Added Triangle.GetPoint and Triangle.GetPoints. Both working with tests in the examples repo.

Author: photonstorm

v3/src/geom/triangle/GetPoint.js

@@ -0,0 +1,62 @@
+var Point = require('../point/Point');
+var Length = require('../line/Length');
+
+//  Position is a value between 0 and 1
+var GetPoint = function (triangle, position, out)
+{
+    if (out === undefined) { out = new Point(); }
+
+    var line1 = triangle.getLineA();
+    var line2 = triangle.getLineB();
+    var line3 = triangle.getLineC();
+
+    if (position <= 0 || position >= 1)
+    {
+        out.x = line1.x1;
+        out.y = line1.y1;
+
+        return out;
+    }
+
+    var length1 = Length(line1);
+    var length2 = Length(line2);
+    var length3 = Length(line3);
+
+    var perimeter = length1 + length2 + length3;
+
+    var p = perimeter * position;
+    var localPosition = 0;
+
+    //  Which line is it on?
+
+    if (p < length1)
+    {
+        //  Line 1
+        localPosition = p / length1;
+
+        out.x = line1.x1 + (line1.x2 - line1.x1) * localPosition;
+        out.y = line1.y1 + (line1.y2 - line1.y1) * localPosition;
+    }
+    else if (p > length1 + length2)
+    {
+        //  Line 3
+        p -= length1 + length2;
+        localPosition = p / length3;
+
+        out.x = line3.x1 + (line3.x2 - line3.x1) * localPosition;
+        out.y = line3.y1 + (line3.y2 - line3.y1) * localPosition;
+    }
+    else
+    {
+        //  Line 2
+        p -= length1;
+        localPosition = p / length2;
+
+        out.x = line2.x1 + (line2.x2 - line2.x1) * localPosition;
+        out.y = line2.y1 + (line2.y2 - line2.y1) * localPosition;
+    }
+
+    return out;
+};
+
+module.exports = GetPoint;

v3/src/geom/triangle/GetPoints.js

@@ -0,0 +1,66 @@
+var Length = require('../line/Length');
+var Point = require('../point/Point');
+
+var GetPoints = function (triangle, quantity, stepRate, out)
+{
+    if (out === undefined) { out = []; }
+
+    var line1 = triangle.getLineA();
+    var line2 = triangle.getLineB();
+    var line3 = triangle.getLineC();
+
+    var length1 = Length(line1);
+    var length2 = Length(line2);
+    var length3 = Length(line3);
+
+    var perimeter = length1 + length2 + length3;
+
+    //  If quantity is a falsey value (false, null, 0, undefined, etc) then we calculate it based on the stepRate instead.
+    if (!quantity)
+    {
+        quantity = perimeter / stepRate;
+    }
+
+    for (var i = 0; i < quantity; i++)
+    {
+        var p = perimeter * (i / quantity);
+        var localPosition = 0;
+
+        var point = new Point();
+
+        //  Which line is it on?
+
+        if (p < length1)
+        {
+            //  Line 1
+            localPosition = p / length1;
+
+            point.x = line1.x1 + (line1.x2 - line1.x1) * localPosition;
+            point.y = line1.y1 + (line1.y2 - line1.y1) * localPosition;
+        }
+        else if (p > length1 + length2)
+        {
+            //  Line 3
+            p -= length1 + length2;
+            localPosition = p / length3;
+
+            point.x = line3.x1 + (line3.x2 - line3.x1) * localPosition;
+            point.y = line3.y1 + (line3.y2 - line3.y1) * localPosition;
+        }
+        else
+        {
+            //  Line 2
+            p -= length1;
+            localPosition = p / length2;
+
+            point.x = line2.x1 + (line2.x2 - line2.x1) * localPosition;
+            point.y = line2.y1 + (line2.y2 - line2.y1) * localPosition;
+        }
+
+        out.push(point);
+    }
+
+    return out;
+};
+
+module.exports = GetPoints;

v3/src/geom/triangle/Triangle.js

@@ -1,4 +1,6 @@
 var Class = require('../../utils/Class');
+var GetPoint = require('./GetPoint');
+var GetPoints = require('./GetPoints');
 var Random = require('./Random');
 
 // A triangle is a plane created by connecting three points.
@@ -23,6 +25,16 @@ var Triangle = new Class({
         this.setTo(x1, y1, x2, y2, x3, y3);
     },
 
+    getPoint: function (position, output)
+    {
+        return GetPoint(this, position, output);
+    },
+
+    getPoints: function (quantity, stepRate, output)
+    {
+        return GetPoints(this, quantity, stepRate, output);
+    },
+
     getRandomPoint: function (point)
     {
         return Random(this, point);