projects / carveJwlIkooP6JGAAIwe30JlM.git / blob
? search:
summary | shortlog | log | commit | commitdiff | tree
history | raw | HEAD
whole
[carveJwlIkooP6JGAAIwe30JlM.git] / rigidbody.h
1 /*
2 * Resources: Box2D - Erin Catto
3 * qu3e - Randy Gaul
4 */
5
6 #include "common.h"
7 #include "bvh.h"
8 #include "scene.h"
9
10 static void rb_tangent_basis( v3f n, v3f tx, v3f ty );
11 static bh_system bh_system_rigidbodies;
12
13 #ifndef RIGIDBODY_H
14 #define RIGIDBODY_H
15
16 /*
17 * -----------------------------------------------------------------------------
18 * (K)onstants
19 * -----------------------------------------------------------------------------
20 */
21
22 static const float
23 k_rb_rate = 60.0f,
24 k_rb_delta = (1.0f/k_rb_rate),
25 k_friction = 0.6f,
26 k_damp_linear = 0.05f, /* scale velocity 1/(1+x) */
27 k_damp_angular = 0.1f, /* scale angular 1/(1+x) */
28 k_limit_bias = 0.02f,
29 k_joint_bias = 0.08f, /* positional joints */
30 k_joint_correction = 0.01f,
31 k_penetration_slop = 0.01f,
32 k_inertia_scale = 4.0f;
33
34 /*
35 * -----------------------------------------------------------------------------
36 * structure definitions
37 * -----------------------------------------------------------------------------
38 */
39
40 typedef struct rigidbody rigidbody;
41 typedef struct contact rb_ct;
42
43 struct rigidbody
44 {
45 v3f co, v, w;
46 v4f q;
47
48 enum rb_shape
49 {
50 k_rb_shape_box = 0,
51 k_rb_shape_sphere = 1,
52 k_rb_shape_capsule = 2,
53 k_rb_shape_scene = 3
54 }
55 type;
56
57 union
58 {
59 struct rb_sphere
60 {
61 float radius;
62 }
63 sphere;
64
65 struct rb_capsule
66 {
67 float height, radius;
68 }
69 capsule;
70
71 struct rb_scene
72 {
73 scene *pscene;
74 }
75 scene;
76 }
77 inf;
78
79 v3f right, up, forward;
80
81 int is_world;
82
83 boxf bbx, bbx_world;
84 float inv_mass;
85
86 /* inertia model and inverse world tensor */
87 v3f I;
88 m3x3f iI, iIw;
89
90 m4x3f to_world, to_local;
91 };
92
93 static struct contact
94 {
95 rigidbody *rba, *rbb;
96 v3f co, n;
97 v3f t[2];
98 float p, bias, norm_impulse, tangent_impulse[2],
99 normal_mass, tangent_mass[2];
100
101 u32 element_id;
102 }
103 rb_contact_buffer[256];
104 static int rb_contact_count = 0;
105
106 /*
107 * -----------------------------------------------------------------------------
108 * Math Utils
109 * -----------------------------------------------------------------------------
110 */
111
112 static float sphere_volume( float radius )
113 {
114 float r3 = radius*radius*radius;
115 return (4.0f/3.0f) * VG_PIf * r3;
116 }
117
118 static void rb_tangent_basis( v3f n, v3f tx, v3f ty )
119 {
120 /* Compute tangent basis (box2d) */
121 if( fabsf( n[0] ) >= 0.57735027f )
122 {
123 tx[0] = n[1];
124 tx[1] = -n[0];
125 tx[2] = 0.0f;
126 }
127 else
128 {
129 tx[0] = 0.0f;
130 tx[1] = n[2];
131 tx[2] = -n[1];
132 }
133
134 v3_normalize( tx );
135 v3_cross( n, tx, ty );
136 }
137
138 /*
139 * -----------------------------------------------------------------------------
140 * Debugging
141 * -----------------------------------------------------------------------------
142 */
143
144 static void rb_debug_contact( rb_ct *ct )
145 {
146 v3f p1;
147 v3_muladds( ct->co, ct->n, 0.1f, p1 );
148 vg_line_pt3( ct->co, 0.025f, 0xff0000ff );
149 vg_line( ct->co, p1, 0xffffffff );
150 }
151
152 static void debug_sphere( m4x3f m, float radius, u32 colour )
