我一直在尝试开发一个简单的 Sprite Kit 游戏，该游戏涉及躲避红球。我正在使用内置的重力机制，但我无法防止玩家从地面掉落。我查找了一个解决方案(设置 ground.physicsBody.dynamic = NO)，但玩家仍然失败。我到底需要做什么？

编辑:绿色和棕色的纹理是地面。现在播放器设置为不动态，所以它是“飞行”

这是我在 MyScene.m 文件中的代码:

//
//  MyScene.m
//  DodgeMan
//
//  Created by Cormac Chester on 3/8/14.
//  Copyright (c) 2014 Testman Industries. All rights reserved.
//

#import "MyScene.h"
#import "EndGameScene.h"

static const uint32_t redBallCategory =  0x1 << 0;
static const uint32_t playerCategory =  0x1 << 1;

@implementation MyScene

-(id)initWithSize:(CGSize)size
{
    if (self = [super initWithSize:size])
    {
        /* Setup your scene here */

        //Sets player location
        playerLocX = 50;
        playerLocY = 100;

        //Sets player score
        score = 0;

        //Set Background
        self.backgroundColor = [SKColor colorWithRed:0.53 green:0.81 blue:0.92 alpha:1.0];

        //Set Ground
        SKSpriteNode *ground = [SKSpriteNode spriteNodeWithImageNamed:@"ground"];
        ground.position = CGPointMake(CGRectGetMidX(self.frame), 34);
        ground.xScale = 0.5;
        ground.yScale = 0.5;
        ground.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:ground.size];
        ground.physicsBody.dynamic = NO;

        //Player
        self.playerSprite = [SKSpriteNode spriteNodeWithImageNamed:@"character"];
        self.playerSprite.position = CGPointMake(playerLocX, playerLocY);

        //Set Player Physics
        self.playerSprite.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:self.playerSprite.size];
        self.playerSprite.physicsBody.dynamic = YES;
        self.playerSprite.physicsBody.categoryBitMask = playerCategory;
        self.playerSprite.physicsBody.contactTestBitMask = redBallCategory;
        self.playerSprite.physicsBody.collisionBitMask = 0;
        self.playerSprite.physicsBody.usesPreciseCollisionDetection = YES;

        //Score Label
        self.scoreLabel = [SKLabelNode labelNodeWithFontNamed:@"Arial-BoldMT"];
        self.scoreLabel.text = @"0";
        self.scoreLabel.fontSize = 40;
        self.scoreLabel.fontColor = [SKColor blackColor];
        self.scoreLabel.position = CGPointMake(50, 260);

        //Pause Button
        self.pauseButton = [SKSpriteNode spriteNodeWithImageNamed:@"pauseButton"];
        self.pauseButton.position = CGPointMake(self.frame.size.width / 2, self.frame.size.height - 40);
        self.pauseButton.name = @"pauseButton";

        //Add nodes
        [self addChild:ground];
        [self addChild:self.playerSprite];
        [self addChild:self.scoreLabel];
        //[self addChild:self.pauseButton];

        //Sets gravity
        self.physicsWorld.gravity = CGVectorMake(0,-2);
        self.physicsWorld.contactDelegate = self;

    }
    return self;
}

-(void)addBall
{
    SKSpriteNode *redBall = [SKSpriteNode spriteNodeWithImageNamed:@"locationIndicator"];
    int minY = redBall.size.height / 2;
    int maxY = self.frame.size.height - redBall.size.height / 2;
    int rangeY = maxY - minY;
    int actualY = (arc4random() % rangeY) + minY;
    NSLog(@"Actual Y: %i", actualY);

    //Initiates red ball offscreen
    if (actualY >= 75)
    {
        //Prevents balls from spawning in the ground
        redBall.position = CGPointMake(self.frame.size.width + redBall.size.width/2, actualY);
        [self addChild:redBall];
    }
    redBall.physicsBody = [SKPhysicsBody bodyWithCircleOfRadius:redBall.size.width/2];
    redBall.physicsBody.dynamic = YES;
    redBall.physicsBody.categoryBitMask = redBallCategory;
    redBall.physicsBody.contactTestBitMask = playerCategory;
    redBall.physicsBody.collisionBitMask = 0;
    redBall.physicsBody.affectedByGravity = NO;
    redBall.physicsBody.usesPreciseCollisionDetection = YES;

    //Determine speed of red ball
    int minDuration = 3.0;
    int maxDuration = 5.0;
    int rangeDuration = maxDuration - minDuration;
    int actualDuration = (arc4random() % rangeDuration) + minDuration;

