From 255bdd68fce7367faa0510d9a4eb6f610a00b36c Mon Sep 17 00:00:00 2001
From: Andrew Ardill <andrew.ardill@gmail.com>
Date: Wed, 10 Jul 2013 11:59:21 +1000
Subject: [PATCH] world.js: Improve road drawing algorithm

Instead of drawing an 'L' shape road to the village, find the closest road,
outpost or village and draw the road to it. Care is taken to ensure that a
road is drawn if you are standing on top of an outpost, as the outpost may be
created before the tile it stands on is connected to the road network.
---
 script/world.js | 61 +++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 51 insertions(+), 10 deletions(-)

diff --git a/script/world.js b/script/world.js
index 7534d80..1342c57 100644
--- a/script/world.js
+++ b/script/world.js
@@ -152,27 +152,68 @@ var World = {
 	},
 	
 	drawRoad: function() {
-		var xDist = World.curPos[0] - World.RADIUS;
-		var yDist = World.curPos[1] - World.RADIUS;
+		var findClosestRoad = function(startPos) {
+			// We'll search in a spiral to find the closest road tile
+			// We spiral out along manhattan distance contour
+			// lines to ensure we draw the shortest road possible.
+			// No attempt is made to reduce the search space for
+			// tiles outside the map.
+			var searchX, searchY, dtmp,
+				x = 0,
+				y = 0,
+				dx = 1,
+				dy = -1;
+			for (var i = 0; i < Math.pow(World.getDistance(startPos, World.VILLAGE_POS) + 2, 2); i++) {
+				searchX = startPos[0] + x;
+				searchY = startPos[1] + y;
+				if (0 < searchX && searchX < World.RADIUS * 2 && 0 < searchY && searchY < World.RADIUS * 2) {
+					// check for road
+					var tile = World.state.map[searchX][searchY];
+					if (
+					 	tile === World.TILE.ROAD ||
+						(tile === World.TILE.OUTPOST && !(x === 0 && y === 0))  || // outposts are connected to roads
+						tile === World.TILE.VILLAGE // all roads lead home
+					 ) {
+						return [searchX, searchY];
+					}
+				}
+				if (x === 0 || y === 0) {
+					// Turn the corner
+					dtmp = dx;
+					dx = -dy;
+					dy =  dtmp;
+				}
+				if (x === 0 && y <= 0) {
+					x++;
+				} else {
+					x += dx;
+					y += dy;
+				}
+			}
+			return World.VILLAGE_POS;
+		};
+		var closestRoad = findClosestRoad(World.curPos);
+		var xDist = World.curPos[0] - closestRoad[0];
+		var yDist = World.curPos[1] - closestRoad[1];
 		var xDir = Math.abs(xDist)/xDist;
 		var yDir = Math.abs(yDist)/yDist;
 		var xIntersect, yIntersect;
 		if(Math.abs(xDist) > Math.abs(yDist)) {
-			xIntersect = World.RADIUS;
-			yIntersect = World.RADIUS + yDist;
+			xIntersect = closestRoad[0];
+			yIntersect = closestRoad[1] + yDist;
 		} else {
-			xIntersect = World.RADIUS + xDist;
-			yIntersect = World.RADIUS;
+			xIntersect = closestRoad[0] + xDist;
+			yIntersect = closestRoad[1];
 		}
 		
 		for(var x = 0; x < Math.abs(xDist); x++) {
-			if(World.isTerrain(World.state.map[World.RADIUS + (xDir*x)][yIntersect])) {
-				World.state.map[World.RADIUS + (xDir*x)][yIntersect] = World.TILE.ROAD;
+			if(World.isTerrain(World.state.map[closestRoad[0] + (xDir*x)][yIntersect])) {
+				World.state.map[closestRoad[0] + (xDir*x)][yIntersect] = World.TILE.ROAD;
 			}
 		}
 		for(var y = 0; y < Math.abs(yDist); y++) {
-			if(World.isTerrain(World.state.map[xIntersect][World.RADIUS + (yDir*y)])) {
-				World.state.map[xIntersect][World.RADIUS + (yDir*y)] = World.TILE.ROAD;
+			if(World.isTerrain(World.state.map[xIntersect][closestRoad[1] + (yDir*y)])) {
+				World.state.map[xIntersect][closestRoad[1] + (yDir*y)] = World.TILE.ROAD;
 			}
 		}
 		World.drawMap();