Best way to randomly move sprite forever in Sprite Kit - ios

Question

I have a sprite and I want to move it to random points forever. I have written this code, but I don't think it is efficient.
-(void)addBoss {
SKSpriteNode *boss = [SKSpriteNode spriteNodeWithImageNamed:#"Spaceship"];
boss.position = CGPointMake(self.size.width + boss.size.width / 2.0, self.size.height / 2.0);
boss.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:boss.size];
boss.physicsBody.dynamic = YES;
boss.physicsBody.categoryBitMask = bossCategory;
boss.physicsBody.contactTestBitMask = bossContact;
boss.physicsBody.collisionBitMask = 0;
boss.zPosition = 1;
self.boss = boss;
self.bossHealth = bossHP;
CGPoint destination = CGPointMake(self.size.width - boss.size.width / 2.0, boss.position.y);
float time = length(boss.position, destination) / bossSpeed;
SKAction *move = [SKAction moveTo:destination duration:time];
[self addChild:boss];
[self.boss runAction:[SKAction sequence:#[move, [SKAction runBlock:^{
[self artificialIntelligence];
}]]]];
}
- (void)moveBoss {
float minimumX = self.size.width / 2.0 + self.boss.size.width / 2.0;
float maximumX = self.size.width - self.boss.size.width / 2.0;
float minimumY = self.boss.size.height / 2.0;
float maximumY = self.size.height - self.boss.size.height / 2.0;
int rangeX = maximumX - minimumX;
int rangeY = maximumY - minimumY;
float x = arc4random() % rangeX + minimumX;
float y = arc4random() % rangeY + minimumY;
CGPoint dest = CGPointMake(x, y);
float duration = length(self.boss.position, dest) / putinSpeed;
[self.boss runAction:[SKAction moveTo:dest duration:duration] completion:^{
[self moveBoss];
}];
}
-(void)artificialIntelligence {
[self moveBoss];
}
This code works fine, but I don't think that calling the move method recursively after movement finished is not the best solution.
What is the best way to solve this kind of problem?

Answer 1

This is a quick and dirty way to do what you asked:
-(void)moveCharacter {
SKNode *playerNode;
// get random position
CGPoint destination = [self randomPosition];
if(!CGPointEqualToPoint(playerNode.position, destination)) {
// check xPos
if(playerNode.position.x > destination.x) {
playerNode.position = CGPointMake(playerNode.position.x-1, playerNode.position.y);
}
if(playerNode.position.x < destination.x) {
playerNode.position = CGPointMake(playerNode.position.x+1, playerNode.position.y);
}
// check yPos
if(playerNode.position.y > destination.y) {
playerNode.position = CGPointMake(playerNode.position.x, playerNode.position.y-1);
}
if(playerNode.position.y < destination.y) {
playerNode.position = CGPointMake(playerNode.position.x, playerNode.position.y+1);
}
} else {
destinationReached = YES;
}
}
-(CGPoint)randomPosition {
CGRect screenRect = [[UIScreen mainScreen] bounds];
int xPos = arc4random() % (int)screenRect.size.width;
int yPos = arc4random() % (int)screenRect.size.height;
return CGPointMake(xPos, yPos);
}
There are many different variations on how to move your character. You could for example divide the difference of x,y into a fixed number of movements as to have the player move in a smooth line from point A to B. If you are physics to move your player, you would have to use CGVector instead of directly changing his x,y position.