+/*
+ * Contact generators
+ *
+ * These do not automatically allocate contacts, an appropriately sized
+ * buffer must be supplied. The function returns the size of the manifold
+ * which was generated.
+ *
+ * The values set on the contacts are: n, co, p, rba, rbb
+ */
+
+/*
+ * By collecting the minimum(time) and maximum(time) pairs of points, we
+ * build a reduced and stable exact manifold.
+ *
+ * tx: time at point
+ * rx: minimum distance of these points
+ * dx: the delta between the two points
+ *
+ * pairs will only ammend these if they are creating a collision
+ */
+typedef struct capsule_manifold capsule_manifold;
+struct capsule_manifold
+{
+ float t0, t1;
+ float r0, r1;
+ v3f d0, d1;
+};
+
+/*
+ * Expand a line manifold with a new pair. t value is the time along segment
+ * on the oriented object which created this pair.
+ */
+VG_STATIC void rb_capsule_manifold( v3f pa, v3f pb, float t, float r,
+ capsule_manifold *manifold )
+{
+ v3f delta;
+ v3_sub( pa, pb, delta );
+
+ if( v3_length2(delta) < r*r )
+ {
+ if( t < manifold->t0 )
+ {
+ v3_copy( delta, manifold->d0 );
+ manifold->t0 = t;
+ manifold->r0 = r;
+ }
+
+ if( t > manifold->t1 )
+ {
+ v3_copy( delta, manifold->d1 );
+ manifold->t1 = t;
+ manifold->r1 = r;
+ }
+ }
+}
+
+VG_STATIC void rb_capsule_manifold_init( capsule_manifold *manifold )
+{
+ manifold->t0 = INFINITY;
+ manifold->t1 = -INFINITY;
+}
+
+VG_STATIC int rb_capsule_manifold_done( rigidbody *rba, rigidbody *rbb,
+ capsule_manifold *manifold, rb_ct *buf )
+{
+ float h = rba->inf.capsule.height,
+ ra = rba->inf.capsule.radius;
+
+ v3f p0, p1;
+ v3_muladds( rba->co, rba->up, -h*0.5f+ra, p0 );
+ v3_muladds( rba->co, rba->up, h*0.5f-ra, p1 );
+
+ int count = 0;
+ if( manifold->t0 <= 1.0f )
+ {
+ rb_ct *ct = buf;
+
+ v3f pa;
+ v3_muls( p0, 1.0f-manifold->t0, pa );
+ v3_muladds( pa, p1, manifold->t0, pa );
+
+ float d = v3_length( manifold->d0 );
+ v3_muls( manifold->d0, 1.0f/d, ct->n );
+ v3_muladds( pa, ct->n, -ra, ct->co );
+
+ ct->p = manifold->r0 - d;
+ ct->rba = rba;
+ ct->rbb = rbb;
+
+ count ++;
+ }
+
+ if( (manifold->t1 >= 0.0f) && (manifold->t0 != manifold->t1) )
+ {
+ rb_ct *ct = buf+count;
+
+ v3f pa;
+ v3_muls( p0, 1.0f-manifold->t1, pa );
+ v3_muladds( pa, p1, manifold->t1, pa );
+
+ float d = v3_length( manifold->d1 );
+ v3_muls( manifold->d1, 1.0f/d, ct->n );
+ v3_muladds( pa, ct->n, -ra, ct->co );
+
+ ct->p = manifold->r1 - d;
+ ct->rba = rba;
+ ct->rbb = rbb;
+
+ count ++;
+ }
+
+ /*
+ * Debugging
+ */
+
+ if( count == 2 )
+ vg_line( buf[0].co, buf[1].co, 0xff0000ff );
+
+ return count;
+}
+
+VG_STATIC int rb_capsule_sphere( rigidbody *rba, rigidbody *rbb, rb_ct *buf )
+{
+ float h = rba->inf.capsule.height,
+ ra = rba->inf.capsule.radius,
+ rb = rbb->inf.sphere.radius;
+
+ v3f p0, p1;
+ v3_muladds( rba->co, rba->up, -h*0.5f+ra, p0 );
+ v3_muladds( rba->co, rba->up, h*0.5f-ra, p1 );
+
+ v3f c, delta;
+ closest_point_segment( p0, p1, rbb->co, c );
+ v3_sub( c, rbb->co, delta );
+
+ float d2 = v3_length2(delta),
+ r = ra + rb;
+
+ if( d2 < r*r )
+ {
+ float d = sqrtf(d2);
+
+ rb_ct *ct = buf;
+ v3_muls( delta, 1.0f/d, ct->n );
+ ct->p = r-d;
+
+ v3f p0, p1;
+ v3_muladds( c, ct->n, -ra, p0 );
+ v3_muladds( rbb->co, ct->n, rb, p1 );
+ v3_add( p0, p1, ct->co );
+ v3_muls( ct->co, 0.5f, ct->co );
+
+ ct->rba = rba;
+ ct->rbb = rbb;
+
+ return 1;
+ }
+
+ return 0;
+}
+
+VG_STATIC int rb_capsule_capsule( rigidbody *rba, rigidbody *rbb, rb_ct *buf )
+{
+ float ha = rba->inf.capsule.height,
+ hb = rbb->inf.capsule.height,
+ ra = rba->inf.capsule.radius,
+ rb = rbb->inf.capsule.radius,
+ r = ra+rb;
+
+ v3f p0, p1, p2, p3;
+ v3_muladds( rba->co, rba->up, -ha*0.5f+ra, p0 );
+ v3_muladds( rba->co, rba->up, ha*0.5f-ra, p1 );
+ v3_muladds( rbb->co, rbb->up, -hb*0.5f+rb, p2 );
+ v3_muladds( rbb->co, rbb->up, hb*0.5f-rb, p3 );
+
+ capsule_manifold manifold;
+ rb_capsule_manifold_init( &manifold );
+
+ v3f pa, pb;
+ float ta, tb;
+ closest_segment_segment( p0, p1, p2, p3, &ta, &tb, pa, pb );
+ rb_capsule_manifold( pa, pb, ta, r, &manifold );
+
+ ta = closest_point_segment( p0, p1, p2, pa );
+ tb = closest_point_segment( p0, p1, p3, pb );
+ rb_capsule_manifold( pa, p2, ta, r, &manifold );
+ rb_capsule_manifold( pb, p3, tb, r, &manifold );
+
+ closest_point_segment( p2, p3, p0, pa );
+ closest_point_segment( p2, p3, p1, pb );
+ rb_capsule_manifold( p0, pa, 0.0f, r, &manifold );
+ rb_capsule_manifold( p1, pb, 1.0f, r, &manifold );
+
+ return rb_capsule_manifold_done( rba, rbb, &manifold, buf );
+}
+
+/*
+ * Generates up to two contacts; optimised for the most stable manifold
+ */
+VG_STATIC int rb_capsule_box( rigidbody *rba, rigidbody *rbb, rb_ct *buf )
+{
+ float h = rba->inf.capsule.height,
+ r = rba->inf.capsule.radius;
+
+ /*
+ * Solving this in symetric local space of the cube saves us some time and a
+ * couple branches when it comes to the quad stage.
