Question

我试图在2D游戏中创建斜坡。这个坡度应该是X度。当现在一个球滚动时＃34;超过＆＃34;这个斜坡。这个斜率的影响应该改变球的行为，以便向后，向前或在其他地方初始化倾斜度。我认为我可以通过带有物理身体的SKSpritenode实现这一点，并且当球滚过时（＆＃34;碰撞＆＃34;）效果应该受到影响，但是我无法实现这一点。

我怎样才能做到这一点？

致以最诚挚的问候，

克里斯

Answer 1

如果我正确地理解了你的问题，你正在寻找斜坡，当它在斜坡上下移动时对球产生物理效应。

查看下面的示例项目（项目处于横向模式，并且show physics设置为YES）。

#import "GameScene.h"

typedef NS_OPTIONS(uint32_t, Level1PhysicsCategory) {
    CategoryBall  = 1 << 0,
    CategoryFloor0  = 1 << 1,
};

@implementation GameScene {
    SKSpriteNode *ballNode;
}

-(void)didMoveToView:(SKView *)view {
    self.backgroundColor = [SKColor whiteColor];

    // create slope floor
    SKSpriteNode *myNode0 = [SKSpriteNode spriteNodeWithColor:[SKColor clearColor] size:CGSizeMake(200, 100)];
    myNode0.position = CGPointMake(500,300);
    myNode0.zPosition = 100;
    CGMutablePathRef trianglePath = CGPathCreateMutable();
    CGPathMoveToPoint(trianglePath, nil, -myNode0.size.width/2, myNode0.size.height/2);
    CGPathAddLineToPoint(trianglePath, nil, myNode0.size.width/2, -myNode0.size.height/2);
    CGPathAddLineToPoint(trianglePath, nil, -myNode0.size.width/2, -myNode0.size.height/2);
    CGPathAddLineToPoint(trianglePath, nil, -myNode0.size.width/2, myNode0.size.height/2);
    myNode0.physicsBody = [SKPhysicsBody bodyWithPolygonFromPath:trianglePath];
    myNode0.physicsBody.dynamic = NO;
    myNode0.physicsBody.restitution = 0;
    myNode0.physicsBody.friction = 0.0;
    myNode0.physicsBody.categoryBitMask = CategoryFloor0;
    myNode0.physicsBody.collisionBitMask = CategoryBall;
    CGPathRelease(trianglePath);
    [self addChild:myNode0];

    // create top floor
    SKSpriteNode *myNode1 = [SKSpriteNode spriteNodeWithColor:[SKColor clearColor] size:CGSizeMake(300, 5)];
    myNode1.position = CGPointMake(250,348);
    myNode1.zPosition = 100;
    myNode1.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:CGSizeMake(300, 5)];
    myNode1.physicsBody.dynamic = NO;
    myNode1.physicsBody.restitution = 0;
    myNode1.physicsBody.friction = 0.0;
    myNode1.physicsBody.categoryBitMask = CategoryFloor0;
    myNode1.physicsBody.collisionBitMask = CategoryBall;
    [self addChild:myNode1];

    // create bottom floor
    SKSpriteNode *myNode2 = [SKSpriteNode spriteNodeWithColor:[SKColor clearColor] size:CGSizeMake(300, 5)];
    myNode2.position = CGPointMake(750,248);
    myNode2.zPosition = 100;
    myNode2.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:CGSizeMake(300, 5)];
    myNode2.physicsBody.dynamic = NO;
    myNode2.physicsBody.restitution = 0;
    myNode2.physicsBody.friction = 0.0;
    myNode2.physicsBody.categoryBitMask = CategoryFloor0;
    myNode2.physicsBody.collisionBitMask = CategoryBall;
    [self addChild:myNode2];

    // create ball
    ballNode = [SKSpriteNode spriteNodeWithColor:[SKColor clearColor] size:CGSizeMake(20, 20)];
    ballNode.position = CGPointMake(770,300);
    ballNode.zPosition = 100;
    ballNode.physicsBody = [SKPhysicsBody bodyWithCircleOfRadius:10];
    ballNode.physicsBody.dynamic = YES;
    ballNode.physicsBody.restitution = 0;
    ballNode.physicsBody.friction = 0.0;
    ballNode.physicsBody.categoryBitMask = CategoryBall;
    ballNode.physicsBody.collisionBitMask = CategoryFloor0;
    [self addChild:ballNode];
}

-(void)update:(CFTimeInterval)currentTime {

    // check if ball has fallen off screen
    // if yes, put ball back in place
    if(ballNode.position.y < 0) {
        ballNode.physicsBody.velocity = CGVectorMake(0, 0);
        ballNode.position = CGPointMake(770, 300);
    }
}

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    // change the dx velocity to apply more or less force to the ball
    [ballNode.physicsBody applyImpulse:CGVectorMake(-7, 0)];
}

斯威夫特＆amp; Spritekit：创建一个斜坡

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