iOS SpriteKit - ray(line) is reflected from bounds - ios

Question

We have line(ray) which moves to bounds and reflects when bound is reached. These images demonstrates the dynamic of movement and reflections.
And i'd like to implement it in SpriteKit(obj-c is prefer) but don't understand from which point I should start.

Answer 1

I found how to implement it. Hope it'll be useful for others
#import "GameScene.h"
static const float GUIDE_MASS = .0015;
static const int SEGMENTS_COUNT = 10;
static const int SEGMENT_LENGTH = 5;
#interface GameScene(private)
-(void) createGuidesAndShot;
#end
#implementation GameScene
SKShapeNode *shot;
NSMutableArray* shotSegments;
-(void)didMoveToView:(SKView *)view {
[self setBackgroundColor:[SKColor whiteColor]];
}
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
/* Called when a touch begins */
}
-(void)update:(CFTimeInterval)currentTime {
CGMutablePathRef pathToDraw = CGPathCreateMutable();
if (shotSegments!=nil) {
bool isFirst = YES;
for (SKNode* segment in shotSegments) {
if(isFirst){
CGPathMoveToPoint(pathToDraw, NULL,
segment.position.x,
segment.position.y);
isFirst =NO;
} else {
CGPathAddLineToPoint(pathToDraw, NULL,
segment.position.x,
segment.position.y);
}
}
shot.path = pathToDraw;
}
}
-(void)didBeginContact:(SKPhysicsContact *)contact {
uint32_t collision = (contact.bodyA.categoryBitMask | contact.bodyB.categoryBitMask);
if (collision == (shotCategory|screenBoundsCategory)){
}
}
-(id)initWithSize:(CGSize)size {
if (self = [super initWithSize:size]) {
shotSegments = [NSMutableArray new];
self.physicsWorld.gravity = CGVectorMake(0.0f, 0.0f);
SKPhysicsBody* borderBody = [SKPhysicsBody bodyWithEdgeLoopFromRect:self.frame];
self.physicsBody = borderBody;
self.physicsBody.friction = 0.0f;
self.physicsBody.categoryBitMask = screenBoundsCategory;
self.physicsBody.contactTestBitMask = shotCategory;
self.physicsWorld.contactDelegate = self;
[self createGuidesAndShot];
}
return self;
}
-(void) createGuidesAndShot{
for (int i = 0; i<SEGMENTS_COUNT*SEGMENT_LENGTH; i+=SEGMENT_LENGTH) {
SKShapeNode* guide = [SKShapeNode shapeNodeWithCircleOfRadius:1];
guide.position = CGPointMake(self.frame.size.width/2+i,
self.frame.size.height/2-i);
// guide.fillColor = [SKColor blackColor];
guide.name = [NSString stringWithFormat:#"guide%i", i];
[self addChild:guide];
[shotSegments addObject:guide];
guide.physicsBody = [SKPhysicsBody bodyWithCircleOfRadius:guide.frame.size.width/2];
guide.physicsBody.friction = 0.0f;
guide.physicsBody.restitution = 1.0f;
guide.physicsBody.linearDamping = 0.0f;
guide.physicsBody.allowsRotation = NO;
guide.physicsBody.categoryBitMask = shotCategory;
guide.physicsBody.contactTestBitMask = screenBoundsCategory;
guide.physicsBody.collisionBitMask = screenBoundsCategory;
guide.physicsBody.mass = GUIDE_MASS;
[guide.physicsBody applyImpulse:CGVectorMake(0.1f, -0.1f)];
}
shot = [SKShapeNode node];
[shot setStrokeColor:[UIColor redColor]];
[self addChild:shot];
}
#end