// return all occluders in all cells that intersect the triangle (p1,p2,p3)
// these occluders do not necessarily intersect (p1,p2,p3), but all possible intersections are included in this set
void Grid::triangleIntersections(Vec3r p0,Vec3r p1,Vec3r p2, set<Polygon3r*> & possibleIntersections)
{
Vec3r triverts[3] = {p0,p1,p2};
// find the bbox of the triangle
vector<Vec3r> vertices;
vertices.push_back(triverts[0]);
vertices.push_back(triverts[1]);
vertices.push_back(triverts[2]);
Vec3r dummy;
Polygon3r triangle(vertices,dummy);
Vec3r min, max;
triangle.getBBox(min, max);
// Compute the cell coordinates for the bbox
Vec3u imax, imin;
getCellCoordinates(max, imax);
getCellCoordinates(min, imin);
// We are now going to iterate over the cells overlapping with the
// polygon bbox.
for (unsigned z = imin[2]; z <= imax[2]; z++)
for (unsigned y = imin[1]; y <= imax[1]; y++)
for (unsigned x = imin[0]; x <= imax[0]; x++)
{
Vec3u coord;
Vec3r boxmin, boxmax;
coord[0] = x;
coord[1] = y;
coord[2] = z;
// We retrieve the box coordinates of the current cell
getCellBox(coord, boxmin, boxmax);
// We check whether the triangle and the box ovewrlap:
Vec3r boxcenter((boxmin + boxmax) / 2.0);
Vec3r boxhalfsize(_cell_size / 2.0);
Cell * cell = getCell(coord);
if (cell != NULL && GeomUtils::overlapTriangleBox(boxcenter, boxhalfsize, triverts))
for(OccludersSet::iterator it = cell->getOccluders().begin(); it != cell->getOccluders().end(); ++it)
possibleIntersections.insert(*it);
}
}
void BoxGrid::assignCells (OccluderSource& /*source*/, GridDensityProvider& density, ViewMap *viewMap)
{
_cellSize = density.cellSize();
_cellsX = density.cellsX();
_cellsY = density.cellsY();
_cellOrigin[0] = density.cellOrigin(0);
_cellOrigin[1] = density.cellOrigin(1);
if (G.debug & G_DEBUG_FREESTYLE) {
cout << "Using " << _cellsX << "x" << _cellsY << " cells of size " << _cellSize << " square." << endl;
cout << "Cell origin: " << _cellOrigin[0] << ", " << _cellOrigin[1] << endl;
}
// Now allocate the cell table and fill it with default (empty) cells
_cells.resize(_cellsX * _cellsY);
for (cellContainer::iterator i = _cells.begin(), end = _cells.end(); i != end; ++i) {
(*i) = NULL;
}
// Identify cells that will be used, and set the dimensions for each
ViewMap::fedges_container& fedges = viewMap->FEdges();
for (ViewMap::fedges_container::iterator f = fedges.begin(), fend = fedges.end(); f != fend; ++f) {
if ((*f)->isInImage()) {
Vec3r point = transform((*f)->center3d());
unsigned int i, j;
getCellCoordinates(point, i, j);
if (_cells[i * _cellsY + j] == NULL) {
// This is an uninitialized cell
real x, y, width, height;
x = _cellOrigin[0] + _cellSize * i;
width = _cellSize;
y = _cellOrigin[1] + _cellSize * j;
height = _cellSize;
// Initialize cell
Cell *b = _cells[i * _cellsY + j] = new Cell();
b->setDimensions(x, y, width, height);
}
}
}
}
BoxGrid::Cell *BoxGrid::findCell(const Vec3r& point)
{
unsigned int x, y;
getCellCoordinates(point, x, y);
return _cells[x * _cellsY + y];
}
void Grid::insertOccluder(Polygon3r* occluder) {
const vector<Vec3r> vertices = occluder->getVertices();
if (vertices.size() == 0)
return;
// add this occluder to the grid's occluders list
addOccluder(occluder);
// find the bbox associated to this polygon
Vec3r min, max;
occluder->getBBox(min, max);
// Retrieve the cell x, y, z cordinates associated with these min and max
Vec3u imax, imin;
getCellCoordinates(max, imax);
getCellCoordinates(min, imin);
// We are now going to fill in the cells overlapping with the
// polygon bbox.
// If the polygon is a triangle (most of cases), we also
// check for each of these cells if it is overlapping with
// the triangle in order to only fill in the ones really overlapping
// the triangle.
unsigned i, x, y, z;
vector<Vec3r>::const_iterator it;
Vec3u coord;
if (vertices.size() == 3) { // Triangle case
Vec3r triverts[3];
i = 0;
for(it = vertices.begin();
it != vertices.end();
it++) {
triverts[i] = Vec3r(*it);
i++;
}
Vec3r boxmin, boxmax;
for (z = imin[2]; z <= imax[2]; z++)
for (y = imin[1]; y <= imax[1]; y++)
for (x = imin[0]; x <= imax[0]; x++) {
coord[0] = x;
coord[1] = y;
coord[2] = z;
// We retrieve the box coordinates of the current cell
getCellBox(coord, boxmin, boxmax);
// We check whether the triangle and the box ovewrlap:
Vec3r boxcenter((boxmin + boxmax) / 2.0);
Vec3r boxhalfsize(_cell_size / 2.0);
if (GeomUtils::overlapTriangleBox(boxcenter, boxhalfsize, triverts)) {
// We must then create the Cell and add it to the cells list
// if it does not exist yet.
// We must then add the occluder to the occluders list of this cell.
Cell* cell = getCell(coord);
if (!cell) {
cell = new Cell(boxmin);
fillCell(coord, *cell);
}
cell->addOccluder(occluder);
}
}
}
else { // The polygon is not a triangle, we add all the cells overlapping the polygon bbox.
for (z = imin[2]; z <= imax[2]; z++)
for (y = imin[1]; y <= imax[1]; y++)
for (x = imin[0]; x <= imax[0]; x++) {
coord[0] = x;
coord[1] = y;
coord[2] = z;
Cell* cell = getCell(coord);
if (!cell) {
Vec3r orig;
getCellOrigin(coord, orig);
cell = new Cell(orig);
fillCell(coord, *cell);
}
cell->addOccluder(occluder);
}
}
}