理解 SpriteKit：移动精灵

Posted 2023-03-16

【中文标题】理解 SpriteKit：移动精灵

【英文标题】：Understanding SpriteKit : Moving Sprites

【发布时间】：2013-10-10 01:07:55

【问题描述】：

这是我的第一篇文章，我正在尝试使用 Apple 的 SpriteKit 框架。

我相信我对如何使用框架移动精灵有误解。我有一个简单的例子，我想在一个简单的UP、DOWN、LEFT、RIGHT 方向上移动一个hero，基于点击位置，相对于“英雄”位置。一旦英雄击中block，“英雄​​”就会停止。

出于测试目的，我只是试图点击上方的“英雄”撞到屏幕顶部的块墙。然后在碰撞发生后，点击下方的“英雄”。我期待着“英雄”朝着最下面一排的积木墙移动；然而，似乎“英雄”继续向上移动并穿过顶墙。我确信我正在犯一个根本性的缺陷，我将不胜感激。

谢谢

这是我写的示例场景：

static inline CGPoint CGPointSubtract(const CGPoint a, const CGPoint b)

    return CGPointMake(a.x - b.x, a.y - b.y);


typedef enum DIRECTION_e

    UP,
    DOWN,
    LEFT,
    RIGHT
 DIRECTION_t;

typedef NS_OPTIONS(uint32_t, CNPhysicsCategory)

    PhysicsCategoryBlock  = 1 << 0,
    PhysicsCategoryHero   = 1 << 1
;

@interface LevelScene ()
    @property (nonatomic) SKSpriteNode * hero;
    @property (nonatomic) BOOL inMotion;
@end

@implementation LevelScene

-(id) initWithSize:(CGSize)size

    if (self = [super initWithSize:size])
    
        self.physicsWorld.gravity = CGVectorMake(0,0);

        self.physicsWorld.contactDelegate = self;

        [self createLevel];
        [self createHero];

        self.inMotion = NO;
    
    return self;


- (void) createHero

    [self addHeroAtRow:5 column:2];


- (void) createLevel

    self.backgroundColor = [SKColor blackColor];
    self.scaleMode = SKSceneScaleModeAspectFit;

    [self addBlockAtRow:1 column:1];
    [self addBlockAtRow:1 column:2];
    [self addBlockAtRow:1 column:3];

    [self addBlockAtRow:10 column:1];
    [self addBlockAtRow:10 column:2];
    [self addBlockAtRow:10 column:3];


- (void) addBlockAtRow:(NSInteger)row column:(NSInteger)column

    SKSpriteNode *block = [[SKSpriteNode alloc] initWithColor:[SKColor brownColor]     size:CGSizeMake(64,64)];
    block.position = CGPointMake(32 + (column * 64), 32 + ((11-row) * 64));
    block.name = @"block";

    block.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:block.size];

    block.physicsBody.dynamic            = NO;
    block.physicsBody.categoryBitMask    = PhysicsCategoryBlock;
    block.physicsBody.collisionBitMask   = PhysicsCategoryBlock | PhysicsCategoryHero;
    block.physicsBody.contactTestBitMask = PhysicsCategoryBlock | PhysicsCategoryHero;

    [self addChild:block];


- (void) addHeroAtRow:(NSInteger)row column:(NSInteger)column

    self.hero = [[SKSpriteNode alloc] initWithColor:[SKColor redColor] size:CGSizeMake(64,64)];
    self.hero.position = CGPointMake(32 + (column * 64), 32 + ((11-row) * 64));
    self.hero.name = @"hero";
    self.hero.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:CGSizeMake(self.hero.size.width/2, self.hero.size.height/2)];
    self.hero.physicsBody.usesPreciseCollisionDetection = YES;

    self.hero.physicsBody.dynamic            = YES;
    self.hero.physicsBody.categoryBitMask    = PhysicsCategoryHero;
    self.hero.physicsBody.collisionBitMask   = PhysicsCategoryHero | PhysicsCategoryBlock;
    self.hero.physicsBody.contactTestBitMask = PhysicsCategoryHero | PhysicsCategoryBlock;

