func draw() {
gl.BindFramebuffer(gl.FRAMEBUFFER, 0)
gl.Clear(gl.COLOR_BUFFER_BIT)
gl.BindBuffer(gl.ARRAY_BUFFER, vertexArrayBuffer)
gl.VertexAttribPointer(attrPos, 4, gl.FLOAT, false, 0, nil)
gl.BindBuffer(gl.ARRAY_BUFFER, colorArrayBuffer)
gl.VertexAttribPointer(attrCol, 3, gl.FLOAT, false, 0, nil)
gl.DrawArrays(gl.TRIANGLES, 0, 3)
gl.Flush()
gl.Finish()
egl.SwapBuffers(display, surface)
}
func initOGL(state *CubeState) {
var (
config egl.Config
numConfig int32
dstRect, srcRect egl.VCRect
nativeWindow egl.EGLDispmanxWindow
)
attr := []int32{
egl.RED_SIZE, 8,
egl.GREEN_SIZE, 8,
egl.BLUE_SIZE, 8,
egl.ALPHA_SIZE, 8,
egl.SURFACE_TYPE, egl.WINDOW_BIT,
egl.NONE,
}
egl.BCMHostInit()
state.display = egl.GetDisplay(0)
egl.Initialize(state.display, nil, nil)
egl.ChooseConfig(state.display, attr, &config, 1, &numConfig)
egl.BindAPI(egl.OPENGL_ES_API)
context := egl.CreateContext(state.display, config, egl.NO_CONTEXT, nil)
state.screen_width, state.screen_height = egl.GraphicsGetDisplaySize(0)
log.Printf("Display size W: %d H: %d\n", state.screen_width, state.screen_height)
dstRect.X = 0
dstRect.Y = 0
dstRect.Width = int32(state.screen_width)
dstRect.Height = int32(state.screen_height)
srcRect.X = 0
srcRect.Y = 0
srcRect.Width = int32(state.screen_width << 16)
srcRect.Height = int32(state.screen_height << 16)
dispman_display := egl.VCDispmanxDisplayOpen(0 /* LCD */)
dispman_update := egl.VCDispmanxUpdateStart(0)
dispman_element := egl.VCDispmanxElementAdd(
dispman_update,
dispman_display,
0, /*layer */
&dstRect,
0, /*src */
&srcRect,
egl.DISPMANX_PROTECTION_NONE,
nil, /*alpha */
nil, /*clamp */
0 /*transform */)
log.Printf("DispmanDisplay 0x%x DispmanUpdate 0x%x DispmanElement 0x%x\n", dispman_display, dispman_update, dispman_element)
nativeWindow.Element = dispman_element
nativeWindow.Width = int(state.screen_width)
nativeWindow.Height = int(state.screen_height)
egl.VCDispmanxUpdateSubmitSync(dispman_update)
surface := egl.CreateWindowSurface(
state.display,
config,
egl.NativeWindowType(unsafe.Pointer(&nativeWindow)),
nil)
log.Printf("Surface 0x%x\n", surface)
// preserve the buffers on swap
egl.SurfaceAttrib(state.display, surface, egl.SWAP_BEHAVIOR, egl.BUFFER_PRESERVED)
// connect the context to the surface
result := egl.MakeCurrent(state.display, surface, surface, context)
log.Printf("MakeCurrent result %d\n", result)
var fb uint32
var rb uint32
gl.GenFramebuffers(1, &fb)
gl.BindFramebuffer(gl.FRAMEBUFFER, fb)
gl.GenRenderbuffers(1, &rb)
gl.BindRenderbuffer(gl.RENDERBUFFER, rb)
gl.RenderbufferStorage(gl.RENDERBUFFER, gl.RGBA4, gl.Sizei(state.screen_width), gl.Sizei(state.screen_height))
// Set background color and clear buffers
gl.ClearColor(0.15, 0.25, 0.35, 1.0)
gl.Clear(gl.COLOR_BUFFER_BIT)
gl.BindFramebuffer(gl.FRAMEBUFFER, fb)
gl.FramebufferRenderbuffer(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.RENDERBUFFER, rb)
gl.BindFramebuffer(gl.FRAMEBUFFER, 0)
gl.Viewport(0, 0, gl.Sizei(state.screen_width), gl.Sizei(state.screen_height))
}