It sounds like what's actually happening is that the stride of the vertex arrays isn't being taken correctly into account when chopping the large arrays into bite-sized chunks...
Keith
--- Begin Message ---Bugs item #677007, was opened at 2003-01-29 20:23 You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=100003&aid=677007&group_id=3Category: mesa-core Group: Rendering Error Status: Open Resolution: None Priority: 5 Submitted By: Nobody/Anonymous (nobody) Assigned to: Nobody/Anonymous (nobody) Summary: glDrawArrays with GL_LINES type Initial Comment: Seems like using glDrawArrays to draw GL_LINES is not working well. The endpoints get mixed up and the lines do not appear were they shoud be. Does the same thing in feedback mode. Just check the attached image. I've noticed this effect since version 3.4.2. Everything was fine in 3.4.1 and earlier. This effect can be seen on Linux ans SGI systems at least since I tested those two. ---------------------------------------------------------------------- Comment By: Heath Feather (heath30) Date: 2003-03-28 17:00 Message: Logged In: YES user_id=744523 I too have the same problem, going through the Mesa source code revealed that the vertices are dispatched in 256 vertex batches. So I changed my code to submit my vertices to gldrawarrays in groups of 256 or less. at this point the crazy lines disappeared, and all worked fine. Vertex arrays of less that 256 vertices work fine too. I then went and took a closer look at "t_array_api.c" _tnl_DrawArrays function. In this function a variable called "minimum" was being initialized to 1 for my "GL_LINES objects", the effect that this was having on the array was that instead of getting x,y...xy...etc. I get yx,yx etc...The first x is never seen, and allsubsequent vertices are now half of one and half of the other. Setting this variable to 0 , rebuilding mesa and running my application again fixed the problem. I took a slightly longer look at the code and think that there is a signifcantly less convoluted way of batching the vertices, "If that's what its trying to do". However I don't have the time to fix and test it adequately. Hope this helps in identifying the issue. P.S. The code in 4.1 and 5.0 appeared to be the same, and have the same problem. Heath. ---------------------------------------------------------------------- Comment By: Brian Paul (brianp) Date: 2003-02-08 15:46 Message: Logged In: YES user_id=983 Can you provide a simple test program? ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=100003&aid=677007&group_id=3 ------------------------------------------------------- This SF.net email is sponsored by: The Definitive IT and Networking Event. Be There! NetWorld+Interop Las Vegas 2003 -- Register today! http://ads.sourceforge.net/cgi-bin/redirect.pl?keyn0001en _______________________________________________ Mesa3d-dev mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/mesa3d-dev
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