Function GetSpecialRotatedPoint

Descent3/TerrainSearch.cpp:349–367

Gets a pre-rotated point that does not fall exactly on one of our 255 height values

// Gets a pre-rotated point that does not fall exactly on one of our 255 height values
void GetSpecialRotatedPoint(g3Point *dest, int x, int z, float yvalue) {
  if (yvalue < 0)
    yvalue = 0;
  if (yvalue > MAX_TERRAIN_HEIGHT)
    yvalue = MAX_TERRAIN_HEIGHT;

  vector up_vector = {0, yvalue, 0};
  vector dyp = up_vector * *TS_View_matrix;

  dest->p3_vec = TS_PreRows[z];
  dest->p3_vec += TS_RVectorAdd * x;
  dest->p3_vec += dyp;

  // also store the unrotated point
  dest->p3_flags |= PF_ORIGPOINT;
  dest->p3_vecPreRot.x = TERRAIN_SIZE * x;
  dest->p3_vecPreRot.y = yvalue;
  dest->p3_vecPreRot.z = TERRAIN_SIZE * z;
}

void Terrain_start_frame(vector *eye, matrix *view_orient) {
  TS_View_position = eye;