Question

我的精灵位置是（screenWidth，screenHeigh / 2）。我尝试了很多代码，使用CGPathAddArc从右到左移动精灵但不成功。苹果文件很难理解。所以我发布在这里希望有人可以帮助我。这是我用过的代码之一。

if (iPad) {
        CGPathAddArc(thePath, NULL, 384.0f , 768, 384.0f , 0.f, -M_PI*3/2, NO);
}
SKAction *moveAction = [SKAction followPath:thePath asOffset:YES orientToPath:NO duration:(5.0f/200.0f)*(iPad ? 384.0f :200.f)];

很多人提前感谢

Answer 1

如果您创建一个空白的SpriteKit项目，这个稍微修改过的GameScene.m默认代码将使太空船沿着半圆路径从右向左飞过。

如果您需要进一步澄清，请发表评论！

您的代码段与[SKAction followPath...] asOffset参数的关键区别为NO，orientToPath为YES。

#import "GameScene.h"

@implementation GameScene

-(void)didMoveToView:(SKView *)view {
    /* Setup your scene here */
    SKLabelNode *myLabel = [SKLabelNode labelNodeWithFontNamed:@"Chalkduster"];

    myLabel.text = @"Hello, World!";
    myLabel.fontSize = 65;
    myLabel.position = CGPointMake(CGRectGetMidX(self.frame),
                                   CGRectGetMidY(self.frame));

    [self addChild:myLabel];
}

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

    for (UITouch *touch in touches) {
        CGPoint location = [touch locationInNode:self];

        SKSpriteNode *sprite = [SKSpriteNode spriteNodeWithImageNamed:@"Spaceship"];

        sprite.xScale = 0.5;
        sprite.yScale = 0.5;
        sprite.position = location;

        // HERE COMES THE MODIFICATION
        CGMutablePathRef thePath = CGPathCreateMutable();
        CGPathAddArc(thePath, NULL, self.frame.size.width/2 , 200, self.frame.size.width/2 , 0.f, -M_PI, NO);
        SKAction *moveAction = [SKAction followPath:thePath asOffset:NO orientToPath:YES duration:5.0];
        [sprite runAction:[SKAction repeatActionForever:moveAction]];
        // HERE ENDS THE MODIFICATION

        [self addChild:sprite];
    }
}

-(void)update:(CFTimeInterval)currentTime {
    /* Called before each frame is rendered */
}

@end

希望这有帮助！

如何使用CGPathAddArc从屏幕的右侧移动精灵

1 个答案: