/// <summary>
/// Binds the array buffer attached to.
/// </summary>
/// <param name='index'>
/// Index.
/// </param>
/// <exception cref='InvalidOperationException'>
/// Is thrown when an operation cannot be performed.
/// </exception>
public void Begin(GraphicsContext ctx, PrimitiveType primitive)
{
CheckThisExistence(ctx);
// Make this feedback buffer current
Bind(ctx);
// Begin transform feedback
switch (primitive)
{
case PrimitiveType.Points:
Gl.BeginTransformFeedback((int)PrimitiveType.Points);
break;
case PrimitiveType.Lines:
case PrimitiveType.LineStrip:
case PrimitiveType.LineLoop:
Gl.BeginTransformFeedback((int)PrimitiveType.Lines);
break;
case PrimitiveType.Triangles:
case PrimitiveType.TriangleStrip:
case PrimitiveType.TriangleFan:
Gl.BeginTransformFeedback((int)PrimitiveType.Triangles);
break;
default:
throw new InvalidOperationException();
}
// Disable rasterizer?
if (EnableRasterizer == false)
{
Gl.Enable(EnableCap.RasterizerDiscard);
}
// Start queries
_PrimitivesGenerated.Begin(ctx);
_PrimitivesWritten.Begin(ctx);
}