Sprite Kit - 使用Switch Case向场景添加随机Sprite节点

Question

我有以下代码来创建随机对象并将它们添加到场景中。最后，在随机延迟后重复该方法。

-(void)createObjects { 

// Create random start point 
float randomStartPoint = arc4random_uniform(4) * 64 + 32; 
CGPoint startPoint = CGPointMake(self.size.width + 50, randomStartPoint); 

// Create random object and add to scene 
switch (arc4random_uniform(2)) { 
    case 0: 
    { 
     SKSpriteNode *crate = [SKSpriteNode spriteNodeWithImageNamed: @"crate"]; 

     crate.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:crate.frame.size]; 
     crate.physicsBody.dynamic = YES; 
     crate.physicsBody.affectedByGravity = NO; 
     crate.physicsBody.categoryBitMask = objectCategory; 
     crate.physicsBody.collisionBitMask = 0; 
     crate.physicsBody.contactTestBitMask = playerCategory; 

     crate.position = startPoint; 
     crate.name = @"object"; 
     crate.zPosition = 20; 

     [self addChild:crate]; 
     break; 
    } 

    case 1: 
    { 
     SKSpriteNode *cactus = [SKSpriteNode spriteNodeWithImageNamed: @"cactus"]; 

     cactus.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:cactus.frame.size]; 
     cactus.physicsBody.dynamic = YES; 
     cactus.physicsBody.affectedByGravity = NO; 
     cactus.physicsBody.categoryBitMask = objectCategory; 
     cactus.physicsBody.collisionBitMask = 0; 
     cactus.physicsBody.contactTestBitMask = playerCategory; 

     cactus.position = startPoint; 
     cactus.name = @"object"; 
     cactus.zPosition = 20; 

     [self addChild:cactus]; 
     break; 
    } 

    default: 
     break; 
} 

// After adding child, call same method at random delay 
float randomNum = arc4random_uniform(4) * 0.4 + 0.25; 
[self performSelector:@selector(createObjects) withObject:nil afterDelay:randomNum]; 
} 

在现实中，我还有更多的情况下，重复很多相同的代码，因为每个节点雪碧具有相同的设置。有没有办法一次创建一个精灵节点，并且在每种情况下都为节点设置一个不同的图像，并将其添加到场景中？

Answer 1

您可以在switch case中创建SKTexture，然后使用该纹理创建节点。

像这样：

-(void)createObjects { 

    // Create random start point 
    float randomStartPoint = arc4random_uniform(4) * 64 + 32; 
    CGPoint startPoint = CGPointMake(self.size.width + 50, randomStartPoint); 

    // Create random object and add to scene 
    SKTexture* objectTexture; 
    switch (arc4random_uniform(2)) { 
     case 0: 
      objectTexture = [SKTexture textureWithImageNamed:@"crate"]; 
      break; 
     case 1: 
      objectTexture = [SKTexture textureWithImageNamed:@"cactus"]; 
      break; 
     default: 
      break; 
    } 
    SKSpriteNode *object = [SKSpriteNode spriteNodeWithTexture:objectTexture]; 

    object.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:crate.frame.size]; 
    object.physicsBody.dynamic = YES; 
    object.physicsBody.affectedByGravity = NO; 
    object.physicsBody.categoryBitMask = objectCategory; 
    object.physicsBody.collisionBitMask = 0; 
    object.physicsBody.contactTestBitMask = playerCategory; 

    object.position = startPoint; 
    object.name = @"object"; 
    object.zPosition = 20; 

    [self addChild: object]; 
} 

另一种方式是之前切换的情况下创建对象，然后简单地创建质感和使用的SetTexture设置在开关的情况下：