Question

正在关注this Free PoBo site中的示例，但想要创建一个＆＃34;交叉＆＃34; （或＆＃34;加＆＃34;）形状而不仅仅是跷跷板。

上传了一个小型测试项目here，基本上它会创建一个如下所示的场景，其中一个跷跷板被其中一个替换为我试图放入的交叉物。 enter image description here

当您点击屏幕上的任何位置时，它会创建一个小球或方形盒子，然后从您敲击的位置下降。当物体撞击跷跷板时，它会按预期旋转。

问题是，交叉对象并不总是按预期旋转 - 只有当对象击中十字形对象的中间绿色圆圈时，它才会旋转。否则，对象只会穿过蓝色矩形，就好像它不存在一样。不知道我做错了什么？!!

这就是＆＃34;交叉＆＃34; （或＆＃34;加＆＃34;）形状已添加到代码中。感谢任何帮助，谢谢！

....
        float wWidth = 100.0f;
        float wHeight = 10.0f;

....  

 [self addCross:CGPointMake(self.frame.size.width*0.75f, self.frame.size.height*0.60f)
                  game:self
             whipWidth:wWidth*0.5f
            whipHeight:wHeight];


....


-(CGMutablePathRef)getCGMutablePathRef:(float)ww thickness:(float)tt {

    CGMutablePathRef boundingPath = CGPathCreateMutable();
    float halfTT = tt*0.5;

    CGPathMoveToPoint(boundingPath, NULL, halfTT, halfTT);
    CGPathAddLineToPoint(boundingPath, NULL, halfTT+ww, halfTT);
    CGPathAddLineToPoint(boundingPath, NULL, halfTT+ww, -halfTT);
    CGPathAddLineToPoint(boundingPath, NULL, halfTT, -halfTT);
    CGPathAddLineToPoint(boundingPath, NULL, halfTT, -halfTT-ww);
    CGPathAddLineToPoint(boundingPath, NULL, -halfTT, -halfTT-ww);
    CGPathAddLineToPoint(boundingPath, NULL, -halfTT, -halfTT);
    CGPathAddLineToPoint(boundingPath, NULL, -halfTT-ww, -halfTT);
    CGPathAddLineToPoint(boundingPath, NULL, -halfTT-ww, halfTT);
    CGPathAddLineToPoint(boundingPath, NULL, -halfTT, halfTT);
    CGPathAddLineToPoint(boundingPath, NULL, -halfTT, halfTT+ww);
    CGPathAddLineToPoint(boundingPath, NULL, halfTT, halfTT+ww);
    CGPathAddLineToPoint(boundingPath, NULL, halfTT, halfTT);

    return boundingPath;

}

-(void)addCross:(CGPoint)pos game:(SKScene*)game  whipWidth:(float)whipWidth whipHeight:(float)whipHeight {

    idNumber++;

    SKSpriteNode * anchor = [SKSpriteNode spriteNodeWithColor:[UIColor clearColor] size:CGSizeMake(1, 1)];
    anchor.position = pos;
    anchor.name = [NSString stringWithFormat:@"whip_anchor-%d",idNumber];
    anchor.physicsBody = [SKPhysicsBody bodyWithCircleOfRadius:1];
    anchor.physicsBody.affectedByGravity = false;
    anchor.physicsBody.dynamic = false;
    [game addChild:anchor];

    CGMutablePathRef boundingPath = [self getCGMutablePathRef:whipWidth thickness:whipHeight];

    CGMutablePathRef boundingPath2 = [self getCGMutablePathRef:whipWidth thickness:whipHeight];

    SKShapeNode* polygon = [[SKShapeNode alloc]init];

    polygon.path = CGPathCreateMutableCopy(boundingPath2);

    polygon.physicsBody = [SKPhysicsBody bodyWithPolygonFromPath:boundingPath];
    CGPathRelease(boundingPath);
    CGPathRelease(boundingPath2);

    polygon.name = @"polygon";

    polygon.lineWidth = 0.01;
    polygon.fillColor = [SKColor blueColor];
    polygon.lineWidth = 0;

    polygon.physicsBody.affectedByGravity = NO;
    [anchor addChild:polygon];

    SKSpriteNode * gear = [SKSpriteNode spriteNodeWithImageNamed:@"ball"];
    gear.size = CGSizeMake(whipHeight+5, whipHeight+5);
    gear.name = [NSString stringWithFormat:@"gear-%d",idNumber];
    [anchor addChild:gear];

    SKPhysicsJointPin* jointPin = [SKPhysicsJointPin jointWithBodyA:anchor.physicsBody
                                                              bodyB:polygon.physicsBody
                                                             anchor:anchor.position];
    [game.physicsWorld addJoint:jointPin];


    idNumber++;

}

Answer 1

最后让它工作，而不是使用多边形绘制十字架，只需使用固定关节（SKPhysicsJointFixed）将2个矩形连接在一起。我的博客上发布了更新的代码（请参阅[2014-09-03更新]下的部分）。感谢。

http://new2objectivec.blogspot.com.au/2014/08/how-to-create-cross-or-plus-shape.html

如何创建一个＆＃34; cross＆＃34; （或＆＃34;加＆＃34;）用Sprite Kit Physics塑造旋转对象？

1 个答案: