//find which side to fly out of
find_exit_side(object *obj)
{
int i;
vms_vector prefvec,segcenter,sidevec;
fix best_val=-f2_0;
int best_side;
segment *pseg = &Segments[obj->segnum];
//find exit side
vm_vec_normalized_dir_quick(&prefvec,&obj->pos,&obj->last_pos);
compute_segment_center(&segcenter,pseg);
best_side=-1;
for (i=MAX_SIDES_PER_SEGMENT;--i >= 0;) {
fix d;
if (pseg->children[i]!=-1) {
compute_center_point_on_side(&sidevec,pseg,i);
vm_vec_normalized_dir_quick(&sidevec,&sidevec,&segcenter);
d = vm_vec_dotprod(&sidevec,&prefvec);
if (labs(d) < MIN_D) d=0;
if (d > best_val) {best_val=d; best_side=i;}
}
}
Assert(best_side!=-1);
return best_side;
}
void physics_apply_shock(vec3d *direction_vec, float pressure, physics_info *pi, matrix *orient, vec3d *min, vec3d *max, float radius)
{
vec3d normal;
vec3d local_torque, temp_torque, torque;
vec3d impact_vec;
vec3d area;
vec3d sin;
if (radius > MAX_RADIUS) {
return;
}
vm_vec_normalize_safe ( direction_vec );
area.xyz.x = (max->xyz.y - min->xyz.z) * (max->xyz.z - min->xyz.z);
area.xyz.y = (max->xyz.x - min->xyz.x) * (max->xyz.z - min->xyz.z);
area.xyz.z = (max->xyz.x - min->xyz.x) * (max->xyz.y - min->xyz.y);
normal.xyz.x = vm_vec_dotprod( direction_vec, &orient->vec.rvec );
normal.xyz.y = vm_vec_dotprod( direction_vec, &orient->vec.uvec );
normal.xyz.z = vm_vec_dotprod( direction_vec, &orient->vec.fvec );
sin.xyz.x = fl_sqrt( fl_abs(1.0f - normal.xyz.x*normal.xyz.x) );
sin.xyz.y = fl_sqrt( fl_abs(1.0f - normal.xyz.y*normal.xyz.y) );
sin.xyz.z = fl_sqrt( fl_abs(1.0f - normal.xyz.z*normal.xyz.z) );
vm_vec_make( &torque, 0.0f, 0.0f, 0.0f );
// find the torque exerted due to the shockwave hitting each face
// model the effect of the shockwave as if the shockwave were a plane of projectiles,
// all moving in the direction direction_vec. then find the torque as the cross prod
// of the force (pressure * area * normal * sin * scale * mass)
// normal takes account the fraction of the surface exposed to the shockwave
// the sin term is not technically needed but "feels" better
// scale factors out the increase in area with larger objects
// more massive objects get less rotation
// find torque due to forces on the right/left face
if ( normal.xyz.x < 0.0f ) // normal < 0, hits the right face
vm_vec_copy_scale( &impact_vec, &orient->vec.rvec, max->xyz.x * pressure * area.xyz.x * normal.xyz.x * sin.xyz.x / pi->mass );
else // normal > 0, hits the left face
vm_vec_copy_scale( &impact_vec, &orient->vec.rvec, min->xyz.x * pressure * area.xyz.x * -normal.xyz.x * sin.xyz.x / pi->mass );
vm_vec_crossprod( &temp_torque, &impact_vec, direction_vec );
vm_vec_add2( &torque, &temp_torque );
// find torque due to forces on the up/down face
if ( normal.xyz.y < 0.0f )
vm_vec_copy_scale( &impact_vec, &orient->vec.uvec, max->xyz.y * pressure * area.xyz.y * normal.xyz.y * sin.xyz.y / pi->mass );
else
vm_vec_copy_scale( &impact_vec, &orient->vec.uvec, min->xyz.y * pressure * area.xyz.y * -normal.xyz.y * sin.xyz.y / pi->mass );
vm_vec_crossprod( &temp_torque, &impact_vec, direction_vec );
vm_vec_add2( &torque, &temp_torque );
