Gravity and ground height.

js/retro/RetroSprite.js

@@ -46,6 +46,21 @@ export default class RetroSprite
         return this.canvas.height;
     }
 
+    getFootHeight()
+    {
+        return new GeometryPoint(this.position.x, this.position.y + this.getHeight());
+    }
+
+    getPositionLeftFoot()
+    {
+        return new GeometryPoint(this.position.x - this.getWidth() * 0.5, this.position.y);
+    }
+
+    getPositionRightFoot()
+    {
+        return new GeometryPoint(this.position.x + this.getWidth() * 0.5, this.position.y);
+    }
+
     draw(context)
     {
         context.drawImage(this.canvas, this.position.x, this.position.y);