Godot Lesson 2: Walk and Push Animations
===================================================

Summary
--------

This lesson covers animations for the player.  We'll import 
a spritesheet and make use of the animation player.

Prerequisites
--------------

* Know how to create a scene and import assets in Godot
* A player that has movement


Video
--------

.. raw:: html

   <iframe width="560" height="315" src="https://www.youtube.com/embed/M4wuhFgubWY" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

Resources
-----------

Spritesheet: https://sprites.retro-dragon.com/index.php/2018/08/27/zlg-player-sprite/

Code
--------

Repository: https://github.com/los-alamos-steam-lab/godot-tutorial/tree/2-walk-and-push-animations

Player Code
^^^^^^^^^^^^^^^^^^^^

Major Changes from the Video:  

* I've used the enums for Vector2 instead of Vector2(0,1), etc.
* I changed the order of the movement if statement to prioritize idle 

.. code-block:: gdscript

    extends KinematicBody2D

    const SPEED = 70
    var movedir = Vector2(0,0)
    var spritedir = "down"

    # _physics_process is called by the game engine
    func _physics_process(delta):
        controls_loop()
        movement_loop()
        spritedir_loop()
        print(spritedir)
        
        # We're setting our animation here.  I've replaced Vector2(0,-1)
        # with Vector2.UP for readability, and so forth.  These are new to godot 3.1 
        # I've also changed the order of the if statement to prioritize being
        # idle if movedir is zero and created a single (very long) if statement
        # for testing the push animation.

    #	if movedir == Vector2.ZERO:
    #		anim_switch("idle")
    ##	elif is_on_wall():
    ##		if (spritedir == "left" and test_move(transform, Vector2.LEFT))\
    ##		or (spritedir == "right" and test_move(transform, Vector2.RIGHT))\
    ##		or (spritedir == "up" and test_move(transform, Vector2.UP))\
    ##		or (spritedir == "down" and test_move(transform, Vector2.DOWN)):
    ##			anim_switch("push")
    #	else: 
    #		anim_switch("walk")
    #
        
        
    # controls_loop looks for player input
    func controls_loop():
        var LEFT		= Input.is_action_pressed("ui_left")
        var RIGHT	= Input.is_action_pressed("ui_right")
        var UP		= Input.is_action_pressed("ui_up")
        var DOWN		= Input.is_action_pressed("ui_down")
        
        # By adding our values together, we make it so that one key 
        # stroke does not take precidence over another, i.e. pushing 
        # left and right keys at the same time
        movedir.x = -int(LEFT) + int(RIGHT)
        movedir.y = -int(UP) + int(DOWN)
        
    # movement_loop makes the character move
    func movement_loop():
        # .normalized makes it so that diagonal movement is 
        # the same length as 4-driectional movement
        var motion = movedir.normalized() * SPEED
        
        # move_and_slide takes care of collisions and has you slide 
        # along walls that are blocking your path
        move_and_slide(motion, Vector2.ZERO)
        
    func spritedir_loop():
        match movedir:
            Vector2.LEFT:
                spritedir = "left"
            Vector2.RIGHT:
                spritedir = "right"
            Vector2.UP:
                spritedir = "up"
            Vector2.DOWN:
                spritedir = "down"
                
    # This changes our player animation.  "animation" is a string 
    # of the sort "idle", "push", or "walk"
    func anim_switch(animation):
        var newanim = str(animation, spritedir)
        if $anim.current_animation != newanim:
            $anim.play(newanim)