fix(sdk): polygon paths can be interpolated

Author: Julien

engine/modules/entities/src/main/java/com/codingame/gameengine/module/entities/Polygon.java

@@ -19,27 +19,52 @@ public Point(int x, int y) {
             this.x = x;
             this.y = y;
         }
-        
+
     }
-    
+
     private List<Point> points = new ArrayList<>();
 
     Polygon() {
         super();
     }
-    
+
     /**
      * Adds a point to the path of this <code>Polygon</code>.
-     * @param x the x coordinate in world units
-     * @param y the x coordinate in world units
+     * 
+     * @param x
+     *            the x coordinate in world units
+     * @param y
+     *            the x coordinate in world units
      * @return this <code>Polygon</code>
      */
     public Polygon addPoint(int x, int y) {
         points.add(new Point(x, y));
         set("points", asString(points));
         return this;
     }
-    
+
+    /**
+     * Clears the path of this <code>Polygon</code>.
+     * 
+     * @return this <code>Polygon</code>
+     */
+    public Polygon clearPoints() {
+        points.clear();
+        set("points", asString(points));
+        return this;
+    }
+
+    /**
+     * Sets the transition used to animate the positions of each point. Only used if the path has the same number of points.
+     * @param curve
+     *            the transition to animate between coordinates of each point in the path.
+     * @return this <code>Polygon</code>
+     */
+    public Polygon setPointsInterpolationCurve(Curve curve) {
+        set("points", asString(points), curve);
+        return this;
+    }
+
     private String asString(List<Point> points) {
         return points.stream().map(p -> p.x + "," + p.y).collect(Collectors.joining(","));
     }

engine/modules/entities/src/main/resources/view/entity-module/properties.js

@@ -117,6 +117,12 @@ export const PROPERTIES = {
         return []
       }
       return value.split(',').map(v => parseInt(v))
+    },
+    lerpMethod: (a, b, u) => {
+      if (a.length === b.length) {
+        return a.map((v, idx) => lerp(v, b[idx], u))
+      }
+      return noLerp(a, b, u)
     }
   }
 }