CODEWITHSUNDEEP
iosobjective-csprite-kitgame-physics
mkeremkeskin
mkeremkeskin

Reputation: 644

SpriteKit physics giving different results each time

In my game I'm creating some balls which are effected by gravity. When game starts they fall from out of screen and get their places at the bottom. No other force is applied to them.

The problem is I'm creating these balls with exact coordinates, exact physics attributes like previous one but the result is not the same. It is similar but not same. But I think it should be exactly the same because in every time the values are same.

You can understand what I've said in these 3 pictures below.enter image description hereenter image description hereenter image description here

Do you have any idea why this is happening? How can I solve it?

This is how I create the sprite nodes:

BallSpriteNode *sprite = [BallSpriteNode spriteNodeWithTexture:ballTexture];
sprite.xScale = scale;
sprite.yScale = scale;
sprite.physicsBody = [SKPhysicsBody bodyWithCircleOfRadius:sprite.size.width/2];
sprite.physicsBody.density = 1.0f;
sprite.physicsBody.restitution = 0;
sprite.physicsBody.dynamic = YES;
sprite.physicsBody.categoryBitMask =  ballHitCategory;
sprite.physicsBody.contactTestBitMask = ballHitCategory;
sprite.physicsBody.collisionBitMask = ballHitCategory;

CGPoint startPosition = CGPointMake(xPosition, yPosition);
sprite.position = startPosition;

[bounceScene addChild:sprite];

Upvotes: 1

Views: 68

Answers (1)

codetiger
codetiger

Reputation: 2779

There are lots of factors involved in making a physics engine less random.

The FPS greatly affects the randomness. In SKSpriteKit Physics, you have a Update method in the SKScene, which is called once every frame and carry the time difference from the previous frames. Usually to make it less random you have to somehow override the method.

Or use other Physics engine's which are customisable (Bullet Physics). It is very easy to get same result by only adjusting the StepSimulation function call.

Upvotes: 2

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