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Example slowing down... (OpenGL/lablgl)
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Date: | 2007-04-12 (07:20) |
From: | Jon Harrop <jon@f...> |
Subject: | Re: [Caml-list] Example slowing down... (OpenGL/lablgl) |
On Wednesday 11 April 2007 23:25, Oliver Bandel wrote: > http://en.wikipedia.org/wiki/OCaml > > ================================================================= > let _ = > ignore( Glut.init Sys.argv ); > Glut.initDisplayMode ~double_buffer:true (); > ignore (Glut.createWindow ~title:"OpenGL Demo"); > let render () = > GlClear.clear [ `color ]; > GlMat.rotate ~angle:(Sys.time() *. 0.01) ~z:1. (); > GlDraw.begins `triangles; > List.iter GlDraw.vertex2 [-1., -1.; 0., 1.; 1., -1.]; > GlDraw.ends (); > Glut.swapBuffers () in > Glut.displayFunc ~cb:render; > Glut.idleFunc ~cb:(Some Glut.postRedisplay); > Glut.mainLoop () > ================================================================= You'll notice the uncanny resemblance of that code to the code from OCaml for Scientists: http://www.ffconsultancy.com/products/ocaml_for_scientists/visualisation/ > Or is the OCaml-code in the above example > written in bad OpenGl-style? Yes. I should not have used Sys.time() in the Wikipedia example because it measures CPU time. Thus, as the program takes longer to run (e.g. in a larger window) the rate of spinning will be affected. So you cannot infer the graphics performance from the rate of spinning. Instead, you must add a time to count how many frames of animation are displayed each second. This may be the problem. However, I'd be surprised if that makes a visible difference because your machine should be easily capable of spinning a triangle using only software rendering. -- Dr Jon D Harrop, Flying Frog Consultancy Ltd. OCaml for Scientists http://www.ffconsultancy.com/products/ocaml_for_scientists