JV-ODE Physics Thread 5

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VIP3R
 #1
Here's a modified car demo capable of much higher speeds. The rear wheels are extremely stable when splitting the physics steps each frame (see the Main Loop), resulting in vastly improved accuracy of the simulation.

; ###################################################################################################
; #										  JV-ODE Car Demo											#
; #									Code by Jim Williams (VIP3R)									#		#
; #						Feel free to use this code, any credit appreciated							#
; ###################################################################################################

AppTitle "JV-ODE Car Demo - High Speed"

Include "JV-ODE.bb"

Graphics3D 800,600,0,2

Global CMass#=200			; ### Car Mass
Global WMass#=14			; ### Wheel Mass

Global WorldERP#=0.8		; ### World Error Correction
Global WorldFriction#=80	; ### World Friction

Global Torque#=48			; ### Joint Torque
Global SuspensionHS#=0.01	; ### Suspension Hardness/Softness (Higher=Softer - Lower=Harder)

Global Force#=0
Global Steer#=0

Global Car
Global CGeom
Global CMesh

Global CarStartY=4

Dim Wheel(4)
Dim WGeom(4)
Dim Joint(4)

Type ODEGeom
	Field body
	Field geom
	Field mesh
End Type

; ###################################################################################################

; ### Setup ODE

Global World=dWorldCreate()
Global Space=dHashSpaceCreate(0)
Global ContactGroup=dJointGroupCreate(0)

dWorldSetAutoDisableFlag(World,1)
dWorldSetGravity(World,0,-0.98,0)
dWorldSetERP(World,WorldERP)

dContactSetMode(dContactSlip1)
dContactSetMu(WorldFriction)

; ### Create car body

ode.ODEGeom=New ODEGeom
ode\body=dBodyCreate(World)
Car=ode\body
dBodySetRotation(ode\body,0,0,0)
dBodySetPosition(ode\body,0,CarStartY,0)
mass=dMassCreate()
dMassSetBoxTotal(mass,CMass,3,1,4)
dMassTranslate(mass,0,-1,0)
dBodySetMass(ode\body,mass)
dMassDestroy(mass)
ode\geom=dCreateBox(Space,3,1,4)
CGeom=ode\geom
dGeomSetBody(ode\geom,ode\body)
ode\mesh=CreateCube()
CMesh=ode\mesh
ScaleMesh ode\mesh,1.5,0.5,2
RotateMesh ode\mesh,0,0,0
PositionMesh ode\mesh,0,0,0
EntityColor ode\mesh,40,80,255
EntityAlpha ode\mesh,1

; ### Create wheels

For count=1 To 4
	ode.ODEGeom=New ODEGeom
	ode\body=dBodyCreate(World)
	Wheel(count)=ode\body
	dBodySetRotation(ode\body,0,0,0)
	dBodySetPosition(ode\body,0,0,0)
	mass=dMassCreate()
	dMassSetSphereTotal(mass,WMass,0.7)
	dBodySetMass(ode\body,mass)
	dMassDestroy(mass)
	ode\geom=dCreateSphere(Space,0.7)
	WGeom(count)=ode\geom
	dGeomSetBody(ode\geom,ode\body)
	ode\mesh=CreateCylinder(8)
	ScaleMesh ode\mesh,0.7,0.25,0.7
	RotateMesh ode\mesh,0,0,90
	PositionMesh ode\mesh,0,0,0
	EntityColor ode\mesh,255,255,255
Next

dBodySetPosition(Wheel(1),-2,CarStartY-0.5,+2)
dBodySetPosition(Wheel(2),+2,CarStartY-0.5,+2)
dBodySetPosition(Wheel(3),-2,CarStartY-0.5,-2)
dBodySetPosition(Wheel(4),+2,CarStartY-0.5,-2)

; ### Create some objects

SeedRnd MilliSecs()

