Ive been constantly lurking the site, but havent been posting much
lately, but now I’ve got another important question!
Im getting geometric boolean objects working at the moment right, but
then I suddenly decided I needed to preserve 2 objects with full uv
intersecting with each other. :)
Ive nearly got it all done, right, but im stuck sorta at the beginning
with this part I left till last, I need a tri tri intersect that
describes not only the 2 intersection points, but uv coordinates for the
2 intersection points also.
At the moment, my system is using a battery of ray tri intersects to
intersect the edges of triangle a with triangle b and vice versa and its
working, but now I need uv coordinates for the two intersection points.
Is there some simple method for doing this, is all im asking, any help
would be nice. When I figure it out I’ll close the thread with a
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Heres an example of a nice tri tri (probably faster than my
implementation out of ray tri’s by a long shot)
but it has no uv calculation, so its no good to me.
Oh that’s easy. Calculate the barycentric coordinates for the
intersection points at both triangles, and then you can simply evaluate
the uv’s at those positions. For example, if (a, b, c) are the
barycentric coordinates for one of the intersection points of triangle
A, then the u at that position is a*v.u + b*v.u + c*v.u.
Same for the v.
Thats not the first time ive ever heard barycentric coordinates
mentioned, but I unfortunately didnt learn it. :(
So off I go on the net “barycentric coordinates”… thanks .oisyn, if
only I had you as a next door neighbour then you could come over and
finish my project for me. hehe.
I read up baricentric coordinates but it blew my mind, went right over
But ive got a solution, I rotate the triangle so its parallel to the
camera then I spin it so edge 0 is totally vertical, then I do a line
intersection using the edge 1 ray direction and measure the distances
along the lines where it intersects.
I then have a weight for both edges then I use the uv’s of edge 0 and
edge 1 to produce the uv coordinate.
I bet thats something to do with baricentrics anyway, even though I
couldnt say it came from what I read at all, it just totally blew me out
of the water.