingMainFramebuffer bool
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}
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func (s *setter) Set(framebuffer interface{}, x, y, width, height int) {
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f := framebuffer.(rendertarget.Framebuffer)
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C.glBindFramebuffer(C.GL_FRAMEBUFFER, C.GLuint(f))
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err := C.glCheckFramebufferStatus(C.GL_FRAMEBUFFER)
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if err != C.GL_FRAMEBUFFER_COMPLETE {
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panic(fmt.Sprintf("glBindFramebuffer failed: %d", err))
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}
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C.glBlendFuncSeparate(C.GL_SRC_ALPHA, C.GL_ONE_MINUS_SRC_ALPHA,
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C.GL_ZERO, C.GL_ONE)
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C.glViewport(C.GLint(x), C.GLint(y),
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C.GLsizei(width), C.GLsizei(height))
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matrix := graphics.OrthoProjectionMatrix(x, width, y, height)
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if s.usingMainFramebuffer {
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actualScreenHeight := s.offscreen.screenHeight * s.offscreen.screenScale
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// Flip Y and move to fit with the top of the window.
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matrix[1][1] *= -1
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matrix[1][3] += float64(actualScreenHeight) / float64(height) * 2
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}
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for j := 0; j < 4; j++ {
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for i := 0; i < 4; i++ {
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s.offscreen.projectionMatrix[i+j*4] = float32(matrix[i][j])
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}
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}
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}
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type drawable struct {
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offscreen *Offscreen
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geometryMatrix matrix.Geometry
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colorMatrix matrix.Color
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}
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func (d *drawable) Draw(native interface{}, quads []gtexture.Quad) {
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shader.DrawTexture(native.(texture.Native),
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d.offscreen.projectionMatrix, quads,
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d.geometryMatrix, d.colorMatrix)
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}
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