func (w Window) init() error {
sdl.GL_SetAttribute(sdl.GL_DOUBLEBUFFER, 1)
sdl.GL_SetAttribute(sdl.GL_RED_SIZE, 8)
sdl.GL_SetAttribute(sdl.GL_GREEN_SIZE, 8)
sdl.GL_SetAttribute(sdl.GL_BLUE_SIZE, 8)
sdl.GL_SetAttribute(sdl.GL_ALPHA_SIZE, 8)
if err := gl.Init(); err != nil {
return errors.New("Cannot initialize OGL: ")
}
gl.Viewport(0, 0, int32(w.Width), int32(w.Height))
Opengl.CreateBuffers(w.Width, w.Height)
return nil
}
func setupGL() int32 {
gl.Disable(gl.DEPTH_TEST)
gl.ClearColor(0.7, 0.7, 0.7, 1)
program, _ := loadResources()
gl.BindFragDataLocation(program, 0, gl.Str("outputColor\x00"))
cameraMatrixUniform := gl.GetUniformLocation(program, gl.Str("cameraMatrix\x00"))
octUniform := gl.GetUniformLocation(program, gl.Str("oct\x00"))
gl.Uniform1i(octUniform, 0)
gl.Viewport(0, 0, winWidth, winHeight)
var vao uint32
gl.GenVertexArrays(1, &vao)
gl.BindVertexArray(vao)
quadVertexBufferData := []float32{
-1, -1, 0,
1, -1, 0,
-1, 1, 0,
-1, 1, 0,
1, -1, 0,
1, 1, 0,
}
var vbo uint32
gl.GenBuffers(1, &vbo)
gl.BindBuffer(gl.ARRAY_BUFFER, vbo)
gl.BufferData(gl.ARRAY_BUFFER, len(quadVertexBufferData)*4, gl.Ptr(quadVertexBufferData), gl.STATIC_DRAW)
vertAttrib := uint32(gl.GetAttribLocation(program, gl.Str("inputPosition\x00")))
gl.EnableVertexAttribArray(vertAttrib)
gl.VertexAttribPointer(vertAttrib, 3, gl.FLOAT, false, 0, gl.PtrOffset(0))
return cameraMatrixUniform
}
// Viewport implements the opengl.OpenGl interface.
func (native *OpenGl) Viewport(x int32, y int32, width int32, height int32) {
gl.Viewport(x, y, width, height)
}