Question

我想知道是否有人知道如何将CCSprite附加到cpConstraint并让它更新物理。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。我在屏幕上有一个轮胎，你可以看到有cpConstraint作为一根绳子悬挂在屏幕顶部并连接到轮胎顶部。我想以某种方式将CCSprite附加到这个约束并让它更新轮胎的摆动或者是否有另一种方法来使用CCSprite并让它随着轮胎的摆动而更新。

我正在使用cocos2d + spaceManager。我听过有人说只是使用CCSprite并用轮胎动作更新它，但我对cocos2d或spaceManger不太熟悉，所以如果有人有一些代码片段或教程告诉我我是怎么做的可以这样做我会非常感激。

Answer 1

我不知道花栗鼠，但你会在你的滴答方法中加入什么

-(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];

在Cocos2d中使用CCSprites

1 个答案: