Polygon Bugs

OpenGL OpenGL: Basic Coding
1

My OGL scene is bugged, I am rendering a box, but the rear and side polygons are overriding the front polygon.

Any ideas what can cause this?

2

Can I see the source code ?

3

Are you sending the vertices to OpenGL in counter-clock-wise order? This may be a problem.

4

Try enableling depth test

glEnable(DEPTH_TEST);

Osku

5

Sounds like a depth test problem. If you’re using glut and linux, also make sure to use GLUT_DEPTH when you call glutInit(). I got burned with that awhile back when I had depth test enabled, but the depth test didn’t seem to work right.

6

I do enable depth testing, but I am not sure about the vertexes being loaded coounter-clockwise.

I copied the vertex code straight from nehe tutorial on texture mapping.

One thing though, I adopted NeHe texture mapping tutorial using QT OpenGL Module. Anyone have experiene using this module, any known problems that might cause these issues.

So far I have only tested it on Windows, it might work without issue on linux. Sigh.

Anyone all input is welcome.

Thanks.

Shep

7

Hmmm… just in case you haven’t, make sure to clear the depth buffer each time you render:

glClear(GL_DEPTH_BUFFER);

8

… and don’t forget glDepthFunc(GL_LESS);