ios - 如何进行脉冲物理学

Question

好吧伙计们，我有两个 Sprite ，一个是敌人，当元素出现时，它会在 map 周围移动以捡起元素，它使用 SKActions 来做到这一点，然后我还有他不应该穿过的墙。反正。我要做的就是让他在撞到墙上时弹开。我该怎么做？

代码如下:

//对于敌人墙我有这个代码:

- (void) EnemyBelongings {
EnemyWall = [SKSpriteNode spriteNodeWithImageNamed:@"EnemyWall@2x"];
EnemyWall.name = @"hisWall";
EnemyWall.position = CGPointMake(512, 260);
EnemyWall.xScale = 0.09;
EnemyWall.yScale = 0.09;
EnemyWall.physicsBody.categoryBitMask = PhysicsCategoryEnemyWall;
EnemyWall.physicsBody.contactTestBitMask = PhysicsCategoryEnemy;
EnemyWall.physicsBody.collisionBitMask = 0;
[self addChild:EnemyWall];

//对于敌人角色我有这个代码

- (void) Enemy {
    _Enemy = [SKSpriteNode spriteNodeWithImageNamed:@"enemy"];
    _Enemy.position = CGPointMake(520, _Enemy.size.height/1.50);
    _Enemy.physicsBody = [SKPhysicsBody bodyWithCircleOfRadius:self.size.width];
    _Enemy.physicsBody.usesPreciseCollisionDetection = YES;
    _Enemy.physicsBody.categoryBitMask = PhysicsCategoryEnemy;
    _Enemy.physicsBody.contactTestBitMask = PhysicsCategoryEnemyWall;
    _Enemy.physicsBody.collisionBitMask = 0;
    [self addChild:_Enemy];
}

//对于敌人的移动我有这段代码

- (void) EnemySpawner {
    [ForEnemy runAction:appear2 completion:^{
    SKAction *wait = [SKAction waitForDuration:1.0];
    [_Enemy runAction:wait];
    SKAction *actionXMove2 = [SKAction moveToX:ForEnemy.position.x duration:0.14];
    SKAction *actionYMove2 = [SKAction moveToY:ForEnemy.position.y duration:0.14];
    [_Enemy runAction:actionYMove2];
    [_Enemy runAction:actionXMove2];
}];

-(void)didBeginContact:(SKPhysicsContact *)contact
{
if (contact.bodyA.categoryBitMask == PhysicsCategoryEnemy && contact.bodyB.categoryBitMask 
    == PhysicsCategoryEnemyWall)
{
    SKNode *enemy = contact.bodyA.node;  // a is the enemy here
       // Code here
    SKNode *wall = contact.bodyB.node; // b is the enemy's wall here
       // Code here
}
else if (contact.bodyB.categoryBitMask == PhysicsCategoryEnemy && 
    contact.bodyA.categoryBitMask == PhysicsCategoryEnemyWall)
{
    SKNode *enemy = contact.bodyB.node;
       // Code here
    SKNode *wall = contact.bodyA.node;
       // Code here
}

Answer 1

您需要在节点的physicsBody上applyImpulse使其自然模拟并与其他physicsBody交互。

请看我的回答here关于如何做同样的事情。

从 tutorial 复制 rwAdd、rwSub、rwMult、rwLength 和 rwNormalize 方法作者:雷文德利希。

然后，尝试使用此代码:

[ForEnemy runAction:appear2 completion:^{
        SKAction *wait = [SKAction waitForDuration:1.0];

        CGPoint offset = rwSub(location, ForEnemy.position);
        CGPoint direction = rwNormalize(offset);
        float forceValue = 200; //Edit this value to get the desired force.
        CGPoint shootAmount = rwMult(direction, forceValue);

        CGVector impulseVector = CGVectorMake(shootAmount.x, shootAmount.y);

        [_Enemy.physicsBody applyImpulse:impulseVector];


         }];