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POSpriteKit gravity confusion
 

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    <p>I have the following SpriteKit code:</p> <pre><code>scene.physicsWorld.gravity = CGVectorMake(0, -10); ... - (void)update:(CFTimeInterval)currentTime { [node.physicsBody applyForce:CGVectorMake(0, 10 * node.physicsBody.mass)]; } </code></pre> <p>Why doesn't the applyForce balance out the gravity? The node falls downwards quite quickly.</p> <p>Full example:</p> <pre><code>@interface HelloScene() @property SKLabelNode *node; @end @implementation HelloScene - (void)didMoveToView:(SKView *)view { self.backgroundColor = [SKColor blueColor]; self.scaleMode = SKSceneScaleModeAspectFit; self.physicsWorld.gravity = CGVectorMake(0, -10); [self addChild:[self newHelloNode]]; } - (SKNode *)newHelloNode { self.node = [SKLabelNode labelNodeWithFontNamed:@"Chalkduster"]; self.node.text = @"Hello, World!"; self.node.fontSize = 42; self.node.position = CGPointMake(CGRectGetMidX(self.frame), CGRectGetMidY(self.frame)); self.node.physicsBody = [SKPhysicsBody bodyWithCircleOfRadius:10.0]; self.node.physicsBody.mass = 1.0; self.node.physicsBody.angularDamping = 0.0; self.node.physicsBody.linearDamping = 0.0; self.node.physicsBody.friction = 0.0; return self.node; } - (void)update:(NSTimeInterval)currentTime { [self.node.physicsBody applyForce:CGVectorMake(0, 10 * self.node.physicsBody.mass)]; } @end </code></pre> <p>EDIT:</p> <p>Looks like it's out by a factor of 150. This seems to work:</p> <pre><code>self.physicsWorld.gravity = CGVectorMake(0, -10.0/150.0); </code></pre> <p>Why would this be the case?</p>
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    1. USDavid Lawson
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