Worms-like destructible terrain in Flash – Part 3

After another truck of Aspirin, Jordi Sanglas Molist is back with the 3rd step of his Worms tutorial.

I’ve finished part 3. I almost got a headache. Forgive me if there are some mistakes, I wrote this post and the comments quickly.

Now the character is affected by the explosions. To do that, I added an horizontal speed and a friction. However, I don’t want the character to slide when I’m using the arrow keys, so:

* The arrow keys won’t use horizontal speed
* If the horizontal speed is different than 0 (an explosion is moving the character), I can’t use the arrow keys

To calculate the impulse, we will need to use trigonometry:

I’ve also solved another bug: if the character was falling (without using the space bar), it could jump in the air. Here I removed the jumping variable and I check if the character is on the ground.

Pay attention!!! Sometimes I check if the character is ON the ground (character.y+10) and sometimes I check if the character is TOUCHING the ground (character.y+9).

KNOWN BUGS:

* The horizontal speed won’t decrease faster or more slowly if the character is on a slope.
* The for loop isn’t exact when the horizontal speed is a decimal number (I think).

What should I do in the next part? I must do it before I start school, or I won’t have time.

While you think about the next part to request, here it is the script:

package {
	import flash.display.Sprite;
	import flash.display.Bitmap;
	import flash.display.BitmapData;
	import flash.display.BlendMode;
	import flash.geom.Point;
	import flash.geom.Rectangle;
	import flash.geom.Matrix;
	import flash.events.Event;
	import flash.events.MouseEvent;
	import flash.events.KeyboardEvent;

	public class worms extends Sprite {

		public var terrain_bmpd:BitmapData=new BitmapData(550,200,true,0xFF00FF00);
		public var terrain_bmp:Bitmap=new Bitmap(terrain_bmpd);
		public var character:Sprite=new Sprite();
		public var x_speed:Number=0;
		public var y_speed:Number=0;
		public var hole:Sprite=new Sprite();
		public var hole_matrix:Matrix;
		public var left_key:Boolean;
		public var right_key:Boolean;
		public var space_key:Boolean;
		public var i:int;
		public var x_diff:Number;//x_diff and y_diff will be the difference between the character and the explosion centre
		public var y_diff:Number;
		public var explosion_radius:Number=100;//That's the radius of the explosion. If the character is inside the radius, it will move away.
		public var explosion_intensity:Number=10;//The explosion intensity is the speed (pixels/frame) that the character will
		//get if the distance between the explosion and the character is 0 (the closest one).
		public var distance:Number;//We will use that variable to store the distance between the character and the explosion
		public var angle:Number;//and that one to store the angle
		public var applied_speed:Number;//That will be the total speed we need to apply (the vector length).
		public var applied_x:Number;//Then, we will separate the applied_speed in applied_x
		public var applied_y:Number;//and applied_y
		public var ground_friction:Number=0.2;//The ground has more friction than the air,
		public var air_friction:Number=0.05;//so I have used different variables
		public function worms() {
			draw_objects();

			stage.addEventListener(Event.ENTER_FRAME,move_character);
			stage.addEventListener(MouseEvent.MOUSE_UP,mouse_up);
			stage.addEventListener(KeyboardEvent.KEY_DOWN,key_down);
			stage.addEventListener(KeyboardEvent.KEY_UP,key_up);
		}

		public function move_character(e:Event) {
			if (left_key&&x_speed==0) {//If the player is moving, we won't be able to control it
				for (i=0; i<3; i++) {
					if (! terrain_bmpd.hitTest(new Point(terrain_bmp.x,terrain_bmp.y),0x01,new Rectangle(character.x-6,character.y-10,1,17))) {
						character.x--;
						while (terrain_bmpd.hitTest(new Point(terrain_bmp.x,terrain_bmp.y),0x01,new Rectangle(character.x-5,character.y+9,10,1))) {
							character.y--;
						}
					}
				}
			}
			if (right_key&&x_speed==0) {//Let's do the same with the right key...
				for (i=0; i<3; i++) {
					if (! terrain_bmpd.hitTest(new Point(terrain_bmp.x,terrain_bmp.y),0x01,new Rectangle(character.x+5,character.y-10,1,17))) {
						character.x++;
						while (terrain_bmpd.hitTest(new Point(terrain_bmp.x,terrain_bmp.y),0x01,new Rectangle(character.x-5,character.y+9,10,1))) {
							character.y--;
						}
					}
				}
			}
			if (x_speed<0) {//This block is similar; however, we don't know the speed,
				for (i=0; i0) {
				for (i=0; i character.y+10
						character.y++;
					} else {
						y_speed=0;
					}
				}
			} else {
				for (i=0; i
And this is the result:

As usual, left and right to move the character, spacebar to make it jump and mouse click to create explosions.
Download the source code and don't forget to request the next part.