CameraZoom does not get tweened

Blitz3D Forums/Blitz3D Programming/CameraZoom does not get tweened

Damien Sturdy

(Posted 2005) [#1]

Hi all.

This is more or less just an FYI:

I was recently looking at one of my projects and noticed that the camera was a bit jerky when zooming in and out.

I found the problem:

CameraZoom values do not get tweened!

A very very simple bit of code to demonstrate:

Graphics3D 640,480,16,2
cube=CreateCube()
camera=CreateCamera()
light=CreateLight()
MoveEntity camera,0,10,0
PointEntity camera,cube
CameraZoom camera,1
CaptureWorld
TurnEntity cube,179,0,0
Repeat
	CameraZoom camera,Rand(2)
	For n#=0 To 1 Step .01
		RenderWorld n#
		Flip
		If KeyHit(1) Then End
	Next
Until False

Um, Is this a bug? (should i post it there?)

I got around it by storing zoom values and doing a bit of maths before rendering, but this is one of the commands useful in creating TV type camera views, and this was a pain in the ass until i found out why it wasnt working!

EDIT:

Heres an example of the "fixed" loop:

Graphics3D 640,480,16,2
cube=CreateCube()
camera=CreateCamera()
light=CreateLight()
MoveEntity camera,0,10,0
PointEntity camera,cube

CameraZoom camera,1
Startzoom#=1 ;Start zoom, part of tween fix

CaptureWorld
TurnEntity cube,179,0,0
Repeat
	newzoom#=Rnd(1,4); Target zoom
	For n#=0 To 1 Step .01
		CameraZoom camera,Float(startzoom+(newzoom-startzoom)*n) 	;The part inside FLOAT calculates what the zoom level should be for this "tween#" value.
;what the zoom level should be for this "tween#" value, using the old and new zoom values.
		RenderWorld n#
		Flip
		If KeyHit(1) Then End
	Next
	Startzoom#=newzoom ;Store the newest zoom

Until False

Damien Sturdy

(Posted 2005) [#2]

Gotta love Blitz' ability to do Function Overloading!!!!

Function CameraZoom(camera,zoom#) 
ScaleEntity camera,1/zoom,1/zoom,1
End Function

^.^

Beaker

(Posted 2005) [#3]

Maybe you could add some useful stuff to the Manual comments:
CameraZoom

Damien Sturdy

(Posted 2005) [#4]

Thanks for pointing that out Beaker :D