111 lines
4.5 KiB
Plaintext
111 lines
4.5 KiB
Plaintext
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Breakable Joints
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================================================================================
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Description:
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This is a small addition to ODE that makes joints breakable. Breakable means
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that if a force on a joint is to high it wil break. I have included a modified
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version of test_buggy.cpp (test_breakable.cpp) so you can see it for your self.
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Just drive your buggy into an obstacle and enjoy!
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================================================================================
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Installation instructions:
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- copy joint.h, joint.cpp, ode.cpp and step.cpp to the ode/src/ directory
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- copy common.h and object.h to the include/ directory
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- copy test_breakable.cpp to the ode/test/ directory
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- add test_breakable.cpp to the ODE_TEST_SRC_CPP object in the makefile.
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- make ode-lib
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- make ode-test
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You can also use the diffs. The above files will quickly go out of sync with the
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rest of ODE but the diffs wil remain valid longer.
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================================================================================
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Functions:
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dJointSetBreakable (dJointID joint, int b)
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If b is 1 the joint is made breakable. If b is 0 the joint is made
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unbreakable.
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void dJointSetBreakCallback (dJointID joint, dJointBreakCallback *callbackFunc)
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Sets the callback function for this joint. If a funtion is set it will be
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called if the joint is broken but before it is actually detached or deleted.
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void dJointSetBreakMode (dJointID joint, int mode)
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Use this functions to set some flags. These flags can be ORred ( | )
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together; ie. dJointSetBreakMode (someJoint,
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dJOINT_BREAK_AT_B1_FORCE|dJOINT_DELETE_ON_BREAK)
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dJOINT_DELETE_ON_BREAK - If the joint breaks it wil be deleted.
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dJOINT_BREAK_AT_B1_FORCE - If the force on body 1 is to high the joint will
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break
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dJOINT_BREAK_AT_B1_TORQUE - If the torque on body 1 is to high the joint will
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break
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dJOINT_BREAK_AT_B2_FORCE - If the force on body 2 is to high the joint will
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break
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dJOINT_BREAK_AT_B2_TORQUE - If the torque on body 2 is to high the joint will
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break
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void dJointSetBreakForce (dJointID joint, int body, dReal x, dReal y, dReal z)
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With this function you can set the maximum force for a body connected to this
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joint. A value of 0 for body means body 1, 1 means body 2. The force is
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relative to the bodies rotation.
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void dJointSetBreakTorque (dJointID joint, int body, dReal x, dReal y, dReal z)
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With this function you can set the maximum torque for a body connected to this
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joint. A value of 0 for body means body 1, 1 means body 2. The torque is
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relative to the bodies rotation.
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int dJointIsBreakable (dJointID joint)
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Returns 1 if this joint is breakable, 0 otherwise.
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int dJointGetBreakMode (dJointID joint)
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Returns the breakmode flag.
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void dJointGetBreakForce (dJointID joint, int body, dReal *force)
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Returns the force at what this joint will break. A value of 0 for body means
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body 1, 1 means body 2. force must have enough space for 3 dReal values.
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void dJointGetBreakTorque (dJointID joint, int body, dReal *torque)
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Returns the torque at what this joint will break. A value of 0 for body
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means body 1, 1 means body 2. force must have enough space for 3 dReal
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values.
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================================================================================
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The callback function is defined like this (in common.h):
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void dJointBreakCallback (dJointID);
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================================================================================
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Problems, known bugs & other issues:
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- If the timestep is very small then joints get a lot weaker. They can even fall
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apart!
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- I have tested all this with the latest checkout from CVS (at the time of
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writing ofcourse). I haven't tested it with earlier versions of ODE.
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- I have modified the code that fills the jointfeedback struct. I haven't tested
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if it still works.
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- I'm not sure if the forces are really relative to the connected bodies.
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- There are some memory leaks in the test_breakable.cpp example.
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================================================================================
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Bugfixes and changes:
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09/08/2003
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- I fixed a bug when there where 0 joints in the simulation
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06/12/2003
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- dJointGetBreakMode() added, by vadim_mcagon@hotmail.com
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11/03/2004
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- Updated files to work with latest CVS checkout.
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- Added support for dWorldStepFast1()
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- Added separate test_breakable.cpp example.
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- Updated the code that breaks and destroys a joint.
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================================================================================
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Send me an e-mail if you have any suggestions, ideas, bugs, bug-fixes, anything!
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e-mail: roelvandijk@home.nl
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Roel van Dijk - 11/03/2004
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