// find torque due to forces on the forward/backward face
if ( normal.xyz.z < 0.0f )
vm_vec_copy_scale( &impact_vec, &orient->vec.fvec, max->xyz.z * pressure * area.xyz.z * normal.xyz.z * sin.xyz.z / pi->mass );
else
vm_vec_copy_scale( &impact_vec, &orient->vec.fvec, min->xyz.z * pressure * area.xyz.z * -normal.xyz.z * sin.xyz.z / pi->mass );
vm_vec_crossprod( &temp_torque, &impact_vec, direction_vec );
vm_vec_add2( &torque, &temp_torque );
// compute delta rotvel, scale according to blast and radius
float scale;
if (radius < MIN_RADIUS) {
scale = 1.0f;
} else {
scale = (MAX_RADIUS - radius)/(MAX_RADIUS-MIN_RADIUS);
}
// set shockwave shake amplitude, duration, flag
pi->shockwave_shake_amp = (float)(MAX_SHAKE*(pressure/STD_PRESSURE)*scale);
pi->shockwave_decay = timestamp( SW_BLAST_DURATION );
pi->flags |= PF_IN_SHOCKWAVE;
// safety dance
if (!(IS_VEC_NULL_SQ_SAFE(&torque))) {
vec3d delta_rotvel;
vm_vec_rotate( &local_torque, &torque, orient );
vm_vec_copy_normalize(&delta_rotvel, &local_torque);
vm_vec_scale(&delta_rotvel, (float)(MAX_ROTVEL*(pressure/STD_PRESSURE)*scale));
// nprintf(("Physics", "rotvel scale %f\n", (MAX_ROTVEL*(pressure/STD_PRESSURE)*scale)));
vm_vec_add2(&pi->rotvel, &delta_rotvel);
}
// set reduced translational damping, set flags
float velocity_scale = (float)MAX_VEL*scale;
pi->flags |= PF_REDUCED_DAMP;
update_reduced_damp_timestamp( pi, velocity_scale*pi->mass );
vm_vec_scale_add2( &pi->vel, direction_vec, velocity_scale );
vm_vec_rotate(&pi->prev_ramp_vel, &pi->vel, orient); // set so velocity will ramp starting from current speed
// check that kick from shockwave is not too large
if (!(pi->flags & PF_USE_VEL) && (vm_vec_mag_squared(&pi->vel) > MAX_SHIP_SPEED*MAX_SHIP_SPEED)) {
// Get DaveA
nprintf(("Physics", "speed reset in physics_apply_shock [speed: %f]\n", vm_vec_mag(&pi->vel)));
vm_vec_normalize(&pi->vel);
vm_vec_scale(&pi->vel, (float)RESET_SHIP_SPEED);
}
}
// Returns TRUE if the weapon will never hit the other object.
// If it can it predicts how long until these two objects need
// to be checked and fills the time in in current_pair.
int weapon_will_never_hit( object *obj_weapon, object *other, obj_pair * current_pair )
{
Assert( obj_weapon->type == OBJ_WEAPON );
weapon *wp = &Weapons[obj_weapon->instance];
weapon_info *wip = &Weapon_info[wp->weapon_info_index];
// mprintf(( "Frame: %d, Weapon=%d, Other=%d, pair=$%08x\n", G3_frame_count, OBJ_INDEX(weapon), OBJ_INDEX(other), current_pair ));
// Do some checks for weapons that don't turn
if ( !(wip->wi_flags & WIF_TURNS) ) {
// This first check is to see if a weapon is behind an object, and they
// are heading in opposite directions. If so, we don't need to ever check
// them again. This is only valid for weapons that don't turn.
float vdot;
if (wip->subtype == WP_LASER) {
vec3d velocity_rel_weapon;
vm_vec_sub(&velocity_rel_weapon, &obj_weapon->phys_info.vel, &other->phys_info.vel);
vdot = -vm_vec_dot(&velocity_rel_weapon, &obj_weapon->orient.vec.fvec);
} else {
vdot = vm_vec_dot( &other->phys_info.vel, &obj_weapon->phys_info.vel);
}
if ( vdot <= 0.0f ) {
// They're heading in opposite directions...
