Code archives/User Input/CameraMouseView

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CameraMouseView by markcw
(Posted 21 years ago)
I couldn't find any code here like this, so I thought I'd add this example. The drag code was the tricky bit, but it seems to be working nicely now.

This is the kind of camera control you get in Milkshape or UltimateUnwrap.

edit: i never liked the way this used a lot of globals, so i've updated it so it uses no globals and instead a bank to hold the "globals". i thought about types but decided this was better as it's simpler to transfer to a project this way.
Open in online IDE
;CameraMouseView, on 10/10/06

Graphics3D 640,480,0,2
SetBuffer BackBuffer()

camerapivot=CreatePivot() ;pivot
camera=CreateCamera(camerapivot) ;camera on pivot
camerabank=CreateBank(48) ;camera bank variables

light=CreateLight()
RotateEntity light,90,0,0

cube=CreateCube()

While Not KeyHit(1)
 UpdateWorld
 RenderWorld

 CameraMouseView(camerapivot,camera,camerabank)

 Text 0,0,"Press LShift to Zoom, LCtrl to Drag"

 Flip
Wend

Function CameraMouseView(camerapivot,camera,camerabank,speed#=0.05)
 ;camerapivot,camera,camerabank=valid handles, speed#=speed of view

 Local movex,movey,camx#,camy#,camz#,pivx#,pivz#,angle#,xaxis#,zaxis#

 ;error messages for invalid handles
 If camerapivot=0 Then RuntimeError "Pivot entity is zero!"
 If camera=0 Then RuntimeError "Camera entity is zero!"
 If camerabank=0 Then RuntimeError "Bank handle is zero!"

 ;set default values
 If speed#<0.01 Then speed#=0.01 ;min speed
 If PeekFloat(camerabank,36)=0 Then PokeFloat camerabank,36,-10 ;no camz

 ;update mouse variables
 PokeInt camerabank,0,PeekInt(camerabank,8) ;lastx=msex
 PokeInt camerabank,4,PeekInt(camerabank,16) ;lasty=msey
 PokeInt camerabank,8,MouseX() ;msex
 PokeInt camerabank,16,MouseY() ;msey
 PokeInt camerabank,20,MouseX()-PeekInt(camerabank,0) ;movex=msex-lastx
 PokeInt camerabank,24,MouseY()-PeekInt(camerabank,4) ;movey=msey-lasty

 ;fill in the position/rotation variables
 movex=PeekInt(camerabank,20)
 movey=PeekInt(camerabank,24)
 camx#=PeekFloat(camerabank,28)
 camy#=PeekFloat(camerabank,32)
 camz#=PeekFloat(camerabank,36)
 pivx#=PeekFloat(camerabank,40)
 pivz#=PeekFloat(camerabank,44)

 If MouseDown(1) ;Left Mouse button
  If KeyDown(29) ;Left Ctrl key, camera drag
   angle#=camy# : xaxis#=speed# : zaxis#=speed# ;init xz axis
   If angle#>90 And angle#<270 Then zaxis#=-zaxis# ;-z if 90..270
   If angle#>180 Then angle#=360-angle# : xaxis#=-xaxis# ;-x if 180..360
   If angle#>90 Then angle#=180-angle# ;reduce y angle to 90
   angle#=angle#*0.011 ;y as fraction of 1, ie. 90->100
   ;set mouse xy movements by y fraction and add to pivot xz positions
   pivx#=pivx#-(movex*(1-angle#)*zaxis#)-(movey*angle#*xaxis#)
   pivz#=pivz#-(movex*angle#*xaxis#)+(movey*(1-angle#)*zaxis#)
  ElseIf KeyDown(42) ;Left Shift key, camera zoom
   camz#=camz#-movey*speed#  ;-msey sets camera z mt
   If camz#>-3 Then camz#=-3 ;limit zoom to 3mt
  Else ;camera rotation
   camx#=camx#+(movey*10*speed#) ;mousey sets camera x dg
   If camx#>90 Then camx#=90   ;limit x to -90..90
   If camx#<-90 Then camx#=-90
   camy#=camy#-(movex*10*speed#) ;-mousex sets camera y dg
   If camy#>359 Then camy#=0   ;limit y to 0..360
   If camy#<0 Then camy#=359
  EndIf
 EndIf