For spheres=1 To 40
	ode.ODEGeom=New ODEGeom
	ode\body=dBodyCreate(World)
	dBodySetRotation(ode\body,0,0,0)
	dBodySetPosition(ode\body,Rnd(-800,800),30,Rnd(-800,800))
	ode\geom=dCreateSphere(Space,4)
	dGeomSetBody(ode\geom,ode\body)
	ode\mesh=CreateSphere()
	ScaleMesh ode\mesh,4,4,4
	RotateMesh ode\mesh,0,0,0
	PositionMesh ode\mesh,0,0,0
	EntityColor ode\mesh,Rnd(255),Rnd(255),Rnd(255)
	EntityAlpha ode\mesh,1
	EntityShininess ode\mesh,0.7
Next

For cylinders=1 To 40
	ode.ODEGeom=New ODEGeom
	ode\body=dBodyCreate(World)
	dBodySetRotation(ode\body,90,0,0)
	dBodySetPosition(ode\body,Rnd(-800,800),30,Rnd(-800,800))
	ode\geom=dCreateCCylinder(Space,1,8)
	dGeomSetBody(ode\geom,ode\body)
	ode\mesh=CreateCylinder(8)
	ScaleMesh ode\mesh,1,5,1
	RotateMesh ode\mesh,90,0,0	; <<< Mesh X-Axis must be rotated 90 degrees to fix cylinder alignment
	PositionMesh ode\mesh,0,0,0
	EntityColor ode\mesh,Rnd(255),Rnd(255),Rnd(255)
	EntityAlpha ode\mesh,1
	EntityShininess ode\mesh,0.7
Next

; ### Create light

Global Light=CreateLight()

RotateEntity Light,45,-90,0
LightColor Light,255,255,255
AmbientLight 130,130,130

; ### Create camera

Global CameraPivot=CreatePivot(CMesh)
PositionEntity CameraPivot,0,2,-7

Global Camera=CreateCamera()
CameraClsColor Camera,0,0,0
CameraRange Camera,1,1000

; ### Create plane

dCreatePlane(Space,0,1,0,0)

Plane=CreatePlane()

EntityAlpha Plane,0.8

PlaneTexture=CreateTexture(128,128,9)

ClsColor 0,200,80
Cls

Color 255,255,255

Rect 0,0,64,64,1
Rect 64,64,64,64,1

CopyRect 0,0,128,128,0,0,BackBuffer(),TextureBuffer(PlaneTexture)
ScaleTexture PlaneTexture,20,20
EntityTexture Plane,PlaneTexture,0,0

Mirror=CreateMirror()

; ###################################################################################################

; ### BLITZ STATIC OBJECT (White)

blitzobject=CreateCube()
ScaleMesh blitzobject,1,4,20
RotateMesh blitzobject,-10,8,4
PositionMesh blitzobject,10,5,40

EntityColor blitzobject,255,255,255
EntityAlpha blitzobject,1

; ### ODE STATIC OBJECT (Blue)

ode.ODEGeom=New ODEGeom
ode\geom=dCreateBox(Space,2,8,40)
dGeomSetRotation(ode\geom,-10,8,4)
dGeomSetPosition(ode\geom,20,5,40)
ode\mesh=CreateCube()
ScaleMesh ode\mesh,1,4,20
RotateMesh ode\mesh,0,0,0
PositionMesh ode\mesh,0,0,0

EntityColor ode\mesh,0,100,200
EntityAlpha ode\mesh,1

; ### ODE STATIC OBJECT (Red)

ode.ODEGeom=New ODEGeom
ode\geom=dCreateBox(Space,18,0.2,40)
dGeomSetRotation(ode\geom,-14,0,0)
dGeomSetPosition(ode\geom,-20,4.9,40)
ode\mesh=CreateCube()
ScaleMesh ode\mesh,9,0.1,20
RotateMesh ode\mesh,0,0,0
PositionMesh ode\mesh,0,0,0

EntityColor ode\mesh,200,0,100
EntityAlpha ode\mesh,1

; ###################################################################################################

SetupCar()

While Not KeyHit(1)

	UpdateKeys()

	PTime=MilliSecs()

	UpdateCar()

	UpdateGeoms()

	dSpaceCollide(Space,World,ContactGroup)
	dWorldQuickStep(World,0.025)
	dJointGroupEmpty(ContactGroup)

	dSpaceCollide(Space,World,ContactGroup)
	dWorldQuickStep(World,0.025)
	dJointGroupEmpty(ContactGroup)

	dSpaceCollide(Space,World,ContactGroup)
	dWorldQuickStep(World,0.025)
	dJointGroupEmpty(ContactGroup)

	dSpaceCollide(Space,World,ContactGroup)
	dWorldQuickStep(World,0.025)
	dJointGroupEmpty(ContactGroup)