// check their positions
vec3d weapon2other;
vm_vec_sub( &weapon2other, &other->pos, &obj_weapon->pos );
float pdot = vm_vec_dot( &obj_weapon->orient.vec.fvec, &weapon2other );
if ( pdot <= -other->radius ) {
// The other object is behind the weapon by more than
// its radius, so it will never hit...
return 1;
}
}
// FUTURE ENHANCEMENT IDEAS
// Given a laser does it hit a slow or not moving object
// in its life or the next n seconds? We'd actually need to check the
// model for this.
}
// This check doesn't care about orient, only looks at the maximum speed
// of the two objects, so it knows that in the next n seconds, they can't
// go further than some distance, so don't bother checking collisions for
// that time. This is very rough, but is so general that it works for
// everything and immidiately gets rid of a lot of cases.
if ( current_pair ) {
// Find the time it will take before these get within each others distances.
// tmp->next_check_time = timestamp(500);
//vector max_vel; //maximum foward velocity in x,y,z
float max_vel_weapon, max_vel_other;
//SUSHI: Fix bug where additive weapon velocity screws up collisions
//Assumes that weapons which don't home don't change speed, which is currently the case.
if (!(wip->wi_flags & WIF_TURNS))
max_vel_weapon = obj_weapon->phys_info.speed;
else if (wp->lssm_stage==5)
max_vel_weapon = wip->lssm_stage5_vel;
else
max_vel_weapon = wp->weapon_max_vel;
max_vel_other = other->phys_info.max_vel.xyz.z;
if (max_vel_other < 10.0f) {
if ( vm_vec_mag_squared( &other->phys_info.vel ) > 100 ) {
// bump up velocity from collision
max_vel_other = vm_vec_mag( &other->phys_info.vel ) + 10.0f;
} else {
max_vel_other = 10.0f; // object may move from collision
}
}
// check weapon that does not turn against sphere expanding at ship maxvel
// compare (weeapon) ray with expanding sphere (ship) to find earliest possible collision time
// look for two time solutions to Xw = Xs, where Xw = Xw0 + Vwt*t Xs = Xs + Vs*(t+dt), where Vs*dt = radius of ship
// Since direction of Vs is unknown, solve for (Vs*t) and find norm of both sides
if ( !(wip->wi_flags & WIF_TURNS) ) {
vec3d delta_x, laser_vel;
float a,b,c, delta_x_dot_vl, delta_t;
float root1, root2, root, earliest_time;
if (max_vel_weapon == max_vel_other) {
// this will give us NAN using the below formula, so check every frame
current_pair->next_check_time = timestamp(0);
return 0;
}
vm_vec_sub( &delta_x, &obj_weapon->pos, &other->pos );
laser_vel = obj_weapon->phys_info.vel;
// vm_vec_copy_scale( &laser_vel, &weapon->orient.vec.fvec, max_vel_weapon );
delta_t = (other->radius + 10.0f) / max_vel_other; // time to get from center to radius of other obj
delta_x_dot_vl = vm_vec_dotprod( &delta_x, &laser_vel );
a = max_vel_weapon*max_vel_weapon - max_vel_other*max_vel_other;
b = 2.0f * (delta_x_dot_vl - max_vel_other*max_vel_other*delta_t);
c = vm_vec_mag_squared( &delta_x ) - max_vel_other*max_vel_other*delta_t*delta_t;
float discriminant = b*b - 4.0f*a*c;
if ( discriminant < 0) {
// never hit
return 1;
} else {
root = fl_sqrt( discriminant );
root1 = (-b + root) / (2.0f * a) * 1000.0f; // get time in ms
root2 = (-b - root) / (2.0f * a) * 1000.0f; // get time in ms
}
// standard algorithm
if (max_vel_weapon > max_vel_other) {
// find earliest positive time
if ( root1 > root2 ) {
float temp = root1;
root1 = root2;
root2 = temp;
}
if (root1 > 0) {
earliest_time = root1;
} else if (root2 > 0) {
// root1 < 0 and root2 > 0, so we're inside sphere and next check should be next frame
current_pair->next_check_time = timestamp(0); // check next time
return 0;
} else {
// both times negative, so never collides
return 1;
}
}
// need to modify it for weapons that are slower than ships
else {
if (root2 > 0) {
earliest_time = root2;
} else {
current_pair->next_check_time = timestamp(0);
return 0;
}
}
// check if possible collision occurs after weapon expires
if ( earliest_time > 1000*wp->lifeleft )
return 1;
// Allow one worst case frametime to elapse (~5 fps)
earliest_time -= 200.0f;
if (earliest_time > 100) {
current_pair->next_check_time = timestamp( fl2i(earliest_time) );
return 0;
} else {
current_pair->next_check_time = timestamp(0); // check next time
return 0;
}
} else {
float dist, max_vel, time;
max_vel = max_vel_weapon + max_vel_other;
// suggest that fudge factor for other radius be changed to other_radius + const (~10)
dist = vm_vec_dist( &other->pos, &obj_weapon->pos ) - (other->radius + 10.0f);
if ( dist > 0.0f ) {
time = (dist*1000.0f) / max_vel;
int time_ms = fl2i(time);
// check if possible collision occurs after weapon expires
if ( time_ms > 1000*wp->lifeleft )
return 1;
time_ms -= 200; // Allow at least one worst case frametime to elapse (~5 fps)
if ( time_ms > 100 ) { // If it takes longer than 1/10th of a second, then delay it
current_pair->next_check_time = timestamp(time_ms);
//mprintf(( "Delaying %d ms\n", time_ms ));
return 0;
}
}
current_pair->next_check_time = timestamp(0); // check next time
}
}
return 0;
}
void objfly_move_to_new_segment( object * obj, short newseg, int first_time )
{
segment *pseg;
int old_object_seg = obj->segnum;
if ( newseg != obj->segnum )
obj_relink(obj-Objects, newseg );
pseg = &Segments[obj->segnum];
if ( first_time || obj->segnum != old_object_seg) { //moved into new seg
vms_vector curcenter,nextcenter;
fix step_size,seg_time;
short entry_side,exit_side; //what sides we entry and leave through
vms_vector dest_point; //where we are heading (center of exit_side)
vms_angvec dest_angles; //where we want to be pointing
//find new exit side
if ( !first_time ) {
entry_side = matt_find_connect_side(obj->segnum,old_object_seg);
exit_side = Side_opposite[entry_side];
}
//if (first_time) obj->fly_info.ft_mode = FP_FORWARD;
if (first_time || entry_side==-1 || (pseg->children[exit_side]==-1) || (obj->fly_info.ft_mode!=FP_FORWARD) ) {
int i;
vms_vector prefvec,segcenter,sidevec;
fix best_val=-f2_0;
int best_side;
//find exit side
if (obj->fly_info.ft_mode == FP_FORWARD) {
if (first_time)
prefvec = obj->orient.fvec;
else
prefvec = obj->fly_info.heading;
vm_vec_normalize(&prefvec);
}
else
prefvec = obj->orient.vecs[obj->fly_info.ft_mode%3];
if (obj->fly_info.ft_mode >= 3) {prefvec.x = -prefvec.x; prefvec.y = -prefvec.y; prefvec.z = -prefvec.z;}
compute_segment_center(&segcenter,pseg);
best_side=-1;
for (i=MAX_SIDES_PER_SEGMENT;--i >= 0;) {
fix d;
if (pseg->children[i]!=-1) {
compute_center_point_on_side(&sidevec,pseg,i);
vm_vec_sub2(&sidevec,&segcenter);
vm_vec_normalize(&sidevec);
d = vm_vec_dotprod(&sidevec,&prefvec);
if (labs(d) < MIN_D) d=0;
if (d > best_val || (d==best_val && i==exit_side)) {best_val=d; best_side=i;}
}
}
if (best_val > 0) obj->fly_info.ft_mode = FP_FORWARD;
Assert(best_side!=-1);
exit_side = best_side;
}
//update target point & angles
compute_center_point_on_side(&dest_point,pseg,exit_side);
//update target point and movement points
vm_vec_sub(&obj->phys_info.velocity,&dest_point,&obj->pos);
step_size = vm_vec_normalize(&obj->phys_info.velocity);
vm_vec_scale(&obj->phys_info.velocity, obj->phys_info.speed);
compute_segment_center(&curcenter,pseg);
