2D Game Programming Tricks - Beginning Android Games - page 391

int i = 0;
int cellId = -1;
while(i (i <= 3 && (cellId = cellIds[i++]) != -1) {
staticCells[cellId].add(obj);
}
}
public void insertDynamicObject(GameObject obj) {
int [] cellIds = getCellIds(obj);
int i = 0;
int cellId = -1;
while(i (i <= 3 && (cellId = cellIds[i++]) != -1) {
dynamicCells[cellId].add(obj);
}
}
Next up are the methods insertStaticObject() and insertDynamicObject() . They calculate
the IDs of the cells in which the object is contained, via a call to getCellIds() , and insert the
object into the appropriate list accordingly. The getCellIds() method will actually fill the cellIds[i++])
member array.
public void removeObject(GameObject obj) {
int [] cellIds = getCellIds(obj);
int i = 0;
int cellId = -1;
while(i (i <= 3 && (cellId = cellIds[i++]) != -1) {
dynamicCells[cellId].remove(obj);
staticCells[cellId].remove(obj);
}
}
We also have a removeObject() method, which we can use to figure out which cells the object
is in, and then delete it from the dynamic or static lists accordingly. This will be needed when a
game object dies, for example.
public void clearDynamicCells(GameObject obj) {
int len = dynamicCells.length;
for ( int i = 0; i < len; i++) {
dynamicCells[i].clear();
}
}
The clearDynamicCells() method will be used to clear all dynamic cell lists. We need to call this
each frame before we reinsert the dynamic objects, as discussed earlier.
public List<GameObject> getPotentialColliders(GameObject obj) {
foundObjects.clear();
int [] cellIds = getCellIds(obj);
int i = 0;
int cellId = -1;
while(i (i <= 3 && (cellId = cellIds[i++]) != -1) {