 ;update position/rotation variables
 PokeFloat camerabank,28,camx#
 PokeFloat camerabank,32,camy#
 PokeFloat camerabank,36,camz#
 PokeFloat camerabank,40,pivx#
 PokeFloat camerabank,44,pivz#

 ;move pivot, rotate and zoom camera
 PositionEntity camerapivot,pivx#,0,pivz# ;drag
 RotateEntity camerapivot,camx#,camy#,0 ;rotate
 PositionEntity camera,0,0,camz# ;zoom

End Function

Comments

markcw
(Posted 20 years ago)
Here is the old code entry, just as a reminder.

;Rotate, Zoom and Drag Camera with Mouse, on 18/11/05, by muk

Graphics3D 640,480,16,2
SetBuffer BackBuffer()

Global camx#,camy#,camz#=-10,pivx#,pivz#,camspd#=0.02 ;camera
Global msex,msey,lastx,lasty,movex,movey ;mouse
Global pivot,camera,light ;entity

pivot=CreatePivot() ;pivot
camera=CreateCamera(pivot) ;camera with pivot parent

light=CreateLight() ;light
RotateEntity light,90,0,0

cube=CreateCube() ;cube

;Main Loop
While Not KeyDown(1)

 UpdateCamera()

RenderWorld

 Text 0,0,"Press LShift to Zoom"
 Text 0,16,"Press LCtrl to Drag"
 Text 0,48,"X dg:"+camx
 Text 0,64,"Y dg:"+camy
 Text 0,80,"Zoom:"+camz
 Text 0,96,"X mts:"+pivx
 Text 0,112,"Z mts:"+pivz

Flip
Wend
End

;Functions
Function UpdateCamera()

lastx=msex : lasty=msey ;get mouse movements
msex=MouseX() : msey=MouseY()
movex=msex-lastx : movey=msey-lasty

If MouseDown(1)
 If KeyDown(29) ;LCtrl key, camera drag
  yrot#=camy : xaxis#=camspd : zaxis#=camspd ;init xz axis
  If yrot>90 And yrot<270 Then zaxis=-zaxis     ;-zaxis if 90-270dg
  If yrot>180 Then yrot=360-yrot : xaxis=-xaxis ;-xaxis if 180-360dg
  If yrot>90 Then yrot=180-yrot ;reduce y rotation to 90dg
  yfr#=yrot*0.011 : ifr#=1-yfr  ;set y as fraction of 1 and get inverse
  mxpx#=movex*ifr*zaxis : mxpz#=movex*yfr*xaxis ;set mouse xy movements
  mypx#=movey*yfr*xaxis : mypz#=movey*ifr*zaxis ;by y fraction and axis
  pivx=pivx-mxpx-mypx : pivz=pivz-mxpz+mypz     ;add to pivot positions
 ElseIf KeyDown(42) ;LShift key, camera zoom
  camz=camz-movey*camspd  ;-mousey sets camera z position
  If camz>-3 Then camz=-3 ;limit z to 3-30mt
  If camz<-30 Then camz=-30
 Else ;Neither keys, camera rotation
  camx=camx+movey*10*camspd ;mousey sets camera x rotation
  If camx>90 Then camx=90   ;limit x to 0-90dg
  If camx<0 Then camx=0
  camy=camy-movex*10*camspd ;-mousex sets camera y rotation
  If camy>359 Then camy=0   ;wrap y to 0-359dg
  If camy<0 Then camy=359
 EndIf
EndIf

RotateEntity pivot,camx,camy,0   ;rotate camera
PositionEntity camera,0,0,camz   ;zoom camera
PositionEntity pivot,pivx,0,pivz ;drag camera

End Function


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