// renders the display on each update
func render() {
gl.Clear(gl.COLOR_BUFFER_BIT)
gl.Enable(gl.BLEND)
gl.Enable(gl.POINT_SMOOTH)
gl.Enable(gl.LINE_SMOOTH)
gl.BlendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)
gl.LoadIdentity()
// draw pipes
for _, pipeBox := range pipe {
gl.PushMatrix()
pos := pipeBox.Body.Position()
gl.Translatef(float32(pos.X), float32(pos.Y), 0.0)
drawSquare(.19, .8, .19, 1) // limegreen
gl.PopMatrix()
}
// draw flappy
for _, flappyBird := range flappyBirds {
gl.PushMatrix()
pos := flappyBird.Body.Position()
gl.Translatef(float32(pos.X), float32(pos.Y), 0.0)
drawSquare(1, .84, 0, 1) // gold
gl.PopMatrix()
}
gl.Color4f(1, 0, 1, 1)
scoreStr := "[ Score: " + strconv.Itoa(score) + " ]"
// draw score
drawScore(scoreStr)
}
func drawSquare(colorRed, colorGreen, colorBlue, alpha float32) {
// first draw the first dark layer
gl.Color4f(0, 0, 0, 1)
gl.Begin(gl.POLYGON)
gl.Vertex2d(float64(pipeSide/2), float64(pipeSide/2))
gl.Vertex2d(float64(-pipeSide/2), float64(pipeSide/2))
gl.Vertex2d(float64(-pipeSide/2), float64(-pipeSide/2))
gl.Vertex2d(float64(pipeSide/2), float64(-pipeSide/2))
gl.End()
// then draw the actual color layer
gl.Color4f(colorRed, colorGreen, colorBlue, alpha)
gl.Begin(gl.POLYGON)
gl.Vertex2d(float64(innerPipeSide/2), float64(innerPipeSide/2))
gl.Vertex2d(float64(-innerPipeSide/2), float64(innerPipeSide/2))
gl.Vertex2d(float64(-innerPipeSide/2), float64(-innerPipeSide/2))
gl.Vertex2d(float64(innerPipeSide/2), float64(-innerPipeSide/2))
gl.End()
gl.Vertex3f(0, 0, 0)
}
