Very Quick Camera Question!

Blitz3D Forums/Blitz3D Beginners Area/Very Quick Camera Question!

DJ3J	(Posted 2004) [#1]

Ahoy! I have a quick question regarding cameras in Blitz3D. My problem might have to do with the fact that I am misunderstanding the way AlignToVector and MoveEntity commands work. Here's a bit of code to illustrate my problem:

Graphics3D 800,600

SetBuffer BackBuffer()

Global mx,my,mz,mzspd,rotup,ticker,camera

camera = CreateCamera()
PositionEntity camera,0,-15,-5
TurnEntity camera,-90,0,0

light = CreateLight()

cube = CreateCube()

Function UpdateCamera()
	If mzspd > 0
		rotup =  1
	ElseIf mzspd < 0
		rotup = -1
	EndIf
	
	If rotup = 1 And ticker < 60
		AlignToVector camera,0,.01,0,2,.01
		MoveEntity camera,0,.1,.1
		ticker = ticker + 1
	ElseIf rotup = -1 And ticker < 60
		AlignToVector camera,0,-.01,0,2,.01
		MoveEntity camera,0,-.1,-.1
		ticker = ticker + 1
	EndIf
	
	If ticker = 60
		rotup = 0
		ticker = 0
	EndIf
End Function

While Not KeyHit(1)
	
	mx = MouseX()
	my = MouseY()
	mz = MouseZ()
	
	UpdateWorld
	RenderWorld
	
	UpdateCamera()

	
	mxspd = MouseXSpeed()
	myspd = MouseYSpeed()
	mzspd = MouseZSpeed()
	
	If MilliSecs()<timer+1000 Then
		frame=frame+1
	Else
		fps=frame
		frame=0
		timer=MilliSecs()
	End If

	Flip
Wend
End

I wanted it to work so that when I scroll up on the mouse button (just one click should do), it moves the camera up and tilts it down on the cube. When I scroll back (again, a single click should do), I want it to _perfectly reverse_ that motion. However, I find that when I scroll back, it doesn't bring the camera back to its starting point! What gives?

If you could offer any help, I'd greatly appreciate it.

Thanks,

-- DJ3J, once again showing just how much of a beginner he really is.

jfk EO-11110

(Posted 2004) [#2]

Maybe this helps:

if rotup=0
 If mzspd > 0
  rotup =  1
 ElseIf mzspd < 0
  rotup = -1
 EndIf
endif

you could also try to store its way upward in an array and simply play the positions inside the array reversly when rotup is -1. you never know, rounding errors and the like.

BTW - pls don't cross-post.