There is a note about that on the TSM project page (http://www.comp.nus.edu.sg/~tants/tsm.html).

Regarding TSM: For certain positions of the light, the 2d view of the trapezoid becomes almost a rectangle. How do you handle those cases? I didn't find anything in the paper for that case. If I try...

I made quite good experiences with Trapezoidal Shadow Maps (http://www.comp.nus.edu.sg/~tants/tsm.html)

As mentioned above, TSM needs only ARB_f_p because it addresses the polygon offset problem. If you want to address the polygon offset problem in other shadow map approaches as well, then I guess you...

"...I haven't implemented the TSM approach yet, but one thing I don't like about it is that I must use a pixel shader for texture coordinate computation (and thus write my own PCF filter) because it...

Ok, I think I got it. Thanks a lot for your help!

Thanks for your reply!

Ok, I know, there is no problem in front of the near plane, but only behind. But how is Opengl doing that? Does then Opengl clip against the near plane in world space?...

Hi,

I have a question concerning clipping in Opengl. By specifying a perspective projection matrix and a camera matrix, there should be the problem of vertices which are in the world space behind...

Is it possible to change the fragment's z-value in a fragment program? If possible, how can it be achieved?

Thanks!!!

It helps, thanks a lot!!!

Sure :) ...I forgot. Shadow Mapping with Today’s OpenGL Hardware ...starting at slide 32.

But it is done in that shadowmap presentation. The texture coordinate is divided by w and then interpolated over the polygon. I don't understand this division, since in the pixel stage we get rid of...

I badly try to understand perspective correct texturing and projective texturing which is used for shadow maps.

Ok, so far as I know...:

on the vertex stage:
calculate s/w, t/w, r/w, q/w (w is...

Cool but how long would that take? - Days, weeks, months, ....? :-)

Yes I have the same understanding in that. I get such a frame rate drop even I am rendering only one sample in to the accumulation buffer.

Hey Guys!!!

I'm just checking out the accumlation buffer with a 5900 FX ultra..it is sooo slow!!! As far as I thought is that floating point buffers on FX are hardware support. Could it be a...

ok, please disregard this thread.

I was impatient :-)

The shadowmap comparison and everything works perfectly, but how can I implement the standard "GL_LINEAR" feature in the fragment program? - Through multiple texture lookups? An then how? Either I'm...

Thanks for the reply guys. I'm gonna check it out.

Hi,

I need to have additional clipping planes in my application. I do certain vertex transformations in a vertex program (ARB). I read in the spec that user defined clip planes can be found in...

Actually its been solved. But it was not because the snippet above was wrong.

Assume the eye frustum is located on a plane, so that the near plane of that frustum gets intersected by the plane and...

No, the perspective division is performed. But now I know the reason: If the near plane of the eye's frustum is not cut by anything from a scene, for example the eye only looks down to a plane, the...

After perfoming the projection matrix, those vertices which where before in the eye's frustum are now in the unit cube. The vertices near the back plane are very near to the unit cube back side, the...

Thanks, it's been solved. It was a driver or better a wrong header problem. Now it's working. :-)

I'm checking out VBO with my FX and Linux. My app crashes when I call glGenBuffersARB. What I am doing wrong?

I found a previous msg on that issue. Either its a driver/card bug (NVIDIA wanted to...