prim_linkability_tut.cpp

Go to the documentation of this file.

#include "linden_common.h"
#include "lltut.h"
#include "llprimlinkinfo.h"
#include "llrand.h"


// helper function
void randomize_sphere(LLSphere& sphere, F32 center_range, F32 radius_range)
{
        F32 radius = ll_frand(2.f * radius_range) - radius_range;
        LLVector3 center;
        for (S32 i=0; i<3; ++i)
        {
                center.mV[i] = ll_frand(2.f * center_range) - center_range;
        }
        sphere.setRadius(radius);
        sphere.setCenter(center);
}

// helper function.  Same as above with a min and max radius.
void randomize_sphere(LLSphere& sphere, F32 center_range, F32 minimum_radius, F32 maximum_radius)
{
        F32 radius = ll_frand(maximum_radius - minimum_radius) + minimum_radius; 
        LLVector3 center;
        for (S32 i=0; i<3; ++i)
        {
                center.mV[i] = ll_frand(2.f * center_range) - center_range;
        }
        sphere.setRadius(radius);
        sphere.setCenter(center);
}

// helper function
bool random_sort( const LLPrimLinkInfo< S32 >&, const LLPrimLinkInfo< S32 >& b)
{
        return (ll_rand(64) < 32);
}

namespace tut
{
        struct linkable_data
        {
                LLPrimLinkInfo<S32> info;
        };

        typedef test_group<linkable_data> linkable_test;
        typedef linkable_test::object linkable_object;
        tut::linkable_test wtf("prim linkability");

        template<> template<>
        void linkable_object::test<1>()
        {
                // Here we test the boundary of the LLPrimLinkInfo::canLink() method 
                // between semi-random middle-sized objects.

                S32 number_of_tests = 100;
                for (S32 test = 0; test < number_of_tests; ++test)
                {
                        // compute the radii that would provide the above max link distance
                        F32 first_radius = 0.f;
                        F32 second_radius = 0.f;
                        
                        // compute a random center for the first sphere
                        // compute some random max link distance
                        F32 max_link_span = ll_frand(MAX_OBJECT_SPAN);
                        if (max_link_span < OBJECT_SPAN_BONUS)
                        {
                                max_link_span += OBJECT_SPAN_BONUS;
                        }
                        LLVector3 first_center(
                                        ll_frand(2.f * max_link_span) - max_link_span, 
                                        ll_frand(2.f * max_link_span) - max_link_span, 
                                        ll_frand(2.f * max_link_span) - max_link_span);

                        // put the second sphere at the right distance from the origin
                        // such that it is within the max_link_distance of the first
                        LLVector3 direction(ll_frand(2.f) - 1.f, ll_frand(2.f) - 1.f, ll_frand(2.f) - 1.f);
                        direction.normalize();
                        F32 half_milimeter = 0.0005f;
                        LLVector3 second_center;

                        // max_span = 3 * (first_radius + second_radius) + OBJECT_SPAN_BONUS
                        // make sure they link at short distances
                        {
                                second_center = first_center + (OBJECT_SPAN_BONUS - half_milimeter) * direction;
                                LLPrimLinkInfo<S32> first_info(0, LLSphere(first_center, first_radius) );
                                LLPrimLinkInfo<S32> second_info(1, LLSphere(second_center, second_radius) );
                                ensure("these nearby objects should link", first_info.canLink(second_info) );
                        }

                        // make sure they fail to link if we move them apart just a little bit
                        {
                                second_center = first_center + (OBJECT_SPAN_BONUS + half_milimeter) * direction;
                                LLPrimLinkInfo<S32> first_info(0, LLSphere(first_center, first_radius) );
                                LLPrimLinkInfo<S32> second_info(1, LLSphere(second_center, second_radius) );
                                ensure("these nearby objects should NOT link", !first_info.canLink(second_info) );
                        }

                        // make sure the objects link or not at medium distances
                        {
                                first_radius = 0.3f * ll_frand(max_link_span - OBJECT_SPAN_BONUS);

