Hi , I must say I was really impressed with performances of DirectFB when compiling Qtopia 4.6.2 and using DirectFB as Gfx driver.... I tested this release on our platform containing an SH4 processor and 2d blitter using underlying hardware acclerated graphics functions in Directfb. The performace gain for a sample QT application, "forever" (which blits random rectangles on screen ASAP) was 10 times (302 rects/per sec) vis-vis simple stock software QWS sans DirectFb (30 rects per sec). And even if I switch off all accleration from DirectFB (DFBARGS=no-hardware), I managed to get 3 times better performnace (90 rects per sec). I would like to understand from DirectFB experts via these queries. My queries: 1. How would you explain this difference in performance, i.e. stock QWS vis-a-vis QT over DirectFB (unaccelerated) 2. For a UMA system with system memory acting as framebuffer, what are benefits when choosing DSCAPS_VIDEO while creating a surface. Is this surface present on the framebuffer or elsewhere? 3. While blitting an updated rectangle, is there an implicit back buffer in DirectFB where this rectangle is first copied before the entire surface is blitted to the framebuffer. 4. I did not use the fusion kernel module from DirectFB for running this QT app. In which use case is it useful and what is its purpose? Thanks so much!! I would really appreciate any explanation/advice.
Regards, M.
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