From: brad schwagler (bschwagg++at++yahoo.com)
Date: 01/14/2002 11:18:45
hello,
I am fairly new to performer so this is probably an
easy question. I tried to make a particle system to
create smoke out of
a chimney. I used a billboard and attached geosets
"particles" to it. Each geoset has a position that is
updated every
frame. I wish to change the alpha value and size of
the geoset as well. This will give the appearance of
the smoke slowly
fading and getting larger. This is what I have, but
it doesn't work:
//update the particle's size accordingly then apply
it to the geoset
(my_particle+c)->size =
(my_particle+c)->initial_size +
(my_particle+c)->delta_size*((my_particle+c)->distance_traveled/(my_particle+c)->max_distance);
pfSetVec3(coords[0], -((my_particle+c)->size),
0, ((my_particle+c)->size));
pfSetVec3(coords[1], -((my_particle+c)->size),
0, -((my_particle+c)->size));
pfSetVec3(coords[2], ((my_particle+c)->size),
0, -((my_particle+c)->size));
pfSetVec3(coords[3], ((my_particle+c)->size),
0, ((my_particle+c)->size));
//coords holds a pfCoord which is the quads
vertices
temp = pfGetGSet(billy, c);
pfGSetAttr(temp, PFGS_COORD3,
PFGS_PER_VERTEX, coords, vertexlist); //change
the size of the particle
..c is the counter for the number of particles.
What aren't I doing to make this work? How can I
change the alpha values as well? The particles do
display and move but
it doesn't look too real. ..Thanks; Brad
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This archive was generated by hypermail 2b29 : Mon Jan 14 2002 - 11:15:27 PST