Update and Render loop for constant update time

[DominicDolan]

Info

The code currently has a way of setting custom logic for updating and rendering. This can be done while configuring the game:

Game.configure {
    setDeltaTimeCalculator(DeltaCalculator.basicConstantCalculator(60.0))
}

There are a lot of default ways of doing this algorithm in the DeltaCalculator companion object but none of them are ideal.

A better way of updating the game loop needs to be worked out. Custom algorithms can be made by extending DeltaCalculator like so:

class BasicConstantCalculator(frameRate: Double) : DeltaCalculator {
    override fun Updater.updateAndRender(lastFrame: Double, thisFrame: Double) {
        // Both update and render have to be called inside this function
        val delta = thisFrame - lastFrame
        update(delta)
        render()
    }
}

Motive

There are two stages to the game loop

• The update stage which should update physics/movement and logic
• The render stage which draws everything to the screen in their already calculated positions

It is generally recommended to, firstly, have the update and render stages decoupled from one another and, secondly, have the update stage simulate a constant amount of time. Most physics engines require an update that takes a constant value and online multiplayer games will also depend on a constant update time. More information about this and how to partially solve this issue can be seen here.

Task

Create an implementation of DeltaCalculator that updates the game with constant delta and does not cause games to look jittery or unsmooth