Camera following a mesh

BlitzMax Forums/MiniB3D Module/Camera following a mesh

ziggy

(Posted 2007) [#1]

I've got this method on my 'camera' type, but I really don't like how it follows the 'main' character of the game I'm writing, I'm sure there will be a better algorithm for camera 'following' the main character. This is the code I'm using right now, any suggestion will be apreciated:

	Method Update()
		Local Dist:Float
		If target = Null Then Return
		Dist = cam.EntityDistance(target)
		
		If dist>maxdistance Then
			pos.PointEntity(target)
			pos.MoveEntity(0,2,0)
		ElseIf dist<mindistance Then
			pos.PointEntity(target)
			pos.MoveEntity(0,-2,0)
		End If
		pos.RotateEntity(0,0,0,True)
		
		cam.PointEntity(target)
	End Method

Notes:
Target is the mesh that has to be followed by the camera.
Pos is a pivot that is part of the camera object, it is used to place the camera.
cam is the camera object, contained as a filed on my camera type.

Amon	(Posted 2007) [#2]

This is B3D code but should work with MiniB3D. It was coded by Antony and imo is a totally cool way for having a camera follow a mesh while avoiding obstructions.

Link here : http://www.blitzbasic.com/codearcs/codearcs.php?code=1083

ziggy

(Posted 2007) [#3]

mmm, any miniB3D version? I've not experience on Blitz3D

Amon	(Posted 2007) [#4]

Well, Since MiniB3D IS B3D for BlitzMax then you should have no problem converting the code.

bradford6

(Posted 2007) [#5]

some nitwit by the name of 'bradford6' posted this 5 yrs ago:
http://www.blitzbasic.com/codearcs/codearcs.php?code=97

so i went ahead and updated it for the animated robot demo

get the robot demo here:
http://www.blitzbasic.com/Community/posts.php?topic=66821

or if you already have it, drop this code in the Robot Animtest folder

Import "MiniB3D.bmx"

Strict

Local width=1024,height=768,depth=32,mode=0 ; Graphics3D width,height,depth,mode

Local cam:TCamera=CreateCamera()
CameraRange cam,.5,1500
Local camdistance:Float = 600
Local camera_mode:Int
Local camera_mode_String:String
PositionEntity cam,0,10,-100

AmbientLight 200,200,200

Local Level:TMesh=LoadMesh("media/gamelevel.b3d")
CreateOctree(level,0,3)					' create mesh octree - makes collision detection faster (MiniB3D only)

Local robot:TMesh=LoadAnimMesh("media/robotwalk.b3d")
ScaleEntity robot,0.025,0.025,0.025

Global robot_pivot:Tpivot =CreatePivot(robot) 
MoveEntity robot_pivot,0,0,camdistance		' move the pivot back a little  For follow effect

EntityType robot,1						' set ROBOT entity type to 1

Local robot_radius:Float =7.25				' set ROBOT radius as it's the source collision entity
EntityRadius robot,robot_radius
Local collsphere:Tmesh = CreateSphere(8,robot)
ScaleEntity Collsphere,robot_radius,robot_radius,robot_radius
EntityType Level,2						' set mesh entity Type To 2
Collisions 1,2,4,2							'  enable colliisons between entity type 1 and 2, with reponse 4

' used by camera code
Local mxs#=0 	;	Local mys#=0	;	Local move#=0.5
MouseXSpeed() 	;	MouseYSpeed() ' initial flush of mouse values

' used by fps code
Local old_ms=MilliSecs()	;	Local renders	 	;	Local fps

' anim stuff
Local frame:Float	,  speed:Float , yspeed:Float


' MAIN LOOP BEGIN
While Not KeyDown(KEY_ESCAPE)		

	If KeyHit(KEY_ENTER) Then DebugStop

	If KeyHit(KEY_SPACE) Then camera_mode = 1 - camera_mode
		
		If camera_mode = 0
			camera_mode_String$ = "mouse look + Arrow keys"
			mxs#=mxs#+(MouseXSpeed()/5.0)
			mys#=mys#+(MouseYSpeed()/5.0)
		
			MoveMouse width/2,height/2
			MouseXSpeed() ' flush
			MouseYSpeed() ' flush
		
			RotateEntity cam,mys#,-mxs#,0
			'PointEntity(cam,robot)
			
			If KeyDown(KEY_UP)=True Then MoveEntity cam,0,0,move#
			If KeyDown(KEY_DOWN)=True Then MoveEntity cam,0,0,-move#
		
		
			If KeyDown(KEY_LEFT)=True Then MoveEntity cam,-move#,0,0 ' move camera left
			If KeyDown(KEY_RIGHT)=True Then MoveEntity cam,move#,0,0 ' move camera right
		
		Else
				camera_mode_String$ = "smoothcam"

				smoothcam(cam,robot_pivot,robot,50,15)
		EndIf
	
	
	If KeyDown(KEY_W)  Then speed:+.009

	If KeyDown(KEY_S) Then speed:-.009


	If KeyDown(KEY_A) Then TurnEntity robot,0,1,0
	If KeyDown(KEY_D) Then TurnEntity robot,0,-1,0

	speed:* 0.99
	yspeed:-0.1
	If yspeed<-3 Then yspeed = 0
	
	MoveEntity robot,0,yspeed,-speed
	
	' manually roll the animation
	frame:+(speed)
	If frame>30 Then frame = 0
	SetAnimTime(robot,frame)
	
	UpdateWorld
	RenderWorld
	renders=renders+1
	' calculate fps
	If MilliSecs()-old_ms>=1000
		old_ms=MilliSecs()
		fps=renders
		renders=0
	EndIf

		Text 0,0,"FPS: "+String(fps)
		text 0,20,"SPACE to change Camera Mode"
		text 0,40," WASD to move ROBOT"
		text 0,60,camera_mode_String$
	Flip 
	
Wend
' MAIN LOOP END

End

Function smoothcam(camera:Tcamera,pivot:Tpivot,target:Tentity,camspeed:Float,height:Float)


	Local curx#=EntityX(camera)
	Local curz#=EntityZ(camera)
	Local cury#=EntityY(target) + height
	Local destx#=EntityX(pivot,True)
	Local destz#=EntityZ(pivot,True)
	
	
	curx#=curx#+((destx#-curx#)/camspeed)
	curz#=curz#+((destz#-curz#)/camspeed)
	

	PositionEntity camera,curx#,cury#,curz#

	PointEntity camera,target
End Function

ziggy

(Posted 2007) [#6]

Thanks!