[ODE] What NearCallback must be like? I cannot place it inside a class!

[michael kapelko]

Now it says:
main.cpp:236: error: invalid conversion from `void (*)(PhysicsBasic*, 
dxGeom*,
    dxGeom*)' to `void (*)(void*, dxGeom*, dxGeom*)'
I tried to set it static, keep void*, set world, space as static. Object 
files were compiled ok.
But compiler cannot link them. Looks like it can't see my static world, 
space anymore:
physics/.obj/basic.o(.text+0x1ad): In function 
`PhysicsBasic::NearCallback(void*, dxGeom*, dxGeom*)':
: undefined reference to `PhysicsBasic::contact_group'
physics/.obj/basic.o(.text+0x1b3): In function 
`PhysicsBasic::NearCallback(void*, dxGeom*, dxGeom*)':
: undefined reference to `PhysicsBasic::world'
physics/.obj/basic.o(.text+0x244): In function 
`PhysicsBasic::CreateWorld()':
: undefined reference to `PhysicsBasic::world'
physics/.obj/basic.o(.text+0x256): In function 
`PhysicsBasic::CreateWorld()':
: undefined reference to `PhysicsBasic::space'
physics/.obj/basic.o(.text+0x268): In function 
`PhysicsBasic::CreateWorld()':
: undefined reference to `PhysicsBasic::contact_group'
physics/.obj/basic.o(.text+0x280): In function 
`PhysicsBasic::CreateWorld()':
: undefined reference to `PhysicsBasic::world'
physics/.obj/basic.o(.text+0x299): In function 
`PhysicsBasic::DestroyWorld()':
: undefined reference to `PhysicsBasic::contact_group'
physics/.obj/basic.o(.text+0x2aa): In function 
`PhysicsBasic::DestroyWorld()':
: undefined reference to `PhysicsBasic::space'
physics/.obj/basic.o(.text+0x2bb): In function 
`PhysicsBasic::DestroyWorld()':
: undefined reference to `PhysicsBasic::world'
.obj/main.o(.text+0x148): In function `Simulate(bool)':
: undefined reference to `PhysicsBasic::space'
.obj/main.o(.text+0x15b): In function `Simulate(bool)':
: undefined reference to `PhysicsBasic::world'
.obj/main.o(.text+0x172): In function `Simulate(bool)':
: undefined reference to `PhysicsBasic::world'
.obj/main.o(.text+0x183): In function `Simulate(bool)':
: undefined reference to `PhysicsBasic::contact_group'
.obj/main.o(.text+0x462): In function `main':
: undefined reference to `PhysicsBasic::space'
collect2: ld returned 1 exit status
make: *** [test] Error 1

callback function:

void PhysicsBasic::NearCallback (void *data, dGeomID o1, dGeomID o2) {
     dBodyID b1 = dGeomGetBody (o1);
     dBodyID b2 = dGeomGetBody (o2);
     // If bodies are connected with a joint, then no collision 
detection needed
     if (b1 && b2 && dAreConnected (b1, b2))
         return;

     // Maximum possible contacts
     const int N = 4;
     dContact contact[N];
     // How much contacts do we actually have?
     int n = dCollide (o1, o2, N, &contact[0].geom, sizeof (dContact));
     if (n > 0)
         for (int i = 0; i < n; i++) {
             // What these parameters mean, you can read in ODE Manual
             contact[i].surface.mode = dContactSlip1 | dContactSlip2 |
                 dContactSoftERP | dContactSoftCFM | dContactApprox1;
             contact[i].surface.mu = dInfinity;
             contact[i].surface.slip1 = 0.1;
             contact[i].surface.slip2 = 0.1;
             contact[i].surface.soft_erp = 0.2;
             contact[i].surface.soft_cfm = 0.2;
             dJointID c = dJointCreateContact (world, contact_group,
                     &contact[i]);
             dJointAttach (c, dGeomGetBody (contact[i].geom.g1),
                     dGeomGetBody (contact[i].geom.g2));
         }
}