153 {
154 v3f ly = { 0.0f, 0.0f, radius },
155 lx = { 0.0f, radius, 0.0f },
156 lz = { 0.0f, 0.0f, radius };
157
158 for( int i=0; i<16; i++ )
159 {
160 float t = ((float)(i+1) * (1.0f/16.0f)) * VG_PIf * 2.0f,
161 s = sinf(t),
162 c = cosf(t);
163
164 v3f py = { s*radius, 0.0f, c*radius },
165 px = { s*radius, c*radius, 0.0f },
166 pz = { 0.0f, s*radius, c*radius };
167
168 v3f p0, p1, p2, p3, p4, p5;
169 m4x3_mulv( m, py, p0 );
170 m4x3_mulv( m, ly, p1 );
171 m4x3_mulv( m, px, p2 );
172 m4x3_mulv( m, lx, p3 );
173 m4x3_mulv( m, pz, p4 );
174 m4x3_mulv( m, lz, p5 );
175
176 vg_line( p0, p1, colour == 0x00? 0xff00ff00: colour );
177 vg_line( p2, p3, colour == 0x00? 0xff0000ff: colour );
178 vg_line( p4, p5, colour == 0x00? 0xffff0000: colour );
179
180 v3_copy( py, ly );
181 v3_copy( px, lx );
182 v3_copy( pz, lz );
183 }
184 }
185
186 static void debug_capsule( m4x3f m, float radius, float h, u32 colour )
187 {
188 v3f ly = { 0.0f, 0.0f, radius },
189 lx = { 0.0f, radius, 0.0f },
190 lz = { 0.0f, 0.0f, radius };
191
192 float s0 = sinf(0.0f)*radius,
193 c0 = cosf(0.0f)*radius;
194
195 v3f p0, p1, up, right, forward;
196 m3x3_mulv( m, (v3f){0.0f,1.0f,0.0f}, up );
197 m3x3_mulv( m, (v3f){1.0f,0.0f,0.0f}, right );
198 m3x3_mulv( m, (v3f){0.0f,0.0f,-1.0f}, forward );
199 v3_muladds( m[3], up, -h*0.5f+radius, p0 );
200 v3_muladds( m[3], up, h*0.5f-radius, p1 );
201
202 v3f a0, a1, b0, b1;
203 v3_muladds( p0, right, radius, a0 );
204 v3_muladds( p1, right, radius, a1 );
205 v3_muladds( p0, forward, radius, b0 );
206 v3_muladds( p1, forward, radius, b1 );
207 vg_line( a0, a1, colour );
208 vg_line( b0, b1, colour );
209
210 v3_muladds( p0, right, -radius, a0 );
211 v3_muladds( p1, right, -radius, a1 );
212 v3_muladds( p0, forward, -radius, b0 );
213 v3_muladds( p1, forward, -radius, b1 );
214 vg_line( a0, a1, colour );
215 vg_line( b0, b1, colour );
216
217 for( int i=0; i<16; i++ )
218 {
219 float t = ((float)(i+1) * (1.0f/16.0f)) * VG_PIf * 2.0f,
220 s1 = sinf(t)*radius,
221 c1 = cosf(t)*radius;
222
223 v3f e0 = { s0, 0.0f, c0 },
224 e1 = { s1, 0.0f, c1 },
225 e2 = { s0, c0, 0.0f },
226 e3 = { s1, c1, 0.0f },
227 e4 = { 0.0f, c0, s0 },
228 e5 = { 0.0f, c1, s1 };
229
230 m3x3_mulv( m, e0, e0 );
231 m3x3_mulv( m, e1, e1 );
232 m3x3_mulv( m, e2, e2 );
233 m3x3_mulv( m, e3, e3 );
234 m3x3_mulv( m, e4, e4 );
235 m3x3_mulv( m, e5, e5 );
236
237 v3_add( p0, e0, a0 );
238 v3_add( p0, e1, a1 );
239 v3_add( p1, e0, b0 );
240 v3_add( p1, e1, b1 );
241
242 vg_line( a0, a1, colour );
243 vg_line( b0, b1, colour );
244
245 if( c0 < 0.0f )
246 {
247 v3_add( p0, e2, a0 );
248 v3_add( p0, e3, a1 );
249 v3_add( p0, e4, b0 );
250 v3_add( p0, e5, b1 );
251 }
252 else
253 {
254 v3_add( p1, e2, a0 );
255 v3_add( p1, e3, a1 );
256 v3_add( p1, e4, b0 );
257 v3_add( p1, e5, b1 );
258 }
259
260 vg_line( a0, a1, colour );
261 vg_line( b0, b1, colour );
262
263 s0 = s1;
264 c0 = c1;
265 }
266 }
267
268 static void rb_debug( rigidbody *rb, u32 colour )
269 {
270 if( rb->type == k_rb_shape_box )
271 {
272 v3f *box = rb->bbx;
273 vg_line_boxf_transformed( rb->to_world, rb->bbx, colour );
274 }
275 else if( rb->type == k_rb_shape_sphere )
276 {
277 debug_sphere( rb->to_world, rb->inf.sphere.radius, colour );
278 }
279 else if( rb->type == k_rb_shape_capsule )
280 {
281 m4x3f m0, m1;
