Function HTextureGetBottomVertexForFace

editor/HTexture.cpp:740–791

returns the index in the face_verts array for the most point on this face

// returns the index in the face_verts array for the most point on this face
int HTextureGetBottomVertexForFace(int roomnum, int facenum) {
  matrix face_matrix, trans_matrix;
  vector fvec;
  vector avg_vert;
  vector verts[MAX_VERTS_PER_FACE];

  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
  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]];
    vector rot_vert;

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

    verts[i] = rot_vert;
  }

  // Find bottom most point
  int bottommost_point = -1;
  float bottommost_y = 900000.0f; // a big number

  for (i = 0; i < Rooms[roomnum].faces[facenum].num_verts; i++) {
    if (verts[i].y < bottommost_y) {
      bottommost_point = i;
      bottommost_y = verts[i].y;
    }
  }

  ASSERT(bottommost_point != -1);

  return bottommost_point;
}

/*void HTextureGetBoxUVLForFace (room *rp,facenum)
{