WMO/Rendering

Lighting

CMapObj::QueryLighting

Lighting for interior WMO groups is prebaked into vertex colors.

In order to light entities (like units, game objects, etc) that exist within interior WMO groups, the game does the following:

1. Query for the closest MOPY.
2. Obtain the 3 relevant MOCV values for the MOPY.
3. Interpolate the values based on the position of the entity relative to the MOPY (ie barycentric interpolation).
4. Derive ambient and diffuse color terms from the interpolated color.
5. Use the static interiorSunDir vector as the interior light direction.

C3Vector

Query lighting when the relevant poly is already known.

bool CMapObj::QueryLighting(CMapObj *this, uint32_t groupIndex, const C3Vector *point, uint16_t polyIdx, CImVector *color, bool *a5) {

  CMapObjGroup group = this->groupList[groupIndex];

  if (!this->unk6[16] || !(group->unk14 & 1) || group->flags & (SMOGroup::EXTERIOR | SMOGroup::EXTERIOR_LIT)) {

    return 0;

  }

  bool lightRes = CMapObjGroup::QueryLighting(group, point, polyIdx, color, a5);

  return lightRes;

}

C3Segment

Query lighting when the exact poly is not yet known. Uses a C3Segment to perform a ranged query for possible tris.

bool CMapObj::QueryLighting(CMapObj *this, uint32_t groupIndex, const C3Segment *seg, CImVector *color, bool *a5) {

  CMapObjGroup group = this->groupList[groupIndex];

  if (!this->unk6[16] || !(group->unk14 & 1) || group->flags & (SMOGroup::EXTERIOR | SMOGroup::EXTERIOR_LIT)) {

    return 0;

  }

  World::TriData::resultFlags = 0;
  World::TriData::nBatches = 0;
  World::TriData::nTriIndices = 0;
  World::TriData::nVertexIndices = 0;
  World::TriData::nMatrices = 0;

  float hitT = 1.0;

  bool triRes = CMapObjGroup::GetTris(group, seg, &hitT, 0, 8, (int)&a2 + 3, 0);

  if (!triRes) {

    return 0;

  }

  // Obtain point matching intersection between segment and tri

  C3Vector point;

  point.x = seg->start.x + hitT * (seg->end.x - seg->start.x);
  point.y = seg->start.y + hitT * (seg->end.y - seg->start.y);
  point.z = seg->start.z + hitT * (seg->end.z - seg->start.z);

  unsigned __int16 hitPoly = word_CD8094;

  bool lightRes = CMapObjGroup::QueryLighting(group, &point, hitPoly, color, a5);

  return lightRes;

}