Function GetUVLForRoomPoint

editor/Erooms.cpp:639–741

Important - vertnum is the index into the face_verts[] array in the face structure, not an index into the verts[] array of the room structure

// Important - vertnum is the index into the face_verts[] array in the face structure,
// not an index into the verts[] array of the room structure
void GetUVLForRoomPoint(int roomnum, int facenum, int vertnum, roomUVL *uvl) {
  matrix face_matrix, trans_matrix;
  vector fvec;
  vector avg_vert;
  vector verts[MAX_VERTS_PER_FACE];
  vector rot_vert;

  ASSERT(Rooms[roomnum].used);
  ASSERT(Rooms[roomnum].faces[facenum].num_verts >= 3);

  // find the center point of this face
  vm_MakeZero(&avg_vert);
  for (int i = 0; i < Rooms[roomnum].faces[facenum].num_verts; i++)
    avg_vert += Rooms[roomnum].verts[Rooms[roomnum].faces[facenum].face_verts[i]];

  avg_vert /= i;

  // Make the orientation matrix
  // Reverse the normal because we're looking "at" the face, not from it
  fvec = -Rooms[roomnum].faces[facenum].normal;

  vm_VectorToMatrix(&face_matrix, &fvec, NULL, NULL);
  // Make the transformation matrix

  angvec avec;
  vm_ExtractAnglesFromMatrix(&avec, &face_matrix);
  vm_AnglesToMatrix(&trans_matrix, avec.p, avec.h, avec.b);

  // Rotate all the points
  for (i = 0; i < Rooms[roomnum].faces[facenum].num_verts; i++) {
    vector vert = Rooms[roomnum].verts[Rooms[roomnum].faces[facenum].face_verts[i]];

    vert -= avg_vert;
    vm_MatrixMulVector(&rot_vert, &vert, &trans_matrix);

    verts[i] = rot_vert;
  }

  // Find left most point
  int leftmost_point = -1;
  float leftmost_x = 900000.00f; // a big number

  for (i = 0; i < Rooms[roomnum].faces[facenum].num_verts; i++) {
    if (verts[i].x < leftmost_x) {
      leftmost_point = i;
      leftmost_x = verts[i].x;
    }
  }

  ASSERT(leftmost_point != -1);

  // Find top most point
  int topmost_point = -1;
  float topmost_y = -900000.0f; // a big number

  for (i = 0; i < Rooms[roomnum].faces[facenum].num_verts; i++) {
    if (verts[i].y > topmost_y) {
      topmost_point = i;