+ */
+ v3f centroid;
+ v3_add( rbb->bbx[0], rbb->bbx[1], centroid );
+ v3_muls( centroid, 0.5f, centroid );
+
+ boxf bbx;
+ v3_sub( rbb->bbx[0], centroid, bbx[0] );
+ v3_sub( rbb->bbx[1], centroid, bbx[1] );
+
+ v3f pc, p0w, p1w, p0, p1;
+ v3_muladds( rba->co, rba->up, -h*0.5f+r, p0w );
+ v3_muladds( rba->co, rba->up, h*0.5f-r, p1w );
+
+ m4x3_mulv( rbb->to_local, p0w, p0 );
+ m4x3_mulv( rbb->to_local, p1w, p1 );
+ v3_sub( p0, centroid, p0 );
+ v3_sub( p1, centroid, p1 );
+ v3_add( p0, p1, pc );
+ v3_muls( pc, 0.5f, pc );
+
+ /*
+ * Finding an appropriate quad to collide lines with
+ */
+ v3f region;
+ v3_div( pc, bbx[1], region );
+
+ v3f quad[4];
+ if( (fabsf(region[0]) > fabsf(region[1])) &&
+ (fabsf(region[0]) > fabsf(region[2])) )
+ {
+ float px = vg_signf(region[0]) * bbx[1][0];
+ v3_copy( (v3f){ px, bbx[0][1], bbx[0][2] }, quad[0] );
+ v3_copy( (v3f){ px, bbx[1][1], bbx[0][2] }, quad[1] );
+ v3_copy( (v3f){ px, bbx[1][1], bbx[1][2] }, quad[2] );
+ v3_copy( (v3f){ px, bbx[0][1], bbx[1][2] }, quad[3] );
+ }
+ else if( fabsf(region[1]) > fabsf(region[2]) )
+ {
+ float py = vg_signf(region[1]) * bbx[1][1];
+ v3_copy( (v3f){ bbx[0][0], py, bbx[0][2] }, quad[0] );
+ v3_copy( (v3f){ bbx[1][0], py, bbx[0][2] }, quad[1] );
+ v3_copy( (v3f){ bbx[1][0], py, bbx[1][2] }, quad[2] );
+ v3_copy( (v3f){ bbx[0][0], py, bbx[1][2] }, quad[3] );
+ }
+ else
+ {
+ float pz = vg_signf(region[2]) * bbx[1][2];
+ v3_copy( (v3f){ bbx[0][0], bbx[0][1], pz }, quad[0] );
+ v3_copy( (v3f){ bbx[1][0], bbx[0][1], pz }, quad[1] );
+ v3_copy( (v3f){ bbx[1][0], bbx[1][1], pz }, quad[2] );
+ v3_copy( (v3f){ bbx[0][0], bbx[1][1], pz }, quad[3] );
+ }
+
+ capsule_manifold manifold;
+ rb_capsule_manifold_init( &manifold );
+
+ v3f c0, c1;
+ closest_point_aabb( p0, bbx, c0 );
+ closest_point_aabb( p1, bbx, c1 );
+
+ v3f d0, d1, da;
+ v3_sub( c0, p0, d0 );
+ v3_sub( c1, p1, d1 );
+ v3_sub( p1, p0, da );
+
+ v3_normalize(d0);
+ v3_normalize(d1);
+ v3_normalize(da);
+
+ if( v3_dot( da, d0 ) <= 0.01f )
+ rb_capsule_manifold( p0, c0, 0.0f, r, &manifold );
+
+ if( v3_dot( da, d1 ) >= -0.01f )
+ rb_capsule_manifold( p1, c1, 1.0f, r, &manifold );
+
+ for( int i=0; i<4; i++ )
+ {
+ int i0 = i,
+ i1 = (i+1)%4;
+
+ v3f ca, cb;
+ float ta, tb;
+ closest_segment_segment( p0, p1, quad[i0], quad[i1], &ta, &tb, ca, cb );
+ rb_capsule_manifold( ca, cb, ta, r, &manifold );
+ }
+
+ /*
+ * Create final contacts based on line manifold
+ */
+ m3x3_mulv( rbb->to_world, manifold.d0, manifold.d0 );
+ m3x3_mulv( rbb->to_world, manifold.d1, manifold.d1 );
+
+ /*
+ * Debugging
+ */
+
+#if 0
+ for( int i=0; i<4; i++ )
+ {
+ v3f q0, q1;
+ int i0 = i,
+ i1 = (i+1)%4;
+
+ v3_add( quad[i0], centroid, q0 );
+ v3_add( quad[i1], centroid, q1 );
+
+ m4x3_mulv( rbb->to_world, q0, q0 );
+ m4x3_mulv( rbb->to_world, q1, q1 );
+
+ vg_line( q0, q1, 0xffffffff );
+ }
+#endif
+
+ return rb_capsule_manifold_done( rba, rbb, &manifold, buf );
+}
+
+VG_STATIC int rb_sphere_box( rigidbody *rba, rigidbody *rbb, rb_ct *buf )
+{
+ v3f co, delta;
+
+ closest_point_obb( rba->co, rbb, co );
+ v3_sub( rba->co, co, delta );
+
+ float d2 = v3_length2(delta),
+ r = rba->inf.sphere.radius;
+
+ if( d2 <= r*r )
+ {
+ float d;
+
+ rb_ct *ct = buf;
+ if( d2 <= 0.0001f )
+ {
+ v3_sub( rba->co, rbb->co, delta );
+
+ /*
+ * some extra testing is required to find the best axis to push the
+ * object back outside the box. Since there isnt a clear seperating
+ * vector already, especially on really high aspect boxes.
