Top-Down RPG Shooter — Part 3 — Player Rotation

Hey everyone! Here’s a super brief tutorial. Just to hold you over for another week while I write the next big one ;)

The Code

We’ll be modifying the Player.as class so that the player rotates in the direction of the mouse. It only takes a few lines of code. (You can actually do it in one line of code, I’m just spelling everything out to make it nice and simple.)

Put all of these lines inside the bottom of the loop function in the Player.as class.

//calculate these values, which we will use to determine the angle we need to rotate to
var yDifference:Number = stageRef.mouseY - y;
var xDifference:Number = stageRef.mouseX - x;
//this constant will convert our angle from radians to degrees
var radiansToDegrees:Number = 180/Math.PI;
//this final line uses trigonometry to calculate the rotation
rotation = Math.atan2(yDifference, xDifference) * radiansToDegrees;

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Top-Down RPG Shooter — Part 2 — Player Movement

Welcome back to the second part of my “Top-Down RPG Shooter” flash game tutorial. In the last part, we set up a new project and linked it to an external Document Class, and we added the Player to the stage. In this tutorial, we’re going to program keyboard controls to move the player.

Step 1: KeyObject.as

We are going to make use of a really great open-source class called “KeyObject.as“. This class was written by a talented developer named senocular. It provides a really simple but powerful way to check which keyboard keys are pressed.

Copy and paste this class into a new .as actionscript file, and save it as “KeyObject.as” in the same folder as your main project:

package {

	import flash.display.Stage;
	import flash.events.KeyboardEvent;
	import flash.ui.Keyboard;
	import flash.utils.Proxy;
	import flash.utils.flash_proxy;

	/**
	 * The KeyObject class recreates functionality of
	 * Key.isDown of ActionScript 1 and 2
	 *
	 * Usage:
	 * var key:KeyObject = new KeyObject(stage);
	 * if (key.isDown(key.LEFT)) { ... }
	 */
	dynamic public class KeyObject extends Proxy {

		private static var stage:Stage;
		private static var keysDown:Object;

		public function KeyObject(stage:Stage) {
			construct(stage);
		}

		public function construct(stage:Stage):void {
			KeyObject.stage = stage;
			keysDown = new Object();
			stage.addEventListener(KeyboardEvent.KEY_DOWN, keyPressed);
			stage.addEventListener(KeyboardEvent.KEY_UP, keyReleased);
		}

		flash_proxy override function getProperty(name:*):* {
			return (name in Keyboard) ? Keyboard[name] : -1;
		}

		public function isDown(keyCode:uint):Boolean {
			return Boolean(keyCode in keysDown);
		}

		public function deconstruct():void {
			stage.removeEventListener(KeyboardEvent.KEY_DOWN, keyPressed);
			stage.removeEventListener(KeyboardEvent.KEY_UP, keyReleased);
			keysDown = new Object();
			KeyObject.stage = null;
		}

		private function keyPressed(evt:KeyboardEvent):void {
			keysDown[evt.keyCode] = true;
		}

		private function keyReleased(evt:KeyboardEvent):void {
			delete keysDown[evt.keyCode];
		}
	}
}

How do we use this class? Basically, we’re going to create an instance of it called “key” in our Player class (or wherever we need to access the keyboard controls). Then in that class, we can check the Boolean value of the keyObject’s isDown() function for specific keys. We can refer to keys by their unique keyCode. For example, if key.isDown(65) returns true, it means that the “A” keyboard key is currently being pressed.

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Top-Down RPG Shooter — Part 1 — Setting Up

Hello everyone! If you’re reading this, that means you haven’t given up on AS3GameTuts, despite my year-long hiatus. Thanks for your patience!

Today I’m going to start up a brand new tutorial series that I’m really excited about. How to make a top-down RPG shooter game! This tutorial is going to be slightly faster-paced than my previous tutorials. If you haven’t programmed before, I’d recommend starting with my Pong series, and then proceeding with the Platformer before you attempt this. We will be coding using AS3 in external .as files, instead of using the timeline.

What is a Top-Down RPG Shooter?

Personally, I think this is a pretty awesome game genre. I find these types of games to be genuinely fun to play.

