How can I program graphics on a graphics card with XNA?
(How do I move the workload onto the graphics card)
How can I program graphics on a graphics card with XNA?
(How do I move the workload onto the graphics card)
Explained in a very simplified way:
All of the graphics are automatically drawn by the graphics card. There is no software rendererer mode in XNA.
The way XNA is set up most geometry is transferred to the graphics card Vertex Buffer Objects. A fixed pipeline approximization or shaders are then applied to the data by the graphics card and displayed on screen.
In short: If you want to do operations on your data while it's on the graphics card. Use vertex and pixel shaders.
EDIT:
You should also delve into the details of the graphics pipeline to understand better how graphic cards work.
http://www.riemers.net is a greate site for understanding XNA and graphics programming in general.
Have you tried doing some pixel shaders through DirectX? NVIDIA has programming guides. You may also want to check out GP GPU.