+}
+
+/*
+ * -----------------------------------------------------------------------------
+ * Collision matrix
+ * -----------------------------------------------------------------------------
+ */
+
+/*
+ * 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;
+}
+
+__attribute__ ((deprecated))
+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;
+ ct->type = k_contact_type_default;
+
+ 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;
+ ct->type = k_contact_type_default;
+
+ count ++;
+ }
+
+ /*
+ * Debugging
+ */
+
+ if( count == 2 )
+ vg_line( buf[0].co, buf[1].co, 0xff0000ff );
+
+ return count;
+}
+
+VG_STATIC int rb_capsule__manifold_done( m4x3f mtx, rb_capsule *c,
+ capsule_manifold *manifold,
+ rb_ct *buf )
+{
+ v3f p0, p1;
+ v3_muladds( mtx[3], mtx[1], -c->height*0.5f+c->radius, p0 );
+ v3_muladds( mtx[3], mtx[1], c->height*0.5f-c->radius, 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, -c->radius, ct->co );
+
+ ct->p = manifold->r0 - d;
+ ct->type = k_contact_type_default;
+ 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, -c->radius, ct->co );
+
+ ct->p = manifold->r1 - d;
+ ct->type = k_contact_type_default;
+
+ 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;
+ ct->type = k_contact_type_default;
+
+ return 1;
+ }
+
+ return 0;
+}
+
+VG_STATIC int rb_capsule_capsule( rigidbody *rba, rigidbody *rbb, rb_ct *buf )
+{
+ if( !box_overlap( rba->bbx_world, rbb->bbx_world ) )
+ return 0;
+
+ 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->bbx, rbb->to_world, rbb->to_local, 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;
+ ct->type = k_contact_type_default;
+ return 1;
+ }