SpriteKit之漫谈SKAction常用属性

SKAction属性介绍

在使用动作过程当中,对于属性的设置是必不可少的,本文将说说最常用的属性,分别是速度,时间,曲线方式.下面就分模块说一下三个常用的属性.我们首先先把我们的准备工作做好,创建好背景和精灵,代码如下所示.

#import "GameScene.h"

@implementation GameScene

-(instancetype)initWithSize:(CGSize)size{

    if (self = [super initWithSize:size]) {
        
        self.backgroundColor = [SKColor whiteColor];
        
    }

    return self;

}

-(void)didMoveToView:(SKView *)view{

    [super didMoveToView:view];

    [self backgroundNode];
    
    [self planeNode];

    
}

#pragma mark ----创建背景----

-(void)backgroundNode{

    SKSpriteNode *backgroundNode = [SKSpriteNode spriteNodeWithImageNamed:@"bg_02.jpg"];

    backgroundNode.position = CGPointZero;
    
    backgroundNode.zPosition = 0;
    
    backgroundNode.anchorPoint = CGPointZero;
    
    backgroundNode.size = self.size;
    
    [self addChild:backgroundNode];
    
    
    
}

#pragma mark ---- 创建两个飞船 ----

-(void)planeNode{

    SKSpriteNode *planeNode = [SKSpriteNode spriteNodeWithImageNamed:@"飞机.png"];
    
    planeNode.position = CGPointMake(self.size.width/2, self.size.height/2);
    
    planeNode.anchorPoint = CGPointMake(0.5, 0.5);
    
    planeNode.zPosition = 1;
    
    planeNode.name = @"plane";
    
    [self addChild:planeNode];
    
    
    SKSpriteNode *planeNode1 = [SKSpriteNode spriteNodeWithImageNamed:@"飞机.png"];
    
    planeNode1.position = CGPointMake(self.size.width/2+100, self.size.height/2);
    
    planeNode1.anchorPoint = CGPointMake(0.5, 0.5);
    
    planeNode1.zPosition = 1;
    
    planeNode1.name = @"plane1";
    
    [self addChild:planeNode1];

}

speed(速度属性)

速度因素调整动作的动画速度。例如,速度2.0倍意味着动画运行速度的两倍。速度的默认值为1.0.下面就是API文档中的SKAction的speed属性的介绍.

下面就用两个精灵说明速度属性.代码如下.



#pragma mark ---- 移动飞船 ----


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


    SKSpriteNode *planeNode = (SKSpriteNode *)[self childNodeWithName:@"plane"];
    
    SKAction *moveAction = [SKAction moveToY:0 duration:1];
    
    //设置速度
    moveAction.speed = 0.5;
    
    [planeNode runAction:moveAction];
    
    SKSpriteNode *planeNode1 = (SKSpriteNode *)[self childNodeWithName:@"plane1"];

    SKAction *moveAction1 = [SKAction moveToY:0 duration:1];
    
    //设置速度
    moveAction1.speed = 2;
    
    [planeNode1 runAction:moveAction1];
}


@end

效果图如下所示.

效果图

duration(时间属性)

想要设置或者是获取动作所需要的时间,需要使用到duration这个属性.在API文章的duration属性介绍如下图所示.

API文档中duration属性介绍

在上面的速度代码中,我们直接添加上获取时间的代码.如下所示,修改duration属性也是一样,这里我们只做获取的操作.

