Rigid Body Simulation

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Rigid Body Simulation by Sweenie
This is the beginning of a simple Rigid Body simulation in Blitz. No collisions so far.(So the difficult part is yet to be done)
Open in online IDE Graphics3D 800,600,0,2 SetBuffer BackBuffer() camera = CreateCamera() PositionEntity camera,0,0,-10 WireFrame True Global Cprod_x# Global Cprod_y# Global Cprod_z# Const NEARZERO# = 0.0001 ;RigidBody Type Type RigidBody Field Mass# Field Com_x# ; Center Of Mass Field Com_y# Field Com_z# Field Linearvel_x# ; Linear Velocity Field Linearvel_y# Field Linearvel_z# Field Linearacc_x# ; Linear Acceleration Field Linearacc_y# Field Linearacc_z# Field Forcevec_x# ; Force Vector Field Forcevec_y# Field Forcevec_z# Field Forceloc_x# ; Force Location Field Forceloc_y# Field Forceloc_z# Field Rotangle_x# ; Rotation Angle (Orientation) Field Rotangle_y# Field Rotangle_z# Field Angularvel_x# ; Angular Velocity Field Angularvel_y# Field Angularvel_z# Field Angularacc_x# ; Angular Acceleration Field Angularacc_y# Field Angularacc_z# Field Inertia_x# ; Rotational Inertia Field Inertia_y# Field Inertia_z# Field Torque_x# ; eh... Just Torque ;) Field Torque_y# Field Torque_z# Field Coeff# ; Coefficient of restitution / "Bounce Factor" 0.0 = Not elastic, 1.0 = VERY elastic, 1.1 = Too Elastic ;) Field Friction# ; * Not implemented yet * Field LinearDamping# Field AngularDamping# End Type RB.RigidBody = New RigidBody RB\Mass#=1.0 RB\Inertia_x#=0.4 RB\Inertia_y#=0.4 RB\Inertia_z#=0.4 RB\LinearDamping# = 0.001 RB\AngularDamping# = 0.01 RB_Mesh = CreateSphere() While Not KeyHit(1) UpdateBody RB,0.02 PositionEntity RB_Mesh,RB\Com_x#,RB\Com_y#,RB\Com_z# RotateEntity RB_Mesh,RB\Rotangle_x#,-RB\Rotangle_y#,RB\Rotangle_z# If KeyDown(205) Then ; Right RB\Forcevec_x# = 1.0 RB\Forcevec_y# = 0.0 RB\Forcevec_z# = 0.0 RB\Forceloc_x# = 0.0 RB\Forceloc_y# = 25.0 RB\Forceloc_z# = -25.0 ElseIf KeyDown(203) Then ; Left RB\Forcevec_x# = -2.0 RB\Forcevec_y# = 0.0 RB\Forcevec_z# = 0.0 RB\Forceloc_x# = 0.0 RB\Forceloc_y# = 15.0 RB\Forceloc_z# = -5.0 Else RB\Forcevec_x# = 0.0 RB\Forcevec_y# = 0.0 RB\Forcevec_z# = 0.0 EndIf RenderWorld Flip Wend End Function UpdateBody(Body.RigidBody,dt#) ; * Linear Dynamics * ;Linear Acceleration If Body\Mass#>0 Then Body\Linearacc_x# = Body\Forcevec_x# / Body\Mass# Body\Linearacc_y# = Body\Forcevec_y# / Body\Mass# Body\Linearacc_z# = Body\Forcevec_z# / Body\Mass# EndIf ;Linear Velocity Body\Linearvel_x# = Body\Linearvel_x# + Body\Linearacc_x# * dt# Body\Linearvel_y# = Body\Linearvel_y# + Body\Linearacc_y# * dt# Body\Linearvel_z# = Body\Linearvel_z# + Body\Linearacc_z# * dt# ;Center Of Mass Body\Com_x# = Body\Com_x# + Body\Linearvel_x# * dt# Body\Com_y# = Body\Com_y# + Body\Linearvel_y# * dt# Body\Com_z# = Body\Com_z# + Body\Linearvel_z# * dt# ; * Rotational Dynamics * ;Torque CrossProduct Body\Forceloc_x#,Body\Forceloc_y#,Body\Forceloc_z#,Body\Forcevec_x#,Body\Forcevec_y#,Body\Forcevec_z# Body\Torque_x#=Cprod_x# Body\Torque_y#=Cprod_y# Body\Torque_z#=Cprod_z# ;Angular Acceleration Body\Angularacc_x# = Body\Torque_x# / Body\Inertia_x# Body\Angularacc_y# = Body\Torque_y# / Body\Inertia_y# Body\Angularacc_z# = Body\Torque_z# / Body\Inertia_z# ;Angular Velocity Body\Angularvel_x# = Body\Angularvel_x# + Body\Angularacc_x# * dt# Body\Angularvel_y# = Body\Angularvel_y# + Body\Angularacc_y# * dt# Body\Angularvel_z# = Body\Angularvel_z# + Body\Angularacc_z# * dt# ;Angles of rotation / Orientation Body\Rotangle_x# = Body\Rotangle_x# + Body\Angularvel_x# * dt# Body\Rotangle_y# = Body\Rotangle_y# + Body\Angularvel_y# * dt# Body\Rotangle_z# = Body\Rotangle_z# + Body\Angularvel_z# * dt# ;Damp Linear & Angular Velocity Body\Linearvel_x#=Body\Linearvel_x#(1.0-Body\LinearDamping#) Body\Linearvel_y#=Body\Linearvel_y#(1.0-Body\LinearDamping#) Body\Linearvel_z#=Body\Linearvel_z#(1.0-Body\LinearDamping#) Body\Angularvel_x#=Body\Angularvel_x#(1.0-Body\AngularDamping#) Body\Angularvel_y#=Body\Angularvel_y#(1.0-Body\AngularDamping#) Body\Angularvel_z#=Body\Angularvel_z#(1.0-Body\AngularDamping#) ;Reset Velocities If Near Zero Value / Hack ;) Not necessary but prevents jittering when Body is considered not moving. If Abs(Body\Linearvel_x#)<NEARZERO# Then Body\Linearvel_x#=0.0 If Abs(Body\Linearvel_y#)<NEARZERO# Then Body\Linearvel_y#=0.0 If Abs(Body\Linearvel_z#)<NEARZERO# Then Body\Linearvel_z#=0.0 If Abs(Body\Angularvel_x#)<NEARZERO# Then Body\Angularvel_x#=0.0 If Abs(Body\Angularvel_y#)<NEARZERO# Then Body\Angularvel_y#=0.0 If Abs(Body\Angularvel_z#)<NEARZERO# Then Body\Angularvel_z#=0.0 End Function Function DotProduct#(x1#,y1#,z1#,x2#,y2#,z2#) Return (x1#x2#)+(y1#y2#)+(z1#z2#) End Function Function CrossProduct(x1#,y1#,z1#,x2#,y2#,z2#) Cprod_x#=(y1#z2#)-(z1#y2#) Cprod_y#=(z1#x2#)-(x1#z2#) Cprod_z#=(x1#y2#)-(y1#*x2#) End Function