282 float h = rb->inf.capsule.height,
283 r = rb->inf.capsule.radius;
284
285 debug_capsule( rb->to_world, r, h, colour );
286 }
287 else if( rb->type == k_rb_shape_scene )
288 {
289 vg_line_boxf( rb->bbx, colour );
290 }
291 }
292
293 /*
294 * -----------------------------------------------------------------------------
295 * Integration
296 * -----------------------------------------------------------------------------
297 */
298
299 /*
300 * Update world space bounding box based on local one
301 */
302 static void rb_update_bounds( rigidbody *rb )
303 {
304 box_copy( rb->bbx, rb->bbx_world );
305 m4x3_transform_aabb( rb->to_world, rb->bbx_world );
306 }
307
308 /*
309 * Commit transform to rigidbody. Updates matrices
310 */
311 static void rb_update_transform( rigidbody *rb )
312 {
313 q_normalize( rb->q );
314 q_m3x3( rb->q, rb->to_world );
315 v3_copy( rb->co, rb->to_world[3] );
316
317 m4x3_invert_affine( rb->to_world, rb->to_local );
318
319 m3x3_mulv( rb->to_world, (v3f){1.0f,0.0f, 0.0f}, rb->right );
320 m3x3_mulv( rb->to_world, (v3f){0.0f,1.0f, 0.0f}, rb->up );
321 m3x3_mulv( rb->to_world, (v3f){0.0f,0.0f,-1.0f}, rb->forward );
322
323 m3x3_mul( rb->iI, rb->to_local, rb->iIw );
324 m3x3_mul( rb->to_world, rb->iIw, rb->iIw );
325
326 rb_update_bounds( rb );
327 }
328
329 /*
330 * Initialize rigidbody and calculate masses, inertia
331 */
332 static void rb_init( rigidbody *rb )
333 {
334 float volume = 1.0f;
335
336 if( rb->type == k_rb_shape_box )
337 {
338 v3f dims;
339 v3_sub( rb->bbx[1], rb->bbx[0], dims );
340 volume = dims[0]*dims[1]*dims[2];
341
342 if( !rb->is_world )
343 vg_info( "Box volume: %f\n", volume );
344 }
345 else if( rb->type == k_rb_shape_sphere )
346 {
347 volume = sphere_volume( rb->inf.sphere.radius );
348 v3_fill( rb->bbx[0], -rb->inf.sphere.radius );
349 v3_fill( rb->bbx[1], rb->inf.sphere.radius );
350
351 vg_info( "Sphere volume: %f\n", volume );
352 }
353 else if( rb->type == k_rb_shape_capsule )
354 {
355 float r = rb->inf.capsule.radius,
356 h = rb->inf.capsule.height;
357 volume = sphere_volume( r ) + VG_PIf * r*r * (h - r*2.0f);
358
359 v3_fill( rb->bbx[0], -rb->inf.sphere.radius );
360 v3_fill( rb->bbx[1], rb->inf.sphere.radius );
361 rb->bbx[0][1] = -h;
362 rb->bbx[1][1] = h;
363 }
364 else if( rb->type == k_rb_shape_scene )
365 {
366 rb->is_world = 1;
367 box_copy( rb->inf.scene.pscene->bbx, rb->bbx );
368 }
369
370 if( rb->is_world )
371 {
372 rb->inv_mass = 0.0f;
373 v3_zero( rb->I );
374 m3x3_zero(rb->iI);
375 }
376 else
377 {
378 float mass = 2.0f*volume;
379 rb->inv_mass = 1.0f/mass;
380
381 v3f extent;
382 v3_sub( rb->bbx[1], rb->bbx[0], extent );
383 v3_muls( extent, 0.5f, extent );
384
385 /* local intertia tensor */
386 float scale = k_inertia_scale;
387 float ex2 = scale*extent[0]*extent[0],
388 ey2 = scale*extent[1]*extent[1],
389 ez2 = scale*extent[2]*extent[2];
390
391 rb->I[0] = ((1.0f/12.0f) * mass * (ey2+ez2));
392 rb->I[1] = ((1.0f/12.0f) * mass * (ex2+ez2));
393 rb->I[2] = ((1.0f/12.0f) * mass * (ex2+ey2));
394
395 m3x3_identity( rb->iI );
396 rb->iI[0][0] = rb->I[0];
397 rb->iI[1][1] = rb->I[1];
398 rb->iI[2][2] = rb->I[2];
399 m3x3_inv( rb->iI, rb->iI );
400 }
401
402 v3_zero( rb->v );
403 v3_zero( rb->w );
404
405 rb_update_transform( rb );
406 }
407
408 static void rb_iter( rigidbody *rb )
409 {
410 v3f gravity = { 0.0f, -9.8f, 0.0f };
