在Cocos2d中使用CCSprites

Question

我想知道是否有人知道我如何将CCSprite到cpConstraint并使其随物理原理更新。 这是我的代码：

upper = [game.spaceManager addPolyAt:cpv(70,195) mass:300 rotation:0 numPoints:6 points:cpv(2,12), cpv(28,8), cpv(33,0), cpv(36,-10), cpv(-33,-10), cpv(-20,8)];
upper->collision_type = kTireCollisionType;

cpShape *lower = [game.spaceManager addPolyAt:cpv(70,125) mass:300 rotation:0 numPoints:7 points:cpv(34,8), cpv(31,0), cpv(25,-9), cpv(7,-13), cpv(-20,-8), cpv(-30,0), cpv(-35,8)];
lower->collision_type = kTireCollisionType;

//HIT POINT
cpShape *sensor = [game.spaceManager addCircleAt:cpv(70,160) mass:10 radius:10];
sensor->sensor = YES;
sensor->collision_type = kScoreCollisionType;

cpShape *sensor2 = [game.spaceManager addCircleAt:cpv(70, 160) mass:10 radius:10];
sensor2->sensor = YES;

//Combine them into one body!
[game.spaceManager combineShapes:upper, lower, sensor, sensor2, nil];

//The "rope"
cpVect a1 = cpv(0,30);      //Local coordinates of tire
cpVect a2 = cpv(70,320);    //World coordinates (staticBody is at (0,0))

//calculate the length of the rope
float max = cpvdist(cpBodyLocal2World(upper->body, a1), a2);
cpConstraint *rope = [game.spaceManager addSlideToBody:upper->body fromBody:game.spaceManager.staticBody toBodyAnchor:a1 fromBodyAnchor:a2 minLength:1 maxLength:max];

cpConstraintNode *ropeNode = [cpConstraintNode nodeWithConstraint:rope];
ropeNode.color = ccBLUE;
[game addChild:ropeNode];

//Attach a sprite to the sensor, lucky for us it's exactly in the center
//of the tire... otherwise this wouldn't work
[game addChild:[super initWithShape:sensor file:@"TractorTireFront.png"] z:3];
[game addChild:[cpCCSprite spriteWithShape:sensor2 file:@"TractorTireBack.png"] z:1];

ivGame = game;

//Free the shape when we are released
self.spaceManager = game.spaceManager;
self.autoFreeShape = YES;

[self schedule:@selector(step:) interval:.1];

return self;

这是init方法的代码。 我的屏幕上有一个轮胎，如您所见，有一个cpConstraint充当绳子，它从屏幕的顶部悬挂并连接到轮胎的顶部。 我想以某种方式将CCSprite附加到此约束，并使其随轮胎的摆动而更新，或者是否存在使用CCSprite另一种方法，并使其随轮胎的摆动而更新。

我正在使用cocos2d + spaceManager。 我听说有人说只使用CCSprite并根据轮胎运动来更新它，但是我对cocos2d或spaceManger并不足够熟悉，所以如果有人有一些代码片段或一个教程向我展示如何解决这个问题我非常感谢。

Answer 1

我不知道花栗鼠，但是您将在tick方法中输入的内容是

-(void) tick() {

// not sure how you get position in chipmunk, somehow convert it to cgPoint
CGPoint * p = ccp(cpConstraint->position.x, cpConstraint->position.y);

//find out the offset of the tire compared to the cpConstraint then add it to p

p = ccp(p.x + offset.x, p.y + offset.y);

//assign it to your CCSprite

sprite.position = p;

}

初始化CCSprite

CCSprite * s = [CCSprite spritreWithFile:"picture.png"];

//add to CCLayer with is self here

[self addChild:s];