Chris Huff <chr### [at] maccom> wrote:

> In article <3A9### [at] darwincwruedu>, spo### [at] corecom wrote:

>> Well, I just saw the thread on Chris Huff's portal patch, so I 
>> thought I'd post this.  This is one type of image that would be much 
>> easier to do with such a patch, I'd imagine (though the patch doesn't 
>> allow light to pass through) 

> Actually, it would be possible to simulate the effect of light shining 
> through the portal...just create another copy of the lights you want to 
> shine through the portal, transform them to where they would be on the 
> "other side" when seen through the portal, and use the projected_through 
> feature to make them shine through the portal.
> This wouldn't be perfect...a shadow on the other side of the portal 
> wouldn't pass through it. It would work in most situations, though.

Is the projected_through available now?  Last I heard, portals only did a
pigment, no light through the portal or photons or such.  Has it progressed,
then?


>> It would certainly be faster than my method.

> What was your method?

I was waiting for someone to ask. ;).  I created both scenes, then cut them
in half.  One half is set no_image and scaled <1,-1,1> (I use z as up.  More
intuitive for me) while the other is no_reflection.  Then I set up a perfect
mirror with a hole in it at the right place, and use light groups to get the
reflections lights to work right.

Only problem is that this makes essentially the entire picture one big
intersection.  Bounding goes out the window, and with all those isosurface
stone blocks, it slows to a crawl.  I've gotten away with a few things (the
tree, for instance doesn't pass the invisible wall so doesn't need to be
intersected), but for the most part, things get slow really quickly.

The advantage of doing all this is being able to set the camera up wherever
is convenient, and getting easy light pass through.  One disadvantage that I
noticed last night is that I can't use focal blur (post process), because
only the summer side gets blurred.  The winter side is all at the mirror
distance, rather than its 'true' distance, so doesn't get appropriately
blurred.  On the other hand, a portal would have the opposite problem, with
only the winter side blurring.

Geoff

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