Question

我正在尝试使用这个GLWidget来开发使用OpenTK和GTK＃，这似乎是一件好事，但遗憾的是它旁边没有任何文档。我试图了解如何在该Widget中呈现任何内容。到目前为止，我创建了一个monodevelop解决方案，添加了对OpenTK和GLWidget的引用，现在我在Stetic的工具窗格中看到了GLWidget，我添加了一个带有两个插槽的Vbox，在上面一个我添加了一个菜单栏，而在下面一个着名的GLWidget。我还为OnRender事件和Initialized事件创建了一个事件处理程序，但我甚至无法绘制三角形。有没有人曾经使用过GLWidget，可以给我一些建议吗？这是我的MainWindow.cs代码：

   using System;
   using Gtk;
   using OpenTK;
   using OpenTK.Graphics;
   using OpenTK.Graphics.OpenGL;
   using OpenTK.Audio;
   using OpenTK.Audio.OpenAL;
   using OpenTK.Input;

   public partial class MainWindow : Gtk.Window{

    public MainWindow () : base(Gtk.WindowType.Toplevel)
    {
    Build ();
     }

   protected void GLWidgetInitialize (object sender, System.EventArgs e)
   {
    int width = 0, height = 0;
    //glwidget7.GdkWindow.GetSize(out width, out height);   
    this.vbox3.GetSizeRequest(out width, out height);
    GL.Viewport(0, 0, width, height);
    GL.ClearColor(1.0f, 1.0f,1.0f,1.0f);
    GL.Clear(ClearBufferMask.ColorBufferBit);
}

protected void OnDeleteEvent (object sender, DeleteEventArgs a)
{
    Application.Quit ();
    a.RetVal = true;
}


protected void OnRenderFrameWidget (object sender, System.EventArgs e)
{

    GL.ClearColor(1.0f, 1.0f,1.0f,1.0f);
    GL.Begin(BeginMode.Triangles);

        GL.Color3(1.0f, 1.0f, 0.0f); GL.Vertex3(-1.0f, -1.0f, 4.0f);
        GL.Color3(1.0f, 0.0f, 0.0f); GL.Vertex3(1.0f, -1.0f, 4.0f);
        GL.Color3(0.2f, 0.9f, 1.0f); GL.Vertex3(0.0f, 1.0f, 4.0f);

    GL.End();
}

}

顺便说一下，更改GLClearColor值会使我的GLWidget更改背景颜色。

Answer 1

好吧，我终于能够让它工作了，MainWindow代码应该是这样的：

  public partial class MainWindow : Gtk.Window
  {

public bool GLinit;

public MainWindow () : base(Gtk.WindowType.Toplevel)
{
    Build ();
    GLinit = false;
}

protected virtual void GLWidgetInitialize (object sender, System.EventArgs e)
{
    //this might be overkill to some people, but worked for me

    int width = 0, height = 0;  
    this.vbox3.GetSizeRequest(out width, out height);
    float aspectRatio = width/ height; 
    GL.Viewport(0, 0, width, height);
    GL.ClearColor(1.0f, 1.0f,1.0f,1.0f);
    GL.Clear(ClearBufferMask.ColorBufferBit);
    GL.MatrixMode(MatrixMode.Modelview);
    GL.LoadIdentity();
    GL.ShadeModel(ShadingModel.Smooth);         
    Matrix4 projection = Matrix4.CreatePerspectiveFieldOfView((float)Math.PI / 4, aspectRatio, 1.0f, 64.0f);
    GL.MatrixMode(MatrixMode.Projection);           
    GL.LoadMatrix(ref projection);          
    GL.ClearDepth(1);              
    GL.Disable(EnableCap.DepthTest);    
    GL.Enable(EnableCap.Texture2D); 
    GL.Enable(EnableCap.Blend);
    GL.DepthFunc(DepthFunction.Always);     
    GL.Hint(HintTarget.PerspectiveCorrectionHint, HintMode.Nicest); 
    //add idle event handler to process rendering whenever and as long as time is availble.
    GLinit = true;
    GLib.Idle.Add(new GLib.IdleHandler(OnIdleProcessMain));

}

protected void OnDeleteEvent (object sender, DeleteEventArgs a)
{
    Application.Quit ();
    a.RetVal = true;
}


protected void RenderFrame(){

    //Here's where you write your OpenGL code to draw whatever you want
            //Don't forget to swap your buffers

        OpenTK.Graphics.GraphicsContext.CurrentContext.SwapBuffers();

}

protected bool OnIdleProcessMain ()
{
    if (!GLinit) return false;
    else{
             RenderFrame();
         return true;
    }
}   
 }

有关详细信息，请参阅此处：http://www.opentk.com/node/2910

Answer 2

此页面应该为您提供缺失的部分http://www.opentk.com/doc/chapter/2/glcontrol - 请参阅SetupViewport方法（如下所示） - 执行类似的GL.Ortho操作以在您的设置中设置投影矩阵（也称为“相机”）。 p>

private void SetupViewport()
{
  int w = glControl1.Width;
  int h = glControl1.Height;
  GL.MatrixMode(MatrixMode.Projection);
  GL.LoadIdentity();
  GL.Ortho(0, w, 0, h, -1, 1); // Bottom-left corner pixel has coordinate (0, 0)
  GL.Viewport(0, 0, w, h); // Use all of the glControl painting area
}

如何在Monodevelop中使用OpenTK GLWidget进行渲染？

2 个答案: