Author Topic: Patch [committed]: customized asteroid split rules  (Read 990 times)

0 Members and 1 Guest are viewing this topic.

Offline zookeeper

  • *knock knock* Who's there? Poe. Poe who?
  • 210
Patch [committed]: customized asteroid split rules
Here's a patch which allows asteroid types in asteroids.tbl to define which types of other asteroids and how many of them they will split into when destroyed. You can do things like make a big asteroid split into 3-9 small ones and 2-4 medium ones, or a small asteroid split into 12 big ones (hardly advisable though!); that is, whatever you happen to want.

Example tabling for the former more reasonable example would look like this:

Code: [Select]
$Name:            Large Asteroid
;blablabla
$Split:           0
+Min:             3
+Max:             9
$Split:           1
+Min:             2
+Max:             4

It would have been a bit tricky to elegantly allow the asteroid names to be used as the values of $Split, so I used the standard numbering instead; the first one (small) is 0, second one (medium) is 1, third one (big) is 2.

When you use this option, the new roids are spawned using a completely different algorithm which makes sure that they all fly in different enough directions to minimize the chances of clipping no matter how many there are.

Code: [Select]
Index: asteroid.cpp
===================================================================
--- asteroid.cpp (revision 7927)
+++ asteroid.cpp (working copy)
@@ -1433,8 +1433,10 @@
 void asteroid_maybe_break_up(object *asteroid_obj)
 {
  asteroid *asp;
+ asteroid_info *asip;
 
  asp = &Asteroids[asteroid_obj->instance];
+ asip = &Asteroid_info[asp->asteroid_type];
 
  if ( timestamp_elapsed(asp->final_death_time) ) {
  vec3d relvec, vfh, tvec;
@@ -1446,10 +1448,9 @@
 
  // multiplayer clients won't go through the following code.  asteroid_sub_create will send
  // a create packet to the client in the above named function
- if ( !MULTIPLAYER_CLIENT ) {
- // if this isn't true it's just debris, and debris doesn't break up
- if (asp->asteroid_type <= ASTEROID_TYPE_LARGE)
- {
+ // if the second condition isn't true it's just debris, and debris doesn't break up
+ if ( !MULTIPLAYER_CLIENT && (asp->asteroid_type <= ASTEROID_TYPE_LARGE)) {
+ if (asip->split_info.empty()) {
  switch (asp->asteroid_type) {
  case ASTEROID_TYPE_SMALL:
  break;
@@ -1483,6 +1484,61 @@
  default: // this isn't going to happen.. really
  break;
  }
+ } else {
+ SCP_vector<int> roids_to_create;
+ SCP_vector<asteroid_split_info>::iterator split;
+ for (split = asip->split_info.begin(); split != asip->split_info.end(); ++split) {
+ int num_roids = split->min;
+ int num_roids_var = split->max - split->min;
+
+ if (num_roids_var > 0)
+ num_roids += rand() % num_roids_var;
+
+ if (num_roids > 0)
+ for(int i=0; i<num_roids; i++)
+ roids_to_create.push_back(split->asteroid_type);   
+ }
+
+ random_shuffle(roids_to_create.begin(), roids_to_create.end());
+
+ int total_roids = roids_to_create.size();
+ for (int i = 0; i < total_roids; i++) {
+ vec3d dir_vec,final_vec;
+ vec3d parent_vel,hit_rel_vec;
+
+ // The roid directions are picked from the so-called
+ // "golden section spiral" to prevent them from
+ // clustering and thus clipping
+
+ float inc = PI * (3.0f - sqrt(5.0f));
+ float offset = 2.0f / total_roids;
+
+ float y = i * offset - 1 + (offset / 2);
+ float r = sqrt(1.0f - y*y);
+ float phi = i * inc;
+
+ dir_vec.xyz.x = cos(phi)*r;
+ dir_vec.xyz.y = sin(phi)*r;
+ dir_vec.xyz.z = y;
+
+ // Randomize the direction a bit
+ vec3d tempv = dir_vec;
+ vm_vec_random_cone(&dir_vec, &tempv, (360.0f / total_roids / 2));
+
+ // Make the roid inherit half of the parent's velocity
+ vm_vec_copy_normalize(&parent_vel, &asteroid_obj->phys_info.vel);
+ vm_vec_scale(&parent_vel, 0.5f);
+
+ // Make the hit position affect the direction, but only a little
+ vm_vec_sub(&hit_rel_vec, &asteroid_obj->pos, &asp->death_hit_pos);
+ vm_vec_normalize(&hit_rel_vec);
+ vm_vec_scale(&hit_rel_vec, 0.25f);
+
+ vm_vec_avg3(&final_vec, &parent_vel, &hit_rel_vec, &dir_vec);
+ vm_vec_normalize(&final_vec);
+
+ asteroid_sub_create(asteroid_obj, roids_to_create[i], &final_vec);
+ }
  }
  }
  asp->final_death_time = timestamp(-1);
@@ -1752,6 +1808,31 @@
 
  required_string("$Hitpoints:");
  stuff_float(&asip->initial_asteroid_strength);
+
+ while(optional_string("$Split:")) {
+ int split_type;
+
+ stuff_int(&split_type);
+
+ if (split_type>=0 && split_type<NUM_DEBRIS_SIZES) {
+ asteroid_split_info new_split;
+
+ new_split.asteroid_type = split_type;
+
+ if(optional_string("+Min:"))
+ stuff_int(&new_split.min);
+ else
+ new_split.min = 0;
+
+ if(optional_string("+Max:"))
+ stuff_int(&new_split.max);
+ else
+ new_split.max = 0;
+
+ asip->split_info.push_back( new_split );
+ } else
+ Warning(LOCATION, "Invalid asteroid reference %i used for $Split in asteroids table, ignoring.", split_type);
+ }
 }
 
 /**
Index: asteroid.h
===================================================================
--- asteroid.h (revision 7927)
+++ asteroid.h (working copy)
@@ -44,6 +44,14 @@
 extern asteroid_obj Asteroid_obj_list;
 
 
+// Data structure for determining a type and amount of other asteroids an
+// asteroid will split to when destroyed.
+typedef struct asteroid_split_info {
+ int asteroid_type;
+ int min;
+ int max;
+} asteroid_split_info;
+
 typedef struct asteroid_info {
  char name[NAME_LENGTH]; // name for the asteroid
  char pof_files[NUM_DEBRIS_POFS][MAX_FILENAME_LEN]; // POF files to load/associate with ship
@@ -57,6 +65,7 @@
  float damage; // maximum damage applied from area effect explosion
  float blast; // maximum blast impulse from area effect explosion
  float initial_asteroid_strength; // starting strength of asteroid
+ SCP_vector< asteroid_split_info > split_info;
  polymodel *modelp[NUM_DEBRIS_POFS];
  int model_num[NUM_DEBRIS_POFS];
 

Reviewers wanted. :D

EDIT: Committed to trunk in r7977.
« Last Edit: November 13, 2011, 04:34:47 am by zookeeper »

 

Offline Dragon

  • Citation needed
  • 212
  • The sky is the limit.
Re: Patch: customized asteroid split rules
Looks awesome. Can't wait for commit.