Re: [Algorithms] VIPM and UV texturing

[Conor S. <cs...@tp...>]

> But if I have the scenario where one triangle is mapped with UVs : u1,v1,
> u2,v2, u3,v3
> and an adjacent triangle mapped with u6,v6, u7,v7, u8,v8; the adjacency is
> along the edge
> of (u1,v1 & u6,v6) - (u3,v3 & u8,v8), where u1,v1 and u6,v6 actual
vertices
> are coincident, as is the case with u3,v3 and u8,v8.
>
> What happens when I drop out the edge ?
>
> Wouldn't the texture coords will be interpolated from u2,v2 to u7,v7 which
> may be totally screwed ?  I must be missing some fundamental stuff here
...
>

    Well, I think the thing you missed is that VIPM is mainly aimed towards
meshes that are more like skinned meshes (ie, all points only have a single
vertex associated with them - Hence each set of adjacent triangles must be
specifiable as a strip). I like to call these sort of meshes, highly
connected meshes (HCM), for the simple purpose that with appearance to the
renderer, they share vertices, and are therefore connected.

    I've moved towards using HCM to describe more things in my engine worlds
now (although, I need to get some art together to show off the benefit - Its
not going to work as well with the incredibly simple cubes etc I  turn out
by hand). This should provide higher performance on complex worlds (due to
more vertex coherancy) and allow more LoD.

Also, new today, I actually finally updated my column, on VIPM of all things
:) http://www.flipcode.com/dp/issue04.shtml

Conor Stokes