Spritekit PhysicsBody applyTorque
I am working on a universal app.
I want applyTorque
to Paddle
But the problem is that the paddle is larger on an ipad than on one iphone.
How can I calculate the torque to apply the same effect to the physical Paddle logic?
SKSpriteNode *bar = [SKSpriteNode spriteNodeWithImageNamed:nameImage];
bar.name = @"bar";
bar.size = CGSizeMake(PaddleWidth, PaddleHeight);
bar.physicsBody =[SKPhysicsBody bodyWithTexture:bar.texture size:bar.size];
bar.physicsBody.restitution = 0.2;
bar.physicsBody.angularDamping = 0;
bar.physicsBody.friction = 0.02;
bar.physicsBody.mass=.2;
[paddle addChild:bar];
SKSpriteNode *anchor = [SKSpriteNode spriteNodeWithColor:[SKColor clearColor] size:CGSizeMake(PaddleWidth, PaddleHeight)];
anchor.name = @"anchor";
anchor.size = CGSizeMake(PaddleHeight, PaddleHeight);
anchor.position = CGPointMake(bar.position.x + bar.size.width/2, 0);
[paddle addChild:anchor];
CGFloat anchorRadius = anchor.size.width/20;
anchor.physicsBody = [SKPhysicsBody bodyWithCircleOfRadius:anchorRadius];
anchor.physicsBody.dynamic = NO;
CGPoint positionInScene = [self convertPoint:anchor.position toNode:self.scene];
pin = [SKPhysicsJointPin jointWithBodyA:bar.physicsBody
bodyB:anchor.physicsBody
anchor:positionInScene];
pin.shouldEnableLimits = YES;
pin.lowerAngleLimit = -0.5;
pin.upperAngleLimit = 0.5;
[self.scene.physicsWorld addJoint:pin];
- (void) {flip
SKNode *bar=[self childNodeWithName:@"bar"];
CGFloat torque;
torque=10;
[bar.physicsBody applyTorque:torque];
}
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You can use the paddle size as a factor in the amount of torque:
CGSize paddleSize = <Initialize with paddle size>
CGFloat torque=paddleSize.width * factor; // factor will be the value you need to multiply in order to reach your desired value
So if for example paddle width a 100
constant factor is used 0.05
On an iPad different paddle widths will calculate the torque value using the same factor as above.
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You can set a constant physical body mass so that the applied torque acts on the paddle in the same way, regardless of the node size.
//While instantiating the physicsBody for the "bar" node
bar.physicsBody.mass = 0.2; //This will need to be adjusted according to your needs.
From the documentation :
The mass of a body affects its momentum as well as how forces are applied to an object.
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