为什么物理不按我想要的方式工作？

Question

好的，所以在我的游戏中，我有一段代码每 x 时间生成一个精灵 ('enemy')。它在高处生成精灵，然后精灵掉下来。

应该发生的事情是这样的： sprite 掉落下来，它接触到地面或另一个敌人，然后变为静止状态，因此无法移动。

这是怎么回事： 有时有效，但有时（尤其是当 x 时间量较小且精灵生成更频繁时）精灵突然变为静态，同时它还在空中。

为什么会这样？

这是一些代码：

in GameScene.m,在createSceneContents中，didMoveToView调用的方法：

self.physicsWorld.contactDelegate = self;

SKSpriteNode *bottom = [SKSpriteNode spriteNodeWithColor:[SKColor whiteColor] size:CGSizeMake(self.frame.size.width, 10)];
bottom.position = CGPointMake(self.frame.size.width/2, 0);
bottom.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:bottom.size];
bottom.physicsBody.dynamic = NO;
bottom.physicsBody.restitution = 0;
bottom.physicsBody.categoryBitMask = self.bottomCategory;
bottom.physicsBody.contactTestBitMask = self.enemyCategory;

[self spawnObject];
[self addChild:self.world];
[self.world addChild:bottom];

在 spawnObject 中，一个由 createSceneContents 调用的方法：

if (self.isPaused == NO){

    self.spawningSpeed = 1;
    self.enemyData = [[Enemy alloc]init];
    SKAction *wait = [SKAction waitForDuration:self.spawningSpeed];
    SKAction *run = [SKAction runBlock:^{

        SKSpriteNode *aNewEnemy = [self.enemyData createEnemyWithSize:self.customUnit andWidth:self.frame.size.width andHeight:self.frame.size.height + self.player.position.y andPlayerPosition:self.player.position.x];
        aNewEnemy.physicsBody.allowsRotation = NO;
        aNewEnemy.physicsBody.categoryBitMask = self.enemyCategory;
        aNewEnemy.physicsBody.collisionBitMask = self.enemyCategory | self.bottomCategory;
        aNewEnemy.physicsBody.contactTestBitMask = self.enemyCategory | self.bottomCategory;
        [self.world addChild:aNewEnemy];



    }];
    SKAction *action = [SKAction repeatActionForever:[SKAction sequence:@[wait,run]]];
    [self runAction:action withKey:@"action"];

在createEnemyWithSize:andWidth:andHeight:andPlayerPosition:,在Enemy.m:

self.enemy = [SKSpriteNode spriteNodeWithImageNamed:@"block.png"];
self.enemy.size = CGSizeMake(size - 5, size - 5);
self.enemy.name = @"fallingEnemy";
self.enemy.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:CGSizeMake(size - 1, size - 1)];
self.enemy.physicsBody.restitution = 0;
self.enemy.physicsBody.allowsRotation = NO;

int column1 = width/7;
int column2 = column1 * 2;
int column3 = column1 * 3;
int column4 = column1 * 4;
int column5 = column1 * 5;
int column6 = column1 * 6;
int halfAColumn = column1/2;

if (position > 0 && position < column1) {
    self.enemy.position = CGPointMake(halfAColumn, height - size);

}else if (position > column1 && position < column2) {
    self.enemy.position = CGPointMake((column2-halfAColumn), height - size);

}else if (position > column2 && position < column3) {
    self.enemy.position = CGPointMake((column3-halfAColumn), height - size);

}else if (position > column3 && position < column4) {
    self.enemy.position = CGPointMake((column4-halfAColumn), height - size);

}else if (position > column4 && position < column5) {
    self.enemy.position = CGPointMake((column5-halfAColumn), height - size);

}else if (position > column5 && position < column6) {
    self.enemy.position = CGPointMake((column6-halfAColumn), height - size);

}else if (position > column6 && position < width) {
    self.enemy.position = CGPointMake((width-halfAColumn), height - size);

}

return self.enemy;

在 didBeginContact 中，在 GameScene.m 中：

SKPhysicsBody *enemyBodyA, *bottomBodyA, *enemyBodyB, *bottomBodyB;
if (contact.bodyA.categoryBitMask == self.enemyCategory) {
        enemyBodyA = contact.bodyA;

}else if (contact.bodyA.categoryBitMask == self.bottomCategory) {

        bottomBodyA = contact.bodyA;

}
    if (contact.bodyB.categoryBitMask == self.enemyCategory) {
        enemyBodyB = contact.bodyB;

}else if (contact.bodyB.categoryBitMask == self.bottomCategory) {

        bottomBodyB = contact.bodyB;

}

        if (enemyBodyA == contact.bodyA && enemyBodyB == contact.bodyB) {

        [self.enemyData changeBlock];


        NSLog(@"Change1");
    }
    if (contact.bodyA == enemyBodyA && contact.bodyB == bottomBodyB) {
        NSLog(@"Change2");
        [self.enemyData changeBlock];


    }
    if (contact.bodyB == enemyBodyB && contact.bodyA == bottomBodyA) {
        NSLog(@"Change3");
        [self.enemyData changeBlock];


    }

在changeBlock中，在Enemy.m中：

-(void)changeBlock {
self.enemy.physicsBody.dynamic = NO;
self.enemy.name = @"staticEnemy";
}

createSceneContents 中的位掩码值：

self.playerCategory = 1;
self.enemyCategory = 2;
self.edgeCategory = 4;
self.bottomCategory = 8;

Answer 1

您可能会丢失对敌人的引用，该敌人在另一个生成之前没有收到联系。因此需要进行一些更改。你根本不需要敌人 class 中的 self.enemy 属性。

首先，修改changeBlock方法，使其可以在作为参数传递的任何块上执行。

-(void)changeBlock:(SKSpriteNode*)block {
    block.physicsBody.dynamic = NO;
    block.name = @"staticEnemy";
}

然后清理联系人委托方法。

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

    //This is a useful technique for organising bodies in the contact delegate
    if (contact.bodyA.categoryBitMask < contact.bodyB.categoryBitMask) {
        firstBody = contact.bodyA;
        secondBody = contact.bodyB;
    } else {
        firstBody = contact.bodyB;
        secondBody = contact.bodyA;
    }
    //Since enemyCategory < bottomCategory, the firstBody is an enemy node, and second either an enemy or bottom node

    if (firstBody.categoryBitMask == self.enemyCategory && secondBody.categoryBitMask == self.bottomCategory) {
        [self.enemyData changeBlock: (SKSpriteNode*)firstBody.node];
    } else if (firstBody.categoryBitMask == self.enemyCategory && secondBody.categoryBitMask == self.enemyCategory) {
        [self.enemyData changeBlock: (SKSpriteNode*)firstBody.node];
        [self.enemyData changeBlock: (SKSpriteNode*)secondBody.node];
    }
}

我不确定你的游戏是关于什么的，所以改变是你想要的。但我希望你能明白。

为什么物理不按我想要的方式工作？

Why isn't the physics working the way I want it to?

objective-c

ios

sprite-kit