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sprite-kit

Velocity: Meters per second or pixels per second?

Apple documentation states that a physics body's velocity is measured in meters per second.

Is this true? Is there a relationship between pixels and meters? If there is, what is it?

Or is this an error in the documentation and it's really pixels per second?

Solution

  • An answer to anyone and myself

    There is nothing to really define a pixel within apples SKSpriteKit, this is a misnomer in my question. A point on the other hand is well defined.

    Everybody probably already knows this but if you attach a SKPhysicsBody to a Node and assign the following properties:

        seg.physicsBody?.isDynamic = true
    seg.physicsBody?.affectedByGravity = false
    seg.physicsBody?.allowsRotation = false
    seg.physicsBody?.usesPreciseCollisionDetection = true
    seg.physicsBody?.mass = 0
    seg.physicsBody?.restitution = 1
    seg.physicsBody?.linearDamping = 0

    Then applying a velocity dy component of 200 results in the object moving at 200 points per second. This says to me that with all external forces remove Sprite kits physics world translates to 1m/s = 1point/s.