Lerp function (Linear Interpolation)

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Pakz	Created : 12 November 2017 Language : Monkey-X Lerp function (Linear Interpolation) Return number between low and high Flash example of this code
Import mojo Class MyGame Extends App Field enemyx:Int,enemyy:Int Field startx:Int=100,starty:Int=100 Field destx:Int=320,desty:Int=230 Field percentage:Float=0 ' how far in the path are we Field stp:Float=0.01 ' how fast do we move Method OnCreate() SetUpdateRate(60) ' Fps enemyx = startx enemyy = starty End Method Method OnUpdate() ' Get our new x and y position enemyx = lerp(percentage,startx,destx) enemyy = lerp(percentage,starty,desty) ' Set the new position percentage+=stp ' Keep inside the value of 0.0 and 1.0 If percentage<=0 Or percentage>=1 Then stp=-stp End Method Method OnRender() Cls 0,0,0 SetColor 255,255,255 ' Draw the enemy sprite DrawRect enemyx,enemyy,32,32 ' DrawText 'Lerp(Linear Interpolation) Patrolling - example',0,0 End Method ' Percentage 0 to 1 returns number between a and b Function lerp:Int(t:Float , a:Float, b:Float) Return a + t * (b - a) End Function End Class Function Main() New MyGame() End Function --v
Latest Update I noticed this lerp function yesterday while watching a episode from The Coding Train. Here they used the lerp function to create a morphing effect.(#circlemorphing - see this twitter hasktag for example animated gifs) Lerp I think is short for Linear Interpolation. The Lerp function basically takes a input value from 0.0 to 1.0 and returns a value based on the from low to high. So Lerp(0,5,0,10) returns 5 Lerp(0.0,20,30) returns 20 I think maybe this linear interpolation is quite useful. I created a patrolling example here. It probably can be used to make a lot more. I am not that experienced with math so I was quite happy to learn this one.

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Sunday, 12 November 2017, 07:58
GfK	Yeah it means linear interpolation. Unity has Mathf.lerp() which does this. Also has built in functionality to lerp between vector2/3/4s, quaternions, colours and materials. Handy stuff to use for transitioning gradually from one state of affairs to another.
Sunday, 12 November 2017, 08:19
Jayenkai	Personally I tend to put the percentage at the end, so itâ€™s From, To, Perc... Oh, and I use percentages instead of 0-1.0 Iâ€™ve had this kind of function in my past few Frameworks, but havenâ€™t yet added it to my latest, mostly because I simply havenâ€™t really used it all that much. Itâ€™s great for mixing colours, but then youâ€™re better off making an RGB specific version just for that purpose. Instead I tend to use my smooth-transition thing of From=From-((From-To)/ApproxFrames), which starts the transition off fast, then smooths off towards the end. Smooth scrolling, score "ticking up" and more, are all done with that. Iâ€™ve become very reliant on it, but oddly it doesnâ€™t seem to be working very well in c++... hmmm..
Sunday, 12 November 2017, 09:39
Pakz	I noticed that Monkey2 has a Blend option that can be used after a color command. color = New Color(0.5,0.5,0.5).Blend(New Color(1.0,0,0),.5) I quite like that. I want to spend more time googling for math functions and their uses. It seems I am still in the dark ages with these things.

Lerp function (Linear Interpolation)

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