                                // This is the exact second radius that will link at exactly our random max_link_distance
                                second_radius = ((max_link_span - OBJECT_SPAN_BONUS) / 3.f) - first_radius;
                                second_center = first_center + (max_link_span - first_radius - second_radius - half_milimeter) * direction;

                                LLPrimLinkInfo<S32> first_info(0, LLSphere(first_center, first_radius) );
                                LLPrimLinkInfo<S32> second_info(1, LLSphere(second_center, second_radius) );

                                ensure("these objects should link", first_info.canLink(second_info) );
                        }

                        // make sure they fail to link if we move them apart just a little bit
                        {
                                // move the second sphere such that it is a little too far from the first
                                second_center += (2.f * half_milimeter) * direction;
                                LLPrimLinkInfo<S32> first_info(0, LLSphere(first_center, first_radius) );
                                LLPrimLinkInfo<S32> second_info(1, LLSphere(second_center, second_radius) );
                                
                                ensure("these objects should NOT link", !first_info.canLink(second_info) );
                        }

                        // make sure things don't link at far distances
                        {
                                second_center = first_center + (MAX_OBJECT_SPAN + 2.f * half_milimeter) * direction;
                                second_radius = 0.3f * MAX_OBJECT_SPAN;
                                LLPrimLinkInfo<S32> first_info(0, LLSphere(first_center, first_radius) );
                                LLPrimLinkInfo<S32> second_info(1, LLSphere(second_center, second_radius) );
                                ensure("these objects should NOT link", !first_info.canLink(second_info) );
                        }
                        
                }
        }

        template<> template<>
        void linkable_object::test<2>()
        {

                // Consider a row of eight spheres in a row, each 10m in diameter and centered
                // at 10m intervals:  01234567.

                F32 radius = 5.f;
                F32 spacing = 10.f;

                LLVector3 line_direction(ll_frand(2.f) - 1.f, ll_frand(2.f) - 1.f, ll_frand(2.f) - 1.f);
                line_direction.normalize();

                LLVector3 first_center(ll_frand(2.f * spacing) -spacing, ll_frand(2.f * spacing) - spacing, ll_frand(2.f * spacing) - spacing);

                LLPrimLinkInfo<S32> infos[8];

                for (S32 index = 0; index < 8; ++index)
                {
                        LLVector3 center = first_center + ((F32)(index) * spacing) * line_direction;
                        infos[index].set(index, LLSphere(center, radius));
                }

                // Max span for 2 spheres of 5m radius is 3 * (5 + 5) + 1 = 31m
                // spheres 0&2 have a 30m span (from outside edge to outside edge) and should link
                {
                        LLPrimLinkInfo<S32> root_info = infos[0];
                        std::list< LLPrimLinkInfo<S32> > info_list;
                        info_list.push_back(infos[2]);
                        root_info.mergeLinkableSet(info_list);
                        S32 prim_count = root_info.getPrimCount();
                        ensure_equals("0&2 prim count should be 2", prim_count, 2);
                        ensure_equals("0&2 unlinkable list should have length 0", (S32) info_list.size(), 0);
                }

                
                // spheres 0&3 have a 40 meter span and should NOT link outright
                {
                        LLPrimLinkInfo<S32> root_info = infos[0];
                        std::list< LLPrimLinkInfo<S32> > info_list;
                        info_list.push_back(infos[3]);
                        root_info.mergeLinkableSet(info_list);
                        S32 prim_count = root_info.getPrimCount();
                        ensure_equals("0&4 prim count should be 1", prim_count, 1);
                        ensure_equals("0&4 unlinkable list should have length 1", (S32) info_list.size(), 1);
                }

                
                // spheres 0-4 should link no matter what order : 01234
                // Total span = 50m, 012 link with a r=15.5 giving max span of 3 * (15.5 + 5) + 1 = 62.5, but the cap is 54m
                {
                        LLPrimLinkInfo<S32> root_info = infos[0];
                        std::list< LLPrimLinkInfo<S32> > info_list;
                        for (S32 index = 1; index < 5; ++index)
                        {
                                info_list.push_back(infos[index]);
                        }
                        root_info.mergeLinkableSet(info_list);
                        S32 prim_count = root_info.getPrimCount();
                        ensure_equals("01234 prim count should be 5", prim_count, 5);
                        ensure_equals("01234 unlinkable list should have length 0", (S32) info_list.size(), 0);
                }

