SpriteKit生成随机curl线

我正在做一个项目，我需要完成的是产生随机curl线。 在这一点上，我已经有一个随机生成的线，但不curl。 我每0.5秒在不同的x位置产生点，并将这些点与bezier连接起来。 除了不curl之外，一切都很完美。 在下面的图片显示在1）我现在怎么拥有它和2）我想如何做到这一点。 任何想法，我可以做到这一点？ 我正在使用SpriteKit – Objective C

Answer 1

基本上你需要做的和随机化一个贝塞尔（参数）曲线是控制点 。

当你阅读这个好的答案并熟悉术语之后，你可以试试这个例子（我假设你的场景和视图大小已经设置正确）：

GameScene.m

#import "GameScene.h" @implementation GameScene -(void)didMoveToView:(SKView *)view { } -(NSInteger)randomNumberBetween:(NSInteger)from to:(NSInteger)to { return (int)from + arc4random() % (to-from+1); } - (CGMutablePathRef)generatePath { CGMutablePathRef path = CGPathCreateMutable(); CGPoint p0 = CGPointMake(CGRectGetMidX(self.frame),self.scene.size.height-20.0f); //starting point just little below the upper edge of the screen CGPathMoveToPoint(path, nil, p0.x, p0.y); CGPoint p1 = CGPointMake([self randomNumberBetween:150 to:300], self.scene.size.height- [self randomNumberBetween:150 to:300]); CGPoint p2 = CGPointMake([self randomNumberBetween:150 to:300],[self randomNumberBetween:150 to:300]); CGPoint p3 = CGPointMake(CGRectGetMidX(self.frame),0 + 20.0f); //ending point, just little above the bottom edge of the screen CGFloat v = 0.3; CGFloat cp1x = p1.x+v * (p1.x-p0.x); CGFloat cp1y = p1.y+v * (p1.y-p0.y); CGFloat cp2x = p2.xv * (p3.x-p2.x); CGFloat cp2y = p2.yv * (p3.y-p2.y); CGPathAddCurveToPoint(path,nil,cp1x,cp1y,cp2x,cp2y,p3.x,p3.y); /*Debug - not needed*/ SKSpriteNode *sp0 = [SKSpriteNode spriteNodeWithColor:[SKColor yellowColor] size:CGSizeMake(5.0f,5.0f)]; sp0.zPosition = 5; sp0.position = p0; SKLabelNode *lp0 = [SKLabelNode labelNodeWithFontNamed:@"ArialMT"]; lp0.fontColor = [SKColor whiteColor]; lp0.fontSize = 20.0f; lp0.text = @"p0"; lp0.position = CGPointMake(0.0f,-20.0f); [sp0 addChild:lp0]; [self addChild:sp0]; SKSpriteNode *sp1 = [SKSpriteNode spriteNodeWithColor:[SKColor yellowColor] size:CGSizeMake(5.0f,5.0f)]; sp1.zPosition = 5; sp1.position = p1; SKLabelNode *lp1 = [SKLabelNode labelNodeWithFontNamed:@"ArialMT"]; lp1.fontColor = [SKColor whiteColor]; lp1.fontSize = 20.0f; lp1.position = CGPointMake(0.0f,15.0f); lp1.text = @"p1"; [sp1 addChild:lp1]; [self addChild:sp1]; SKSpriteNode *sp2 = [SKSpriteNode spriteNodeWithColor:[SKColor yellowColor] size:CGSizeMake(5.0f,5.0f)]; sp2.zPosition = 5; sp2.position = p2; SKLabelNode *lp2 = [SKLabelNode labelNodeWithFontNamed:@"ArialMT"]; lp2.fontColor = [SKColor whiteColor]; lp2.fontSize = 20.0f; lp2.position = CGPointMake(0.0f,15.0f); lp2.text = @"p2"; [sp2 addChild:lp2]; [self addChild:sp2]; SKSpriteNode *sp3 = [SKSpriteNode spriteNodeWithColor:[SKColor yellowColor] size:CGSizeMake(5.0f,5.0f)]; sp3.zPosition = 5; sp3.position = p3; SKLabelNode *lp3 = [SKLabelNode labelNodeWithFontNamed:@"ArialMT"]; lp3.fontColor = [SKColor whiteColor]; lp3.fontSize = 20.0f; lp3.position = CGPointMake(0.0f,15.0f); lp3.text = @"p3"; [sp3 addChild:lp3]; [self addChild:sp3]; SKShapeNode *p0p1 = [SKShapeNode node]; p0p1.zPosition = 2; CGMutablePathRef path1 = CGPathCreateMutable(); CGPathMoveToPoint(path1, NULL, p0.x, p0.y); CGPathAddLineToPoint(path1, NULL, p1.x, p1.y); p0p1.path = path1; [p0p1 setStrokeColor:[UIColor greenColor]]; [self addChild:p0p1]; SKShapeNode *p2p3 = [SKShapeNode node]; p2p3.zPosition = 2; CGMutablePathRef path2 = CGPathCreateMutable(); CGPathMoveToPoint(path2, NULL, p2.x, p2.y); CGPathAddLineToPoint(path2, NULL, p3.x, p3.y); p2p3.path = path2; [p2p3 setStrokeColor:[UIColor greenColor]]; [self addChild:p2p3]; return path; } -(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { [self removeAllChildren]; SKShapeNode *yourline = [SKShapeNode node]; yourline.zPosition = 1; yourline.path = [self generatePath]; [yourline setLineWidth:5]; [yourline setStrokeColor:[SKColor redColor]]; [self addChild:yourline]; } 

大部分代码用于可视化debugging，而不需要为了随机化曲线。 重要的部分是generatePath方法的第一部分。 结果如下：