From 29d97c2a5fd5b6ea65faead393a22a666d7ce0f4 Mon Sep 17 00:00:00 2001
From: ballparts <ballparts@ballpartss-Mac-mini.local>
Date: Mon, 23 Mar 2015 19:40:06 -0700
Subject: [PATCH] Allow options for diagonal pathfinding

Add option to disallow pathfinding between walls diagonally.
---
 astar.js | 48 +++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 47 insertions(+), 1 deletion(-)

diff --git a/astar.js b/astar.js
index 3c617c7..22c8853 100644
--- a/astar.js
+++ b/astar.js
@@ -159,6 +159,8 @@ function Graph(gridIn, options) {
     options = options || {};
     this.nodes = [];
     this.diagonal = !!options.diagonal;
+    this.diagonalIfAtMostOne = !!options.diagonalIfAtMostOne;
+    this.diagonalOnlyWhenNoObstacles = !!options.diagonalOnlyWhenNoObstacles;
     this.grid = [];
     for (var x = 0; x < gridIn.length; x++) {
         this.grid[x] = [];
@@ -238,6 +240,50 @@ Graph.prototype.neighbors = function(node) {
         }
     }
 
+    if (this.diagonalIfAtMostOne) {
+        // Southwest
+        if(grid[x-1] && grid[x-1][y-1] && (grid[x-1][y].weight || grid[x][y-1].weight)) {
+            ret.push(grid[x-1][y-1]);
+        }
+
+        // Southeast
+        if(grid[x+1] && grid[x+1][y-1] && (grid[x+1][y].weight || grid[x][y-1].weight)) {
+            ret.push(grid[x+1][y-1]);
+        }
+
+        // Northwest
+        if(grid[x-1] && grid[x-1][y+1] && (grid[x-1][y].weight || grid[x][y+1].weight)) {
+            ret.push(grid[x-1][y+1]);
+        }
+
+        // Northeast
+        if(grid[x+1] && grid[x+1][y+1] && (grid[x+1][y].weight || grid[x][y+1].weight)) {
+            ret.push(grid[x+1][y+1]);
+        }
+    }
+
+    if(this.diagonalOnlyWhenNoObstacles) {
+        // Southwest
+        if(grid[x-1] && grid[x-1][y-1] && grid[x-1][y].weight && grid[x][y-1].weight) {
+            ret.push(grid[x-1][y-1]);
+        }
+
+        // Southeast
+        if(grid[x+1] && grid[x+1][y-1] && grid[x+1][y].weight && grid[x][y-1].weight) {
+            ret.push(grid[x+1][y-1]);
+        }
+
+        // Northwest
+        if(grid[x-1] && grid[x-1][y+1] && grid[x-1][y].weight && grid[x][y+1].weight) {
+            ret.push(grid[x-1][y+1]);
+        }
+
+        // Northeast
+        if(grid[x+1] && grid[x+1][y+1] && grid[x+1][y].weight && grid[x][y+1].weight) {
+            ret.push(grid[x+1][y+1]);
+        }
+    }
+
     return ret;
 };
 
@@ -404,4 +450,4 @@ return {
     Graph: Graph
 };
 
-});
+});
\ No newline at end of file