Hi, "Stephen J Baker" <sjbaker@xxxxxxxx> writes: > It might be interesting to consider doing some of the work of compositing > in the graphics card - where the hardware supports it. > > The latest generations of nVidia and ATI cards have support for full > floating point pixel operations and floating point frame buffers. If > you stored each layer as a texture and wrote a 'fragment shader' to > implement the GIMP's layer combiners, you'd have something that would > be *FAR* faster than anything you could do in the CPU. apart from the point that we don't have the resources to implement graphics-card dependant GIMP backends this approach would only help to speed up the display pipeline. This is because reading from a gfxcard framebuffer is incredibly slow. If you need access to the results of the gfx operations, you better perform them on the CPU. Only if the result is only to be displayed it makes sense to use the gfx card. This is at least true for typical consumer hardware. > Of course only people with sexy new graphics cards would reap the > benefits - but I presume that people who care enough to want high > precision pixels are probably professionals to whom a $500 graphics > card wouldn't be an obstacle if it helped their work. well, if you could come up with the detailed specs of these sexy new graphics cards we could certainly consider to use these features. However judging from my experience as a DirectFB developer I'd say there's not much chance that the hardware vendors will give away these details unless you sign a pile of ugly contracts that effectively forbid to use the knowledge in an open source project. Salut, Sven
