Code archives/3D Graphics - Misc/Smart 3rd person camera

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Smart 3rd person camera by AntMan - Banned in the line of duty.
(Posted 23 years ago)
Will track an entity and will ensure no geo is obscuring it.

It will only avoid entities that are using a collision pick mode. I suggest 2 for levels. (i.e entityPickMode mesh,2,true)

xoff,yoff,zoff is the offset vector to where the camera should *try* to be. It may not be there, if there's geo in the line of sight between it and the entity.

spd is in a range of 0 to 1. 1=instant.0=never. 
type csys.sys
   field cx#,cy#,cz#
   field mx#,my#,sps
end type
Function chaseCam(cam,entity,xoff#,yoff#=2,zoff#=-5,spd#=0.8)
      sys.csys=first csys
      if sys=null 
             sys=new cSys
             sys\sps=createpivot()
      endif
      sys\mx=mousex()
      sys\my=mousey()
sps=sys\sps
PositionEntity sps,EntityX(entity),EntityY(entity),EntityZ(entity)
TFormVector xOff,yOff,zOff,entity,0
ex#=EntityX(entity)
ey#=EntityY(entity)
ez#=EntityZ(entity)
nx#=ex+TFormedX()
ny#=ey+TFormedY()
nz#=ez+TFormedZ()
dx#=nx-ex
dy#=ny-ey
dz#=nz-ez
hit=LinePick(ex,ey,ez,dx,dy,dz,0.2)
If hit
nx=PickedX()
ny=PickedY()
nz=PickedZ()
EndIf
sys\cx=sys\cx+(nx-sys\cx)*spd
sys\cy=sys\cy+(ny-sys\cy)*spd
sys\cz=sys\cz+(nz-sys\cz)*spd
positionEntity cam,sys\cx,sys\cy,sys\cz
pointentity cam,entity,0
End Function

Comments

AntMan - Banned in the line of duty.
(Posted 23 years ago)
SimonH, you need to sort the archives out...half the time they don't work, and even when they do things like this happen..(Formatting screwed up.)

AntMan - Banned in the line of duty.
(Posted 23 years ago)
Double post. (And this is another thing..adding comments nearly always hangs the browser. This doesn't happen on the regular forums so I doubt it's anything else)

aCiD2
(Posted 23 years ago)
Very impressive Otacon!! For those who aren't sure how to use it: here's an example
; ID: 1083
; Author: Otacon
; Date: 2004-06-13 04:37:46
; Title: Smart 3rd person camera
; Description: Follows a entity and avoids geo.

Type CSys

   Field cx#, cy#, cz#
   Field mx#, my#, sps%
   
End Type

Function ChaseCam(cam, Entity, XOff#, YOff# = 2, ZOff# = -5, Spd# = 0.8)

	Local sys.csys = First csys
	Local nx#, ny#, nz#
	Local dx#, dy#, dz#
	Local ex#, ey#, ez#
	Local hit%
	
	If sys = Null 
		sys = New cSys
		sys\sps = CreatePivot()
	EndIf
	
	sys\mx = MouseX()
	sys\my = MouseY()
	sps = sys\sps
	PositionEntity sps, EntityX(entity), EntityY(entity), EntityZ(entity)
	TFormVector xOff, yOff, zOff, entity, 0
	ex# = EntityX(entity)
	ey# = EntityY(entity)
	ez# = EntityZ(entity)
	nx# = ex+TFormedX()
	ny# = ey+TFormedY()
	nz# = ez+TFormedZ()
	dx# = nx-ex
	dy# = ny-ey
	dz# = nz-ez
	hit = LinePick(ex, ey, ez, dx, dy, dz, 0.2)
	
	If hit
		nx = PickedX()
		ny = PickedY()
		nz = PickedZ()
	EndIf
	
	sys\cx = sys\cx+(nx-sys\cx)*spd
	sys\cy = sys\cy+(ny-sys\cy)*spd
	sys\cz = sys\cz+(nz-sys\cz)*Spd
	
	PositionEntity cam, sys\cx, sys\cy, sys\cz
	PointEntity Cam, Entity, 0

End Function


Graphics3D 800, 600, 0, 2
SetBuffer BackBuffer()

Global cube = CreateCube()
Global cam = CreateCamera()
Global ops = CreateCube()
ScaleEntity ops, 10, 10, 1
	MoveEntity ops, 0, 0, -5
	EntityPickMode ops, 2

While Not KeyHit(1)
	
	Cls
	
	ChaseCam(cam, cube, 0, 2, -20, .1)
	
	MoveEntity ops, KeyDown(205) - KeyDown(203), 0, 0
	
	UpdateWorld
	RenderWorld
	
	Flip
	
Wend


Jeroen
(Posted 23 years ago)
aCid2: your demonstration made it less clear, not more :0

jfk EO-11110
(Posted 22 years ago)
We disussed such a smart camera some time ago in theory. So thanks for posting a working example. Very useful.

