Function BreakGlassFace

Descent3/damage.cpp:1480–1599

Break the specified (glass) face into shards Parameters: rp, facenum - the face to break. The face must be a portal face. hitpnt - the point on the face where the face shatters. If NULL, uses center point of face hitvec - the direction in which the thing that's breaking the glass is moving. If NULL, uses the negative of the surface normal

// face 					hitvec - the direction in which the thing that's breaking the glass is
// moving.  If NULL, 						uses the negative of the surface normal
void BreakGlassFace(room *rp, int facenum, vector *hitpnt, vector *hitvec) {
  int roomnum;
  vector t_hitpnt, t_hitvec;
  face *fp = &rp->faces[facenum];

  ASSERT(fp->portal_num != -1);
  portal *pp0 = &rp->portals[fp->portal_num];
  portal *pp1 = &Rooms[pp0->croom].portals[pp0->cportal];

  // If face already broken, bail
  if (!(pp0->flags & PF_RENDER_FACES))
    return;

  // Set hitpnt if not specified
  if (hitpnt == NULL) {
    ComputeCenterPointOnFace(&t_hitpnt, rp, facenum);
    hitpnt = &t_hitpnt;
  }

  // Set hitvec if not specified
  if (hitvec == NULL) {
    t_hitvec = -fp->normal;
    hitvec = &t_hitvec;
  }

  // Get roomnum
  if (rp->flags & RF_EXTERNAL)
    roomnum = MAKE_ROOMNUM(GetTerrainCellFromPos(hitpnt));
  else
    roomnum = ROOMNUM(rp);

  // Play sound
  pos_state pos;
  pos.position = hitpnt;
  pos.orient = (matrix *)&Identity_matrix;
  pos.roomnum = roomnum;

  if (sound_override_glass_breaking == -1)
    Sound_system.Play3dSound(SOUND_BREAKING_GLASS, SND_PRIORITY_HIGH, &pos);
  else
    Sound_system.Play3dSound(sound_override_glass_breaking, SND_PRIORITY_HIGH, &pos);

  // Clear render flags
  pp0->flags &= ~PF_RENDER_FACES;
  pp1->flags &= ~PF_RENDER_FACES;

  // Get the UV for the hit point
  float hitpnt_u, hitpnt_v;
  FindHitpointUV(&hitpnt_u, &hitpnt_v, hitpnt, rp, facenum);

  // Calculate shard movement vector
  vector shardvec = *hitvec;
  vm_NormalizeVectorFast(&shardvec);

  // Create shards
  vector prevpoint = rp->verts[fp->face_verts[fp->num_verts - 1]];
  float prev_u = fp->face_uvls[fp->num_verts - 1].u, prev_v = fp->face_uvls[fp->num_verts - 1].v;
  for (int vertnum = 0; vertnum < fp->num_verts;) {