Converting blitz2d to max

I have this code in Blitz2D, and I want it work in blitzmax but there is no copyrect or imagebuffers. I think you should be able to do everything in blitzmax that you could do in blitz2d... but this code needs to run very fast. And it is fast in blitz2d.


Heres basically what the code looks like:
Each loop it has to write to every fire image buffer using copyrect and writepixelfast.

I haven't ever used pixmaps, can they do this?
Is there some sort of copyrect function?

Function FireUpdate(Fire.Fire)	
	
	SetBuffer ImageBuffer(Fire\image)
	
	For whatever
		X=Rnd()
		Y=Rnd()
		AddX=Rand(-1,1)
		CopyRect X,Y,Rnd(5,7),Rnd(5,10), X+AddX, Y - 1
	Next
	
	LockBuffer ImageBuffer(Fire\image)
	For whatever
		X=Rnd()
		Y=Rnd()
		WritePixelFast X,Y,0
	Next
	UnlockBuffer ImageBuffer(Fire\image)
	
End Function