如何计算场景中的位置和随机数。SpriteKit

Question

下面是一段代码：

static inline CGFloat randomInRange(CGFloat low, CGFloat high) {



CGFloat value = arc4random_uniform(UINT32_MAX) / (CGFloat)UINT32_MAX;
return value * (high - low) +low;
}

static const CGFloat HALO_LOW_ANGLE = 200.0 * M_PI / 180;
static const CGFloat HALO_HIGH_ANGLE = 340.0 * M_PI / 180;
static const CGFloat HALO_SPEED = 100.0;

-(void) spawnHalo {

SKSpriteNode *halo = [SKSpriteNode spriteNodeWithImageNamed:@"Halo"];
halo.position = CGPointMake(randomInRange(halo.size.width / 2, self.size.width - (halo.size.width / 2)), self.size.height + (halo.size.height / 2));
halo.physicsBody = [SKPhysicsBody bodyWithCircleOfRadius:16];
CGVector direction = radiansToVector(randomInRange(HALO_LOW_ANGLE, HALO_HIGH_ANGLE));
halo.physicsBody.velocity = CGVectorMake(direction.dx * HALO_SPEED, direction.dy * HALO_SPEED);
halo.physicsBody.restitution = 1.0;
halo.physicsBody.linearDamping = 0.0;
halo.physicsBody.friction = 0.0;
[self.mainLayer addChild:halo];

我知道我们首先想要得到一个介于0-1之间的随机值。但我真正不明白的是如何计算坐标。

如果我想从任何地方产生精灵，使其位于场景的右侧、左侧或底部，该怎么办？我到底该如何计算呢？

Answer 1

这应该能起到作用：

CGPoint randomPosition = CGPointMake(arc4random() % (int)CGRectGetWidth(yourSceneInstance.frame),
                                     arc4random() % (int)CGRectGetHeight(yourSceneInstance.frame));