Added Triangle.Centroid and Triangle.InCenter methods for determining the centers of a Triangle shape.

Author: photonstorm

v3/src/checksum.js

@@ -1,4 +1,4 @@
 var CHECKSUM = {
-build: '237de9e0-14b5-11e7-9970-cb460f4880e6'
+build: 'a69a1650-14e2-11e7-b8c3-bdb77b9e9c3e'
 };
 module.exports = CHECKSUM;

v3/src/geom/triangle/Centroid.js

@@ -0,0 +1,15 @@
+//  The three medians (the lines drawn from the vertices to the bisectors of the opposite sides)
+//  meet in the centroid or center of mass (center of gravity).
+//  The centroid divides each median in a ratio of 2:1
+
+var Centroid = function (triangle, out)
+{
+    if (out === undefined) { out = { x: 0, y: 0 }; }
+
+    out.x = (triangle.x1 + triangle.x2 + triangle.x3) / 3;
+    out.y = (triangle.y1 + triangle.y2 + triangle.y3) / 3;
+
+    return out;
+};
+
+module.exports = Centroid;

v3/src/geom/triangle/InCenter.js

@@ -0,0 +1,38 @@
+// The three angle bisectors of a triangle meet in one point called the incenter.
+// It is the center of the incircle, the circle inscribed in the triangle.
+
+function getLength (x1, y1, x2, y2)
+{
+    var x = x1 - x2;
+    var y = y1 - y2;
+    var magnitude = (x * x) + (y * y);
+
+    return Math.sqrt(magnitude);
+}
+
+var InCenter = function (triangle, out)
+{
+    if (out === undefined) { out = { x: 0, y: 0 }; }
+
+    var x1 = triangle.x1;
+    var y1 = triangle.y1;
+
+    var x2 = triangle.x2;
+    var y2 = triangle.y2;
+
+    var x3 = triangle.x3;
+    var y3 = triangle.y3;
+
+    var d1 = getLength(x3, y3, x2, y2);
+    var d2 = getLength(x1, y1, x3, y3);
+    var d3 = getLength(x2, y2, x1, y1);
+
+    var p = d1 + d2 + d3;
+
+    out.x = (x1 * d1 + x2 * d2 + x3 * d3) / p;
+    out.y = (y1 * d1 + y2 * d2 + y3 * d3) / p;
+
+    return out;
+};
+
+module.exports = InCenter;

v3/src/geom/triangle/index.js

@@ -2,7 +2,9 @@
 
 var Triangle = require('./Triangle');
 
+Triangle.Centroid = require('./Centroid');
 Triangle.Contains = require('./Contains');
 Triangle.ContainsPoint = require('./ContainsPoint');
+Triangle.InCenter = require('./InCenter');
 
 module.exports = Triangle;