	PhysicsTime#=MilliSecs()-PTime

	UpdateCam()

	UpdateWorld

	RenderWorld

	Text 0,0,"JV-ODE Version "+dGetVersion()
	Text 0,15,"Physics Time:"+PhysicsTime
	Text 0,50,"Force:"+Force
	Text 0,65,"Torque:"+Torque
	Text 640,0,"A - Accelerate"
	Text 640,15,"Z - Brake/Reverse"
	Text 640,30,"Arrows - Steering"
	Text 640,45,"Space - Reset Car"

	Flip

Wend

dJointGroupDestroy(ContactGroup)
dSpaceDestroy(Space)
dWorldDestroy(World)
dCloseODE()

End

; ###################################################################################################

Function SetupCar()

For count=1 To 4
	Joint(count)=dJointCreateHinge2(World,0)
	dJointAttach(Joint(count),Car,Wheel(count))
	dJointSetHinge2Anchor(Joint(count),dBodyGetPositionX(Wheel(count)),dBodyGetPositionY(Wheel(count)),dBodyGetPositionZ(Wheel(count)))
	dJointSetHinge2Axis1(Joint(count),0,1,0)
	dJointSetHinge2Axis2(Joint(count),-1,0,0)
	dJointSetHinge2Param(Joint(count),dParamSuspensionERP,0.8)
	dJointSetHinge2Param(Joint(count),dParamSuspensionCFM,SuspensionHS)
	If count>2
		dJointSetHinge2Param(Joint(count),dParamLoStop,0)
		dJointSetHinge2Param(Joint(count),dParamHiStop,0)
		End If
Next

Force=0

End Function

; ###################################################################################################

Function UpdateKeys()

If KeyDown(30)=1
	Force=Force+0.08
	If Force>140 Then Force=140
	End If

If KeyDown(44)=1
	Force=Force-0.1
	If Force<-10 Then Force=-10
	If Force>0 Then Force=Force*0.97
	End If

If KeyDown(30)=0 And KeyDown(44)=0 Then Force=Force*0.99

If KeyDown(203)=1 Or KeyDown(205)=1
	If KeyDown(203)=1
		Steer=0.5
		Else
		Steer=-0.5
		End If
	Else
	Steer=0
	End If

If KeyHit(57)=1
	Force=0
	dBodySetRotation(Car,dGeomGetPitch#(CGeom),dGeomGetYaw#(CGeom),0)
	End If

End Function

; ###################################################################################################

Function UpdateCar()

For count=1 To 4
	dBodyEnable(Wheel(count))
Next

dBodyEnable(Car)

For count=1 To 4
	dJointSetHinge2Param(Joint(count),dParamVel2,Force)
	dJointSetHinge2Param(Joint(count),dParamFMax2,Torque)
Next

For count=1 To 2
	angle#=Steer-dJointGetHinge2Angle1(Joint(count))
	dJointSetHinge2Param(Joint(count),dParamVel,angle)
	dJointSetHinge2Param(Joint(count),dParamFMax,400)
Next

End Function

; ###################################################################################################

Function UpdateCam()

PositionEntity CameraPivot,0,3,-12

camx#=EntityX(CameraPivot,1)-EntityX(Camera)
camy#=EntityY(CameraPivot,1)-EntityY(Camera)
camz#=EntityZ(CameraPivot,1)-EntityZ(Camera)

TranslateEntity Camera,camx*0.5,camy*0.5,camz*0.5

PointEntity Camera,CMesh

End Function

; ###################################################################################################

Function UpdateGeoms()

For ode.ODEGeom=Each ODEGeom
	RotateEntity ode\mesh,dGeomGetPitch#(ode\geom),dGeomGetYaw#(ode\geom),dGeomGetRoll#(ode\geom)
	PositionEntity ode\mesh,dGeomGetPositionX#(ode\geom),dGeomGetPositionY#(ode\geom),dGeomGetPositionZ#(ode\geom)
Next

End Function

; ###################################################################################################