func initStars() {
// Create the first stars
for loop, _ := range stars {
stars[loop] = &Star{
angle: 0.0,
dist: (gl.GLfloat(loop) / gl.GLfloat(num)) * 5.0,
r: gl.GLubyte(rand.Float32() * 255),
g: gl.GLubyte(rand.Float32() * 255),
b: gl.GLubyte(rand.Float32() * 255),
}
}
}
// Here goes our drawing code
func drawGLScene() {
// Clear the screen and depth buffer
gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)
gl.BindTexture(gl.TEXTURE_2D, uint(texture))
for loop, star := range stars {
gl.LoadIdentity()
gl.Translatef(0.0, 0.0, float32(zoom))
gl.Rotatef(float32(tilt), 1.0, 0.0, 0.0)
gl.Rotatef(float32(star.angle), 0.0, 1.0, 0.0)
gl.Translatef(float32(star.dist), 0.0, 0.0)
gl.Rotatef(float32(-star.angle), 0.0, 1.0, 0.0)
gl.Rotatef(float32(-tilt), 1.0, 0.0, 0.0)
if twinkle {
other := stars[(num-loop)-1]
gl.Color4ub(uint8(other.r), uint8(other.g), uint8(other.b), 255)
gl.Begin(gl.QUADS)
gl.TexCoord2f(0.0, 0.0)
gl.Vertex3f(-1.0, -1.0, 0.0)
gl.TexCoord2f(1.0, 0.0)
gl.Vertex3f(1.0, -1.0, 0.0)
gl.TexCoord2f(1.0, 1.0)
gl.Vertex3f(1.0, 1.0, 0.0)
gl.TexCoord2f(0.0, 1.0)
gl.Vertex3f(-1.0, 1.0, 0.0)
gl.End()
}
gl.Rotatef(float32(spin), 0.0, 0.0, 1.0)
gl.Color4ub(uint8(star.r), uint8(star.g), uint8(star.b), 255)
gl.Begin(gl.QUADS)
gl.TexCoord2f(0.0, 0.0)
gl.Vertex3f(-1.0, -1.0, 0.0)
gl.TexCoord2f(1.0, 0.0)
gl.Vertex3f(1.0, -1.0, 0.0)
gl.TexCoord2f(1.0, 1.0)
gl.Vertex3f(1.0, 1.0, 0.0)
gl.TexCoord2f(0.0, 1.0)
gl.Vertex3f(-1.0, 1.0, 0.0)
gl.End()
spin += 0.01
star.angle += gl.GLfloat(loop) / gl.GLfloat(num)
star.dist -= 0.01
if star.dist < 0.0 {
star.dist += 5.0
star.r = gl.GLubyte(rand.Float32() * 255)
star.g = gl.GLubyte(rand.Float32() * 255)
star.b = gl.GLubyte(rand.Float32() * 255)
}
}
// Draw to the screen
sdl.GL_SwapBuffers()
// Gather our frames per second
frames++
t := sdl.GetTicks()
if t-t0 >= 5000 {
seconds := (t - t0) / 1000.0
fps := frames / seconds
fmt.Println(frames, "frames in", seconds, "seconds =", fps, "FPS")
t0 = t
frames = 0
}
}