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From: Christopher B. <Chr...@no...> - 2009-09-29 20:03:46
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Gökhan Sever wrote: > This is technically called OpenGL backend, isn't it? well, I think it's different -- he's not really using the standard backend API. The trick with doing a real OpenGL back-end, is that a lot of computation time is spend doing transforms, and that can't be fully pushed to the back-end, because MPL provided arbitrary transforms. There is also a fair bi tof time spent pushing data to the back-end. I think to really get the benefit of OpenGL, you'd need the back-end to be semi-perstent -- you'd pass data in, and teh back-end would render it without having to pass the data in again. This would only support transforms that the back-end supports (linear only?). However, I think there could still be areal performance benefit bey breaking the transform pipeline into two parts -- one from arbitrary coordinates to something orthogonal and linear, and then a final one from that to screen coordinates (zooming and panning). Then you'd at least get full hardware accelerated performance for zooming and panning We're doing this for a high-performance interactive mapping app, and it's working pretty well. However, OpenGL is pretty darn low-level, so there's a lot of code to write! -Chris -- Christopher Barker, Ph.D. Oceanographer Emergency Response Division NOAA/NOS/OR&R (206) 526-6959 voice 7600 Sand Point Way NE (206) 526-6329 fax Seattle, WA 98115 (206) 526-6317 main reception Chr...@no... |