    // Create the actions
    SKAction *actionMove = [SKAction moveTo:CGPointMake(-redBall.size.width/2, actualY) duration:actualDuration];
    SKAction *actionMoveDone = [SKAction removeFromParent];
    SKAction *ballCross = [SKAction runBlock:^{
        score++;
        self.scoreString = [NSString stringWithFormat:@"%i", score];
        self.scoreLabel.text = self.scoreString;
        NSLog(@"Score was incremented. Score is now %d", score);
    }];
    [redBall runAction:[SKAction sequence:@[actionMove, ballCross, actionMoveDone]]];
}

- (void)updateWithTimeSinceLastUpdate:(CFTimeInterval)timeSinceLast
{
    self.lastSpawnTimeInterval += timeSinceLast;
    if (self.lastSpawnTimeInterval > 0.5) {
        self.lastSpawnTimeInterval = 0;
        [self addBall];
    }
}

-(void)update:(CFTimeInterval)currentTime
{
    /* Called before each frame is rendered */
    // Handle time delta.
    //Prevents bad stuff happening
    CFTimeInterval timeSinceLast = currentTime - self.lastUpdateTimeInterval;
    self.lastUpdateTimeInterval = currentTime;
    if (timeSinceLast > 1) { // more than a second since last update
        timeSinceLast = 1.0 / 120.0;
        self.lastUpdateTimeInterval = currentTime;
    }

    [self updateWithTimeSinceLastUpdate:timeSinceLast];
}

NSDate *startTime;

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    /* Called when a touch begins */
    [super touchesBegan:touches withEvent:event];

    //Starts Timer
    startTime = [NSDate date];

    UITouch *touch = [touches anyObject];
    CGPoint location = [touch locationInNode:self];
    SKNode *node = [self nodeAtPoint:location];

    //Pauses Scene
    if ([node.name isEqualToString:@"pauseButton"])
    {
        NSLog(@"Pause button pressed");
    }

}

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    /* Called when a touch ends */
    [super touchesEnded:touches withEvent:event];

    NSTimeInterval elapsedTime = [startTime timeIntervalSinceNow];
    NSString *elapsedTimeString = [NSString stringWithFormat:@"Elapsed time: %f", elapsedTime];
    NSLog(@"%@", elapsedTimeString);


    for (UITouch *touch in touches)
    {
        //Gets location of touch
        CGPoint location = [touch locationInNode:self];
        NSLog(@"Touch Location X: %f \n Touch Location Y: %f", location.x, location.y);

        //Prevents destination from being in the ground
        if (location.y < 88)
        {
            location.y = 87.5;
        }

        //Moves and animates player
        //int velocity = elapsedTime * -3000;
        int velocity = 800.0/1.0;
        NSLog(@"Velocity: %i", velocity);
        float realMoveDuration = self.size.width / velocity;
        SKAction *actionMove = [SKAction moveTo:location duration:realMoveDuration];
        [self.playerSprite runAction:[SKAction sequence:@[actionMove]]];
    }

    NSLog(@"Touch ended");
}

//Collision between ball and player
- (void)redBall:(SKSpriteNode *)redBall didCollideWithPlayer:(SKSpriteNode *)playerSprite
{
    NSLog(@"Player died");
    [redBall removeFromParent];
    [playerSprite removeFromParent];

    SKTransition *reveal = [SKTransition crossFadeWithDuration:0.5];
    SKScene *endGameScene = [[EndGameScene alloc] initWithSize:self.size gameEnded:YES];
    [self.view presentScene:endGameScene transition: reveal];
}

- (void)didBeginContact:(SKPhysicsContact *)contact
{
    SKPhysicsBody *firstBody, *secondBody;

    if (contact.bodyA.categoryBitMask < contact.bodyB.categoryBitMask)
    {
        firstBody = contact.bodyA;
        secondBody = contact.bodyB;
    }
    else
    {
        firstBody = contact.bodyB;
        secondBody = contact.bodyA;
    }

    //Red ball collides with the player
    if ((firstBody.categoryBitMask & redBallCategory) != 0 && (secondBody.categoryBitMask & playerCategory) != 0)
    {
        [self redBall:(SKSpriteNode *) firstBody.node didCollideWithPlayer:(SKSpriteNode *) secondBody.node];
    }
}

@end

最佳答案

绝对不能把它的动态设置成无哥。你需要那个玩家的重力效果。 (他不受物理世界的影响，所以他现在正在飞行。我们需要他掉到地上，不是吗？:)

所以这是一个简单的解决方案。想法是您在具有物理 body 的地面上创建一个“隐形矩形 block ”。并且你需要将它的动态设置为 no 以防止它掉落

所以这个 block 显然是一个节点，它的大小:与地面一样高，与屏幕一样宽。你需要稍微调整一下位置，让它的上界正好在地面上。

祝你好运

其实我画了一张图，但是因为我的名声我不能把它贴在这里:(

关于ios - 防止玩家从地面掉落 - Sprite Kit，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/22286897/