    [self addChild:self.hero];

    NSLog(@"ADDING HERO: %f, %f", self.hero.position.x, self.hero.position.y);


- (void)didBeginContact:(SKPhysicsContact *)contact

    if (contact.bodyA.categoryBitMask == PhysicsCategoryBlock && contact.bodyB.categoryBitMask == PhysicsCategoryHero)
    
        [self.hero removeAllActions];
        self.hero.position = contact.bodyB.node.position;
        NSLog(@"COLLISION: %f, %f", self.hero.position.x, self.hero.position.y);
        self.inMotion = NO;
    
    else if (contact.bodyB.categoryBitMask == PhysicsCategoryBlock && contact.bodyA.categoryBitMask == PhysicsCategoryHero)
    
        [self.hero removeAllActions];
        self.hero.position = contact.bodyA.node.position;
        NSLog(@"COLLISION: %f, %f", self.hero.position.x, self.hero.position.y);
        self.inMotion = NO;
    



- (void) moveHeroTowardDirection:(DIRECTION_t)direction

    CGPoint location;

    switch (direction)
    
        case UP:
        
            location = CGPointMake(self.hero.position.x, self.hero.position.y + 600);
        
            break;

        case DOWN:
        
            location = CGPointMake(self.hero.position.x, self.hero.position.y + -600);
        
            break;

        case LEFT:
        
            location = CGPointMake(self.hero.position.x + -600, self.hero.position.y);
        
            break;

        case RIGHT:
        
            location = CGPointMake(self.hero.position.x + 600, self.hero.position.y);
        
            break;

        default: return;
    

    NSLog(@"MOVE POSITION: %f, %f", location.x, location.y);

    SKAction *action = [SKAction moveTo:location duration:10];
    [self.hero runAction:action];


-(void) touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event

    if (self.inMotion)
        return;

    self.inMotion = YES;

    UITouch *touch = [touches anyObject];
    CGPoint touchLocation = [touch locationInView:self.view];
    CGPoint diff = CGPointSubtract(self.hero.position, touchLocation);

    NSLog(@"TOUCH POSITION: %f, %f", touchLocation.x, touchLocation.y);
    NSLog(@"HERO POSITION:  %f, %f", self.hero.position.x, self.hero.position.y);
    NSLog(@"DIFF POSITION:  %f, %f", diff.x, diff.y);

    //
    // Magnitude to find out which direction is dominate
    //
    if (abs(diff.x) > abs(diff.y))
    
        if (touchLocation.x > self.hero.position.x)
        
            NSLog(@"LEFT");
            [self moveHeroTowardDirection:LEFT];
        
        else
        
            NSLog(@"RIGHT");
            [self moveHeroTowardDirection:RIGHT];
        
    
    else
    
        if (touchLocation.y < self.hero.position.y)
        
            NSLog(@"UP");
            [self moveHeroTowardDirection:UP];
        
        else
        
            NSLog(@"DOWN");
            [self moveHeroTowardDirection:DOWN];
        
    


@end

【问题讨论】：

这将有助于***.com/questions/19172140/skaction-move-forward/…

@Smick 太棒了。谢谢

@Smick 我想感谢您的回答。最好的方法是什么？对不起，我是新来的。

【参考方案1】：

这里试试这个，你也需要删除/禁用你的触摸结束

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

for (UITouch *touch in touches) 

    for (UITouch *touch in touches) 

        CGPoint location = [touch locationInNode:self];

        CGPoint diff = CGPointMake(location.x - self.hero.position.x, location.y - self.hero.position.y);

        CGFloat angleRadians = atan2f(diff.y, diff.x);

        [self.hero runAction:[SKAction sequence:@[
                                                  [SKAction rotateToAngle:angleRadians duration:1.0],
                                                  [SKAction moveByX:diff.x y:diff.y duration:3.0]
                                                  ]]];