+ */
+ float lx = v3_dot( rbb->right, delta ),
+ ly = v3_dot( rbb->up, delta ),
+ lz = v3_dot( rbb->forward, delta ),
+ px = rbb->bbx[1][0] - fabsf(lx),
+ py = rbb->bbx[1][1] - fabsf(ly),
+ pz = rbb->bbx[1][2] - fabsf(lz);
+
+ if( px < py && px < pz )
+ v3_muls( rbb->right, vg_signf(lx), ct->n );
+ else if( py < pz )
+ v3_muls( rbb->up, vg_signf(ly), ct->n );
+ else
+ v3_muls( rbb->forward, vg_signf(lz), ct->n );
+
+ v3_muladds( rba->co, ct->n, -r, ct->co );
+ ct->p = r;
+ }
+ else
+ {
+ d = sqrtf(d2);
+ v3_muls( delta, 1.0f/d, ct->n );
+ ct->p = r-d;
+ v3_copy( co, ct->co );
+ }
+
+ ct->rba = rba;
+ ct->rbb = rbb;
+ return 1;
+ }
+
+ return 0;
+}
+
+VG_STATIC int rb_sphere_sphere( rigidbody *rba, rigidbody *rbb, rb_ct *buf )
+{
+ v3f delta;
+ v3_sub( rba->co, rbb->co, delta );
+
+ float d2 = v3_length2(delta),
+ r = rba->inf.sphere.radius + rbb->inf.sphere.radius;
+
+ if( d2 < r*r )
+ {
+ float d = sqrtf(d2);
+
+ rb_ct *ct = buf;
+ v3_muls( delta, 1.0f/d, ct->n );
+
+ v3f p0, p1;
+ v3_muladds( rba->co, ct->n,-rba->inf.sphere.radius, p0 );
+ v3_muladds( rbb->co, ct->n, rbb->inf.sphere.radius, p1 );
+ v3_add( p0, p1, ct->co );
+ v3_muls( ct->co, 0.5f, ct->co );
+ ct->p = r-d;
+ ct->rba = rba;
+ ct->rbb = rbb;
+ return 1;
+ }
+
+ return 0;
+}
+
+#define RIGIDBODY_DYNAMIC_MESH_EDGES
+
+VG_STATIC int rb_sphere_triangle( rigidbody *rba, rigidbody *rbb,
+ v3f tri[3], rb_ct *buf )
+{
+ v3f delta, co;
+
+#ifdef RIGIDBODY_DYNAMIC_MESH_EDGES
+ closest_on_triangle( rba->co, tri, co );
+#else
+ closest_on_triangle_1( rba->co, tri, co );
+#endif
+
+ v3_sub( rba->co, co, delta );
+
+ vg_line( rba->co, co, 0xffff0000 );
+ vg_line_pt3( rba->co, 0.1f, 0xff00ffff );
+
+ float d2 = v3_length2( delta ),
+ r = rba->inf.sphere.radius;
+
+ if( d2 < r*r )
+ {
+ rb_ct *ct = buf;
+
+ v3f ab, ac, tn;
+ v3_sub( tri[2], tri[0], ab );
+ v3_sub( tri[1], tri[0], ac );
+ v3_cross( ac, ab, tn );
+ v3_copy( tn, ct->n );
+ v3_normalize( ct->n );
+
+ float d = sqrtf(d2);
+
+ v3_copy( co, ct->co );
+ ct->p = r-d;
+ ct->rba = rba;
+ ct->rbb = rbb;
+ return 1;
+ }
+
+ return 0;
+}
+
+VG_STATIC int rb_sphere_scene( rigidbody *rba, rigidbody *rbb, rb_ct *buf )
+{
+ scene *sc = rbb->inf.scene.bh_scene->user;
+
+ u32 geo[128];
+
+ int len = bh_select( rbb->inf.scene.bh_scene, rba->bbx_world, geo, 128 );
+ int count = 0;
+
+#ifdef RIGIDBODY_DYNAMIC_MESH_EDGES
+ /* !experimental! build edge array on the fly. time could be improved! */
+
+ v3f co_picture[128*3];
+ int unique_cos = 0;
+
+ struct face_info
+ {
+ int unique_cos[3]; /* indexes co_picture array */
+ int collided;
+ v3f normal;
+ u32 element_id;
+ }
+ faces[128];
+
+ /* create geometry picture */
+ for( int i=0; i<len; i++ )
+ {
+ u32 *tri_indices = &sc->arrindices[ geo[i]*3 ];
+ struct face_info *inf = &faces[i];
+ inf->element_id = tri_indices[0];
+ inf->collided = 0;
+
+ for( int j=0; j<3; j++ )
+ {
+ struct mdl_vert *pvert = &sc->arrvertices[tri_indices[j]];
+
+ for( int k=0; k<unique_cos; k++ )
+ {
+ if( v3_dist( pvert->co, co_picture[k] ) < 0.01f*0.01f )
+ {
+ inf->unique_cos[j] = k;
+ goto next_vert;
+ }
+ }
+
+ inf->unique_cos[j] = unique_cos;
+ v3_copy( pvert->co, co_picture[ unique_cos ++ ] );
+next_vert:;
+ }
+
+ v3f ab, ac;
+ v3_sub( co_picture[inf->unique_cos[2]],
+ co_picture[inf->unique_cos[0]], ab );
+
+ v3_sub( co_picture[inf->unique_cos[1]],
+ co_picture[inf->unique_cos[0]], ac );
+ v3_cross( ac, ab, inf->normal );
+ v3_normalize( inf->normal );
+ }
+
+
+ /* build edges brute force */
+ int edge_picture[ 128*3 ][4];
+ int unique_edges = 0;
+
+ for( int i=0; i<len; i++ )
+ {
+ struct face_info *inf = &faces[i];
+
+ for( int j=0; j<3; j++ )
+ {
+ int i0 = j,
+ i1 = (j+1)%3,