                
                // spheres 0-5 should link no matter what order : 04321
                {
                        LLPrimLinkInfo<S32> root_info = infos[0];
                        std::list< LLPrimLinkInfo<S32> > info_list;
                        for (S32 index = 4; index > 0; --index)
                        {
                                info_list.push_back(infos[index]);
                        }
                        root_info.mergeLinkableSet(info_list);
                        S32 prim_count = root_info.getPrimCount();
                        ensure_equals("04321 prim count should be 5", prim_count, 5);
                        ensure_equals("04321 unlinkable list should have length 0", (S32) info_list.size(), 0);
                }

                // spheres 0-4 should link no matter what order : 01423
                {
                        LLPrimLinkInfo<S32> root_info = infos[0];
                        std::list< LLPrimLinkInfo<S32> > info_list;
                        info_list.push_back(infos[1]);
                        info_list.push_back(infos[4]);
                        info_list.push_back(infos[2]);
                        info_list.push_back(infos[3]);
                        root_info.mergeLinkableSet(info_list);
                        S32 prim_count = root_info.getPrimCount();
                        ensure_equals("01423 prim count should be 5", prim_count, 5);
                        ensure_equals("01423 unlinkable list should have length 0", (S32) info_list.size(), 0);
                }

                // spheres 0-5 should NOT fully link, only 0-4 
                {
                        LLPrimLinkInfo<S32> root_info = infos[0];
                        std::list< LLPrimLinkInfo<S32> > info_list;
                        for (S32 index = 1; index < 6; ++index)
                        {
                                info_list.push_back(infos[index]);
                        }
                        root_info.mergeLinkableSet(info_list);
                        S32 prim_count = root_info.getPrimCount();
                        ensure_equals("012345 prim count should be 5", prim_count, 5);
                        ensure_equals("012345 unlinkable list should have length 1", (S32) info_list.size(), 1);
                        std::list< LLPrimLinkInfo<S32> >::iterator info_itr = info_list.begin();
                        if (info_itr != info_list.end())
                        {
                                // examine the contents of the unlinked info
                                std::list<S32> unlinked_indecies;
                                info_itr->getData(unlinked_indecies);
                                // make sure there is only one index in the unlinked_info
                                ensure_equals("012345 unlinkable index count should be 1", (S32) unlinked_indecies.size(), 1);
                                // make sure its value is 6
                                std::list<S32>::iterator unlinked_index_itr = unlinked_indecies.begin();
                                S32 unlinkable_index = *unlinked_index_itr;
                                ensure_equals("012345 unlinkable index should be 5", (S32) unlinkable_index, 5);
                        }
                }
                
                // spheres 0-7 should NOT fully link, only 0-5 
                {
                        LLPrimLinkInfo<S32> root_info = infos[0];
                        std::list< LLPrimLinkInfo<S32> > info_list;
                        for (S32 index = 1; index < 8; ++index)
                        {
                                info_list.push_back(infos[index]);
                        }
                        root_info.mergeLinkableSet(info_list);
                        S32 prim_count = root_info.getPrimCount();
                        ensure_equals("01234567 prim count should be 5", prim_count, 5);
                        // Should be 1 linkinfo on unlinkable that has 2 prims
                        ensure_equals("01234567 unlinkable list should have length 1", (S32) info_list.size(), 1);
                        std::list< LLPrimLinkInfo<S32> >::iterator info_itr = info_list.begin();
                        if (info_itr != info_list.end())
                        {
                                // make sure there is only one index in the unlinked_info
                                std::list<S32> unlinked_indecies;
                                info_itr->getData(unlinked_indecies);
                                ensure_equals("0123456 unlinkable index count should be 3", (S32) unlinked_indecies.size(), 3);

