gametemplate.fs

#if INTERACTIVE
  #r "OpenTK.dll"
#endif

open System
open System.Drawing
open System.Collections.Generic

open OpenTK
open OpenTK.Graphics
open OpenTK.Graphics.OpenGL
open OpenTK.Input

[<AbstractClass>]
type Game(width, height, title) =
  inherit GameWindow(width, height, GraphicsMode.Default, title)

  do base.VSync <- VSyncMode.On

  override x.OnLoad e =
    base.OnLoad(e)
    GL.Enable(EnableCap.DepthTest)
    x.setup()

  override x.OnResize e =
    base.OnResize(e)
    x.onResize()

  override x.OnUpdateFrame e =
    base.OnUpdateFrame(e)
    x.update()

  override x.OnRenderFrame e =
    base.OnRenderFrame e
    GL.Clear(ClearBufferMask.ColorBufferBit ||| ClearBufferMask.DepthBufferBit)
    let mutable modelview = Matrix4.LookAt(Vector3.Zero, Vector3.UnitZ, Vector3.UnitY)
    GL.MatrixMode(MatrixMode.Modelview)
    GL.LoadMatrix(&modelview)
    x.render()
    base.SwapBuffers()

  abstract member setup : unit -> unit
  abstract member update : unit -> unit
  abstract member render : unit -> unit
  abstract member onResize : unit -> unit

type Game1() =
  inherit Game(640, 480, "Hello World")

  let colorCube() =
    for z in [ 0.0f; 1.0f ] do
      GL.Begin(BeginMode.Quads)
      for x, y in [ 0.0f, 0.0f
                    0.0f, 1.0f
                    1.0f, 1.0f
                    1.0f, 0.0f ] do
        GL.Color3(x, y, z)
        GL.Vertex3(x, y, z)
      GL.End()

    for y in [ 0.0f; 1.0f ] do
      GL.Begin(BeginMode.Quads)
      for x, z in [ 0.0f, 0.0f
                    0.0f, 1.0f
                    1.0f, 1.0f
                    1.0f, 0.0f ] do
        GL.Color3(x, y, z)
        GL.Vertex3(x, y, z)
      GL.End()

    for x in [ 0.0f; 1.0f ] do
      GL.Begin(BeginMode.Quads)
      for y, z in [ 0.0f, 0.0f
                    0.0f, 1.0f
                    1.0f, 1.0f
                    1.0f, 0.0f ] do
        GL.Color3(x, y, z)
        GL.Vertex3(x, y, z)
      GL.End()

  override x.setup() =
    GL.ClearColor(0.0f, 0.0f, 0.0f, 0.0f)

  override x.update() =
    ()

  override x.render() =
    let mx, my = x.Mouse.X, x.Mouse.Y
    GL.LineWidth(2.0f)
    GL.Translate(0.0f, 0.0f, 5.0f)
    GL.Rotate(float(mx) / 640.0 * 360.0, new Vector3d(0.0, 0.5, 0.0))
    GL.Rotate(float(my) / 480.0 * 360.0, new Vector3d(0.5, 0.0, 0.0))

    for x, y, z in [ 1.0f, 0.0f, 0.0f
                     0.0f, 1.0f, 0.0f
                     0.0f, 0.0f, 1.0f ] do
      GL.Begin(BeginMode.Lines)
      GL.Color3(x, y, z)
      GL.Vertex3(x, y, z)
      GL.Vertex3(x * 2.0f, y * 2.0f, z * 2.0f)
      GL.End()

    colorCube()

  override x.onResize() =
    GL.Viewport(base.ClientRectangle.X, base.ClientRectangle.Y, base.ClientRectangle.Width, base.ClientRectangle.Height)
    let mutable projection = Matrix4.CreatePerspectiveFieldOfView(float32 (Math.PI / 4.), float32 base.Width / float32 base.Height, 1.f, 64.f)
    GL.MatrixMode(MatrixMode.Projection)
    GL.LoadMatrix(&projection)

do
  (new Game1()).Run(30.)