Possible projection problem on Intel HD Graphics

Hi guys!

I’ve got a maze generator I’ve been working on. I’ve plotted a bunch of vertices on a grid, starting at 0,0,-1 and increase from there. I am using a formula to set the projection using glOrtho with a near of 1 and far of 1000 (per a tutorial I saw, I could probably clip the far quite a bit).

on all of my work computers that I’ve tried this on, things look just fine with the occasional perspective glitch because my formula for aspect ratio is in need of some work…probably worthy of another thread…but on this one laptop that’s using an intel HD Graphics card, I get some mazes drawn all scrambled…I’m wondering if any of you have seen this before and what I should do to fix it?

here’s some screenshots. http://imgur.com/a/KpANE

These were taken on the same computer…in my code I press space bar to generate a new maze, and the majority of them come out scrambled like that, but every now and then one comes out fine like the first one. This does not happen on any other computers that I’ve tried it on.

Thanks everyone!

No one’s ever seen anything like this? I’ll post my aspect ratio code tomorrow when I get to work.

That does not look like a problem with projection. To me it looks like vertex positions are good, but indexing goes wrong. Try to render the maze with point primitives instead of lines. What index type you are using?

I’m using GL_ELEMENT_ARRAY_BUFFER for the indices and passing it a vector array.

this thread has my buffer object code: http://www.opengl.org/discussion_boards/ubbthreads.php?ubb=showflat&Number=306770#Post306770