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Type: Posts; User: ugluk

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by ugluk
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They used to be hosted on Randi Rost's site, but it is apparently down. Does anyone know where to pull them from now?
2. ## Thread: perspective GUI frustum

by ugluk
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0
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1,466

### perspective GUI frustum

I was thinking about constructing the following perspective frustum:

l = - w / 2
r = w / 2
t = h / 2
b = - h / 2

n = w / (2 * tan(HFOV / 2)), f at infinity

with HFOV = 90 degrees, n = w /...

by ugluk
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5
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2,930

But (GLSL) shaders had their precursors too, if you can call them precursors. Maybe one of those early shading languages influenced the paper.

by ugluk
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5
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2,930

### Too bad I haven't thought of this myself....

Too bad I haven't thought of this myself. Certainly, it's thanks to the shaders, we have this scalar part = w convention. I've written an expression template library (as TVMET is slowly starting to...

by ugluk
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5
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2,930

### quaternion indices

If you check math books, the scalar part of a quaternion is usually at index 0 of a quaternion list, but in some code I've looked up, the scalar part is at index 3. Do there exist any practical...
6. ## Thread: GL viewports & displays

by ugluk
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1
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980

### GL viewports & displays

Does GL offer any way to choose on which display a viewport is to be shown, or is this functionality OS dependent? Here, I mean some game consoles, which offer multiple displays and also the usual...

by ugluk
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31
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11,491

For some reason many people are unwilling to make the investment of time to learn this. To them this is a command-line thing and they prefer using python or some other scripting language - a pity,...

by ugluk
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31
Views
11,491

Yeah, and there's a nifty library called >>tvmet<< for your vector needs :).

You can also convert to .png, if you don't want to lose quality of your images.

by ugluk
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31
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11,491

Try this:
- when including the library...

by ugluk
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31
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11,491

Since she does not know how to compile&amp;link, a simple library like stb_image might do the trick.

And certainly "uploading" an "image" using DevIL means she's pretty new to GL.

by ugluk
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31
Views
11,491

It is a wrapper around libpng, libjpeg, ... and you need to compile&amp;link those.
12. ## Thread: GL + timer queue

by ugluk
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1
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846

### Re: GL + timer queue

Yeah, I think after issueCommands() would be a good place.

Rationale:
Timer callbacks can alter textures, VBOs ... and might stall the pipeline, if they were called before issueCommands().
13. ## Thread: Placing many different 2D elements in a window

by ugluk
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4
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1,250

### Re: Placing many different 2D elements in a window

glViewport() works for fixed-pipeline GLs all the way to 4.2 and if that is an issue it might be a better solution. I don't think you will notice much of a speed difference between the two methods,...

by ugluk
Replies
31
Views
11,491

From my memory DevIL is just a wrapper library. Check http://nothings.org/stb_image.c if you want to rid yourself of linker errors.
15. ## Thread: GL + timer queue

by ugluk
Replies
1
Views
846

### GL + timer queue

If my rendering loop looks like this:

{
issueCommands();
swapBuffers();
}
Where is the best place to process a timer queue (processTimerQueue()), before swapping or after? I am pretty...
16. ## Thread: Known minimal OBB database

by ugluk
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5
Views
2,169

### Re: Known minimal OBB database

The book Real-Time Collision Detection and site provides a good survey of global algorithms.

The books itself starts with a guess and then proceeds with an empirical optimization algorithm (prone...
17. ## Thread: modelview matrix pairing

by ugluk
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6
Views
1,934

### Re: modelview matrix pairing

I decompose the modelview and the viewing matrices into a product of matrices M (some arbitrary matrix) and T, a translation matrix.

The rationale then is, matrix upload is a greater evil than...
18. ## Thread: modelview matrix pairing

by ugluk
Replies
6
Views
1,934

### Re: modelview matrix pairing

viewing_matrix = M' * T(-view_origin)
model_matrix = T(model_origin) * M''

you get:
19. ## Thread: modelview matrix pairing

by ugluk
Replies
6
Views
1,934

### modelview matrix pairing

Why is the model matrix often "paired" with the viewing matrix in tutorials and examples, such as?

gl_Position = proj_matrix * (mv_matrix * in_vertex);

Would there be something wrong, if I...
20. ## Thread: streaming VBO and VAO

by ugluk
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9
Views
6,238

### Re: streaming VBO and VAO

It is about this in addition to holding static data. In a way the VBO is a caching store. Dark Photon's refinement of an earlier Rob Barris' idea.

I guess an example is in order:

template...
21. ## Thread: streaming VBO and VAO

by ugluk
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9
Views
6,238

### Re: streaming VBO and VAO

_blitz: yes, I mean the "mutable VAO".

It seems to me both of you are using your streaming VBO(s) for "true" streaming, i.e. content generated/changed on the CPU and then uploaded to the GPU every...
22. ## Thread: streaming VBO and VAO

by ugluk
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9
Views
6,238

### Re: streaming VBO and VAO

Do you have any bench results comparing the VAO approach with the non-VAO (manual state-setting) approach? I didn't see any bench results when googling, only assertions that using VAOs "should"...
23. ## Thread: Linux PC for OpenGL Development

by ugluk
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3
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3,379

### Re: Linux PC for OpenGL Development

Linux systems are particularly good when money _is_ a consideration. For example, you can more easily setup software rendering on Linux, with shader support (GLSL 1.2), than on Windows.

So, you...
24. ## Thread: streaming VBO and VAO

by ugluk
Replies
9
Views
6,238

### streaming VBO and VAO

Say there are 2 or more VAO, always referring to the same VBO and one binds from one of the VAOs to some other of the VAOs. Is the performance hit less than binding a different VBO (that is, does one...
25. ## Thread: openGL/Facial Expression Recognition

by ugluk
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3
Views
1,811

### Re: openGL/Facial Expression Recognition

By "template" she means a meta-model, to which you would assign some parameter values and voila a new face would jump from the meta-model.

Anette, this is a research-topic and AFAIK, yes, such...
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