Function TriangulateFace

editor/HRoom.cpp:2094–2181

Splits a face unto triangles, by fanning Parameters: rp,facenum - the face to triangulate vertnum - the vert that is the base of the fan

// Parameters:	rp,facenum - the face to triangulate
//					vertnum - the vert that is the base of the fan
void TriangulateFace(room *rp, int facenum, int vertnum) {
  face *fp = &rp->faces[facenum], *nfp;
  int num_new_faces, first_new_face, i;

  if (fp->num_verts == 3) {
    OutrageMessageBox("Face %d has three verts and cannot be split.", facenum);
    return;
  }

  if (fp->portal_num != -1) {
    OutrageMessageBox("You cannot split a face that's part of a portal.");
    return;
  }

  if (fp->flags & (FF_HAS_TRIGGER + FF_FLOATING_TRIG)) {
    OutrageMessageBox("You cannot split a face that has a trigger.");
    return;
  }

  // Add new faces
  num_new_faces = fp->num_verts - 2;
  first_new_face = RoomAddFaces(rp, num_new_faces);

  // Reset pointer to our old face
  fp = &rp->faces[facenum];

  // Set up each face
  for (i = 0, nfp = &rp->faces[first_new_face]; i < num_new_faces; i++, nfp++) {
    InitRoomFace(nfp, 3);

    // Set verts & uvls for this face
    nfp->face_verts[0] = fp->face_verts[vertnum];
    nfp->face_uvls[0] = fp->face_uvls[vertnum];
    for (int v = 1; v < 3; v++) {
      nfp->face_verts[v] = fp->face_verts[(vertnum + i + v) % fp->num_verts];
      nfp->face_uvls[v] = fp->face_uvls[(vertnum + i + v) % fp->num_verts];
    }

    // Copy other data for this face
    CopyFaceFlags(nfp, fp);
#ifndef NEWEDITOR
    nfp->tmap = fp->tmap;
#else
    // Apply texture
    HTextureApplyToRoomFace(rp, first_new_face + i, nfp->tmap);
#endif
    nfp->light_multiple = fp->light_multiple;

    // Compute the normal for this face
    ComputeFaceNormal(rp, first_new_face + i);
  }

  // Delete original face
  DeleteRoomFace(rp, facenum);

  // Check for degenerate faces (caused by colinear points) and merge with adjacent faces
  first_new_face--; // original face deleted, causing shift
  bool ok;