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View Full Version : Applying a weighting to pixel values using projection texture mapping



jmt
03-30-2001, 08:58 AM
Hi,
Thank you for your help thus far.

I was wondering if there was a way to apply a weighting (using depth cueing/fog??) to a texture when it is projected.

The geometry is best described as the following. Image a projector projecting an image rotated 90 degrees from the direction of the eye (viewing direction). Within the field of the projection there is a quad that is perpendicular to the projection and parrallel to the eye direction. So basically the shape of the projected texture on the quad will look something like this.

| \
| \
| \
| \
| |
| /
| /
| /
| /

What I would like to do is dither the pixels such that, the small end of the shape above has the brightest intensity since it would be closest to the projector and use a linear interpolation weighting toward the long end which would be darker since it is further away from the projector.
The ultimate picture that should be render is a quad with the texture smeared into the above geometry with the correct intensity weighting applied across the shape.
I have read that this can be done by using fog?? but I can't seem to get it to work. Any help would be deeply appreciated.

Thanks

jmt
03-30-2001, 09:00 AM
Hmm...I guess when I posted my spacing got stripped out of my poor Ascii rendering of the geometry. It should look like a trapezoid.