1.在.h文件中添加私有变量 b2MouseJoint *_mouseJoint;//用来拖拽手臂
2.在.m文件的init文件添加可以触摸 self.touchEnabled = YES;
3.实现touch-delegate 的下列方法
[code lang=”objc”]
#pragma mark – 触摸方法
-(void)ccTouchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
if (_mouseJoint!=NULL) {
return;
}
for (UITouch *touch in touches) {
CGPoint location=[touch locationInView:[touch view]];
location=[[CCDirector sharedDirector] convertToGL:location];
b2Vec2 worldLocation=[Helper metersFromPoint:location];
//得到手臂的夹具
b2Fixture *armFixture=_armBody->GetFixtureList();
if (armFixture->TestPoint(worldLocation)) { //判断touch坐标点是否选中了手臂刚体
//定义鼠标关节
b2MouseJointDef mouseDef;
mouseDef.bodyA=_groundBody;
mouseDef.bodyB=_armBody;
mouseDef.target=worldLocation; //用来指明移动的目标
mouseDef.maxForce=_armBody->GetMass()*1000.f;//maxForce越大移动越简单
_mouseJoint=(b2MouseJoint *)world->CreateJoint(&mouseDef);
}
}
}
-(void)ccTouchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
for (UITouch *touch in touches) {
CGPoint location=[touch locationInView:[touch view]];
location=[[CCDirector sharedDirector] convertToGL:location];
b2Vec2 worldLocation=[Helper metersFromPoint:location];
if (_mouseJoint) {
_mouseJoint->SetTarget(worldLocation);
}
}
}
-(void)ccTouchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event{
if (_mouseJoint) {
world->DestroyJoint(_mouseJoint);
_mouseJoint=NULL;
}
}
– (void)ccTouchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
//Add a new body/atlas sprite at the touched location
for( UITouch *touch in touches ) {
CGPoint location = [touch locationInView: [touch view]];
location = [[CCDirector sharedDirector] convertToGL: location];
if (_mouseJoint) {
world->DestroyJoint(_mouseJoint);
_mouseJoint=NULL;
//计算射击的方向和用力的大小
CGFloat shootAngle=_armBody->GetAngle();
int power=20;
float x1=cos(shootAngle);
float y1=sin(shootAngle);
//2.根据计算出来的角度计算发射的力，因为力是矢量所以有大小和方向
b2Vec2 force=b2Vec2(x1*power, y1*power);
//3.创建子弹刚体
b2BodyDef bulletDef;
bulletDef.position=_armBody->GetWorldCenter()+(4.0/PTM_RATIO)*b2Vec2(x1, y1);
bulletDef.bullet=true;
bulletDef.type=b2_dynamicBody;
bulletDef.fixedRotation=true;
bulletDef.linearDamping=0.5f;
b2Body *bulletBody=world->CreateBody(&bulletDef);
//将sprite关联到body的userData上 ，然后就可以通过userData的到精灵
int *bulletTag=new int(kTagBulletBody); //将刚体与精灵关联
bulletBody->SetUserData(bulletTag);
b2CircleShape bulletShap;
bulletShap.m_radius=5.0/PTM_RATIO;
b2FixtureDef bulletFixture;
bulletFixture.shape=&bulletShap;
bulletFixture.friction=0.4f; //摩擦力
bulletFixture.restitution=0.2f; //恢复力
bulletFixture.density=10.0f; //密度
bulletFixture.filter.categoryBits=0x0001; //默认状态下category也是1
bulletFixture.filter.maskBits=0xffff; //设置与所有的刚体发生碰撞
bulletFixture.filter.groupIndex=4; //大于0总是会参与碰撞
bulletBody->CreateFixture(&bulletFixture);
//4.给子弹施加计算的力
bulletBody->ApplyLinearImpulse(force, bulletBody->GetLocalCenter());
}
}
}
[/code]
🙂