Platform engine using Box2D
2009-10-18 00:00:00 来源:WEB开发网I am also using the input class included in Box2D, why writing my own one if that one works?
At the moment it’s only a bunch of lines starting from the Hello World example, but starting from tomorrow I’ll code the main character shooting as seen in Rick Triqui.
package {
import flash.display.Sprite;
import flash.events.Event;
import Box2D.Dynamics.*;
import Box2D.Collision.*;
import Box2D.Collision.Shapes.*;
import Box2D.Common.Math.*;
import General.Input;
import flash.events.MouseEvent;
public class HelloWorld extends Sprite {
public var m_world:b2World;
public var pixels_in_a_meter:int=30;
public var bodyDef:b2BodyDef;
public var boxDef:b2PolygonDef;
public var m_input:Input;
public var xspeed:int=0;
var body:b2Body;
public function HelloWorld() {
addEventListener(Event.ENTER_FRAME, Update, false, 0, true);
var worldAABB:b2AABB = new b2AABB();
worldAABB.lowerBound.Set(-100.0, -100.0);
worldAABB.upperBound.Set(100.0, 100.0);
var gravity:b2Vec2=new b2Vec2(0.0,10.0);
var doSleep:Boolean=true;
m_world=new b2World(worldAABB,gravity,doSleep);
var m_sprite:Sprite;
m_sprite = new Sprite();
addChild(m_sprite);
var dbgDraw:b2DebugDraw = new b2DebugDraw();
var dbgSprite:Sprite = new Sprite();
m_sprite.addChild(dbgSprite);
dbgDraw.m_sprite=m_sprite;
dbgDraw.m_drawScale=30;
dbgDraw.m_alpha=1;
dbgDraw.m_fillAlpha=0.5;
dbgDraw.m_lineThickness=1;
dbgDraw.m_drawFlags=b2DebugDraw.e_shapeBit;
m_world.SetDebugDraw(dbgDraw);
var bodyDef:b2BodyDef;
var boxDef:b2PolygonDef;
var circleDef:b2CircleDef;
square_tile(250,395,500,10);
hero(100,370,10,40);
// Box2D input class - why should I bother making my one?
m_sprite = new Sprite();
addChild(m_sprite);
// input
m_input=new Input(m_sprite);
}
public function square_tile(px:int,py:int,w:int,h:int) {
bodyDef = new b2BodyDef();
bodyDef.position.Set(px/pixels_in_a_meter, py/pixels_in_a_meter);
boxDef = new b2PolygonDef();
boxDef.SetAsBox(real_pixels(w), real_pixels(h));
boxDef.friction=0.3;
boxDef.density=0;
body=m_world.CreateBody(bodyDef);
body.CreateShape(boxDef);
body.SetMassFromShapes();
}
public function hero(px:int, py:int, w:int, h:int) {
bodyDef = new b2BodyDef();
bodyDef.position.Set(px/pixels_in_a_meter, py/pixels_in_a_meter);
boxDef = new b2PolygonDef();
boxDef.SetAsBox(real_pixels(w), real_pixels(h));
boxDef.density=1.0;
boxDef.friction=0.3;
boxDef.restitution=0.2;
bodyDef.userData = new Sprite();
bodyDef.userData.name="Player";
body=m_world.CreateBody(bodyDef);
body.SetBullet(true);
body.CreateShape(boxDef);
body.SetMassFromShapes();
}
public function real_pixels(n:int) {
return (n/pixels_in_a_meter/2);
}
public function Update(e:Event):void {
m_world.Step(1/30, 10);
for (var bb:b2Body = m_world.m_bodyList; bb; bb = bb.m_next) {
if (bb.GetUserData()!=null) {
if (Input.isKeyPressed(39)) {
xspeed=3;
} else if (Input.isKeyPressed(37)) {
xspeed=-3;
}
if (xspeed) {
bb.WakeUp();
bb.m_linearVelocity.x=xspeed;
}
bb.m_sweep.a = 0;
}
}
Input.update();
}
}
}
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