                                // make sure its values are 6 and 7
                                std::list<S32>::iterator unlinked_index_itr = unlinked_indecies.begin();
                                S32 unlinkable_index = *unlinked_index_itr;
                                ensure_equals("0123456 first unlinkable index should be 5", (S32) unlinkable_index, 5);
                                ++unlinked_index_itr;
                                unlinkable_index = *unlinked_index_itr;
                                ensure_equals("0123456 second unlinkable index should be 6", (S32) unlinkable_index, 6);
                                ++unlinked_index_itr;
                                unlinkable_index = *unlinked_index_itr;
                                ensure_equals("0123456 third unlinkable index should be 7", (S32) unlinkable_index, 7);

                        }
                }
        }

        template<> template<>
        void linkable_object::test<3>()
        {
                // Here we test the link results between an LLPrimLinkInfo and a set of
                // randomized LLPrimLinkInfos where the expected results are known.
                S32 number_of_tests = 5;
                for (S32 test = 0; test < number_of_tests; ++test)
                {
                        // the radii are known
                        F32 first_radius = 1.f;
                        F32 second_radius = 2.f;
                        F32 third_radius = 3.f;

                        // compute the distances
                        F32 half_milimeter = 0.0005f;
                        F32 max_first_second_span = 3.f * (first_radius + second_radius) + OBJECT_SPAN_BONUS;
                        F32 linkable_distance = max_first_second_span - first_radius - second_radius - half_milimeter;

                        F32 max_full_span = 3.f * (0.5f * max_first_second_span + third_radius) + OBJECT_SPAN_BONUS;
                        F32 unlinkable_distance = max_full_span - 0.5f * linkable_distance - third_radius + half_milimeter;

                        // compute some random directions
                        LLVector3 first_direction(ll_frand(2.f) - 1.f, ll_frand(2.f) - 1.f, ll_frand(2.f) - 1.f);
                        first_direction.normalize();
                        LLVector3 second_direction(ll_frand(2.f) - 1.f, ll_frand(2.f) - 1.f, ll_frand(2.f) - 1.f);
                        second_direction.normalize();
                        LLVector3 third_direction(ll_frand(2.f) - 1.f, ll_frand(2.f) - 1.f, ll_frand(2.f) - 1.f);
                        third_direction.normalize();
        
                        // compute the centers
                        LLVector3 first_center = ll_frand(10.f) * first_direction;
                        LLVector3 second_center = first_center + ll_frand(linkable_distance) * second_direction;
                        LLVector3 first_join_center = 0.5f * (first_center + second_center);
                        LLVector3 third_center = first_join_center + unlinkable_distance * third_direction;

                        // make sure the second info links and the third does not
                        {
                                // initialize the infos
                                S32 index = 0;
                                LLPrimLinkInfo<S32> first_info(index++, LLSphere(first_center, first_radius));
                                LLPrimLinkInfo<S32> second_info(index++, LLSphere(second_center, second_radius));
                                LLPrimLinkInfo<S32> third_info(index++, LLSphere(third_center, third_radius));
        
                                // put the second and third infos in a list
                                std::list< LLPrimLinkInfo<S32> > info_list;
                                info_list.push_back(second_info);
                                info_list.push_back(third_info); 
        
                                // merge the list with the first_info
                                first_info.mergeLinkableSet(info_list);
                                S32 prim_count = first_info.getPrimCount();

                                ensure_equals("prim count should be 2", prim_count, 2);
                                ensure_equals("unlinkable list should have length 1", (S32) info_list.size(), 1);
                        }

                        // reverse the order and make sure we get the same results
                        {
                                // initialize the infos
                                S32 index = 0;
                                LLPrimLinkInfo<S32> first_info(index++, LLSphere(first_center, first_radius));
                                LLPrimLinkInfo<S32> second_info(index++, LLSphere(second_center, second_radius));
                                LLPrimLinkInfo<S32> third_info(index++, LLSphere(third_center, third_radius));
        
                                // build the list in the reverse order
                                std::list< LLPrimLinkInfo<S32> > info_list;
                                info_list.push_back(third_info); 
                                info_list.push_back(second_info);
        
                                // merge the list with the first_info
                                first_info.mergeLinkableSet(info_list);
                                S32 prim_count = first_info.getPrimCount();

