limiting revolute joint question

mykyl66

I am using this code and have two objects attached. I am now trying to limit the rotation but keeping getting a nil value for setlimits.

Any ideas where I am obviously going wrong.

local myJoint = b2.createRevoluteJointDef(myMan.body, myArm.body, randX-50 , randY)
myJoint:setLimits(1,1)
myJoint:enableLimit(true)
--local myJoint = b2.createDistanceJointDef(myMan.body, myArm.body, randX, randY, randX-50, randY)
myworld:createJoint(myJoint)

Mike

atilim

Joint definition tables are just ordinary Lua tables without any functions or metatable. Therefore you just set the fields of them and pass the joint definition table to the createJoint function.

After you create your joint definition table with createXXXJointDef function, you directly set the limits

local myJointDef = b2.createRevoluteJointDef(myMan.body, myArm.body, randX-50 , randY) myJointDef.enableLimit = true myJointDef.lowerAngle = angle1 * math.pi / 180 myJointDef.upperAngle = angle2 * math.pi / 180

and then create your joint

local myJoint = myworld:createJoint(myJointDef)

Optionally, you can set the limits after creating the joint:

myJoint:enableLimit(true) myJoint:setLimits(angle1 * math.pi / 180, angle2 * math.pi / 180)

(I know it's not very clear at first sight )

mykyl66

Right. I think I understand it now.

Mike