root/cobra/trunk/HowTo/710-OpenTK.cobra

# .skip.
# .compile-only.
"""
How To User OpenTK

OpenTK provides type-safe, well organized wrappers around OpenGL, OpenCL and OpenAL.

http://www.opentk.com/


If you're on Mono, and you want to build OpenTK from source, try:

svn co https://opentk.svn.sourceforge.net/svnroot/opentk/trunk opentk
cd opentk/
xbuild

Then look in Binaries/ subdirectory for the OpenTK binary libraries.

Tested on Mac OS X 10.6 with Mono 2.6.7 and OpenTK subversion revisions 2755 and 2780.

"""

@ref 'System.Drawing'
@ref 'OpenTK'
@number float64

use OpenTK
use OpenTK.Graphics
use OpenTK.Graphics.OpenGL
use OpenTK.Audio
use OpenTK.Audio.OpenAL
use OpenTK.Input


class ThisGameWindow inherits GameWindow

    var _rotation = 0.0
    var _rotationSpeed = 20.0

    cue init
        """ Creates a 800x600 window with the specified title. """
        base.init(800, 600, GraphicsMode.default, 'OpenTK Quick Start Sample')
        # .windowState = WindowState.Fullscreen   # to run in fullscreen
        .vSync = if(.windowState == WindowState.Fullscreen, VSyncMode.On, VSyncMode.Off)

    def onLoad(e as EventArgs?) is protected, override
        """ Load resources here. """
        base.onLoad(e)
        GL.clearColor(0.1f32, 0.2f32, 0.5f32, 0.0f32)
        GL.enable(EnableCap.DepthTest)
        .printDisplayDevices

    def printDisplayDevices
        for device in DisplayDevice.availableDisplays
            print
            print 'DisplayDevice'
            trace device
            trace device.isPrimary
            trace device.bounds
            trace device.refreshRate
            trace device.bitsPerPixel
            # for res in device.availableResolutions, trace res
        print

    def onResize(e as EventArgs?) is protected
        """
        Called when your window is resized. Set your viewport here. It is also
        a good place to set up your projection matrix (which probably changes
        along when the aspect ratio of your window).
        """
        base.onResize(e)
        cr = .clientRectangle
        GL.viewport(cr.x, cr.y, cr.width, cr.height)
        projection = Matrix4d.createPerspectiveFieldOfView(
            Math.pi / 4, .width / (.height to number), 1.0, 64.0)
        GL.matrixMode(MatrixMode.Projection)
        GL.loadMatrix(inout projection)

    def onUpdateFrame(e as FrameEventArgs?) is protected
        """ Called when it is time to setup the next frame. Add you game logic here. """
        base.onUpdateFrame(e)
        if .keyboard[Key.Escape], .exit

    def onRenderFrame(e as FrameEventArgs?) is protected
        """ Called when it is time to render the next frame. Add your rendering code here. """
        base.onRenderFrame(e)

        GL.clear(ClearBufferMask.ColorBufferBit | ClearBufferMask.DepthBufferBit)

        modelview = Matrix4.lookAt(Vector3.zero, Vector3.unitZ, Vector3.unitY)
        GL.matrixMode(MatrixMode.Modelview)
        GL.loadMatrix(inout modelview)

        dt = e.time
        _rotation += _rotationSpeed * dt
        # trace _rotation, dt
        GL.rotate(_rotation, 0, 0, 1)
        
        GL.begin(BeginMode.Triangles)

        GL.color3(1.0, 1.0, 0.0)
        GL.vertex3(-1.0, -1.0, 4.0)
        
        GL.color3(1.0, 0.0, 0.0)
        GL.vertex3(1.0, -1.0, 4.0)
        
        GL.color3(0.2, 0.9, 1.0)
        GL.vertex3(0.0, 1.0, 4.0)

        GL.end

        .swapBuffers

    def main is shared has STAThread
        # The 'using' idiom guarantees proper resource cleanup.
        # We request 30 UpdateFrame events per second, and unlimited
        # RenderFrame events (as fast as the computer can handle).
        using game = ThisGameWindow()
            game.run(30.0)