func Cylinder(r, h gl.Float, slices int, hollow, solid bool) {
res := 2 * math.Pi / float64(slices)
mode := gl.LINE_LOOP
if solid {
mode = gl.QUADS
}
gl.Begin(gl.Enum(mode))
for a := 0.0; a < 2*math.Pi; a += res {
gl.Normal3f(gl.Float(math.Cos(a)), gl.Float(math.Sin(a)), 0)
gl.Vertex3f(r*gl.Float(math.Cos(a)), r*gl.Float(math.Sin(a)), 0)
gl.Vertex3f(r*gl.Float(math.Cos(a)), r*gl.Float(math.Sin(a)), h)
a += res
gl.Vertex3f(r*gl.Float(math.Cos(a)), r*gl.Float(math.Sin(a)), h)
gl.Vertex3f(r*gl.Float(math.Cos(a)), r*gl.Float(math.Sin(a)), 0)
}
gl.End()
if !hollow {
// X Y plane
if h < 0 {
gl.Normal3f(0, 0, 1)
} else {
gl.Normal3f(0, 0, -1)
}
Circle(r, slices, solid)
// Top (or bottom)
if h < 0 {
gl.Normal3f(0, 0, -1)
} else {
gl.Normal3f(0, 0, 1)
}
gl.Translatef(0, 0, h)
Circle(r, slices, solid)
}
}
func Box(x, y, z float32, solid bool) {
mode := gl.LINE_LOOP
if solid {
mode = gl.QUADS
}
X := gl.Float(x) / 2
Y := gl.Float(y) / 2
Z := gl.Float(z) / 2
gl.Begin(gl.Enum(mode))
gl.Normal3f(0, 0, 1) // Positive Z Face
gl.Vertex3f(-X, -Y, Z)
gl.Vertex3f(X, -Y, Z)
gl.Vertex3f(X, Y, Z)
gl.Vertex3f(-X, Y, Z)
gl.Normal3f(0, 0, -1) // Negative Z Face
gl.Vertex3f(-X, -Y, -Z)
gl.Vertex3f(-X, Y, -Z)
gl.Vertex3f(X, Y, -Z)
gl.Vertex3f(X, -Y, -Z)
gl.Normal3f(0, 1, 0) // Positive Y Face
gl.Vertex3f(-X, Y, -Z)
gl.Vertex3f(-X, Y, Z)
gl.Vertex3f(X, Y, Z)
gl.Vertex3f(X, Y, -Z)
gl.Normal3f(0, -1, 0) // Negative Y Face
gl.Vertex3f(-X, -Y, -Z)
gl.Vertex3f(X, -Y, -Z)
gl.Vertex3f(X, -Y, Z)
gl.Vertex3f(-X, -Y, Z)
gl.Normal3f(1, 0, 0) // Positive X Face
gl.Vertex3f(X, -Y, -Z)
gl.Vertex3f(X, Y, -Z)
gl.Vertex3f(X, Y, Z)
gl.Vertex3f(X, -Y, Z)
gl.Normal3f(-1, 0, 0) // Negative X Face
gl.Vertex3f(-X, -Y, -Z)
gl.Vertex3f(-X, -Y, Z)
gl.Vertex3f(-X, Y, Z)
gl.Vertex3f(-X, Y, -Z)
gl.End()
}
func drawScene() {
gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)
gl.MatrixMode(gl.MODELVIEW)
gl.LoadIdentity()
gl.Translatef(0, 0, -3.0)
gl.Rotatef(rotx, 1, 0, 0)
gl.Rotatef(roty, 0, 1, 0)
rotx += 0.5
roty += 0.5
gl.BindTexture(gl.TEXTURE_2D, texture)
gl.Color4f(1, 1, 1, 1)
gl.Begin(gl.QUADS)
gl.Normal3f(0, 0, 1)
gl.TexCoord2f(0, 0)
gl.Vertex3f(-1, -1, 1)
gl.TexCoord2f(1, 0)
gl.Vertex3f(1, -1, 1)
gl.TexCoord2f(1, 1)
gl.Vertex3f(1, 1, 1)
gl.TexCoord2f(0, 1)
gl.Vertex3f(-1, 1, 1)
gl.Normal3f(0, 0, -1)
gl.TexCoord2f(1, 0)
gl.Vertex3f(-1, -1, -1)
gl.TexCoord2f(1, 1)
gl.Vertex3f(-1, 1, -1)
gl.TexCoord2f(0, 1)
gl.Vertex3f(1, 1, -1)
gl.TexCoord2f(0, 0)
gl.Vertex3f(1, -1, -1)
gl.Normal3f(0, 1, 0)
gl.TexCoord2f(0, 1)
gl.Vertex3f(-1, 1, -1)
gl.TexCoord2f(0, 0)
gl.Vertex3f(-1, 1, 1)
gl.TexCoord2f(1, 0)
gl.Vertex3f(1, 1, 1)
gl.TexCoord2f(1, 1)
gl.Vertex3f(1, 1, -1)
gl.Normal3f(0, -1, 0)
gl.TexCoord2f(1, 1)
gl.Vertex3f(-1, -1, -1)
gl.TexCoord2f(0, 1)
gl.Vertex3f(1, -1, -1)
gl.TexCoord2f(0, 0)
gl.Vertex3f(1, -1, 1)
gl.TexCoord2f(1, 0)
gl.Vertex3f(-1, -1, 1)
gl.Normal3f(1, 0, 0)
gl.TexCoord2f(1, 0)
gl.Vertex3f(1, -1, -1)
gl.TexCoord2f(1, 1)
gl.Vertex3f(1, 1, -1)
gl.TexCoord2f(0, 1)
gl.Vertex3f(1, 1, 1)
gl.TexCoord2f(0, 0)
gl.Vertex3f(1, -1, 1)
gl.Normal3f(-1, 0, 0)
gl.TexCoord2f(0, 0)
gl.Vertex3f(-1, -1, -1)
gl.TexCoord2f(1, 0)
gl.Vertex3f(-1, -1, 1)
gl.TexCoord2f(1, 1)
gl.Vertex3f(-1, 1, 1)
gl.TexCoord2f(0, 1)
gl.Vertex3f(-1, 1, -1)
gl.End()
}
// Wraps gl.Normal3f
func Normal3f(x, y, z float32) {
gl.Normal3f(gl.Float(x), gl.Float(y), gl.Float(z))
}