GC-Martijn
(Posted 22 years ago)
@The Dude
The first good / stable / short code camerafollow function !
its working very cool :)

When I found a problem I mail you ! ;)

AntMan - Banned in the line of duty.
(Posted 22 years ago)
Glad you guys found it useful.

(Puts out hand in expectation of brown envelope)

Caff
(Posted 22 years ago)
Thanks a lot, nice bit of code.

(Hands over empty brown envelope) ;)

AntMan - Banned in the line of duty.
(Posted 22 years ago)
Excellent, excellent...

Now, bring me a stamp!

AntMan - Banned in the line of duty.
(Posted 22 years ago)
dp.

Sanosake1
(Posted 18 years ago)
type csys.sys
; ID: 1083
; Author: Otacon
; Date: 2004-06-13 04:37:46
; Title: Smart 3rd person camera
; Description: Follows a entity and avoids geo.

Type CSys

Field cx#, cy#, cz#
Field mx#, my#, sps%

End Type

Function ChaseCam(cam, Entity, XOff#, YOff# = 2, ZOff# = -5, Spd# = 0.8)

Local sys.CSys = First CSys
Local nx#, ny#, nz#
Local dx#, dy#, dz#
Local ex#, ey#, ez#
Local hit%

If sys = Null
sys = New CSys
sys\sps = CreatePivot()
EndIf

sys\mx = MouseX()
sys\my = MouseY()
sps = sys\sps
PositionEntity sps, EntityX(Entity), EntityY(Entity), EntityZ(Entity)
TFormVector XOff, YOff, ZOff, Entity, 0
ex# = EntityX(Entity)
ey# = EntityY(Entity)
ez# = EntityZ(Entity)
nx# = ex+TFormedX()
ny# = ey+TFormedY()
nz# = ez+TFormedZ()
dx# = nx-ex
dy# = ny-ey
dz# = nz-ez
hit = LinePick(ex, ey, ez, dx, dy, dz, 0.2)

If hit
nx = PickedX()
ny = PickedY()
nz = PickedZ()
EndIf

sys\cx = sys\cx+(nx-sys\cx)*Spd
sys\cy = sys\cy+(ny-sys\cy)*Spd
sys\cz = sys\cz+(nz-sys\cz)*Spd

PositionEntity cam, sys\cx, sys\cy, sys\cz
PointEntity cam, Entity, 0

End Function


Graphics3D 800, 600, 0, 2
SetBuffer BackBuffer()


plane=CreatePlane()
Global cube = CreateCube()



Global cam = CreateCamera()
Global ops = CreateCube()
ScaleEntity ops, 10, 10, 1
MoveEntity ops, 0, 0, -5
EntityPickMode ops, 2


;[Block]
; all of this is used to make pretty grids to help you see what's happening
EntityColor plane,25,100,150
PositionEntity plane ,x,-20,0
grid_tex2=CreateTexture( 32,32,8 )
ScaleTexture grid_tex2,10,10
SetBuffer TextureBuffer( grid_tex2 )
Color 0,0,0:Rect 0,0,32,32
Color 0,255,0:Rect 0,0,32,32,False
EntityTexture plane,grid_tex2



grid_tex1=CreateTexture( 32,32,8 )
ScaleTexture grid_tex1,.1,.2
SetBuffer TextureBuffer( grid_tex1 )
Color 0,0,255:Rect 0,0,32,32
Color 255,255,0:Rect 0,0,32,32,False
EntityTexture cube,grid_tex1

SetBuffer BackBuffer()
;[End Block]



While Not KeyHit(1)

Cls

ChaseCam(cam, cube, 0, 2, -20, .1)

MoveEntity ops, KeyDown(205) - KeyDown(203), 0, 0

UpdateWorld
RenderWorld

Flip

Wend

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