I just tried it again, but I didn' find a good solution yet. Calculating the 3D Locations of the Screens Pixels is fast, but it takes ages to determine the visibility of the light source from the point of view of these Locations.
Now if we could reverse the process and check for the visibility of the 3D locations, watched from the lights position, then we may be able to use something much faster:
I had the idea to position 640*480 Point Sprites and use a UNIQUE COLOR for each one of them. The Color will be produced by x (shl 12) or (y+10). Then we position a cubemap camera at the lights position and take 6 renders, just like a cubemap. Then we only have to readpixelfast all pixels. If they are not black, we can use their color to calculate the xy screen position of this location, this means if such a coloured point sprite is visible from the light location, it will not be inside the shadow.
Well, using this ICU Method with point sprites, with the help of the new Direct3D7 Extensions of Version 1.88 it may be possible.
I already tried it with ordinary sprites, but the polycount und number of surfaces was way too much for my system and it started to use harddrive swapspace and finally MAVed.
At least it would be true raytracing. I'd really like to test this, and I will test it as soon as someone offers a solution for point sprites.
Now if we could reverse the process and check for the visibility of the 3D locations, watched from the lights position, then we may be able to use something much faster:
I had the idea to position 640*480 Point Sprites and use a UNIQUE COLOR for each one of them. The Color will be produced by x (shl 12) or (y+10). Then we position a cubemap camera at the lights position and take 6 renders, just like a cubemap. Then we only have to readpixelfast all pixels. If they are not black, we can use their color to calculate the xy screen position of this location, this means if such a coloured point sprite is visible from the light location, it will not be inside the shadow.
Well, using this ICU Method with point sprites, with the help of the new Direct3D7 Extensions of Version 1.88 it may be possible.
I already tried it with ordinary sprites, but the polycount und number of surfaces was way too much for my system and it started to use harddrive swapspace and finally MAVed.
At least it would be true raytracing. I'd really like to test this, and I will test it as soon as someone offers a solution for point sprites.