public void DrawIndexed(int startIndex, int indexCount, int baseVertex) { PreDraw(baseVertex); var effectiveOffset = indexOffset + startIndex * indexFormat.GetSize(); GL.DrawElements( (PrimitiveType)GLHelper.GetGLPrimitiveType(primitiveTopology), indexCount, (DrawElementsType)GLHelper.GetGLDrawElementsType(indexFormat), new IntPtr(effectiveOffset)); GLHelper.CheckGLErrors(); }