void gun_shell::check_collision_voxel(ship& s, const vector3f& oldrelpos, const vector3f& newrelpos)
{
// positions are relative to bbox of s.
matrix4f obj2voxel = s.get_model().get_base_mesh_transformation().inverse();
vector3f oldvoxpos = obj2voxel * oldrelpos, newvoxpos = obj2voxel * newrelpos;
vector3f diffvoxpos = newvoxpos - oldvoxpos;
// now iterate in 8 steps between oldvoxpos to newvoxpos,
// transform both to voxel coordinates (0...N)
// and determine voxel number by pos.
// if coordinate is invalid, no hit, otherwise check voxel state (volume > 0.25 or similar)
// if the voxel is filled.
vector3f voxel_size_rcp = s.get_model().get_voxel_size().rcp();
const vector3i& vres = s.get_model().get_voxel_resolution();
vector3i vidxmax = vres - vector3i(1, 1, 1);
vector3f voxel_pos_trans = vector3f(vres) * 0.5f;
int lastvn = -1;
log_debug("check collision voxel");
for (unsigned k = 0; k <= 10; ++k) {
float kf = k/10.0f;
vector3f voxpos = oldvoxpos + diffvoxpos * kf;
vector3i v = vector3i(voxpos.coeff_mul(voxel_size_rcp) + voxel_pos_trans);
v = v.max(vector3i(0,0,0)).min(vidxmax);
int vn = (v.z * vres.y + v.y)*vres.x + v.x;
if (vn != lastvn) {
lastvn = vn;
log_debug("voxel hit k="<<k<<" voxpos="<<voxpos<<" v="<<v<<" vn="<<vn);
const model::voxel* vox = s.get_model().get_voxel_by_pos(v);
if (vox) {
// we hit a part of the object!
log_debug("..... Object hit! .....");
// first compute exact real word position of impact
vector3 impactpos = s.get_pos()
+ s.get_orientation().rotate(s.get_model().
get_base_mesh_transformation() * voxpos);
// move gun shell pos to hit position to
// let the explosion be at right position
position = impactpos;
log_debug("Hit object at real world pos " << impactpos);
log_debug("that is relative: " << s.get_pos()-impactpos);
// now damage the ship
if (s.damage(impactpos, int(damage_amount))) { // fixme, crude
gm.ship_sunk(&s);
} else {
s.ignite();
}
#if 0
//spawn some location marker object for testing
//at exact impact position
gm.spawn_particle(new marker_particle(impactpos));
#endif
gm.add_event(new event_shell_explosion(get_pos()));
kill(); // grenade is used and dead
return; // no more checks
}
}
}
}
void gun_shell::check_collision_precise(ship& s, const vector3& oldrelpos,
const vector3& newrelpos)
{
// transform positions to s' local bbox space
quaternion qco = s.get_orientation().conj();
vector3f oldrelbbox = vector3f(qco.rotate(oldrelpos));
vector3f newrelbbox = vector3f(qco.rotate(newrelpos));
// now the model::get_min/get_max values can be used to compute the axis aligned bbox
float tmin = 0.0f, tmax = 1.0f;
// clip the line oldrelbbox->newrelbbox with the bbox
vector3f d = newrelbbox - oldrelbbox;
const vector3f& b = oldrelbbox;
vector3f bmin = s.get_model().get_min();
vector3f bmax = s.get_model().get_max();
if (fabs(d.x) > 1e-5) {
float t0 = (bmin.x - b.x) / d.x;
float t1 = (bmax.x - b.x) / d.x;
float ta = std::min(t0, t1);
float tb = std::max(t0, t1);
tmax = std::min(tmax, tb);
tmin = std::max(tmin, ta);
}
if (fabs(d.y) > 1e-5) {
float t0 = (bmin.y - b.y) / d.y;
float t1 = (bmax.y - b.y) / d.y;
float ta = std::min(t0, t1);
float tb = std::max(t0, t1);
tmax = std::min(tmax, tb);
tmin = std::max(tmin, ta);
}
if (fabs(d.z) > 1e-5) {
float t0 = (bmin.z - b.z) / d.z;
float t1 = (bmax.z - b.z) / d.z;
float ta = std::min(t0, t1);
float tb = std::max(t0, t1);
tmax = std::min(tmax, tb);
tmin = std::max(tmin, ta);
}
if (tmin <= tmax) {
//log_debug("shell hit object?!");
vector3f d = newrelbbox - oldrelbbox;
check_collision_voxel(s, oldrelbbox + d * tmin, oldrelbbox + d * tmax);
if (alive_stat == dead) return; // no more checks after hit
}
}