physics car - GameCreators Forum

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shadey

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Joined: 25th Jan 2010

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Posted: 4th Jul 2013 16:23

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can anyone show me a small example of a car using the box2d physics? using simply a couple of spheres and a rectangle, I think you use joints is it?

Hail to the king, baby!

http://davidjohnwheeler.blogspot.co.uk

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Markus

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Joined: 10th Apr 2004

Location: Germany

Posted: 4th Jul 2013 17:40

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not a car but something with a rectangle wheel

+ Code Snippet

//setphysicsgravity(0,0)
setphysicsdebugon()

w1=createsprite(0)
setspriteposition(w1,50-10,50)
setspritephysicson(w1,2)

w2=createsprite(0)
setspriteposition(w2,50+10,50)
setspritephysicson(w2,2)

j1=CreateRevoluteJoint(w1, w2, getspritexbyoffset(w1), getspriteybyoffset(w1),0 )

SetJointMotorOn( j1, -1, 100 )

do
 Print("hello car")
 Sync()
loop

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shadey

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Joined: 25th Jan 2010

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Posted: 4th Jul 2013 20:56 Edited at: 4th Jul 2013 20:59

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yeh,I was just looking into this createrevolute joint, the thing is,how do you get both wheels using a motor! if i simply add another revolute joint for the 2nd wheel in relation to the first, it seems to cancel the first motor out!

+ Code Snippet

function createcar()
rem left wheel
    createsprite(wheel1,100)
    setspritesize(wheel1,4,2)
    setspriteposition(wheel1,getspritexbyoffset(cursorsprite),getspriteybyoffset(cursorsprite)-8)
    setspriteshape(wheel1,1)

    SetSpritePhysicsOn(wheel1,2)

    rem right wheel
    createsprite(wheel2,100)
    setspritesize(wheel2,4,2)
    setspriteposition(wheel2,getspritex(wheel1)+10,getspritey(wheel1))
    setspriteshape(wheel2,1)
    setspritephysicson(wheel1,2)
    SetSpritePhysicsOn(wheel2,2)
    CreateRevoluteJoint(1,wheel2,wheel1,getspritexbyoffset(wheel1),getspriteybyoffset(wheel1),0)
     CreateRevoluteJoint(2,wheel1,wheel2,getspritexbyoffset(wheel2),getspriteybyoffset(wheel2),0)
     SetJointMotorOn( 2, -30, 100 )
endfunction

Hail to the king, baby!

http://davidjohnwheeler.blogspot.co.uk

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Markus

Valued Member

20

Years of Service

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Joined: 10th Apr 2004

Location: Germany

Posted: 5th Jul 2013 13:21

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so?

+ Code Snippet

//setphysicsgravity(0,0)
setphysicsdebugon()

b1=createsprite(0)
setspriteposition(b1,50,50)
setspritephysicson(b1,2)

w1=createsprite(0)
setspriteposition(w1,50-10,50)
setspritephysicson(w1,2)

w2=createsprite(0)
setspriteposition(w2,50+10,50)
setspritephysicson(w2,2)

j1=CreateRevoluteJoint(w1, b1, getspritexbyoffset(w1), getspriteybyoffset(w1),0 )
j2=CreateRevoluteJoint(w2, b1, getspritexbyoffset(w2), getspriteybyoffset(w2),0 )

SetJointMotorOn( j1, -1, 100 )
SetJointMotorOn( j2, -1, 100 )

do
 Print("hello car")
 Sync()
loop

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