new algorithm draft for diag moves; committed missing files

2022-02-03 00:56:31 +01:00
parent 429ce51805
commit 1b4fe0634d
8 changed files with 296 additions and 20 deletions
@@ -154,41 +154,42 @@ TArray<AHexTile*> AAdventureMap::FindPathAStar(AHexTile* Start, AHexTile* Goal,

 		// expand frontier & adjust path data
 		for (AHexTile* Neighbor : Neighbors(Candidate, true)) {
-			if (Neighbor->Distance(Candidate) > 1) { continue; }
 			if (!Neighbor->bFree) { continue; }
 			if (Processed.Contains(Neighbor)) { continue; }

 			bool bInToExamine = ToExamine.Contains(Neighbor);
-			float NewGCost = Candidate->GCost + Neighbor->MoveCost * 10.f;
+			float NewGCost = Candidate->GCost + Neighbor->MoveCost;

 			if (NewGCost < Neighbor->GCost || !bInToExamine) {
 				Neighbor->GCost = NewGCost;
 				Neighbor->CameFrom = Candidate; // chain
+				Neighbor->bDiagMove = false;

 				if (!bInToExamine) {
-					Neighbor->HCost = Neighbor->Distance(Goal) * 10.f;
+					Neighbor->HCost = Neighbor->Distance(Goal);
 					ToExamine.Add(Neighbor);
 			}	}
 		}
+		/*
 		if (bDiags) {
 			for (AHexTile* Diag : FreeDiagonals(Candidate)) {
-				if (Diag->Distance(Candidate) > 2) { continue; }
 				if (!Diag->bFree) { continue; }
 				if (Processed.Contains(Diag)) { continue; }

 				bool bInToExamine = ToExamine.Contains(Diag);
-				float NewGCost = Candidate->GCost + 1 + Diag->MoveCost * 10.f;
+				float NewGCost = Candidate->GCost + Diag->MoveCost;

 				if (NewGCost < Diag->GCost || !bInToExamine) {
 					Diag->GCost = NewGCost;
 					Diag->CameFrom = Candidate; // chain
+					Diag->bDiagMove = true;

