Hello, and thank you for reading this!
I am trying to solve a problem with an application I'm developing and I need to ask for help from the community. The short description is: I have two triangles on a mesh with vertices (A, B, C) and (B, D, C). I have a point inside the first triangle (P), and this point describes the center of a circle having radius r. A portion of the circle overlaps the second triangle. See the figure below:
[attachment=30292:CG Texture Problem - composite.jpg]
Now we move to the texture space for that given mesh. The first triangle maps to some region in the texture with UV coordinates A', B', and C'... like this:
[attachment=30293:CG Texture Problem - triangle 1.jpg]
In this image, the point P has been translated to P' in the texture map. I believe I can use a couple of relatively simple calculations (barycentric coordinates, distance from a point) to determine if a given texel is within my desired radius from P'.
The second triangle maps to a different region of the texture with UV coordinates B", D", and C"... like this:
[attachment=30294:CG Texture Problem - triangle 2.jpg]
I believe I can use the same relatively simple calculations (barycentric coordinates, distance from a point) to determine if a given texel is within my desired radius from P".
My challenge, though, is: How do I calculate the location of P" on the texture map relative to B" and C"? The location of P" is the unknown for which I need a solution.
I hope this makes sense. I've got 25+ years of programming experience, but only about 2-3 months of experience working with meshes and textures (even the concept of "barycentric" is still a bit shaky just yet, and things like "dot product" and "cross product" are stored in brain cells that haven't been dusted off in a couple of decades). I know it's possible... I just don't know how.
Can anyone help me figure this out?
THANKS!
