linepicks & collisions

Blitz3D Forums/Blitz3D Beginners Area/linepicks & collisions

Aussie

(Posted 2010) [#1]

Gday all,
I am useing linepicks & collisions together & am having a few problems.

From what i can inderstand a linepick will cast a line from a specified point, say ( Entityx(blah),Entityy(blah),Entityz(blah) ) that being point 0,0,0 of that entity and will then cast the line at a specified distance along the X,Y,Z axis from that entity, say ( 0,0,1 ) will cast a line of 1 unit in length along the z axis of that entity?

Pickedx(),Pickedy(),PickedZ() will return a point that has been picked in a global position? Say if the entity is picking along its Z axis but is aligned to the X world axis the Pickedx() would return a value & not the Pickedz()
is this how the linepick works?

I am using a linepick to keep a player above the ground & to set a flag for jumping, i also want to use a linepick to keep the player away from walls because when i use normal collisions i have problems with parts of the mesh going into them & in areas where there is a step up around 1 unit in hight the collisions get all kind of jittery.

With line picks running in the z direction of the player the player keeps moving & i wouldn't think it would be picking anything as the player is more then 1 unit away from a wall.

This is the code i have so far

Graphics3D 800,600,32,2

Global plxv#,plyv#,speed#=.02
Global walking,standing,jumping
Global heading,h_0 = 0, h_e = 1, h_w = 2
Global inair
Global camx#,camy#
Global psphere
Global world_col = 1
Global player_col = 2


camera = CreateCamera()
	PositionEntity camera,0,3,-10
	CameraClsColor camera,180,180,180
	
light = CreateLight()
	RotateEntity light,25,90,0


world = LoadAnimMesh("test2.b3d")
	PositionEntity world,0,0,0
	EntityType world,1,True
	
psphere = CreateSphere()
	ScaleEntity psphere,.25,1.25,.25
	EntityRadius psphere,.5,1
	EntityAlpha psphere,.4
	PositionEntity psphere,-6,10,0
	EntityType psphere,2
	RotateEntity psphere,0,-90,0
	
player = LoadAnimMesh("model/ninja.b3d")
	;EntityParent player,psphere,False
	ScaleEntity player,.25,.25,.25
	RotateEntity player,0,-90,0
	;EntityRadius player,.001,.01
	PositionEntity player,0,-.9,0
	;EntityType player,2
	plyv# = 0
	plxv# = 0
	walk = ExtractAnimSeq(player,1,14)
	stand = ExtractAnimSeq(player,184,205)
	jump = ExtractAnimSeq(player,103,111)
	jumping_a = ExtractAnimSeq(player,104,104)
	jump2 = ExtractAnimSeq(player,94,102)
	stand2 = ExtractAnimSeq(player,206,250)
	heading = h_e
	
	
	
Collisions player_col,world_col,2,2


RecursiveSearchMesh(world)
Animate player,1,.2,2,10

While Not KeyHit(1)


;;;;;;;;;;;;;;;;;;;;;;;;;;player collisions, linepicks & controlls;;;;;;;;;;;;;;;;;;;;;;;;;;

LinePick EntityX(psphere),EntityY(psphere),EntityZ(psphere),0,-1.1,0,.1

	If PickedEntity() <> 0 Then
		PositionEntity psphere,EntityX(psphere),PickedY()+1.1,EntityZ(psphere)
	plyv# = 0
	plyv# = -.001
	inair = False
	Else plyv# = plyv# - .02
	inair = True
End If

If heading = h_w ; do linepick heading west & position psphere 1 unit away from wall
	LinePick EntityX(psphere),EntityY(psphere),EntityZ(psphere),0,0,1,0
		PositionEntity psphere,PickedX()+1,EntityY(psphere),EntityZ(psphere)	
	If KeyDown(205)
	RotateEntity psphere,0,-90,0
	RotateEntity player,0,-90,0
	heading = h_e
End If
End If

 
If heading = h_e ; do line pick heading east psphere 1 unit away from wall
	LinePick EntityX(psphere),EntityY(psphere),EntityZ(psphere),0,0,1,0
		PositionEntity psphere,PickedX()-1,EntityY(psphere),EntityZ(psphere)
	If KeyDown(203)
	RotateEntity psphere,0,90,0 
	RotateEntity player,0,90,0
	heading = h_w
End If
End If


If heading = h_e
	If KeyDown(205)
	plxv# = plxv# + speed#
	heading = h_e
	walking = True
	standing = False
Else
	walking = False
	standing = True
End If
End If

		
If heading = h_w
	If KeyDown(203)
	plxv# = plxv# + speed#
	walking = True
	standing = False
Else
	walking = False
	standing = True
End If
End If

If inair = False
	If KeyHit(57) plyv = .3
	jumping = False
Else If inair = True
	plyv = plyv
	jumping = True
	walking = False
End If
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
	

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;animation;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;;
;; 1 = walking
;; 2 = idle
;;

If walking = True Then
	If AnimSeq(player) <> walk Then 
	Animate player,1,.5,1,10
End If