 					if (!bInToExamine) {
-						Diag->HCost = Diag->Distance(Goal) * 10.f; // not accounting for diagonals
+						Diag->HCost = Diag->Distance(Goal);
 						ToExamine.Add(Diag);
 				}	}
 			}
-		}
+		}*/
 	}
 	TArray<AHexTile*> Path;
 	if (!IsValid(Goal->CameFrom)) { return Path; }
@@ -198,5 +199,106 @@ TArray<AHexTile*> AAdventureMap::FindPathAStar(AHexTile* Start, AHexTile* Goal,
 		iPathNode = iPathNode->CameFrom;
 	}
 	Algo::Reverse(Path);
+
+	if (bDiags) {
+		Path = ShortcutAStar(Path);
+	}
+
 	return Path;
+}
+
+
+TArray<AHexTile*> AAdventureMap::ShortcutAStar(TArray<AHexTile*> Path) 
+{
+	TArray<AHexTile*> Shortcut;
+	int32 Len = Path.Num();
+	AHexTile* Milestone;
+	int32 BeforeBend;
+	int32 AfterBend;
+	int32 HexIter = 1;
+	FHexVector pDir;
+	FHexVector DirA;
+	FHexVector DirB;
+	AHexTile* Current = Path[0]; // beginning of curve (starts at Start)
+
+	while (Milestone != Path[Len - 1]) {
+		// find Milestone (i.e. end of first curve) & determine curve data
+		BeforeBend = 1;
+		for (HexIter; HexIter < Len; HexIter++) {
+			pDir = FHexVector(Path[HexIter], Path[HexIter - 1]);
+			DirA = FHexVector(Path[HexIter + 1], Path[HexIter]);
+			if (DirA == pDir) { BeforeBend++; }
+			else { break; }
+		}
+		AfterBend = 1;
+		for (HexIter; HexIter < Len; HexIter++) {
+			pDir = FHexVector(Path[HexIter], Path[HexIter - 1]);
+			DirB = FHexVector(Path[HexIter + 1], Path[HexIter]);
+			if (DirB == pDir) { AfterBend++; }
+			else { break; }
+		}
+		FHexVector Diag = UnitDiagFromUnitNB(DirA, DirB); // cardinal direction for potential shortcut
+		TArray<AHexTile*> WorkingSegment; // current curve
+		for (int32 i = Path.Find(Current); i < HexIter; i++) { WorkingSegment.Add(Path[i]); }
+		Milestone = Path[HexIter]; // end of curve
+		int32 ShoCutLen;
+		int32 NumDiags; // max number of tries to take a Diagonal
+		if (BeforeBend >= AfterBend) {
+			ShoCutLen = BeforeBend;
+			NumDiags = AfterBend;
+		}
+		if (BeforeBend < AfterBend) {
+			ShoCutLen = AfterBend;
+			NumDiags = BeforeBend;
+		}
+
+		TArray<AHexTile*> NewSegment;
+		// link from Current to Milestone with diagonals
+		for (int32 i = 0; i < NumDiags; i++) {
+			AHexTile* NewCandidate = Grid[GridIndex(Current->Q + Diag.Q, Current->R + Diag.R)];
+
+			if (i==0 && !DiagIsReachable(Current, Diag) || i==0 && !NewCandidate->bFree) {
+				Current = WorkingSegment[i + 1];
+				i++;
+				continue;
+			}
+			NewSegment.Add(NewCandidate);
+		}
+		// connect the rest via A* probably, think about checking whether the result is really shorter
+		int32 CIndex = WorkingSegment.Find(Current);
+		while (Current != Milestone) {
+			Current = WorkingSegment[CIndex];
+			NewSegment.Add(Current);
+			CIndex++;
+		}
+
+		
+	}
+
+	// Construct shortcut
+	return Shortcut;
+}
+
+
+FHexVector AAdventureMap::UnitDiagFromUnitNB(FHexVector InVecA, FHexVector InVecB) {
+	if (InVecA == NNW && InVecB == NNE||InVecB == NNW && InVecA == NNE)	{ return N; }
+	if (InVecA == NNE && InVecB == E  ||InVecB == NNE && InVecA == E)	{ return ENE; }
+	if (InVecA == E   && InVecB == SSE||InVecB == E   && InVecA == SSE)	{ return ESE; }
+	if (InVecA == SSE && InVecB == SSW||InVecB == SSE && InVecA == SSW)	{ return S; }
+	if (InVecA == SSW && InVecB == W  ||InVecB == SSW && InVecA == W)	{ return WSW; }
+	if (InVecA == W   && InVecB == NNW||InVecB == W   && InVecA == NNW)	{ return WNW; }
+	return FHexVector();
+}
+bool AAdventureMap::DiagIsReachable(AHexTile* InStart, FHexVector InDiagUnitVec) {
+	FHexVector BlockA;
+	FHexVector BlockB;
+	if (InDiagUnitVec == N) { BlockA = NNW, BlockB = NNE; }
+	if (InDiagUnitVec == ENE) { BlockA = NNE, BlockB = E; }
+	if (InDiagUnitVec == ESE) { BlockA = E, BlockB = SSE; }
+	if (InDiagUnitVec == S)	{ BlockA = SSE, BlockB = SSW; }
+	if (InDiagUnitVec == WSW) { BlockA = SSW, BlockB = W; }
+	if (InDiagUnitVec == WNW) { BlockA = W, BlockB = NNW; }
+	AHexTile* HexA = Grid[GridIndex(InStart->Q + BlockA.Q, InStart->R + BlockA.R)];
+	AHexTile* HexB = Grid[GridIndex(InStart->Q + BlockB.Q, InStart->R + BlockB.R)];
+	return (HexA->bFree && HexB->bFree);
 }