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c#openglopengl-esxamarin.iosvertex-buffer

MonoTouch / OpenGL ES: Exception when drawing with GL.DrawElements


i try to draw a mesh with Ope When calling GL.DrawElements i got the following exception.

Stacktrace:

at (wrapper managed-to-native) OpenTK.Graphics.ES20.GL/Core.DrawElements(OpenTK.Graphics.ES20.All,int,OpenTK.Graphics.ES20.All,intptr) <IL 0x00026, 0xffffffff>
at OpenTK.Graphics.ES20.GL.DrawElements (OpenTK.Graphics.ES20.All,int,OpenTK.Graphics.ES20.All,intptr) [0x00000] in /Developer/MonoTouch/Source/monotouch/src/OpenGLES/OpenTK/Graphics/ES20.iPhone/GL.cs:1659
at App.PipedreamWrapper.Resource.Model.VertexBuffer.Render () [0x00067] in /Users/felixk/Projects/Windkraft/App/PipedreamWrapper/Resource/Model/VertexBuffer.cs:74

Thats the drawing code:

// Bind buffers
GL.BindBuffer(All.ArrayBufferBinding, _ElementsBuffer);
GL.BindBuffer(All.ElementArrayBufferBinding, _IndexBuffer);

for (int i = 0; i < _Data.Length; i++)
{
    VertexData data = _Data[i];
    // Using fixed size here, just using 3 floats for the drawing
    GL.VertexAttribPointer(i, data.Size, data.Type, data.Normalized, 12, new IntPtr(0));
    GL.EnableVertexAttribArray(i);
}

// Draw elements
GL.DrawElements(All.Triangles, _Triangles, All.UnsignedShort, IntPtr.Zero);

// Unbind buffers
GL.BindBuffer(All.ArrayBufferBinding, 0);
GL.BindBuffer(All.ElementArrayBufferBinding, 0);

And here is the code for the initialization:

public VertexBuffer(UInt16[] indices, Byte[] data, params VertexData[] vertexData)
{
    _Data = vertexData;
    _Triangles = indicies.Length / 3;

    // Generate buffer id's
    Int32[] buffers = new Int32[2];
    GL.GenBuffers(2, buffers);
    _IndexBuffer = buffers[0];
    _ElementsBuffer = buffers[1];



    unsafe
    {
       // Bind indices buffer
       GL.BindBuffer(All.ElementArrayBufferBinding, _IndexBuffer);

       // Buffer indices
       fixed (UInt16* f = indices)
       {
           GL.BufferData(All.ElementArrayBuffer,
                         new IntPtr(2 * indices.Length),
                         new IntPtr((void*)f),
                         All.StaticDraw);

       }

       // Bind data buffer
       GL.BindBuffer(All.ArrayBufferBinding, _ElementsBuffer);

       // Buffer vertex data
       fixed (Byte* f = data) {
           GL.BufferData(All.ArrayBuffer,
                         new IntPtr(data.Length),
                         new IntPtr((void*)f),
                         All.StaticDraw);
       }
   }


   // Unbind buffers
   GL.BindBuffer(All.ArrayBufferBinding, 0);
   GL.BindBuffer(All.ElementArrayBufferBinding, 0);
}

Edit: Formatting issue...and stack overflow do not want me to commit something.


Solution

  • It turns out that "ElementArrayBufferBinding" is not used to bind something. Instead i have to use "ElementArrayBuffer".