Well, I tried to help Pierre, but he has suddenly disappeared... May be, has been frightened of my french? :)
And yes, I liked that panda... Didn't you like it? ;)

Pourriez vous me dire, quelles choses sont meme differentes (sauf VBO). Parce que votre code est regardee tout a fait raison. Peut etre, quelque autre shader quand VBO est active, ou autre chose.
Et...

Thanks, Aleksander! Very actual info, and as Dark Photon has mentioned, it is real experience, and thank you for sharing it here.

P.S. Sorry, other guys, but there is no points for argues or...

First of all, you have wrong comprehension of how perspective works. Actually, it's nothing more then matrix multiplication and homogenous division. So the best you can do (and what you have to do...

Actually, as far as I get projection matrix, it's impossible to create such a projection matrix, which would make parallel projection alons one axis and perspective along other.
Imagine simple...

And what about that integer in float form may cause some FP exceptions? I've heard somewhere, that if we are loading integers, we SHOULD call integer function, not float one. I mean, loading just as...

Actually, viewport transformation has nothing common with projection. They are 2 different transformations. MVP, then homogenous division, then viewport transformation. So don't mess them up! :)

Here are our versions of that algorithm (quite fast for me, but can be done much faster).
http://slil.ru/27912469

MarkS,
that link sould help you more: http://www.opengl.org/discussion_boards/ubbthreads.php?ubb=showflat&Number=235320

The code you should use is something like this:

textureGrad2DArray(tex, vec3(fract(TexCoord.xy), TexCoord.z), dFdx(TexCoord.xy), dFdy(TexCoord.xy))

It works with GL_REPEAT not because of GL_REPEAT, but because you removed fractioning from your shader code, and derivatives are constant across whole triangle.

Jan is right, that is because of derivative constructions and mip-mapping. I can't say nothing on special handling for 1 and zero, but when you call "fract", you always have two neighbor fragments...

Thanks, wSpace, very interesting reading!

It is all up to floating point representation. When your points are within [256..512) range, you have constant step of 256/2^23 between them. It equals to 0.000030517578125. Which is greater then...

Just a question.
Does making buffer resident mean it's now sort of GPU-located? I mean, doesn't it result, that we can't exceed VRAM with resident VBOs?
And second reason why I'm asking that - is...

Look, camrades, it was a friday night, Mark was surely exhausted after a hard week... So he took some bottles of beer or smth else and left such an affective post. He's not a robot in any, he has his...

I think, somebody in their drivers developer group is not very orderly person. They implemented VS+GS+FS, but didn't want to be in a stew with fixed pipeline functionality support, and that's all....

Actually, I was speaking only about 256*256 viewport, and that's only 64K points. May be, for larger resolutions it won't be the case, as I've mentioned. But right now it doesn't matter, because...

Well, Madoc, that's not LOL with points )) 2 years ago that was the only way to make some very specific task run quite fast. Yeah, it's not elegant at all, but depth-replace was more costly.

Interesting.
What's the overdraw ratio for your typical scenes? If you have high overdraw, your approach must have been slower, then blitting depth somehow. But I wouldn't count on it and I totally...

Hello.
Yes, if you're working in 3D, so you have to make your segment normals also lying in plane, planar to projection plane. Doing it so makes your quads to be correctly projected.
If you have...

Approach is rather simple.
Imagine, you have only 1 line segment (for simplicity). You want to draw it with quad in 2 pixels (independent from zooming).
You make quad, where first 2 vertices hold...

You're welcome!
I'm also often messing up with these formats/internal formats, especially for FP targets :)

Mine suggested method creates quadstrip from linestrip. So how could there be any gaps, if it is stripped quad?
I construct it such a way, that first 2 vertices for each next quad are the last 2...

Well, first of all - sometimes it's too hard to get correct results, because you can have a stitch of radius, say, 1, but your widening offset is for example 2, and you have no way to achieve ideal...