我认为使用ignoresSiblingOrder和zPosition对SpriteKit渲染性能没有影响

Question

在SpriteKit文档以及WWDC的视频中，Apple建议使用zPosition来提高SpriteKit渲染性能。

我试图测量效果。不幸的是我看不到任何影响。

我创建了一个标准游戏项目：

并使用以下代码替换 touchesBegan 方法：

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {

// Determine the center of the view
CGPoint loc = CGPointMake(CGRectGetMidX(self.frame), CGRectGetMidY(self.frame));

// My expectation was that this has a huge defect on the FPS
self.view.ignoresSiblingOrder = YES;


// Create thousands of sprites on different layers
for (int i=-25; i<=25; i++) {
    for (int j=-50; j<=50; j++) {

        // create a node to group the sprites
        SKNode *node = [[SKNode alloc] init];
        node.position = CGPointMake(loc.x+10*i, loc.y+10*j);
        node.zPosition=100;
        [self addChild:node];

        // Create sprites for layer 1
        SKSpriteNode *sprite1 = [SKSpriteNode spriteNodeWithImageNamed:@"Spaceship"];
        sprite1.zRotation=0.0;
        sprite1.size=CGSizeMake(10, 10);
        if (self.view.ignoresSiblingOrder) sprite1.zPosition=1;
        [node addChild:sprite1];

        // Create sprites for layer 2
        SKSpriteNode *sprite2 = [SKSpriteNode spriteNodeWithImageNamed:@"Spaceship"];
        sprite2.size=CGSizeMake(10, 10);
        sprite2.zRotation=0.75;
        if (self.view.ignoresSiblingOrder) sprite2.zPosition=2;
        [node addChild:sprite2];

        // Create sprites for layer 3
        SKSpriteNode *sprite3 = [SKSpriteNode spriteNodeWithImageNamed:@"Spaceship"];
        sprite3.size=CGSizeMake(10, 10);
        sprite3.zRotation=1.5;
        if (self.view.ignoresSiblingOrder) sprite3.zPosition=3;
        [node addChild:sprite3];

        // Create sprites for layer 4
        SKSpriteNode *sprite4 = [SKSpriteNode spriteNodeWithImageNamed:@"Spaceship"];
        sprite4.size=CGSizeMake(10, 10);
        sprite4.zRotation=2.2;
        if (self.view.ignoresSiblingOrder) sprite4.zPosition=4;
        [node addChild:sprite4];

        // Create sprites for layer 5
        SKSpriteNode *sprite5 = [SKSpriteNode spriteNodeWithImageNamed:@"Spaceship"];
        sprite5.size=CGSizeMake(10, 10);
        sprite5.zRotation=3.14;
        if (self.view.ignoresSiblingOrder) sprite5.zPosition=5;
        [node addChild:sprite5];

        // Add some animations
        SKAction *action = [SKAction rotateByAngle:M_PI duration:1];
        [sprite1 runAction:[SKAction repeatActionForever:action]];
        [sprite2 runAction:[SKAction repeatActionForever:action]];
        [sprite3 runAction:[SKAction repeatActionForever:action]];
        [sprite4 runAction:[SKAction repeatActionForever:action]];
        [sprite5 runAction:[SKAction repeatActionForever:action]];

    }
}}

我的期望是在两种情况之间看到巨大差异：

self.view.ignoresSiblingOrder = YES;

和

self.view.ignoresSiblingOrder = NO;

但它只有一个FPS。

效果是低还是我做错了？我已经在iOS 5 Beta 4的iPhone 5上进行了测试。

我知道这是许多精灵在iPhone上玩真实游戏的方法。我开始使用少量精灵，发现没有效果，增加了精灵的数量，......

非常感谢 斯蒂芬

考虑到LearnCocos2d的评论，我改变了测试场景的代码。精灵更大，每个节点3个精灵完全覆盖自己。

令人惊讶的是，self.view.ignoresSiblingOrder = NO比4 FPS更快。现在我真的很困惑......

这是我的新测试代码：

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {

int iSpriteSize =100;

// Determine the center of the view
CGPoint loc = CGPointMake(CGRectGetMidX(self.frame), CGRectGetMidY(self.frame));

// My expectation was that this has a huge defect on the FPS
self.view.ignoresSiblingOrder = NO;


// Create thousands of sprites on different layers
for (int i=-5; i<=5; i++) {
    for (int j=-5; j<=5; j++) {

        // create a node to group the sprites
        SKNode *node = [[SKNode alloc] init];
        node.position = CGPointMake(loc.x+iSpriteSize*i, loc.y+iSpriteSize*j);
        node.zPosition=100;
        [self addChild:node];

        // Create sprites for layer 1
        SKSpriteNode *sprite1 = [SKSpriteNode spriteNodeWithImageNamed:@"Spaceship"];
        sprite1.zRotation=0.0;
        sprite1.size=CGSizeMake(iSpriteSize, iSpriteSize);
        if (self.view.ignoresSiblingOrder) sprite1.zPosition=1;
        [node addChild:sprite1];

        // Create sprites for layer 2
        SKSpriteNode *sprite2 = [SKSpriteNode spriteNodeWithImageNamed:@"Spaceship"];
        sprite2.size=CGSizeMake(iSpriteSize, iSpriteSize);
        sprite2.zRotation=0.0;
        if (self.view.ignoresSiblingOrder) sprite2.zPosition=2;
        [node addChild:sprite2];

        // Create sprites for layer 3
        SKSpriteNode *sprite3 = [SKSpriteNode spriteNodeWithImageNamed:@"Spaceship"];
        sprite3.size=CGSizeMake(iSpriteSize, iSpriteSize);
        sprite3.zRotation=0.0;
        if (self.view.ignoresSiblingOrder) sprite3.zPosition=3;
        [node addChild:sprite3];

        // Create sprites for layer 4
        SKSpriteNode *sprite4 = [SKSpriteNode spriteNodeWithImageNamed:@"Spaceship"];
        sprite4.size=CGSizeMake(iSpriteSize, iSpriteSize);
        sprite4.zRotation=2.2;
        if (self.view.ignoresSiblingOrder) sprite4.zPosition=4;
        [node addChild:sprite4];

        // Create sprites for layer 5
        SKSpriteNode *sprite5 = [SKSpriteNode spriteNodeWithImageNamed:@"Spaceship"];
        sprite5.size=CGSizeMake(iSpriteSize, iSpriteSize);
        sprite5.zRotation=3.14;
        if (self.view.ignoresSiblingOrder) sprite5.zPosition=5;
        [node addChild:sprite5];

        // Add some animations
        SKAction *action = [SKAction rotateByAngle:M_PI duration:1];
        [sprite1 runAction:[SKAction repeatActionForever:action]];
        [sprite2 runAction:[SKAction repeatActionForever:action]];
        [sprite3 runAction:[SKAction repeatActionForever:action]];
        [sprite4 runAction:[SKAction repeatActionForever:action]];
        [sprite5 runAction:[SKAction repeatActionForever:action]];

    }
}}