Here's a little piece of code that implements the drag select found in RTS games.
' RTS Drag Select
' By ZoqFotPik
Type dragrect ' a mousedrag rect
Field upperleft:Int, upperright:Int, lowerleft:Int, lowerright:Int
End Type
Global objects:TList = New TList
Type selectobject
Field x:Int
Field y:Int
Field selected:Int
Method draw()
SetColor 255,255,255
DrawRect x-5,y-5,10,10
If selected = 1
SetColor 0,255,0
DrawRect x-10,y-10,15,15
EndIf
End Method
End Type
Graphics 640, 480
For i = 1 To 100
Local tempobj:selectobject = New selectobject
tempobj.x = Rand(640)
tempobj.y = Rand(480)
objects.addlast(tempobj)
Next
Global selectx:Int
Global selecty:Int ' these are the x and y origins of a select box
Global selectflag:Int ' is a selectbox active?
Print leastof(5,10)
Print greaterof(5,10)
While Not KeyHit(KEY_ESCAPE)
Cls
If MouseDown(1)
If Selectflag = 0
selectflag = 1
selectx = MouseX()
selecty = MouseY()
EndIf
EndIf
Local tempobj2:selectobject = New selectobject
For tempobj2 = EachIn objects
tempobj2.draw()
Next
If selectflag = 1
SetColor 0,255,0
DrawLine selectx, selecty, MouseX(), selecty
DrawLine MouseX(),selecty, MouseX(),MouseY()
DrawLine MouseX(),MouseY(), selectx,MouseY()
DrawLine selectx,MouseY(),selectx,selecty
If Not MouseDown(1)
selectflag = 0
Local ux:Int = leastof (MouseX(),selectx)
Local uy:Int = leastof(MouseY(),selecty)
Local lx:Int = greaterof(MouseX(),selectx)
Local ly:Int = greaterof(MouseY(),selecty)
For tempobj2 = EachIn objects
If tempobj2.x > ux And tempobj2.y > uy And tempobj2.x<lx And tempobj2.y <ly
tempobj2.selected = 1
Else
tempobj2.selected = 0
EndIf
Next
EndIf
EndIf
Flip
Wend
'leastof and greaterof are necessary in case of a leftward or upward drag of the select box
Function leastof(n1:Int, n2:Int)
Local least:Int
If n1>n2 least = n2
If n2>n1 least = n1
Return least
End Function
Function greaterof(n1:Int, n2:Int)
Local greater:Int
If n1>n2 greater= n1
If n2>n1 greater= n2
Return greater
End Function
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