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danfis / libccd

Library for collision detection between two convex shapes
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findPenetr() can divide by zero. #49

Closed stolk closed 5 years ago

stolk commented 6 years ago

In some cases, findPenetr() can cause a division by zero, generating NaN.

In mpr.c:331 If *depth is zero, then the ccdVec3Normalize() will divide by zero.

It should report "No Penetration" if the penetration depth is zero, or alternatively, generate a proper direction instead of dividing by zero.

>>> where
#0  0x0000555555607b59 in ccdVec3Normalize (d=0x7fffffffc500) at /home/bram/src/libccd/src/ccd/vec3.h:315
#1  findPenetr (obj1=0x7fffffffc550, obj2=0x7fffffffc590, ccd=0x7fffffffc4c0, portal=0x7fffffffc400, depth=0x7fffffffc4bc, pdir=0x7fffffffc500, pos=0x7fffffffc50c) at /home/bram/src/libccd/src/mpr.c:331
#2  0x00005555556033eb in ccdMPRPenetration (obj1=0x7fffffffc550, obj2=0x7fffffffc590, ccd=0x7fffffffc4c0, depth=0x7fffffffc4bc, dir=0x7fffffffc500, pos=0x7fffffffc50c) at /home/bram/src/libccd/src/mpr.c:144
#3  0x000055555559ca8c in ccdCollide (o1=o1@entry=0x555555873a90, o2=o2@entry=0x555555870550, flags=flags@entry=32, contact=contact@entry=0x7fffffffc650, obj1=obj1@entry=0x7fffffffc550, supp1=supp1@entry=0x55555559b390 <ccdSupportConvex(void const*, ccd_vec3_t const*, ccd_vec3_t*)>, obj2=0x7fffffffc590, supp2=0x55555559b390 <ccdSupportConvex(void const*, ccd_vec3_t const*, ccd_vec3_t*)>, skip=<optimized out>, cen2=0x55555559b5d0 <ccdCenter(void const*, ccd_vec3_t*)>, cen1=0x55555559b5d0 <ccdCenter(void const*, ccd_vec3_t*)>) at collision_libccd.cpp:339
#4  0x000055555559d1bb in ccdCollide (skip=<optimized out>, cen2=0x55555559b5d0 <ccdCenter(void const*, ccd_vec3_t*)>, supp2=0x55555559b390 <ccdSupportConvex(void const*, ccd_vec3_t const*, ccd_vec3_t*)>, obj2=0x7fffffffc590, cen1=0x55555559b5d0 <ccdCenter(void const*, ccd_vec3_t*)>, supp1=0x55555559b390 <ccdSupportConvex(void const*, ccd_vec3_t const*, ccd_vec3_t*)>, obj1=0x7fffffffc550, contact=0x7fffffffc650, flags=32, o2=0x555555870550, o1=0x555555873a90) at collision_libccd.cpp:319
#5  dCollideConvexConvexCCD (o1=0x555555873a90, o2=0x555555870550, flags=32, contact=0x7fffffffc650, skip=<optimized out>) at collision_libccd.cpp:457
#6  0x000055555555e3a9 in nearCallback (o1=<optimized out>, o2=<optimized out>, data=<optimized out>) at demo_convex.cpp:88
#7  0x0000555555569829 in collideAABBs (callback=<optimized out>, data=0x0, g2=0x555555870550, g1=0x555555873a90) at collision_space_internal.h:77
#8  dxHashSpace::collide (this=0x55555585e9e0, data=0x0, callback=0x55555555e490 <nearCallback(void*, dGeomID, dGeomID)>) at collision_space.cpp:569
#9  0x000055555555de2e in simLoop (pause=<optimized out>) at demo_convex.cpp:230
#10 0x0000555555562a26 in processDrawFrame (frame=0x7fffffffdc00, fn=<optimized out>) at x11.cpp:337
#11 0x00005555555630ab in dsPlatformSimLoop (window_width=window_width@entry=1920, window_height=window_height@entry=1080, fn=fn@entry=0x7fffffffde90, initial_pause=initial_pause@entry=0) at x11.cpp:416
#12 0x000055555556159f in dsSimulationLoop (argc=1, argv=0x7fffffffe038, window_width=1920, window_height=1080, fn=0x7fffffffde90) at drawstuff.cpp:1291
#13 0x000055555555d9b0 in main (argc=1, argv=0x7fffffffe038) at demo_convex.cpp:429