func renderToScreen() {
gl.BindFramebuffer(gl.FRAMEBUFFER, 0)
gl.Viewport(0, 0, winWidth, winHeight)
gl.UseProgram(shaderTextureDisplay.glProg)
gl.BindTexture(gl.TEXTURE_2D, rttFrameTex)
gl.Uniform1i(shaderTextureDisplay.unifTex, 0)
gl.BindBuffer(gl.ARRAY_BUFFER, dispVertBuf)
gl.EnableVertexAttribArray(shaderTextureDisplay.attrPos)
gl.VertexAttribPointer(shaderTextureDisplay.attrPos, 3, gl.FLOAT, gl.FALSE, 0, gl.Pointer(nil))
gl.DrawArrays(gl.TRIANGLE_FAN, 0, 4)
gl.DisableVertexAttribArray(shaderTextureDisplay.attrPos)
gl.BindBuffer(gl.ARRAY_BUFFER, 0)
}
func renderToTexture() {
gl.BindFramebuffer(gl.FRAMEBUFFER, rttFrameBuf)
gl.Viewport(0, 0, texSize, texSize)
gl.ClearColor(0.9, 0.6, 0.3, 1)
gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)
gl.UseProgram(shaderTextureCreator.glProg)
gl.BindBuffer(gl.ARRAY_BUFFER, rttVertBuf)
gl.EnableVertexAttribArray(shaderTextureCreator.attrPos)
gl.VertexAttribPointer(shaderTextureCreator.attrPos, 2, gl.FLOAT, gl.FALSE, 0, gl.Pointer(nil))
gl.DrawArrays(gl.TRIANGLE_FAN, 0, 4)
gl.DisableVertexAttribArray(shaderTextureCreator.attrPos)
gl.BindBuffer(gl.ARRAY_BUFFER, 0)
}
func glFillTextureFromImageFile(filePath string) {
var file, err = os.Open(filePath)
var img image.Image
if err != nil {
panic(err)
}
defer file.Close()
if img, _, err = image.Decode(file); err != nil {
panic(err)
}
w, h := img.Bounds().Dx(), img.Bounds().Dy()
rgba := image.NewRGBA(image.Rect(0, 0, w, h))
for x := 0; x < w; x++ {
for y := 0; y < h; y++ {
rgba.Set(x, y, img.At(x, y))
}
}
gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.Sizei(w), gl.Sizei(h), 0, gl.RGBA, gl.UNSIGNED_BYTE, gl.Pointer(&rgba.Pix[0]))
}
func glFillBuffer(vals []gl.Float, buf *gl.Uint) {
gl.GenBuffers(1, buf)
gl.BindBuffer(gl.ARRAY_BUFFER, *buf)
gl.BufferData(gl.ARRAY_BUFFER, gl.Sizeiptr(len(vals)*4), gl.Pointer(&vals[0]), gl.STATIC_DRAW)
gl.BindBuffer(gl.ARRAY_BUFFER, 0)
}