Rigid Body Simulation by Sweenie

This is the beginning of a simple Rigid Body simulation in Blitz.
No collisions so far.(So the difficult part is yet to be done)

Open in online IDE

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

camera = CreateCamera()
PositionEntity camera,0,0,-10

WireFrame True

Global Cprod_x#
Global Cprod_y#
Global Cprod_z#
Const NEARZERO# = 0.0001

;RigidBody Type

Type RigidBody

 Field Mass#

 Field Com_x# ; Center Of Mass
 Field Com_y# 
 Field Com_z#
 Field Linearvel_x# ; Linear Velocity
 Field Linearvel_y#
 Field Linearvel_z#
 Field Linearacc_x# ; Linear Acceleration
 Field Linearacc_y#
 Field Linearacc_z#
 Field Forcevec_x# ; Force Vector
 Field Forcevec_y#
 Field Forcevec_z#
 Field Forceloc_x# ; Force Location
 Field Forceloc_y#
 Field Forceloc_z#

 Field Rotangle_x# ; Rotation Angle (Orientation)
 Field Rotangle_y#
 Field Rotangle_z#
 Field Angularvel_x# ; Angular Velocity
 Field Angularvel_y#
 Field Angularvel_z#
 Field Angularacc_x# ; Angular Acceleration
 Field Angularacc_y#
 Field Angularacc_z#
 Field Inertia_x# ; Rotational Inertia
 Field Inertia_y#
 Field Inertia_z#
 Field Torque_x# ; eh... Just Torque ;)
 Field Torque_y#
 Field Torque_z#

 Field Coeff# ; Coefficient of restitution / "Bounce Factor" 0.0 = Not elastic, 1.0 = VERY elastic, 1.1 = Too Elastic ;) 
 Field Friction# ; * Not implemented yet *
 Field LinearDamping# 
 Field AngularDamping#

End Type


RB.RigidBody = New RigidBody
RB\Mass#=1.0
RB\Inertia_x#=0.4
RB\Inertia_y#=0.4
RB\Inertia_z#=0.4
RB\LinearDamping# = 0.001
RB\AngularDamping# = 0.01

RB_Mesh = CreateSphere()

While Not KeyHit(1)

UpdateBody RB,0.02

PositionEntity RB_Mesh,RB\Com_x#,RB\Com_y#,RB\Com_z#
RotateEntity RB_Mesh,RB\Rotangle_x#,-RB\Rotangle_y#,RB\Rotangle_z#

