update method

game.js

@@ -2,16 +2,25 @@
  const sctx = scrn.getContext("2d");
  sctx.fillStyle = "#30c0df";
  let frames = 0;
- const gnd = {
-     sprite : new Image(),
+const gnd = {
+    animations :
+    [
+        {sprite : new Image()},
+        {sprite : new Image()},
+    ],
      x : 0,
      y :0,
+     frame : 0,
      draw : function() {
-        y = parseFloat(scrn.height-this.sprite.height);
-        sctx.drawImage(this.sprite,this.x,y);
+        y = parseFloat(scrn.height-this.animations[this.frame].sprite.height);
+        sctx.drawImage(this.animations[this.frame].sprite,this.x,y);
+     },
+     update : function(){
+        this.frame += (frames%10==0) ? 1 : 0;
+        this.frame = this.frame%this.animations.length;
      }
     };
- const bg = {
+const bg = {
     sprite : new Image(),
     x : 0,
     y :0,
@@ -43,11 +52,17 @@ const bird = {
     frame:0,
     draw : function() {
         sctx.drawImage(this.animations[this.frame].sprite,this.x,this.y);
+    },
+    update : function() {
+        this.frame += (frames%10==0) ? 1 : 0;
+        this.frame = this.frame%this.animations.length;
+        this.y += (frames%10==0) ? (Math.random()-0.5)*2 : 0;
     }
     
 };
 
-gnd.sprite.src="img/ground.png";
+gnd.animations[0].sprite.src="img/ground/g0.png";
+gnd.animations[1].sprite.src="img/ground/g1.png";
 bg.sprite.src="img/BG.png";
 gr.sprite.src="img/getready.png";
 bird.animations[0].sprite.src="img/bird/b0.png";
@@ -68,9 +83,8 @@ gameLoop();
 
  function update()
  {
-    bird.frame += (frames%5==0) ? 1 : 0;
-    bird.frame = bird.frame%4;
-    bird.y += (frames%5==0) ? (Math.random()-0.5)*2 : 0;
+  bird.update();  
+  gnd.update();
  }
  function draw()
  {