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[Gagege]

Here's a video of my game:




I'm have a problem with it though. Sometimes my GL_POLYGON will "skip" a vertex and just draw a straight line between the previous and next vertex. At the very beginning of the video if you look near the lowest vertex of the blue polygon you can see how the color blue is spilling outside of the polygon's outline. It usually happens when the vertex is "inside" the polygon. Where it should be a concave part of the polygon it just flattens it out, but only sometimes.
 
Question:
Has anyone else has had problems with openGL "skipping" vertices? If so, do you know what's causing it or how I can fix it?

[mcc]

GL_POLYGON only supports convex polygons. Period.

[muku]

I think GL_POLYGON supports only convex polygons.

EDIT: Haha that was close

[Polly]

Solution : Triangulate concave polygons.

[Gagege]

Then how am I able to have a concave part elsewhere in my polygon?

Am I wrong to think that the blue polygon (in the video) is somewhat concave on the bottom?

[muku]

Then how am I able to have a concave part elsewhere in my polygon?

The spec doesn't guarantee that GL_POLYGON will fail with concave polygons, it just doesn't guarantee that it will work

GLU seems to have a tesselator, check this out: http://www.flipcode.com/archives/Polygon_Tessellation_In_OpenGL.shtml

[Gagege]

Got it. Thank you guys.
I guess i'll just have to look for another solution.
Thanks for the tip muku.