compute_segment_center(&nextcenter,&Segments[pseg->children[exit_side]]);
vm_vec_sub(&obj->fly_info.heading,&nextcenter,&curcenter);
angles_from_vector(&dest_angles,&obj->fly_info.heading); //extract angles
if (first_time)
angles_from_vector(&obj->phys_info.rotvel,&obj->orient.fvec);
seg_time = fixdiv(step_size,obj->phys_info.speed); //how long through seg
if (seg_time) {
obj->fly_info.angle_step.p = fixdiv(delta_ang(obj->phys_info.rotvel.p,dest_angles.p),seg_time);
obj->fly_info.angle_step.b = fixdiv(delta_ang(obj->phys_info.rotvel.b,dest_angles.b),seg_time);
obj->fly_info.angle_step.h = fixdiv(delta_ang(obj->phys_info.rotvel.h,dest_angles.h),seg_time);
}
else {
obj->phys_info.rotvel = dest_angles;
obj->fly_info.angle_step.p = obj->fly_info.angle_step.b = obj->fly_info.angle_step.h = 0;
}
}
}
/**
* When inside radius of big ship, check if we can cull collision pair determine the time when pair should next be checked
* @return 1 if pair can be culled
* @return 0 if pair can not be culled
*/
int check_inside_radius_for_big_ships( object *ship, object *weapon, obj_pair *pair )
{
vec3d error_vel; // vel perpendicular to laser
float error_vel_mag; // magnitude of error_vel
float time_to_max_error, time_to_exit_sphere;
float ship_speed_at_exit_sphere, error_at_exit_sphere;
float max_error = (float) ERROR_STD / 150.0f * ship->radius;
if (max_error < 2)
max_error = 2.0f;
time_to_exit_sphere = (ship->radius + vm_vec_dist(&ship->pos, &weapon->pos)) / (weapon->phys_info.max_vel.xyz.z - ship->phys_info.max_vel.xyz.z);
ship_speed_at_exit_sphere = estimate_ship_speed_upper_limit( ship, time_to_exit_sphere );
// update estimated time to exit sphere
time_to_exit_sphere = (ship->radius + vm_vec_dist(&ship->pos, &weapon->pos)) / (weapon->phys_info.max_vel.xyz.z - ship_speed_at_exit_sphere);
vm_vec_scale_add( &error_vel, &ship->phys_info.vel, &weapon->orient.vec.fvec, -vm_vec_dotprod(&ship->phys_info.vel, &weapon->orient.vec.fvec) );
error_vel_mag = vm_vec_mag_quick( &error_vel );
error_vel_mag += 0.5f * (ship->phys_info.max_vel.xyz.z - error_vel_mag)*(time_to_exit_sphere/ship->phys_info.forward_accel_time_const);
// error_vel_mag is now average velocity over period
error_at_exit_sphere = error_vel_mag * time_to_exit_sphere;
time_to_max_error = max_error / error_at_exit_sphere * time_to_exit_sphere;
// find the minimum time we can safely check into the future.
// limited by (1) time to exit sphere (2) time to weapon expires
// if ship_weapon_check_collision comes back with a hit_time > error limit, ok
// if ship_weapon_check_collision comes finds no collision, next check time based on error time
float limit_time; // furthest time to check (either lifetime or exit sphere)
if ( time_to_exit_sphere < Weapons[weapon->instance].lifeleft ) {
limit_time = time_to_exit_sphere;
} else {
limit_time = Weapons[weapon->instance].lifeleft;
}
// Note: when estimated hit time is less than 200 ms, look at every frame
int hit_time; // estimated time of hit in ms
// modify ship_weapon_check_collision to do damage if hit_time is negative (ie, hit occurs in this frame)
if ( ship_weapon_check_collision( ship, weapon, limit_time, &hit_time ) ) {
// hit occured in while in sphere
if (hit_time < 0) {
// hit occured in the frame
return 1;
} else if (hit_time > 200) {
pair->next_check_time = timestamp(hit_time - 200);
return 0;
// set next check time to time - 200
} else {
// set next check time to next frame
pair->next_check_time = 1;
return 0;
}
} else {
if (limit_time > time_to_max_error) {
