while I''m here this is how FS generates the two verts for each point on the spline (this is actualy from the beam rendering code but it''s prety much identical)
void beam_calc_facing_pts( vector *top, vector *bot, vector *fvec, vector *pos, float w, float z_add ){ vector uvec, rvec; vector temp; temp = *pos; vm_vec_sub( &rvec, &Eye_position, &temp ); vm_vec_normalize( &rvec ); vm_vec_crossprod(&uvec,fvec,&rvec); vm_vec_normalize(&uvec); vm_vec_scale_add( top, &temp, &uvec, w/2.0f ); vm_vec_scale_add( bot, &temp, &uvec, -w/2.0f ); }
you see you take the cross product between the normalized vector from the point to your eye position and the forward vector of the segment (this can be determined in trails as the relitive position of the next segment from the last, exept for the first and last segment were you can just use the point it''self for one of the two) and then scale the result by the width of the trail at that segment both positivly and negitivly and that will be the two points for youre segment, just pop them into a tristrip vertex buffer then render it.
simple :D
Bobboau, bringing you products that work... in theory
Bobboau, bringing you products that work... in theory
or...
I don''t really like the homeworld exhausts (2nd pic) because I think they are too long and too bright and look too cartooney. jmho...
I kind of like the first one best. I am currently doing this:
1. Create a polygon mesh aft of the ship, using points of where the ship has been (see pic)
2. Make 2 polygon meshes perpendicular to each other so that it doesn''t look thin from the top (see pic)
3. Then depending on the thrust use points further away or closer to the ship
4. Map an exhaust gradient texture to the polygon stream them alpha blend to get the glow.
This method looks good but not nearly as good as the top 2 pics. I also notice that in a big battle seen on Homeworld there are a ton of trails and fps is still high, so I don''t think they are using any kind of particle system.
Any suggestions on how to do this better...
rhuala