+ e0 = VG_MIN( inf->unique_cos[i0], inf->unique_cos[i1] ),
+ e1 = VG_MAX( inf->unique_cos[i0], inf->unique_cos[i1] ),
+ matched = 0;
+
+ for( int k=0; k<unique_edges; k ++ )
+ {
+ int k0 = VG_MIN( edge_picture[k][0], edge_picture[k][1] ),
+ k1 = VG_MAX( edge_picture[k][0], edge_picture[k][1] );
+
+ /* matched ! */
+ if( (k0 == e0) && (k1 == e1) )
+ {
+ edge_picture[ k ][3] = i;
+ matched = 1;
+ break;
+ }
+ }
+
+ if( !matched )
+ {
+ /* create new edge */
+ edge_picture[ unique_edges ][0] = inf->unique_cos[i0];
+ edge_picture[ unique_edges ][1] = inf->unique_cos[i1];
+
+ edge_picture[ unique_edges ][2] = i;
+ edge_picture[ unique_edges ][3] = -1;
+
+ unique_edges ++;
+ }
+ }
+ }
+#endif
+
+ v3f tri[3];
+
+ for( int i=0; i<len; i++ )
+ {
+#ifdef RIGIDBODY_DYNAMIC_MESH_EDGES
+ struct face_info *inf = &faces[i];
+
+ float *v0 = co_picture[inf->unique_cos[0]],
+ *v1 = co_picture[inf->unique_cos[1]],
+ *v2 = co_picture[inf->unique_cos[2]];
+
+ v3_copy( v0, tri[0] );
+ v3_copy( v1, tri[1] );
+ v3_copy( v2, tri[2] );
+
+ buf[count].element_id = inf->element_id;
+#else
+ u32 *ptri = &sc->arrindices[ geo[i]*3 ];
+
+ for( int j=0; j<3; j++ )
+ v3_copy( sc->arrvertices[ptri[j]].co, tri[j] );
+
+ buf[count].element_id = ptri[0];
+#endif
+
+ vg_line( tri[0],tri[1],0x10ffffff );
+ vg_line( tri[1],tri[2],0x10ffffff );
+ vg_line( tri[2],tri[0],0x10ffffff );
+
+ int hits = rb_sphere_triangle( rba, rbb, tri, buf+count );
+#ifdef RIGIDBODY_DYNAMIC_MESH_EDGES
+ if( hits )
+ inf->collided = 1;
+#endif
+ count += hits;
+
+ if( count == 12 )
+ {
+ vg_warn( "Exceeding sphere_vs_scene capacity. Geometry too dense!\n" );
+ return count;
+ }
+ }
+
+#ifdef RIGIDBODY_DYNAMIC_MESH_EDGES
+ for( int i=0; i<unique_edges; i++ )
+ {
+ int *edge = edge_picture[i];
+
+ if( edge[3] == -1 )
+ continue;
+
+ struct face_info *inf_i = &faces[edge[2]],
+ *inf_j = &faces[edge[3]];
+
+ if( inf_i->collided || inf_j->collided )
+ continue;
+
+ v3f co, delta;
+ closest_point_segment( co_picture[edge[0]], co_picture[edge[1]],
+ rba->co, co );
+
+ v3_sub( rba->co, co, delta );
+ float d2 = v3_length2( delta ),
+ r = rba->inf.sphere.radius;
+
+ if( d2 < r*r )
+ {
+ float d = sqrtf(d2);
+
+ v3_muls( delta, 1.0f/d, delta );
+ float c0 = v3_dot( inf_i->normal, delta ),
+ c1 = v3_dot( inf_j->normal, delta );
+
+ if( c0 < 0.0f || c1 < 0.0f )
+ continue;
+
+ rb_ct *ct = buf+count;
+
+ v3_muls( inf_i->normal, c0, ct->n );
+ v3_muladds( ct->n, inf_j->normal, c1, ct->n );
+ v3_normalize( ct->n );
+
+ v3_copy( co, ct->co );
+ ct->p = r-d;
+ ct->rba = rba;
+ ct->rbb = rbb;
+ ct->element_id = inf_i->element_id;
+
+ count ++;
+
+ if( count == 12 )
+ {
+ vg_warn( "Geometry too dense!\n" );
+ return count;
+ }
+ }
+ }
+#endif
+
+ return count;
+}
+
+VG_STATIC int rb_box_scene( rigidbody *rba, rigidbody *rbb, rb_ct *buf )
+{
+ scene *sc = rbb->inf.scene.bh_scene->user;
+
+ u32 geo[128];
+ v3f tri[3];
+ int len = bh_select( rbb->inf.scene.bh_scene, rba->bbx_world, geo, 128 );
+
+ int count = 0;
+
+ for( int i=0; i<len; i++ )
+ {
+ u32 *ptri = &sc->arrindices[ geo[i]*3 ];
+
+ for( int j=0; j<3; j++ )
+ v3_copy( sc->arrvertices[ptri[j]].co, tri[j] );
+
+ if( rb_box_triangle_sat( rba, tri ) )
+ {
+ vg_line(tri[0],tri[1],0xff50ff00 );
+ vg_line(tri[1],tri[2],0xff50ff00 );
+ vg_line(tri[2],tri[0],0xff50ff00 );
+ }
+ else
+ {
+ vg_line(tri[0],tri[1],0xff0000ff );
+ vg_line(tri[1],tri[2],0xff0000ff );
+ vg_line(tri[2],tri[0],0xff0000ff );
+
+ continue;
+ }
+
+ v3f v0,v1,n;
+ v3_sub( tri[1], tri[0], v0 );
+ v3_sub( tri[2], tri[0], v1 );
+ v3_cross( v0, v1, n );
+ v3_normalize( n );
+
+ /* find best feature */
+ float best = v3_dot( rba->right, n );
+ int axis = 0;
+
