From 740f2191578dc380f68342e89396b1bc89ffd9ee Mon Sep 17 00:00:00 2001
From: Francisco Dans <fdansv@gmail.com>
Date: Tue, 6 Oct 2015 16:55:29 +0200
Subject: [PATCH] optimises march with bounds wip

---
 lib/torque/renderer/iso.js | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/lib/torque/renderer/iso.js b/lib/torque/renderer/iso.js
index c0ddb37..0e19927 100644
--- a/lib/torque/renderer/iso.js
+++ b/lib/torque/renderer/iso.js
@@ -16,6 +16,7 @@ function IsoRenderer (canvas, options) {
 	this.TILE_SIZE = 256;
 	this.contourValues = [1,2,4,8,10,16,32];
 	this.lines = [];
+	this.bounds = {n: 10000, s: 0, e: 0, w: 100000};
 }
 
 torque.extend(IsoRenderer.prototype, torque.Event, {
@@ -76,8 +77,9 @@ torque.extend(IsoRenderer.prototype, torque.Event, {
 
   _renderTile: function(tile, key, frame_offset, sprites, shader, pos) {
   	if (!this._canvas) return;
-  	var ctx = this._ctx;
-  	this._gridData(tile);
+  	if (tile.x.length > 0) {
+  		this._gridData(tile);
+  	}
   },
 
   _gridData: function(tile){
@@ -95,6 +97,10 @@ torque.extend(IsoRenderer.prototype, torque.Event, {
     	var x = tile.x[i], y = tile.y[i];
     	this.globalGrid[baseIndex.y + (256 - y) / this.options.resolution -1][baseIndex.x + x/this.options.resolution] = tile.renderData[i];
     }
+    if (tile.x < this.bounds.w) this.bounds.w = tile.x;
+    else if (tile.x > this.bounds.e) this.bounds.e = tile.x;
+    if (tile.y < this.bounds.n) this.bounds.n = tile.y;
+    else if (tile.y > this.bounds.s) this.bounds.s = tile.y;
   },
 
   _getPipe: function(cell, contour){
@@ -536,9 +542,14 @@ torque.extend(IsoRenderer.prototype, torque.Event, {
 			for (var c = 0; c < contourValues.length; c++) {
 				this.lines[c] = [];
 				var pointsTraveled = new Set();
-				var pointerX = 0, pointerY = 0, x = 0, y = 0;
+				var pointerX = this.bounds.w, 
+					pointerY = this.bounds.n, 
+					x = 0, 
+					y = 0,
+					limitX = this.bounds.e,
+					limitY = this.bounds.s;
 				var line = [];
-				var xy = march(0,0);
+				var xy = march(pointerX, pointerY);
 
 				while(xy){
 					xy = march(xy.x, xy.y);