Mesa 3D slower than GDI+

Question

I am running a 3d realtime application (C++) on Virtual Machine (VMWare WinXP SP2). I have 3d acceleration always disabled in VMWare. I have tested it running with both the normal windows GDI OpenGL 1.1 and Mesa 3D (7.8.2). When running on Mesa I have full OpenGL functionality (VertexBufferObjects etc.) but it is much slower than the GDI implementation. I know Mesa is a software rastizer but I guess so is the GDI implementation. So why is Mesa slower? Or should Mesa be faster and its actually a problem in my application?

Answer 1

Mesa supports a fully programmable pipeline and hence the software rasterizer, which at some points uses Just-In-Time compilation and hence is not as aggressively optimized as the Win32 GDI one. This is a tradeoff between features and performance.