#pragma mark ---- 移动飞船 ----


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


    SKSpriteNode *planeNode = (SKSpriteNode *)[self childNodeWithName:@"plane"];
    
    SKAction *moveAction = [SKAction moveToY:0 duration:1];
    
    //设置速度
    moveAction.speed = 0.5;
    
    [planeNode runAction:moveAction];
    
    SKSpriteNode *planeNode1 = (SKSpriteNode *)[self childNodeWithName:@"plane1"];

    SKAction *moveAction1 = [SKAction moveToY:0 duration:1];
    
    //设置速度
    moveAction1.speed = 2;
    
    [planeNode1 runAction:moveAction1];
    
    NSLog(@"动作一的所需时间:%f",moveAction.duration);
    
    NSLog(@"动作二的所需时间:%f",moveAction1.duration);

    
}


@end

控制台打印信息如下.我们看到我们获得了动作的时间属性.

timingMode(曲线方式属性)

动作的曲线方式其实就是动画总体变化的时间曲线,动作的曲线方式的设置以及获取需要使用到timingMode这个一个属性,timingMode的取值一共有4个,如下表所示.

曲线方式	功能
SKActionTimingLinear	动画在其持续时间内平均分布
SKActionTimingEaseIn	动画在开始的时候较慢,然后渐渐加快
SKActionTimingEaseOut	动画开始的时候较快,然后渐渐变慢
SKActionTimingEaseInEaseOut	动画开始的时候慢,然后渐渐加速到中间,然后在渐渐变慢到完成

如果不对曲线方式属性进行设置的话,默认的是SKActionTimingLinear.下面我们就用看一下代码示例.我们在速度代码的基础上加以修改,来验证曲线方式.

#pragma mark ---- 创建两个飞船 ----

-(void)planeNode{

    SKSpriteNode *planeNode = [SKSpriteNode spriteNodeWithImageNamed:@"飞机.png"];
    
    planeNode.position = CGPointMake(self.size.width/2, self.size.height/2);
    
    planeNode.anchorPoint = CGPointMake(0.5, 0.5);
    
    planeNode.zPosition = 1;
    
    planeNode.name = @"plane";
    
    [self addChild:planeNode];
    
    SKSpriteNode *planeNode1 = [SKSpriteNode spriteNodeWithImageNamed:@"飞机.png"];
    
    planeNode1.position = CGPointMake(self.size.width/2+100, self.size.height/2);
    
    planeNode1.anchorPoint = CGPointMake(0.5, 0.5);
    
    planeNode1.zPosition = 1;
    
    planeNode1.name = @"plane1";
    
    [self addChild:planeNode1];
    
    SKSpriteNode *planeNode2 = [SKSpriteNode spriteNodeWithImageNamed:@"飞机.png"];
    
    planeNode2.position = CGPointMake(self.size.width/2-100, self.size.height/2);
    
    planeNode2.anchorPoint = CGPointMake(0.5, 0.5);
    
    planeNode2.zPosition = 1;
    
    planeNode2.name = @"plane2";
    
    [self addChild:planeNode2];

}

#pragma mark ---- 移动飞船 ----


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


    SKSpriteNode *planeNode = (SKSpriteNode *)[self childNodeWithName:@"plane"];
    
    SKAction *moveAction = [SKAction moveToY:0 duration:2];
    
    //设置曲线方式
    moveAction.timingMode = SKActionTimingEaseIn;

    
    [planeNode runAction:moveAction];
    
    SKSpriteNode *planeNode1 = (SKSpriteNode *)[self childNodeWithName:@"plane1"];

    SKAction *moveAction1 = [SKAction moveToY:0 duration:2];
    
    //设置曲线方式
    moveAction1.timingMode = SKActionTimingEaseOut;
    
    [planeNode1 runAction:moveAction1];
    
    SKSpriteNode *planeNode2 = (SKSpriteNode *)[self childNodeWithName:@"plane2"];
    
    SKAction *moveAction2 = [SKAction moveToY:0 duration:2];
    
    //设置曲线方式
    moveAction2.timingMode = SKActionTimingEaseInEaseOut;
    
    [planeNode2 runAction:moveAction1];


}

下面我们就看一下效果图,

各个精灵对象设置的曲线方式

效果图

总结:SKAction常用属性速度,时间,曲线方式基本就写到这了.下一篇博客,就是游戏中的重头戏:物理引擎,希望大家关注,谢谢.最后废话不多说,Demo双手奉上.

SpriteKit之漫谈SKAction常用属性