Same speed on all machines and Tweening

It's not necessary at all. Just draw everything at whatever position they are currently at. If you're using a high rate (e.g. 200 updates per second or more), using tweening for the display is going to make little visual difference to the player. Tweening and/or delta only come into it when the updates per second are less than the refresh rate of the display.

However, some people like to combine the two methods to give the smoothest possible experience, but I think it's a lot of effort for little gain. Only the programmer is going to notice any difference becaise they are looking for it. The casual gamer will be too involved in the game to notice any difference - as long as the game looks and feels smooth.


Each of your objects needs to have separate Update and Draw methods. In terms of the coding, the following is a little program I wrote when I first started experimenting with this. It's probably the simplest way of doing things, but will serve as a good starting point.

Strict

' ----- Preferences -----

Const scrWidth:Int=640,scrHeight:Int=480	' screen resolution to use
Const scrDepth:Int=32				' bitdepth to use
Const monitorFPS:Int=85				' preferred monitor frequency
Const logicFPS:Int=200				' number of times to update logic per second
Const logicMaxUpdates:Int=logicFPS/20		' maximum number of logic updates in any one loop

' ----- Constants -----

Const logicSpeed:Int=1000/logicFPS		' time difference between logic updates

' ----- Control Globals -----

Global systemTime:Int				' holds system time before entering logic update loop
Global gameTime:Int				' current time in relation to system time
Global logicCount:Int				' used to check if game is running slow

' ----- Set Up Graphics -----

Graphics scrWidth,scrHeight,scrDepth,monitorFPS	' set up graphics
HideMouse

' ----- Main Loop -----

Global mx:Int,my:Int	' just used for testing

Global rectX:Int=0,rectY:Int=0,rectW:Int=16,rectH:Int=scrHeight	' constantly moving object

systemTime=MilliSecs()	' grab system time
gameTime=systemTime	' put game at same point

While Not KeyHit(key_escape)
	logicCount=0
	systemTime=MilliSecs()
	While gameTime<=systemTime
		UpdateLogic()
		gameTime:+logicSpeed			' update game time
		logicCount:+1				' increase update count
		If logicCount>logicMaxUpdates Then Exit	' quit update loop if max updates reached
	Wend
	
	Render
	
	' check for timer wrap (they'll be a stutter, but heck, it happens every 1200 hours!!!)
	If MilliSecs()<systemTime Then gameTime=MilliSecs()
Wend

' ----- Support Functions -----

Function UpdateLogic()
	' grab mouse co-ordinates
	mx=MouseX()
	my=MouseY()
	' update rectangle
	rectX:+1
	If rectX=(scrWidth-rectW) Then rectX=0
EndFunction

Function Render()
	Cls
	SetColor 255,255,0
	DrawRect rectX,rectY,rectW,rectH
	SetColor 255,255,255
	DrawLine mx-16,my,mx+16,my
	DrawLine mx,my-16,mx,my+16
	Flip
EndFunction

Hope it helps.