[ODE] Ray queries with GIMPACT.

[Michael Anderson]

Hmmm, looks like it's a vertex winding issue. If I flip the vertex winding
ray - mesh tests work, but everything else fails...

On 4/24/07, Michael Anderson <christiancoder at gmail.com> wrote:
>
> Lately we have been experiencing capsule - mesh jitter with OPCODE. After
> reading that GIMPACT seems to solve these collision problems I made the
> switch. After adding dInitODE and dCloseODE to our application I was up and
> running. GIMPACT appears to have solved the jitter problem, but I have lost
> ray - mesh intersections. Our ray cast method follows, it basically takes a
> global ray (that does not belong to any collision space) and calls dCollide
> passing in our collision space as the second geom. Does GIMPACT support ray
> - mesh (in my experience this is the easiest of all intersection tests)?  If
> so what am I missing?
>
>
> //=============================================================================
>
> bool castRay( RayCastResult& result, const VectorF& start, const VectorF&
> end, const U32 types )
> {
>    // Calc direction and length of ray.
>    VectorF dir = end - start;
>    F32 const len = dir.len();
>    dir *= (1.0f / len);
>
>    // Create ray.
>    dGeomRaySetLength( gRayId, len );
>    dGeomRaySet( gRayId, start.x, start.y, start.z, dir.x , dir.y, dir.z );
>
>    // Set collide bits for ray.
>    dGeomSetCollideBits( gRayId, types );
>
>    // Collide ray with world.
>    dContactGeom contacts[64];
>    const int c = dCollide( gRayId, (dGeomID)gSpace, 64, contacts, sizeof(
> dContactGeom ) );
>
>    // Did ray intersect world?
>    if (!c)
>    {
>       return false;
>    }
>
>    // Find the closest intersection.
>    U32 closest = 0;
>    F32 closestDepth = contacts[0].depth;
>    for (U32 i = 1; i < c; i++)
>    {
>       if (contacts[i].depth < closestDepth)
>       {
>          closest = i;
>          closestDepth = contacts[i].depth;
>       }
>    }
>
>    // Ray intersected world, so get intersection info.
>    dContactGeom& closestContact = contacts[closest];
>    result.object = (SceneObject*)dGeomGetData( closestContact.g2 );
>    result.geom = closestContact.g2;
>    result.entityType = dGeomGetCategoryBits( closestContact.g2 );
>    result.point.set( closestContact.pos[0], closestContact.pos[1],
> closestContact.pos[2] );
>    result.normal.set( closestContact.normal[0], closestContact.normal[1],
> closestContact.normal[2] );
>    result.distance = closestContact.depth;
>
>    return true;
> }
>
>
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