使边框适合“真实”图像，剪裁白色边框SpriteKit物镜c

Question

I am learning Spritekit right now and I want to detect a collision between two images. Just a fun picture as an example :

The image is still a rectangle. How can I fit it that this rectangle will fit to the original face? I don't want the collision early when it hits the rectangle of the Image, I want it to collide when it actually hits the black lines of the face.

I hope you can understand my problem.

Thanks for any help.

EDIT:

Answer 1

If its an image thats got white borders all around it, u can edit it in Preview and use Alpha to get rid of all of the white around it.

I think in that case, the sprite's collision method will collide with the black lines.

Answer 2

There are two issues here:

1. You probably want to set up your SKPhysicsBody to be a path around your SKSpriteNode . For example, something like the following is close:

    UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(-40, -22, 80, 39)]; node.physicsBody = [SKPhysicsBody bodyWithPolygonFromPath:path.CGPath]; 

   That's probably not quite right, so feel free to tweak those values, but hopefully it illustrates the idea: Come up with a path that defines your boundary, and then set the physicsBody accordingly.

   If you want to see the physics outlines, set showsPhysics on the SKView .

2. You probably want to mask your image so that the corners of the image are transparent (ie have an alpha of zero):

   

   So, when that's on a colored background it looks like:

   

   By masking the corners, you don't have to worry about the white corner covering up something else on the scene.