Question

我是 Objective-C 开发的新人，我正致力于使用 {{1 }} 的。我试图创建一个包含角落作为controlPoints的竞技场的场景。

我的代码如下：

MyScene.m：

SpriteKit

}

和MyArena.m

-(id)initWithSize:(CGSize)size {

CGPointArray=[[NSMutableArray alloc] init];         // Kugan: cette instruction ne sert à rien dans initWithSize d'après moi.

if (self = [super initWithSize:size]) {

    // Setting up the scene background
    SKSpriteNode *background = [SKSpriteNode spriteNodeWithImageNamed:@"Background"];
    [background setName: @"background"];
    background.anchorPoint = CGPointZero;

    [self addChild:background];

    // creating the unique instance of the menu at the right side of the scene
    ref=[ElementsMenuSingleton MenuChoice];


    // Creating the points that will represente the borders of the scene
    CGPoint leftBottomPoint = CGPointMake(50, 150);
    CGPoint centerBottomPoint = CGPointMake(350, 150);
    CGPoint rightBottomPoint = CGPointMake(650, 150);
    CGPoint rightCenterPoint = CGPointMake(650, 300);
    CGPoint rightTopPoint = CGPointMake(650, 450);
    CGPoint centerTopPoint = CGPointMake(350, 450);
    CGPoint leftTopPoint = CGPointMake(50, 450);
    CGPoint leftCenterPoint = CGPointMake(50, 300);

    CGPoint positions[] = {
        CGPointMake(leftBottomPoint.x , leftBottomPoint.y),
        CGPointMake(centerBottomPoint.x, centerBottomPoint.y),
        CGPointMake(rightBottomPoint.x, rightBottomPoint.y),
        CGPointMake(rightCenterPoint.x, rightCenterPoint.y),
        CGPointMake(rightTopPoint.x, rightTopPoint.y),
        CGPointMake(centerTopPoint.x, centerTopPoint.y),
        CGPointMake(leftTopPoint.x, leftTopPoint.y),
        CGPointMake(leftCenterPoint.x, leftCenterPoint.y),
    };

    // This array will contain all the selected nodes
    _selectedNodesVector = [[NSMutableArray alloc] init];

    // adding the points to the vector that contains the controlPoints
    for (int i = 0; i < 8; i++) {
        ControlPointNode* controlPointTmp = [[ControlPointNode alloc] init:positions[i] :i];
        [_controlPointsVector addObject:controlPointTmp];
    }
    // create arena with the controlPointVector
    _arena = [[ArenaNode alloc ] init:_controlPointsVector ];

    [self addChild:_arena];

}
return self;

} - （void）drawArena {

-(id) init:(NSMutableArray *)controlPointVector{

if (self = [super init]) {

    controlPointsVector =[[NSMutableArray alloc]init];

    controlPointsVector = controlPointVector;

    self.name = @"arena";

    // set physical aspect of the arena
    self.frictionForce = 0.0;
    self.bouncingForce = 1.0;
    self.acceleration = 1.0;

    // draw the shape of the arena
    [self drawArena];

    for(ControlPointNode* controlPointTmp in controlPointsVector){

        [self addChild:controlPointTmp];
    }

    [self addChild:_shape];

}
return self;

}

问题在于，当我尝试运行/构建时，竞技场不会出现。当我调试我发现 _pathToDraw = CGPathCreateMutable(); CGPathMoveToPoint (_pathToDraw, NULL, [[controlPointsVector objectAtIndex:0] position].x, [[controlPointsVector objectAtIndex:0] position].y ); for(int i=1; i<8; i++){ CGPathAddLineToPoint(_pathToDraw, NULL, [[controlPointsVector objectAtIndex:i] position].x , [[controlPointsVector objectAtIndex:i] position].y ); } CGPathCloseSubpath(_pathToDraw); _shape = [[SKShapeNode alloc]init]; _shape.path = CGPathCreateCopy(_pathToDraw); _shape.fillColor = [UIColor colorWithRed:1.0 green:0.8 blue:0.4 alpha:1.0]; //the following instruction allows the physics bodies that hit the borders of the scene to bounce // From: Documentation - SKPhysicsBody Class Reference _shape.physicsBody = [SKPhysicsBody bodyWithEdgeLoopFromPath:_shape.path]; [self updatePhysicsBody:_shape.physicsBody :@"ArenaNode"]; 始终 controlPointVector 。

请有人帮忙解决这个问题。

N.B：1-我使用了NSMutableArray，因为我需要移动controlPoints，我必须跟踪场景中发生的任何变化。

2-竞技场不是静态的，它必须是动态的，以允许用户更改它。

提前致谢。

Answer 1

实际上，这是初学者错误我没有在正确的位置初始化矢量

controlPointsVector =[[NSMutableArray alloc]init];

应该在之前

 // adding the points to the vector that contains the controlPoints
for (int i = 0; i < 8; i++) {
    ControlPointNode* controlPointTmp = [[ControlPointNode alloc] init:positions[i] :i];
    [_controlPointsVector addObject:controlPointTmp];
}

MyScene.m ，而不是 MyArena.m 。现在我的场景中有竞技场。

如何使用CGPoint的NSMutableArray元素绘制路径

1 个答案: