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Physics World Projectile Calculations

#1

Hello,

I have a physics question about using Sprite Kit. In a Angry Birds game type clone, I was setting up a feature where when the bird is pulled the birds anticipated path would be drawn if the bird was release at that point. Much like the game. An easy way to implement this is to create a sprite node with the same mass as the bird, set its alpha to 0 and apply an impulse to it. Then dot its projection along the way or use a particle emitter. The problem is that this is slower then I want. I can speed up the Physics World speed, but this can cause all kinds of other issues. So instead I am trying to do the physics calculations manually, which would be needed for any type of side scroll game that might require enemies launching projectiles/etc. The problem is Sprite Kit does not seem like there is a wealth of documentation as far as how mass is calculated and any type of meter to pixel or .dot conversion.

The most helpful info I have been able to find out about it is from https://stackoverflow.com/questions/31858973/spritekit-confusion-with-applyforce-opposite-to-gravity

My question is does the Sprite Kit 2d development book cover this specific topic, or any post? I would purchase the book in a second if the physics section dove into this subject. I don’t see much in any of my searches on boards when compared to something like Unity which there appears to be more documentation on the subject.

Thanks for any help,
Erik

opened #3