In case you’re unfamiliar with the genre, let’s break it down:

Top-Down

Top-down refers to the perspective of the game. The world is seen from a bird’s-eye-view, and the player can move around horizontally and vertically. Prominent examples include early titles in the Legend of Zelda and Pokemon series. These games both use tile-based maps, which our game will not, for simplicity’s sake. Instead, we will draw each map individually, giving the game a more unique, hand-drawn look. (You are, of course, welcome to modify the game to use tiles, but I won’t be doing it in this tutorial.)

Our game won’t have a scrolling map. Instead, our map will be built from a series of screens that the player can walk through. When the player walks off one edge of the screen, the map will flip to the next screen.

top down rpg shooter game pokemon map

Pokemon Ruby and Sapphire feature great tile-based top-down maps.

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News! AS3GameTuts Discussion Board

After some debate, I’ve decided to create a discussion board for AS3GameTuts.com

It’s a simple, free forum, but I think it will do a good job at expanding the “comment” sections of this site.

You can find it here: http://as3gametuts.forumatic.com/

Hello Everyone, and welcome to AS3GameTuts’ new discussion board!

When I first started the AS3GameTuts website, I had only a few readers, and so it was easy for me to answer everyone’s questions, and respond to each comment individually. But now, the number of comments and support emails I am receiving is making it impossible to give everyone the attention I’d like to. This forum is how I’m attempting to solve this problem.

By creating an open, shared, easily-navigable discussion board, I am hoping that you will all have an easier time finding answers to your questions. Maybe you will find that someone has had a similar problem to your own, and found a solution. Or perhaps you can help another reader with a problem of their own.

This is also a great place to hear the latest news about the site, and to leave me a suggestion about future tutorials you would like to see written on AS3GameTuts.

Anyways, thanks for all your support, and welcome to the forum!

 

Please join the AS3GameTuts community on this discussion board, and let me know what you think!

Ben Reynolds

Sidescrolling Platformer — Part 12 — Basic Enemies

Welcome back to the side scrolling tutorial series. In this session, we will be adding (very) basic enemies to the game, which you can shoot and destroy with the bullets we created previously. This will create a lot of possibilities for what you can do with your game. In later tutorials we will add a scoring system and more advanced A.I. (artificial intelligence) to the enemies, but for now let’s focus on: creating the Enemy class, adding a few enemies to the game map, and destroying them when they are hit by a bullet.

Creating the Enemy Class

Creating the Enemy class is very similar to creating the Bullet class. If you just read Part 10 and Part 11, most of this step will look the same as when we made the Bullet class and symbol.

First, we need art. We need to create a Movie Clip object to represent the enemy on the stage. Feel free to decorate your enemy however you choose — it could be a random, inanimate object, a crazy monster, or anywhere in between.

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Sidescrolling Platformer — Part 11 — Fixing the bullets

Although we did get some functional bullets last time by using the Bullet class, we still need to make some major improvements. First of all, the bullets are added directly to the stage and have no idea about the scrollX and scrollY variables, so they don’t react when the player moves left, right, up, or down. Also, the bullets move at a sluggish pace — if they did react to the player’s movements, you could practically outrun them. Finally, they are never actually removed from the stage, so we waste precious memory that slows down the game. Imagine that we fired 1,000,000 bullets. The game would still be keeping track of all of them, constantly updating their positions, even if they are no longer on the stage. There’s some more code we can add to the bullets to handle all of this, and we are going to implement it in this tutorial.

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Sidescrolling Platformer — Part 10 — Shooting

Welcome back to the flash game tutorial: how to make a side scrolling platformer game in actionscript 3. I can’t believe we’re already up to part ten! As you can probably tell from the title, this tutorial part will exclusively feature shooting. Not all platformer games require this feature, but I’ve had a bunch of requests for this tutorial — probably because side scrolling shooters are an amazing game genre (for example, the classic Metroid games). We don’t have anything yet for our bullets to interact with, but don’t worry — next tutorial we will add the enemies. For now, let’s just focus on getting our hero to shoot.

Here is a preliminary demo of what we’ll be creating. Use the space bar to fire.

An External Actionscript File

…I knew this moment would arrive eventually… the moment when — *gasp* — we finally need to use a custom class and an external actionscript file. If you’ve never programmed anything with Object Oriented Programming before, and you’ve never created an external .as file, this might seem intimidating. Or perhaps you have no idea what I’m talking about. No matter where you stand right now, I hope that by the end of this tutorial you will have a solid idea of what external classes are, why we use them, and how to create a Class for the bullets. In future tutorials we will go into more depth on the topic.

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