Else
If AnimSeq(player) = True Then	
	Animate player,1,.1,stand2,10
	Else If Not Animating(player)
	Animate player,1,.1,stand2,10
End If
End If




	


If plxv# > .2 plxv# = .2
If plxv# < -.2 plxv# = -.2

If plxv# > 0
	plxv# = plxv# - .01
	If plxv# < 0 plxv# = 0
ElseIf plxv# < 0 
	plxv# = plxv# + .01
	If plxv# > 0 plxv# = 0
ElseIf plxv# = 0
	plxv# = 0
EndIf



MoveEntity psphere,0,0,plxv#

TranslateEntity psphere,0,plyv#,0
;PositionEntity player,EntityX(psphere),EntityY(psphere)-1,EntityZ(psphere)

camx# = EntityX#(psphere)
camy# = EntityY#(psphere)+3

PositionEntity camera,camx#,camy#,-10
PositionEntity player,EntityX(psphere),EntityY(psphere)-1,EntityZ(psphere)
FlushKeys()
UpdateWorld()
RenderWorld()

Text 0,0,"Player Yvel: " + plyv
Text 0,10,"Player Inair: " + inair
Text 0,20,"Player walking: " + walking
Text 0,30,"Player standing: " + standing
Text 0,40,"Player heading (east = 1, west = 2): " + heading
Text 0,50,"Animation Sequence: " + AnimSeq(player)

Flip


Wend
End

Function RecursiveSearchMesh(Mesh)
If CountChildren(Mesh) = 0 And EntityClass(Mesh) = "Mesh" Then EntityPickMode Mesh,2
For C=1 To CountChildren(Mesh)
	Child=GetChild(Mesh,C)
	If EntityClass(Child)="Mesh" Then EntityPickMode Child,2	
	RecursiveSearchMesh(Child)
Next

End Function

Other question, are there any good collision libs around. I have had a look for nuclear glory & the coldet wrapper but none of them seem to be around anymore.

Cheers :)

Last edited 2010

Yue	(Posted 2010) [#2]

Hello, you need a physical library right? I recommend the Px Wrap, was paid but the operator abandoned the project and the release could now say that it is free.

http://blitzbasic.com/Community/posts.php?topic=90281

Yasha

(Posted 2010) [#3]

I've emailed you a copy of ColDet, as it's always handy to have around. Pity the site went down.

Proper physics engines are definitely recommended if you want to do anything more complicated than not falling through walls though.

Aussie

(Posted 2010) [#4]

Thanks Yue I do have JV-ODE & have had a bit of a play with it, i will have a go at using that for collisions. I would still like to get the linepick working correctly though.
Cheers :)

Yue	(Posted 2010) [#5]

Hey Yasha please men, copy Coldet me too. my email.

Aussie

(Posted 2010) [#6]

Cheers for that Yasha :)

Aussie

(Posted 2010) [#7]

Just fowarded it on to you Yue.

Stevie G

(Posted 2010) [#8]

@ Aussie, you're not using linepick correctly.

Firstly, you are not picking in the direction of the player. The direction vector required by the linepick command is a world coord, therefore you have to convert the vector of 0,0,1 from the players local coords to world coords and use the result.

Tformvector 0,0,1,Psphere, 0
picked = LinePick( EntityX(psphere),EntityY(psphere),EntityZ(psphere),TFormedX(), TFormedY(), TFormedZ() )

Secondly, your line pick has a zero radius. Not sure if that is an issue but wouldn't recommend it.

Thirdly, you are not actually checking to see whether the pick has hit an entity. You can move the entity away from the picked normal like so:

If picked > 0
	TranslateEntity psphere, PickedNX(), pickedny(), PickedNZ()
EndIf

Last edited 2010

Last edited 2010

Aussie

(Posted 2010) [#9]

Ok

So would i be right then by saying that say

Tformvector 0,0,1,Psphere,0

Takes the 0,0,1 point of Psphere then using

Linepick(EntityX(psphere),EntityY(psphere),EntityZ(psphere),TFormedx(),TFormedy(),TFormedz())

Is casting the Linepick from Psphere,0,0,0 to where Psphere,0,0,1 local cords would be & converting Psphere,0,0,1 to a global position?

jfk EO-11110

(Posted 2010) [#10]

Actually it should be TFormedX()-EntityX(psphere)

(for the dx parameter of Linepick). Not sure about the rest of it.

Stevie G

(Posted 2010) [#11]

Actually it should be TFormedX()-EntityX(psphere)

(for the dx parameter of Linepick). Not sure about the rest of it.

This is wrong. Note the use of tformvector, rather than tformpoint.

Aussie

(Posted 2010) [#12]

Thanks guys got it going.
Just trying to visualize whats going on. :)

jfk EO-11110

(Posted 2010) [#13]

Stevie. I was just refering to the docs that are saying dx, dy and dz are the distance the line will travel. So it should be the diffrence between point A and point B. Tho, I didn't really analyze what't going on with TForming in the example here.