// no hit, but beyond error tolerance
if (1000*time_to_max_error > 200) {
pair->next_check_time = timestamp( (int)(1000*time_to_max_error) - 200 );
} else {
pair->next_check_time = 1;
}
return 0;
} else {
// no hit and within error tolerance
return 1;
}
}
}
do_flythrough(object *obj,int first_time) //set true if init
{
segment *pseg;
int old_player_seg = obj->segnum;
if (first_time) {
//vms_vector zero_vector = {0,0,0};
obj->control_type = CT_FLYTHROUGH;
//obj->fly_info.angle_step.p = 0;
//obj->fly_info.angle_step.b = 0;
//obj->fly_info.angle_step.h = 0;
//obj->fly_info.heading = zero_vector;
}
//move the player for this frame
if (!first_time) {
//vms_vector tempv;
//fix rot_step;
vm_vec_scale_add2(&obj->pos,&player_step,FrameTime);
angvec_add2_scale(&player_angles,&player_angstep,FrameTime);
vm_angles_2_matrix(&obj->orient,&player_angles);
}
//check new player seg
update_object_seg(obj);
pseg = &Segments[obj->segnum];
if (first_time || obj->segnum != old_player_seg) { //moved into new seg
vms_vector curcenter,nextcenter;
fix step_size,seg_time;
short entry_side,exit_side; //what sides we entry and leave through
vms_vector dest_point; //where we are heading (center of exit_side)
vms_angvec dest_angles; //where we want to be pointing
//find new exit side
if (!first_time) {
entry_side = matt_find_connect_side(obj->segnum,old_player_seg);
exit_side = Side_opposite[entry_side];
}
if (first_time) ft_preference = FP_FORWARD;
if (first_time || entry_side==-1 || pseg->children[exit_side]==-1 || ft_preference!=FP_FORWARD) {
int i;
vms_vector prefvec,segcenter,sidevec;
fix best_val=-f2_0;
int best_side;
//find exit side
if (ft_preference == FP_FORWARD) {
if (first_time) prefvec = obj->orient.fvec;
else prefvec = headvec;
vm_vec_normalize(&prefvec);
}
else
prefvec = obj->orient.vecs[ft_preference%3];
if (ft_preference >= 3) {prefvec.x = -prefvec.x; prefvec.y = -prefvec.y; prefvec.z = -prefvec.z;}
compute_segment_center(&segcenter,pseg);
best_side=-1;
for (i=MAX_SIDES_PER_SEGMENT;--i >= 0;) {
fix d;
if (pseg->children[i]!=-1) {
compute_center_point_on_side(&sidevec,pseg,i);
//vm_vec_sub2(&sidevec,&segcenter);
//vm_vec_normalize(&sidevec);
vm_vec_normalized_dir(&sidevec,&sidevec,&segcenter);
d = vm_vec_dotprod(&sidevec,&prefvec);
if (labs(d) < MIN_D) d=0;
if (d > best_val || (d==best_val && i==exit_side)) {best_val=d; best_side=i;}
}
}
if (best_val > 0) ft_preference = FP_FORWARD;
Assert(best_side!=-1);
exit_side = best_side;
}
//update target point & angles
compute_center_point_on_side(&dest_point,pseg,exit_side);
//update target point and movement points
vm_vec_sub(&player_step,&dest_point,&obj->pos);
step_size = vm_vec_normalize(&player_step);
vm_vec_scale(&player_step,player_speed);
compute_segment_center(&curcenter,pseg);
compute_segment_center(&nextcenter,&Segments[pseg->children[exit_side]]);
vm_vec_sub(&headvec,&nextcenter,&curcenter);
//angles_from_vector(&dest_angles,&headvec); //extract angles
vm_extract_angles_vector(&dest_angles,&headvec); //extract angles
if (first_time)
//angles_from_vector(&player_angles,&obj->orient.fvec);
vm_extract_angles_vector(&player_angles,&obj->orient.fvec);
seg_time = fixdiv(step_size,player_speed); //how long through seg
if (seg_time) {
player_angstep.p = fixdiv(delta_ang(player_angles.p,dest_angles.p),seg_time);
player_angstep.b = fixdiv(delta_ang(player_angles.b,dest_angles.b),seg_time);
player_angstep.h = fixdiv(delta_ang(player_angles.h,dest_angles.h),seg_time);
}
else {
player_angles = dest_angles;
player_angstep.p = player_angstep.b = player_angstep.h = 0;
}
}
}