If KeyDown(205) Then ; Right
 RB\Forcevec_x# = 1.0
 RB\Forcevec_y# = 0.0
 RB\Forcevec_z# = 0.0
 RB\Forceloc_x# = 0.0
 RB\Forceloc_y# = 25.0
 RB\Forceloc_z# = -25.0
ElseIf KeyDown(203) Then ; Left
 RB\Forcevec_x# = -2.0
 RB\Forcevec_y# = 0.0
 RB\Forcevec_z# = 0.0
 RB\Forceloc_x# = 0.0
 RB\Forceloc_y# = 15.0
 RB\Forceloc_z# = -5.0
Else
 RB\Forcevec_x# = 0.0
 RB\Forcevec_y# = 0.0
 RB\Forcevec_z# = 0.0
EndIf


RenderWorld

Flip

Wend
End


Function UpdateBody(Body.RigidBody,dt#)

 ; *** Linear Dynamics ***

 ;Linear Acceleration
 If Body\Mass#>0 Then
  Body\Linearacc_x# = Body\Forcevec_x# / Body\Mass#
  Body\Linearacc_y# = Body\Forcevec_y# / Body\Mass#
  Body\Linearacc_z# = Body\Forcevec_z# / Body\Mass#
 EndIf

 ;Linear Velocity
 Body\Linearvel_x# = Body\Linearvel_x# + Body\Linearacc_x# * dt#
 Body\Linearvel_y# = Body\Linearvel_y# + Body\Linearacc_y# * dt#
 Body\Linearvel_z# = Body\Linearvel_z# + Body\Linearacc_z# * dt#
 
 ;Center Of Mass
 Body\Com_x# = Body\Com_x# + Body\Linearvel_x# * dt#
 Body\Com_y# = Body\Com_y# + Body\Linearvel_y# * dt#
 Body\Com_z# = Body\Com_z# + Body\Linearvel_z# * dt#
 

 ; *** Rotational Dynamics ***

 ;Torque
 CrossProduct Body\Forceloc_x#,Body\Forceloc_y#,Body\Forceloc_z#,Body\Forcevec_x#,Body\Forcevec_y#,Body\Forcevec_z# 
 Body\Torque_x#=Cprod_x#
 Body\Torque_y#=Cprod_y#
 Body\Torque_z#=Cprod_z#

 ;Angular Acceleration
 Body\Angularacc_x# = Body\Torque_x# / Body\Inertia_x#
 Body\Angularacc_y# = Body\Torque_y# / Body\Inertia_y#
 Body\Angularacc_z# = Body\Torque_z# / Body\Inertia_z#

 ;Angular Velocity
 Body\Angularvel_x# = Body\Angularvel_x# + Body\Angularacc_x# * dt#
 Body\Angularvel_y# = Body\Angularvel_y# + Body\Angularacc_y# * dt#
 Body\Angularvel_z# = Body\Angularvel_z# + Body\Angularacc_z# * dt#

 ;Angles of rotation / Orientation
 Body\Rotangle_x# = Body\Rotangle_x# + Body\Angularvel_x# * dt#
 Body\Rotangle_y# = Body\Rotangle_y# + Body\Angularvel_y# * dt#
 Body\Rotangle_z# = Body\Rotangle_z# + Body\Angularvel_z# * dt#

 ;Damp Linear & Angular Velocity
 Body\Linearvel_x#=Body\Linearvel_x#*(1.0-Body\LinearDamping#)
 Body\Linearvel_y#=Body\Linearvel_y#*(1.0-Body\LinearDamping#)
 Body\Linearvel_z#=Body\Linearvel_z#*(1.0-Body\LinearDamping#)
 Body\Angularvel_x#=Body\Angularvel_x#*(1.0-Body\AngularDamping#)
 Body\Angularvel_y#=Body\Angularvel_y#*(1.0-Body\AngularDamping#)
 Body\Angularvel_z#=Body\Angularvel_z#*(1.0-Body\AngularDamping#)

 ;Reset Velocities If Near Zero Value / *Hack* ;) Not necessary but prevents jittering when Body is considered not moving.
 If Abs(Body\Linearvel_x#)<NEARZERO# Then Body\Linearvel_x#=0.0
 If Abs(Body\Linearvel_y#)<NEARZERO# Then Body\Linearvel_y#=0.0
 If Abs(Body\Linearvel_z#)<NEARZERO# Then Body\Linearvel_z#=0.0
 If Abs(Body\Angularvel_x#)<NEARZERO# Then Body\Angularvel_x#=0.0
 If Abs(Body\Angularvel_y#)<NEARZERO# Then Body\Angularvel_y#=0.0
 If Abs(Body\Angularvel_z#)<NEARZERO# Then Body\Angularvel_z#=0.0


End Function

Function DotProduct#(x1#,y1#,z1#,x2#,y2#,z2#)
	Return (x1#*x2#)+(y1#*y2#)+(z1#*z2#)
End Function

Function CrossProduct(x1#,y1#,z1#,x2#,y2#,z2#)
	Cprod_x#=(y1#*z2#)-(z1#*y2#)
	Cprod_y#=(z1#*x2#)-(x1#*z2#)
	Cprod_z#=(x1#*y2#)-(y1#*x2#)
End Function

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