+ float cy = v3_dot( rba->up, n );
+ if( fabsf(cy) > fabsf(best) )
+ {
+ best = cy;
+ axis = 1;
+ }
+
+ float cz = -v3_dot( rba->forward, n );
+ if( fabsf(cz) > fabsf(best) )
+ {
+ best = cz;
+ axis = 2;
+ }
+
+ v3f manifold[4];
+
+ if( axis == 0 )
+ {
+ float px = best > 0.0f? rba->bbx[0][0]: rba->bbx[1][0];
+ manifold[0][0] = px;
+ manifold[0][1] = rba->bbx[0][1];
+ manifold[0][2] = rba->bbx[0][2];
+ manifold[1][0] = px;
+ manifold[1][1] = rba->bbx[1][1];
+ manifold[1][2] = rba->bbx[0][2];
+ manifold[2][0] = px;
+ manifold[2][1] = rba->bbx[1][1];
+ manifold[2][2] = rba->bbx[1][2];
+ manifold[3][0] = px;
+ manifold[3][1] = rba->bbx[0][1];
+ manifold[3][2] = rba->bbx[1][2];
+ }
+ else if( axis == 1 )
+ {
+ float py = best > 0.0f? rba->bbx[0][1]: rba->bbx[1][1];
+ manifold[0][0] = rba->bbx[0][0];
+ manifold[0][1] = py;
+ manifold[0][2] = rba->bbx[0][2];
+ manifold[1][0] = rba->bbx[1][0];
+ manifold[1][1] = py;
+ manifold[1][2] = rba->bbx[0][2];
+ manifold[2][0] = rba->bbx[1][0];
+ manifold[2][1] = py;
+ manifold[2][2] = rba->bbx[1][2];
+ manifold[3][0] = rba->bbx[0][0];
+ manifold[3][1] = py;
+ manifold[3][2] = rba->bbx[1][2];
+ }
+ else
+ {
+ float pz = best > 0.0f? rba->bbx[0][2]: rba->bbx[1][2];
+ manifold[0][0] = rba->bbx[0][0];
+ manifold[0][1] = rba->bbx[0][1];
+ manifold[0][2] = pz;
+ manifold[1][0] = rba->bbx[1][0];
+ manifold[1][1] = rba->bbx[0][1];
+ manifold[1][2] = pz;
+ manifold[2][0] = rba->bbx[1][0];
+ manifold[2][1] = rba->bbx[1][1];
+ manifold[2][2] = pz;
+ manifold[3][0] = rba->bbx[0][0];
+ manifold[3][1] = rba->bbx[1][1];
+ manifold[3][2] = pz;
+ }
+
+ for( int j=0; j<4; j++ )
+ m4x3_mulv( rba->to_world, manifold[j], manifold[j] );
+
+ vg_line( manifold[0], manifold[1], 0xffffffff );
+ vg_line( manifold[1], manifold[2], 0xffffffff );
+ vg_line( manifold[2], manifold[3], 0xffffffff );
+ vg_line( manifold[3], manifold[0], 0xffffffff );
+
+ for( int j=0; j<4; j++ )
+ {
+ rb_ct *ct = buf+count;
+
+ v3_copy( manifold[j], ct->co );
+ v3_copy( n, ct->n );
+
+ float l0 = v3_dot( tri[0], n ),
+ l1 = v3_dot( manifold[j], n );
+
+ ct->p = (l0-l1)*0.5f;
+ if( ct->p < 0.0f )
+ continue;
+
+ ct->rba = rba;
+ ct->rbb = rbb;
+ count ++;
+
+ if( count >= 12 )
+ return count;
+ }
+ }
+ return count;
+}
+
+VG_STATIC int RB_MATRIX_ERROR( rigidbody *rba, rigidbody *rbb, rb_ct *buf )
+{
+ vg_error( "Collision type is unimplemented between types %d and %d\n",
+ rba->type, rbb->type );
+
+ return 0;
+}
+
+VG_STATIC int rb_sphere_capsule( rigidbody *rba, rigidbody *rbb, rb_ct *buf )
+{
+ return rb_capsule_sphere( rbb, rba, buf );
+}
+
+VG_STATIC int rb_box_capsule( rigidbody *rba, rigidbody *rbb, rb_ct *buf )
+{
+ return rb_capsule_box( rbb, rba, buf );
+}
+
+VG_STATIC int rb_box_sphere( rigidbody *rba, rigidbody *rbb, rb_ct *buf )
+{
+ return rb_sphere_box( rbb, rba, buf );
+}
+
+VG_STATIC int rb_scene_box( rigidbody *rba, rigidbody *rbb, rb_ct *buf )
+{
+ return rb_box_scene( rbb, rba, buf );
+}
+
+VG_STATIC int (*rb_jump_table[4][4])( rigidbody *a, rigidbody *b, rb_ct *buf ) =
+{
+ /* box */ /* Sphere */ /* Capsule */ /* Mesh */
+ { RB_MATRIX_ERROR, rb_box_sphere, rb_box_capsule, rb_box_scene },
+ { rb_sphere_box, rb_sphere_sphere, rb_sphere_capsule, rb_sphere_scene },
+ { rb_capsule_box, rb_capsule_sphere, rb_capsule_capsule, RB_MATRIX_ERROR },
+ { rb_scene_box, RB_MATRIX_ERROR, RB_MATRIX_ERROR, RB_MATRIX_ERROR }
+};
+
+VG_STATIC int rb_collide( rigidbody *rba, rigidbody *rbb )
+{
+ int (*collider_jump)(rigidbody *rba, rigidbody *rbb, rb_ct *buf )
+ = rb_jump_table[rba->type][rbb->type];
+
+ /*
+ * 12 is the maximum manifold size we can generate, so we are forced to abort
+ * potentially checking any more.
