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Type: Posts; User: chennes

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1. ## Thread: Anti-aliasing sample distribution

by chennes
Replies
1
Views
114

### Anti-aliasing sample distribution

I was hoping to find a table of values similar to the one in the red book for antialiasing jitter values, except one that used a more random distribution fo points. I think that a gaussian...
2. ## Thread: Duplication of Complex Models

by chennes
Replies
7
Views
234

### Re: Duplication of Complex Models

Now that I think of it, the limit is probably more along the lines of a memory limit than a constant number (though maybe sizeof(int) or something like that).
3. ## Thread: Duplication of Complex Models

by chennes
Replies
7
Views
234

### Re: Duplication of Complex Models

There is a maximum number of display lists, which I am sure there is a function to query (it's implementation dependant, I believe), but you'll probably never hit it. Besides, from your original...
4. ## Thread: Can i have an explanation of glRotatef()?

by chennes
Replies
3
Views
469

### Re: Can i have an explanation of glRotatef()?

I think the confusion is a misunderstanding of the last three parameters to the function:

In this function, (x,y,z) is defining a vector to rotate about. So what (0,1,1) is saying is rotate...
5. ## Thread: Lighting/Normals help

by chennes
Replies
0
Views
96

### Lighting/Normals help

First, the problem: I calculate and normalize a set of normals for an object, then draw the object with these normals. Works great. However, as I zoom in on the body it becomes "washed out", i.e....
6. ## Thread: The proper way to average and render with normals

by chennes
Replies
3
Views
236

### Re: The proper way to average and render with normals

In addition to what cragwolf said, I also check the angle between the normals before blindly averaging them - if it above a certain threshold (I use 45 degrees) I don't average those normals. This...
7. ## Thread: Looking for the lighting culprit

by chennes
Replies
13
Views
731

### Re: Looking for the lighting culprit

I don't think the direction of the light is the problem (although at this point I'm not ruling anything out!). If the light direction changed I would expect to be able to see that as I zoom in....
8. ## Thread: Need for API functional source code

by chennes
Replies
3
Views
175

### Re: Need for API functional source code

DonDan-

There is an opensource library that implements the OpenGL API - it is called Mesa, and can be found at http://www.mesa3d.org . Alternately, if you are running Linux, it is probably...
9. ## Thread: Converting LOCAL coordinates to WORLD coordinates - How do I do it?

by chennes
Replies
4
Views
890

### Re: Converting LOCAL coordinates to WORLD coordinates - How do I do it?

I'm confused by your question, I think. You want to display list your drawing - that is the end goal, right? If that is what you wnat, then the coordinate conversion is unneccessary. Put you...
10. ## Thread: glortho ?!

by chennes
Replies
1
Views
92

### Re: glortho ?!

You are calling glOrtho to set up your view, and are immediately destroying it with your call to glLoadIdentity - reverse the order of your calls and see what you get.

Chris
11. ## Thread: Looking for the lighting culprit

by chennes
Replies
13
Views
731

### Re: Looking for the lighting culprit

My scaling is uniform.

Thanks,
Chris
12. ## Thread: Store 3D image bitmap after rendering

by chennes
Replies
2
Views
133

### Re: Store 3D image bitmap after rendering

the OpenGL.org FAQ page is a good place to look for info like this. For your particular problem, try:
]http://www.opengl.org/developers/faqs/technical/miscellaneous.htm#misc0050

[This message...
13. ## Thread: Looking for the lighting culprit

by chennes
Replies
13
Views
731

### Re: Looking for the lighting culprit

I can e-mail a set of images to anyone who wants to see - click on the e-mail symbol above to get my address and drop me a line.

Chris
14. ## Thread: Looking for the lighting culprit

by chennes
Replies
13
Views
731

### Re: Looking for the lighting culprit

Directional (infinite viewer type). Pixel shaders aren't really an option - I have to support pretty old hardware. I'm not clear on how GL's per vertex lighting combined with my ortho projection is...
15. ## Thread: Looking for the lighting culprit

by chennes
Replies
13
Views
731

### Re: Looking for the lighting culprit

No- it's an orthographic projection - I'm using glScale().

Chris
16. ## Thread: Looking for the lighting culprit

by chennes
Replies
13
Views
731

### Re: Looking for the lighting culprit

Nope - modelview for all the transforms.

Chris
17. ## Thread: Rendering to pixmap fails

by chennes
Replies
9
Views
524

### Re: Rendering to pixmap fails

Oh, and another thing- as I was re-reading this thread, I noticed someone mentioned backbuffers for offscreen rendering. Don't do this. The back buffer is not really an offscreen context. It can be...
18. ## Thread: Rendering to pixmap fails

by chennes
Replies
9
Views
524

### Re: Rendering to pixmap fails

I had exactly the same problem - it turned out to be a bit-depth issue. The pixmap that the X server was giving me was a 32-bit pixmap, and the visual that glXGetVisual was selecting had a different...
19. ## Thread: Looking for the lighting culprit

by chennes
Replies
13
Views
731

### Looking for the lighting culprit

I have a scene in which I have a polygonal model. It is lit with a single directional light source which moves with the viewpoint. I have GL_NORMALIZE enabled (it's GL 1.1). For...
20. ## Thread: Problem which Color in 3d object

by chennes
Replies
3
Views
543

### Re: Problem which Color in 3d object

As mikael_aronsson pointed out, it's important to knwo whther or not you are using lighting. I'll answer as assuming that you are...

You should probably use glEnable (GL_COLOR_MATERIAL) - that way...
21. ## Thread: Offscreen rendering into a Pixmap

by chennes
Replies
3
Views
246

### Re: Offscreen rendering into a Pixmap

Zico-

Thanks for the response - which feature are you referring to? I figured out how to share the lists across those types (I'm not making any calls directly to glx - that's why I couldn't figure...
22. ## Thread: Offscreen rendering into a Pixmap

by chennes
Replies
3
Views
246

### Offscreen rendering into a Pixmap

I need to do some offscreen rendering into a pixmap - I need this pixmap's rendering context to share display lists with my onscreen rendering contexts.

I am using gtkglarea-- for my onscreen and...
23. ## Thread: Lighting

by chennes
Replies
1
Views
100

### Lighting

I'm having some probelsm getting my lights to behave the way I want then to.

I want to use a directional light source, shining directly away from the viewpoint at the scene. What location do I...
24. ## Thread: Blending issues.

by chennes
Replies
3
Views
185

### Re: Blending issues.

Binary Space Partitioning (Tree). It's a data structure used to do front-to-back drawing. Try Graphics Gems V pp.121, or search this forum - there are about a trillion references to it.

Chris
25. ## Thread: Blending issues.

by chennes
Replies
3
Views
185

### Blending issues.

I have a complex (and non-static) scene - there are typically many objects, some of which are varying levels of transparancy, some of which are opaque. I'm having problems with my blending.

I...
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