                                ensure_equals("prim count should be 2", prim_count, 2);
                                ensure_equals("unlinkable list should have length 1", (S32) info_list.size(), 1);
                        }
                }
        }

        template<> template<>
        void linkable_object::test<4>()
        {
                // Here we test whether linkability is invarient under permutations
                // of link order.  To do this we generate a bunch of random spheres
                // and then try to link them in different ways.
                //
                // NOTE: the linkability will only be invarient if there is only one
                // linkable solution.  Multiple solutions will exist if the set of 
                // candidates are larger than the maximum linkable distance, or more 
                // numerous than a single linked object can contain.  This is easily 
                // understood by considering a very large set of link candidates, 
                // and first linking preferentially to the left until linking fails, 
                // then doing the same to the right -- the final solutions will differ.
                // Hence for this test we must generate candidate sets that lie within 
                // the linkability envelope of a single object.
                //
                // NOTE: a random set of objects will tend to either be totally linkable
                // or totally not.  That is, the random orientations that 

                F32 root_center_range = 0.f;
                F32 min_prim_radius = 0.1f;
                F32 max_prim_radius = 2.f;
                
                // Linkability is min(MAX_OBJECT_SPAN,3 *( R1 + R2 ) + BONUS)
                // 3 * (min_prim_radius + min_prim_radius) + OBJECT_SPAN_BONUS = 6 * min_prim_radius + OBJECT_SPAN_BONUS;
                // Use .45 instead of .5 to gaurantee objects are within the minimum span.
                F32 child_center_range = 0.45f * ( (6*min_prim_radius) + OBJECT_SPAN_BONUS );

                S32 number_of_tests = 100;
                S32 number_of_spheres = 10;
                S32 number_of_scrambles = 10;
                S32 number_of_random_bubble_sorts = 10;

                for (S32 test = 0; test < number_of_tests; ++test)
                {
                        LLSphere sphere;
                        S32 sphere_index = 0;

                        // build the root piece
                        randomize_sphere(sphere, root_center_range, min_prim_radius, max_prim_radius);
                        info.set( sphere_index++, sphere );

                        // build the unlinked pieces
                        std::list< LLPrimLinkInfo<S32> > info_list;
                        for (; sphere_index < number_of_spheres; ++sphere_index)
                        {
                                randomize_sphere(sphere, child_center_range, min_prim_radius, max_prim_radius);
                                LLPrimLinkInfo<S32> child_info( sphere_index, sphere );
                                info_list.push_back(child_info);
                        }

                        // declare the variables used to store the results
                        std::list<S32> first_linked_list;

                        {
                                // the link attempt will modify our original info's, so we
                                // have to make copies of the originals for testing
                                LLPrimLinkInfo<S32> test_info( 0, LLSphere(info.getCenter(), 0.5f * info.getDiameter()) );
                                std::list< LLPrimLinkInfo<S32> > test_list;
                                test_list.assign(info_list.begin(), info_list.end());

                                // try to link
                                test_info.mergeLinkableSet(test_list);
        
                                ensure("All prims should link, but did not.",test_list.empty());

                                // store the results 
                                test_info.getData(first_linked_list);
                                first_linked_list.sort();
                        }

                        // try to link the spheres in various random orders
                        for (S32 scramble = 0; scramble < number_of_scrambles; ++scramble)
                        {
                                LLPrimLinkInfo<S32> test_info(0, LLSphere(info.getCenter(), 0.5f * info.getDiameter()) );

                                // scramble the order of the info_list
                                std::list< LLPrimLinkInfo<S32> > test_list;
                                test_list.assign(info_list.begin(), info_list.end());
                                for (S32 i = 0; i < number_of_random_bubble_sorts; i++)
                                {
                                        test_list.sort(random_sort);
                                }

                                // try to link
                                test_info.mergeLinkableSet(test_list);
        
                                // get the results 
                                std::list<S32> linked_list;
                                test_info.getData(linked_list);
                                linked_list.sort();

                                ensure_equals("linked set size should be order independent",linked_list.size(),first_linked_list.size());
                        }
                }
        }
}

---