在box2d中让精灵以一定角度弹跳

Making sprite bounce in an angle in box2d

本文关键字：box2d 精灵      更新时间：2023-10-16

在我尝试制作的游戏中，我有一个球精灵，由于box2d而弹跳。下面是我当前的代码:

-(id)init
{
    ball = [CCSprite spriteWithFile:@"ball.png"];
    ball.position = ccp(150, winSize.height * 0.78);
    [self addChild:ball];
    ball.tag = 2;
b2BodyDef ballBodyDef;
ballBodyDef.type = b2_dynamicBody;
ballBodyDef.position.Set(150/PTM_RATIO, 450/PTM_RATIO);
ballBodyDef.userData = ball;
_body = _world->CreateBody(&ballBodyDef);
b2CircleShape circle;
circle.m_radius = 26.0/PTM_RATIO;
b2FixtureDef ballShapeDef;
ballShapeDef.shape = &circle;
ballShapeDef.density = 0.5f;
ballShapeDef.friction = 1.0f;
ballShapeDef.restitution = 1.0f;
_ballFixture = _body->CreateFixture(&ballShapeDef);
b2Vec2 force = b2Vec2(160, 375);
_body->ApplyLinearImpulse(force, ballBodyDef.position);}
- (void)update:(ccTime) dt {
if(_isPaused == FALSE)
{
    _world->Step(dt, 10, 10);
    for(b2Body *b = _world->GetBodyList(); b; b=b->GetNext()) {
        if (b->GetUserData() != NULL) {
            CCSprite *sprite = (CCSprite *)b->GetUserData();
            if(sprite.tag == 2)
            {
                sprite.position = ccp(b->GetPosition().x * PTM_RATIO,
                              b->GetPosition().y * PTM_RATIO);
                sprite.rotation = -1 * CC_RADIANS_TO_DEGREES(b->GetAngle());
            }
        }
    }}

弹跳本身很好，我的问题是有些情况下，球会在直线上弹跳，可以这么说，垂直或水平连续，我试图避免。所以我的问题是，我如何让我的球精灵以一个角度而不是直线反弹，这样它就不会在同一个方向无限反弹了?

你可以"随机"或以相同的间隔对物体或世界施加微小的力或重力变化。

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