+ */
+ if( rb_contact_count + 12 > vg_list_size(rb_contact_buffer) )
+ {
+ vg_warn( "Too many contacts made in global collider buffer (%d of %d\n)",
+ rb_contact_count, vg_list_size(rb_contact_buffer) );
+ return 0;
+ }
+
+ /*
+ * FUTURE: Replace this with a more dedicated broad phase pass
+ */
+ if( box_overlap( rba->bbx_world, rbb->bbx_world ) )
+ {
+ int count = collider_jump( rba, rbb, rb_contact_buffer+rb_contact_count);
+ rb_contact_count += count;
+ return count;
+ }
+ else
+ return 0;
+}
+
+/*
+ * -----------------------------------------------------------------------------
+ * Dynamics
+ * -----------------------------------------------------------------------------
+ */
+
+VG_STATIC void rb_solver_reset(void)
+{
+ rb_contact_count = 0;
+}
+
+VG_STATIC rb_ct *rb_global_ct(void)
+{
+ return rb_contact_buffer + rb_contact_count;
+}
+
+/*
+ * Initializing things like tangent vectors
+ */
+VG_STATIC void rb_presolve_contacts( rb_ct *buffer, int len )
+{
+ for( int i=0; i<len; i++ )
+ {
+ rb_ct *ct = &buffer[i];
+ ct->bias = -0.2f * k_rb_rate * vg_minf( 0.0f, -ct->p+k_penetration_slop );
+ rb_tangent_basis( ct->n, ct->t[0], ct->t[1] );
+
+ ct->norm_impulse = 0.0f;
+ ct->tangent_impulse[0] = 0.0f;
+ ct->tangent_impulse[1] = 0.0f;
+
+ v3f ra, rb, raCn, rbCn, raCt, rbCt;
+ v3_sub( ct->co, ct->rba->co, ra );
+ v3_sub( ct->co, ct->rbb->co, rb );
+ v3_cross( ra, ct->n, raCn );
+ v3_cross( rb, ct->n, rbCn );
+
+ /* orient inverse inertia tensors */
+ v3f raCnI, rbCnI;
+ m3x3_mulv( ct->rba->iIw, raCn, raCnI );
+ m3x3_mulv( ct->rbb->iIw, rbCn, rbCnI );
+
+ ct->normal_mass = ct->rba->inv_mass + ct->rbb->inv_mass;
+ ct->normal_mass += v3_dot( raCn, raCnI );
+ ct->normal_mass += v3_dot( rbCn, rbCnI );
+ ct->normal_mass = 1.0f/ct->normal_mass;
+
+ for( int j=0; j<2; j++ )
+ {
+ v3f raCtI, rbCtI;
+ v3_cross( ct->t[j], ra, raCt );
+ v3_cross( ct->t[j], rb, rbCt );
+ m3x3_mulv( ct->rba->iIw, raCt, raCtI );
+ m3x3_mulv( ct->rbb->iIw, rbCt, rbCtI );
+
+ ct->tangent_mass[j] = ct->rba->inv_mass + ct->rbb->inv_mass;
+ ct->tangent_mass[j] += v3_dot( raCt, raCtI );
+ ct->tangent_mass[j] += v3_dot( rbCt, rbCtI );
+ ct->tangent_mass[j] = 1.0f/ct->tangent_mass[j];
+ }
+
+ rb_debug_contact( ct );
+ }
+}
+
+/*
+ * Creates relative contact velocity vector, and offsets between each body
+ */
+VG_STATIC void rb_rcv( rb_ct *ct, v3f rv, v3f da, v3f db )
+{
+ rigidbody *rba = ct->rba,
+ *rbb = ct->rbb;
+
+ v3_sub( ct->co, rba->co, da );
+ v3_sub( ct->co, rbb->co, db );
+
+ v3f rva, rvb;
+ v3_cross( rba->w, da, rva );
+ v3_add( rba->v, rva, rva );
+ v3_cross( rbb->w, db, rvb );
+ v3_add( rbb->v, rvb, rvb );
+
+ v3_sub( rva, rvb, rv );
+}
+
+/*
+ * Apply impulse to object
+ */
+VG_STATIC void rb_linear_impulse( rigidbody *rb, v3f delta, v3f impulse )
+{
+ /* linear */
+ v3_muladds( rb->v, impulse, rb->inv_mass, rb->v );
+
+ /* Angular velocity */
+ v3f wa;
+ v3_cross( delta, impulse, wa );
+
+ m3x3_mulv( rb->iIw, wa, wa );
+ v3_add( rb->w, wa, rb->w );
+}
+
+/*
+ * One iteration to solve the contact constraint
+ */
+VG_STATIC void rb_solve_contacts( rb_ct *buf, int len )
+{
+ for( int i=0; i<len; i++ )
+ {
+ struct contact *ct = &buf[i];
+ rigidbody *rb = ct->rba;
+
+ v3f rv, da, db;
+ rb_rcv( ct, rv, da, db );
+
+ /* Friction */
+ for( int j=0; j<2; j++ )
+ {
+ float f = k_friction * ct->norm_impulse,
+ vt = v3_dot( rv, ct->t[j] ),
+ lambda = ct->tangent_mass[j] * -vt;
+
+ float temp = ct->tangent_impulse[j];
+ ct->tangent_impulse[j] = vg_clampf( temp + lambda, -f, f );
+ lambda = ct->tangent_impulse[j] - temp;
+
+ v3f impulse;
+ v3_muls( ct->t[j], lambda, impulse );
+ rb_linear_impulse( ct->rba, da, impulse );
+
+ v3_muls( ct->t[j], -lambda, impulse );
+ rb_linear_impulse( ct->rbb, db, impulse );
+ }
+
+ /* Normal */
+ rb_rcv( ct, rv, da, db );
+ float vn = v3_dot( rv, ct->n ),
+ lambda = ct->normal_mass * (-vn + ct->bias);
+
