bool removePatternUpdatingHeap(int x, int y, PatternId id, WfcContext cx, Solver solver)
{
if (cx.state.removePatternUpdatingEntropy(x, y, id, cx.model.patterns))
{
return(true);
}
solver.updateHeap(x, y, cx.state.entropies[x, y].entropyWithNoise());
this.removals.Push(new TileRemoval(x, y, id));
return(false);
}
// TODO: on lockin, just remove patterns for performance and then propagate
/// <summary>True if contradicted. Recursively propagates all the removals</summary>
public bool propagateAll(WfcContext cx, Solver solver)
{
// propagate the effect of a removal
while (this.removals.Count > 0)
{
if (this.propagateRemoval(this.removals.Pop(), cx, solver))
{
return(true);
}
}
return(false);
}
/// <summary>Reduces enabler counts around the cell. True if contradicted</summary>
bool propagateRemoval(TileRemoval removal, WfcContext cx, Solver solver)
{
int nPatterns = cx.model.patterns.len;
var gridSize = cx.model.gridSize;
var nb = new Neighbor {
};
for (int dirIndex = 0; dirIndex < 4; dirIndex++)
{
nb.pos = removal.pos + dirVecs[dirIndex];
if (cx.model.filterPos(nb.pos.x, nb.pos.y))
{
continue;
}
// for periodic output
nb.pos += gridSize;
nb.pos %= gridSize;
var dirFromNeighbor = ((Dir4)dirIndex).opposite();
for (int i = 0; i < nPatterns; i++)
{
nb.id = new PatternId(i);
// skip some combinations (not an enabler or already removed)
if (!cx.model.rule.isLegal(nb.id, dirFromNeighbor, removal.id))
{
continue;
}
if (!cx.state.isPossible(nb.pos.x, nb.pos.y, nb.id))
{
continue;
}
// decrement the enabler count for the compatible pattern
if (!cx.state.enablerCounts.decrement(nb.pos.x, nb.pos.y, nb.id, dirFromNeighbor))
{
continue;
}
if (this.removePatternUpdatingHeap(nb.pos.x, nb.pos.y, nb.id, cx, solver))
{
return(true);
}
}
}
return(false);
}
public WfcContext.AdvanceStatus advance(WfcContext cx)
{
if (this.nUnSolved <= 0)
{
return(WfcContext.AdvanceStatus.Success); // every cell is decided
}
var(pos, isContradicted) = Solver.selectNextCellToDecide(ref this.heap, cx.state);
if (isContradicted)
{
System.Console.WriteLine("Unreachable. The heap is empty, but there are remaining cells");
return(WfcContext.AdvanceStatus.Fail);
}
var id = Solver.selectPatternForCell(pos.x, pos.y, cx.state, cx.model.patterns, cx.random);
Solver.solveCellWithPattern(pos.x, pos.y, id, cx.state, cx.model.patterns, this.propagator);
this.nUnSolved -= 1;
return(this.propagator.propagateAll(cx, this) ?
WfcContext.AdvanceStatus.Fail :
WfcContext.AdvanceStatus.Continue);
}
