Code archives/Graphics/zoomable clickable scrollable starfield!

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zoomable clickable scrollable starfield! by Booticus
(Posted 21 years ago)
Here's some code from someone in the forums (I spaced on who posted it originally) and the Chris Camacho added the clickability.

OK this lets you plot some objects, scroll around with the arrow keys, soom with either the mousewheel or the "+" or "-" keys on the NUMPAD. When you click, the object lights up in yellow. 
SuperStrict

Global objList:TList=CreateList()

Graphics 640,480

Global theZoomFactor:Float=1.0
Global oldZoomFactor:Float=0.0

For Local i:Int=1 To 5
	Local o:obj=New obj
	o.x=Rand(-GraphicsWidth(),GraphicsWidth())
	o.y=Rand(-GraphicsHeight(),GraphicsHeight())
Next

Global youX:Float,youY:Float

Global line:Int
While KeyHit(KEY_ESCAPE)=0
Cls	
line=50
	If KeyDown(KEY_NUMADD) Then theZoomFactor:+0.01
	If KeyDown(KEY_NUMSUBTRACT) Then theZoomFactor:-0.01
'	If theZoomFactor<0.1 Then theZoomFactor=0.1
'	If theZoomFactor>4 Then theZoomFactor=4	
	
	
	If KeyDown(KEY_UP) Then youY:-1.0*theZoomFactor
	If KeyDown(KEY_DOWN) Then youY:+1.0*theZoomFactor
	If KeyDown(KEY_LEFT) Then youX:-1.0*theZoomFactor
	If KeyDown(KEY_RIGHT) Then youX:+1.0*theZoomFactor

	If MouseZ() And oldZoomFactor<>MouseZ()
		If oldZoomFactor<MouseZ()
			theZoomFactor:+0.1	
		Else
			theZoomFactor:-0.1			
		EndIf
			If theZoomFactor>4.0
				theZoomFactor=4.0
			End If
			If theZoomFactor<0.2
				theZoomFactor=0.2
			End If
		oldZoomFactor=MouseZ()
	EndIf
	SetColor 255,255,255;DrawText theZoomFactor,0,0


		
	
	updateObjs(MouseDown(1))

	SetColor 0,255,0
	DrawRect (GraphicsWidth()/2)-3,(GraphicsHeight()/2)-3,7*theZoomFactor,7*theZoomFactor
	SetColor 255,255,255;DrawText theZoomFactor,0,0
	DrawText "Press +/- on the numpad to zoom. Cursors to move",0,10
	
Flip
Wend
End


Type obj
	Field x:Int
	Field y:Int
	Field dist:Float
	
	Method New() ListAddLast(objList,Self); End Method
	Method Update()
		Local dx:Int=(youX*theZoomFactor)-GraphicsWidth()/2  'here you have forgotten the scalefactor
		Local dy:Int=(youY*theZoomFactor)-GraphicsHeight()/2 'here you have forgotten the scalefactor
		SetScale 1,1
		SetColor 255,0,0
		If dist<50*thezoomfactor Then SetColor 255,255,0
		DrawRect Int((x*theZoomFactor-3)-dx),Int((y*theZoomFactor-3)-dy),Int(7*theZoomFactor),Int(7*theZoomFactor)
		DrawText dist,10,line
		line:+20
	End Method
End Type	

Function updateObjs(checkmouse:Int)
	Local mx:Float=MouseX()
	Local my:Float=MouseY()
	Local dx:Int=(youX*theZoomFactor)-GraphicsWidth()/2
	Local dy:Int=(youY*theZoomFactor)-GraphicsHeight()/2
	For Local i:obj=EachIn objList
		i.Update()
		If checkmouse Then
			Local xdiff:Float,ydiff:Float
			xdiff=(mx)-(i.x*thezoomfactor-dx)
			ydiff=(my)-(i.y*thezoomfactor-dy)
			i.dist=Sqr((xdiff*xdiff)+(ydiff*ydiff))
	
		Else
			i.dist=1000
		endif
	Next

End Function