+ float temp = ct->norm_impulse;
+ ct->norm_impulse = vg_maxf( temp + lambda, 0.0f );
+ lambda = ct->norm_impulse - temp;
+
+ v3f impulse;
+ v3_muls( ct->n, lambda, impulse );
+ rb_linear_impulse( ct->rba, da, impulse );
+
+ v3_muls( ct->n, -lambda, impulse );
+ rb_linear_impulse( ct->rbb, db, impulse );
+ }
+}
+
+/*
+ * -----------------------------------------------------------------------------
+ * Constraints
+ * -----------------------------------------------------------------------------
+ */
+
+VG_STATIC void draw_angle_limit( v3f c, v3f major, v3f minor,
+ float amin, float amax, float measured,
+ u32 colour )
+{
+ float f = 0.05f;
+ v3f ay, ax;
+ v3_muls( major, f, ay );
+ v3_muls( minor, f, ax );
+
+ for( int x=0; x<16; x++ )
+ {
+ float t0 = (float)x / 16.0f,
+ t1 = (float)(x+1) / 16.0f,
+ a0 = vg_lerpf( amin, amax, t0 ),
+ a1 = vg_lerpf( amin, amax, t1 );
+
+ v3f p0, p1;
+ v3_muladds( c, ay, cosf(a0), p0 );
+ v3_muladds( p0, ax, sinf(a0), p0 );
+ v3_muladds( c, ay, cosf(a1), p1 );
+ v3_muladds( p1, ax, sinf(a1), p1 );
+
+ vg_line( p0, p1, colour );
+
+ if( x == 0 )
+ vg_line( c, p0, colour );
+ if( x == 15 )
+ vg_line( c, p1, colour );
+ }
+
+ v3f p2;
+ v3_muladds( c, ay, cosf(measured)*1.2f, p2 );
+ v3_muladds( p2, ax, sinf(measured)*1.2f, p2 );
+ vg_line( c, p2, colour );
+}
+
+VG_STATIC void rb_debug_constraint_limits( rigidbody *ra, rigidbody *rb, v3f lca,
+ v3f limits[2] )
+{
+ v3f ax, ay, az, bx, by, bz;
+ m3x3_mulv( ra->to_world, (v3f){1.0f,0.0f,0.0f}, ax );
+ m3x3_mulv( ra->to_world, (v3f){0.0f,1.0f,0.0f}, ay );
+ m3x3_mulv( ra->to_world, (v3f){0.0f,0.0f,1.0f}, az );
+ m3x3_mulv( rb->to_world, (v3f){1.0f,0.0f,0.0f}, bx );
+ m3x3_mulv( rb->to_world, (v3f){0.0f,1.0f,0.0f}, by );
+ m3x3_mulv( rb->to_world, (v3f){0.0f,0.0f,1.0f}, bz );
+
+ v2f px, py, pz;
+ px[0] = v3_dot( ay, by );
+ px[1] = v3_dot( az, by );
+
+ py[0] = v3_dot( az, bz );
+ py[1] = v3_dot( ax, bz );
+
+ pz[0] = v3_dot( ax, bx );
+ pz[1] = v3_dot( ay, bx );
+
+ float r0 = atan2f( px[1], px[0] ),
+ r1 = atan2f( py[1], py[0] ),
+ r2 = atan2f( pz[1], pz[0] );
+
+ v3f c;
+ m4x3_mulv( ra->to_world, lca, c );
+ draw_angle_limit( c, ay, az, limits[0][0], limits[1][0], r0, 0xff0000ff );
+ draw_angle_limit( c, az, ax, limits[0][1], limits[1][1], r1, 0xff00ff00 );
+ draw_angle_limit( c, ax, ay, limits[0][2], limits[1][2], r2, 0xffff0000 );
+}
+
+VG_STATIC void rb_limit_cure( rigidbody *ra, rigidbody *rb, v3f axis, float d )
+{
+ if( d != 0.0f )
+ {
+ float avx = v3_dot( ra->w, axis ) - v3_dot( rb->w, axis );
+ float joint_mass = rb->inv_mass + ra->inv_mass;
+ joint_mass = 1.0f/joint_mass;
+
+ float bias = (k_limit_bias * k_rb_rate) * d,
+ lambda = -(avx + bias) * joint_mass;
+
+ /* Angular velocity */
+ v3f wa, wb;
+ v3_muls( axis, lambda * ra->inv_mass, wa );
+ v3_muls( axis, -lambda * rb->inv_mass, wb );
+
+ v3_add( ra->w, wa, ra->w );
+ v3_add( rb->w, wb, rb->w );
+ }
+}
+
+VG_STATIC void rb_constraint_limits( rigidbody *ra, v3f lca,
+ rigidbody *rb, v3f lcb, v3f limits[2] )
+{
+ v3f ax, ay, az, bx, by, bz;
+ m3x3_mulv( ra->to_world, (v3f){1.0f,0.0f,0.0f}, ax );
+ m3x3_mulv( ra->to_world, (v3f){0.0f,1.0f,0.0f}, ay );
+ m3x3_mulv( ra->to_world, (v3f){0.0f,0.0f,1.0f}, az );
+ m3x3_mulv( rb->to_world, (v3f){1.0f,0.0f,0.0f}, bx );
+ m3x3_mulv( rb->to_world, (v3f){0.0f,1.0f,0.0f}, by );
+ m3x3_mulv( rb->to_world, (v3f){0.0f,0.0f,1.0f}, bz );
+
+ v2f px, py, pz;
+ px[0] = v3_dot( ay, by );
+ px[1] = v3_dot( az, by );
+
+ py[0] = v3_dot( az, bz );
+ py[1] = v3_dot( ax, bz );
+
+ pz[0] = v3_dot( ax, bx );
+ pz[1] = v3_dot( ay, bx );
+
+ float r0 = atan2f( px[1], px[0] ),
+ r1 = atan2f( py[1], py[0] ),
+ r2 = atan2f( pz[1], pz[0] );
+
+ /* calculate angle deltas */
+ float dx = 0.0f, dy = 0.0f, dz = 0.0f;
+
+ if( r0 < limits[0][0] ) dx = limits[0][0] - r0;
+ if( r0 > limits[1][0] ) dx = limits[1][0] - r0;
+ if( r1 < limits[0][1] ) dy = limits[0][1] - r1;
+ if( r1 > limits[1][1] ) dy = limits[1][1] - r1;
+ if( r2 < limits[0][2] ) dz = limits[0][2] - r2;
+ if( r2 > limits[1][2] ) dz = limits[1][2] - r2;
+
+ v3f wca, wcb;
+ m3x3_mulv( ra->to_world, lca, wca );
+ m3x3_mulv( rb->to_world, lcb, wcb );
+
+ rb_limit_cure( ra, rb, ax, dx );
+ rb_limit_cure( ra, rb, ay, dy );
+ rb_limit_cure( ra, rb, az, dz );
+}
+
+VG_STATIC void rb_debug_constraint_position( rigidbody *ra, v3f lca,
+ rigidbody *rb, v3f lcb )
+{
+ v3f wca, wcb;
+ m3x3_mulv( ra->to_world, lca, wca );
+ m3x3_mulv( rb->to_world, lcb, wcb );
+
+ v3f p0, p1;
+ v3_add( wca, ra->co, p0 );
+ v3_add( wcb, rb->co, p1 );
+ vg_line_pt3( p0, 0.005f, 0xffffff00 );
+ vg_line_pt3( p1, 0.005f, 0xffffff00 );
+ vg_line( p0, p1, 0xffffff00 );
+}
+
+VG_STATIC void rb_constraint_position( rigidbody *ra, v3f lca,
+ rigidbody *rb, v3f lcb )
+{
+ /* C = (COa + Ra*LCa) - (COb + Rb*LCb) = 0 */
+ v3f wca, wcb;
+ m3x3_mulv( ra->to_world, lca, wca );
+ m3x3_mulv( rb->to_world, lcb, wcb );
+
+ v3f rcv;
+ v3_sub( ra->v, rb->v, rcv );
+
+ v3f rcv_Ra, rcv_Rb;
+ v3_cross( ra->w, wca, rcv_Ra );
+ v3_cross( rb->w, wcb, rcv_Rb );
+ v3_add( rcv_Ra, rcv, rcv );
+ v3_sub( rcv, rcv_Rb, rcv );
+
+ v3f delta;
+ v3f p0, p1;
+ v3_add( wca, ra->co, p0 );
+ v3_add( wcb, rb->co, p1 );
+ v3_sub( p1, p0, delta );
+
+ float dist2 = v3_length2( delta );
+
+ if( dist2 > 0.00001f )
+ {
+ float dist = sqrtf(dist2);
+ v3_muls( delta, 1.0f/dist, delta );
+
+ float joint_mass = rb->inv_mass + ra->inv_mass;
+
+ v3f raCn, rbCn, raCt, rbCt;
+ v3_cross( wca, delta, raCn );
+ v3_cross( wcb, delta, rbCn );
+
+ /* orient inverse inertia tensors */
+ v3f raCnI, rbCnI;
+ m3x3_mulv( ra->iIw, raCn, raCnI );
+ m3x3_mulv( rb->iIw, rbCn, rbCnI );
+ joint_mass += v3_dot( raCn, raCnI );
+ joint_mass += v3_dot( rbCn, rbCnI );
+ joint_mass = 1.0f/joint_mass;
+
+ float vd = v3_dot( rcv, delta ),
+ bias = -(k_joint_bias * k_rb_rate) * dist,
+ lambda = -(vd + bias) * joint_mass;
+
+ v3f impulse;
+ v3_muls( delta, lambda, impulse );
+ rb_linear_impulse( ra, wca, impulse );
+ v3_muls( delta, -lambda, impulse );
+ rb_linear_impulse( rb, wcb, impulse );
+
+ /* 'fake' snap */
+ v3_muladds( ra->co, delta, dist * k_joint_correction, ra->co );
+ v3_muladds( rb->co, delta, -dist * k_joint_correction, rb->co );
+ }
+}
+
+/*
+ * Effectors
+ */
+
+VG_STATIC void rb_effect_simple_bouyency( rigidbody *ra, v4f plane,
+ float amt, float drag )
+{
+ /* float */
+ float depth = v3_dot( plane, ra->co ) - plane[3],
+ lambda = vg_clampf( -depth, 0.0f, 1.0f ) * amt;
+
+ v3_muladds( ra->v, plane, lambda * k_rb_delta, ra->v );
+
+ if( depth < 0.0f )
+ v3_muls( ra->v, 1.0f-(drag*k_rb_delta), ra->v );
+}
+
+/*
+ * -----------------------------------------------------------------------------
+ * BVH implementation, this is ONLY for VG_STATIC rigidbodies, its to slow for
+ * realtime use.
+ * -----------------------------------------------------------------------------
+ */
+
+VG_STATIC void rb_bh_expand_bound( void *user, boxf bound, u32 item_index )
+{
+ rigidbody *rb = &((rigidbody *)user)[ item_index ];
+ box_concat( bound, rb->bbx_world );
+}
+
+VG_STATIC float rb_bh_centroid( void *user, u32 item_index, int axis )
+{
+ rigidbody *rb = &((rigidbody *)user)[ item_index ];
+ return (rb->bbx_world[axis][0] + rb->bbx_world[1][axis]) * 0.5f;
+}
+
+VG_STATIC void rb_bh_swap( void *user, u32 ia, u32 ib )
+{
+ rigidbody temp, *rba, *rbb;
+ rba = &((rigidbody *)user)[ ia ];
+ rbb = &((rigidbody *)user)[ ib ];
+
+ temp = *rba;
+ *rba = *rbb;
+ *rbb = temp;
+}
+
+VG_STATIC void rb_bh_debug( void *user, u32 item_index )
+{
+ rigidbody *rb = &((rigidbody *)user)[ item_index ];
+ rb_debug( rb, 0xff00ffff );
+}
+
+VG_STATIC bh_system bh_system_rigidbodies =
+{
+ .expand_bound = rb_bh_expand_bound,
+ .item_centroid = rb_bh_centroid,
+ .item_swap = rb_bh_swap,
+ .item_debug = rb_bh_debug,
+ .cast_ray = NULL
+};