411 v3_muladds( rb->v, gravity, k_rb_delta, rb->v );
412
413 /* intergrate velocity */
414 v3_muladds( rb->co, rb->v, k_rb_delta, rb->co );
415 v3_lerp( rb->w, (v3f){0.0f,0.0f,0.0f}, 0.0025f, rb->w );
416
417 /* inegrate inertia */
418 if( v3_length2( rb->w ) > 0.0f )
419 {
420 v4f rotation;
421 v3f axis;
422 v3_copy( rb->w, axis );
423
424 float mag = v3_length( axis );
425 v3_divs( axis, mag, axis );
426 q_axis_angle( rotation, axis, mag*k_rb_delta );
427 q_mul( rotation, rb->q, rb->q );
428 }
429
430 /* damping */
431 v3_muls( rb->v, 1.0f/(1.0f+k_rb_delta*k_damp_linear), rb->v );
432 v3_muls( rb->w, 1.0f/(1.0f+k_rb_delta*k_damp_angular), rb->w );
433 }
434
435 /*
436 * -----------------------------------------------------------------------------
437 * Closest point functions
438 * -----------------------------------------------------------------------------
439 */
440
441 /*
442 * These closest point tests were learned from Real-Time Collision Detection by
443 * Christer Ericson
444 */
445 static float closest_segment_segment( v3f p1, v3f q1, v3f p2, v3f q2,
446 float *s, float *t, v3f c1, v3f c2)
447 {
448 v3f d1,d2,r;
449 v3_sub( q1, p1, d1 );
450 v3_sub( q2, p2, d2 );
451 v3_sub( p1, p2, r );
452
453 float a = v3_length2( d1 ),
454 e = v3_length2( d2 ),
455 f = v3_dot( d2, r );
456
457 const float kEpsilon = 0.0001f;
458
459 if( a <= kEpsilon && e <= kEpsilon )
460 {
461 *s = 0.0f;
462 *t = 0.0f;
463 v3_copy( p1, c1 );
464 v3_copy( p2, c2 );
465
466 v3f v0;
467 v3_sub( c1, c2, v0 );
468
469 return v3_length2( v0 );
470 }
471
472 if( a<= kEpsilon )
473 {
474 *s = 0.0f;
475 *t = vg_clampf( f / e, 0.0f, 1.0f );
476 }
477 else
478 {
479 float c = v3_dot( d1, r );
480 if( e <= kEpsilon )
481 {
482 *t = 0.0f;
483 *s = vg_clampf( -c / a, 0.0f, 1.0f );
484 }
485 else
486 {
487 float b = v3_dot(d1,d2),
488 d = a*e-b*b;
489
490 if( d != 0.0f )
491 {
492 *s = vg_clampf((b*f - c*e)/d, 0.0f, 1.0f);
493 }
494 else
495 {
496 *s = 0.0f;
497 }
498
499 *t = (b*(*s)+f) / e;
500
501 if( *t < 0.0f )
502 {
503 *t = 0.0f;
504 *s = vg_clampf( -c / a, 0.0f, 1.0f );
505 }
506 else if( *t > 1.0f )
507 {
508 *t = 1.0f;
509 *s = vg_clampf((b-c)/a,0.0f,1.0f);
510 }
511 }
512 }
513
514 v3_muladds( p1, d1, *s, c1 );
515 v3_muladds( p2, d2, *t, c2 );
516
517 v3f v0;
518 v3_sub( c1, c2, v0 );
519 return v3_length2( v0 );
520 }
521
522 static void closest_point_aabb( v3f p, boxf box, v3f dest )
523 {
524 v3_maxv( p, box[0], dest );
525 v3_minv( dest, box[1], dest );
526 }
527
528 static void closest_point_obb( v3f p, rigidbody *rb, v3f dest )
529 {
530 v3f local;
531 m4x3_mulv( rb->to_local, p, local );
532 closest_point_aabb( local, rb->bbx, local );
533 m4x3_mulv( rb->to_world, local, dest );
534 }
535
536 static float closest_point_segment( v3f a, v3f b, v3f point, v3f dest )
537 {
538 v3f v0, v1;
539 v3_sub( b, a, v0 );
540 v3_sub( point, a, v1 );
541
542 float t = v3_dot( v1, v0 ) / v3_length2(v0);
543 t = vg_clampf(t,0.0f,1.0f);
544 v3_muladds( a, v0, t, dest );
545 return t;
546 }
547
548 static void closest_on_triangle( v3f p, v3f tri[3], v3f dest )
549 {
550 v3f ab, ac, ap;
551 float d1, d2;
552
553 /* Region outside A */
554 v3_sub( tri[1], tri[0], ab );
555 v3_sub( tri[2], tri[0], ac );
556 v3_sub( p, tri[0], ap );
557
558 d1 = v3_dot(ab,ap);
559 d2 = v3_dot(ac,ap);
560 if( d1 <= 0.0f && d2 <= 0.0f )
561 {
562 v3_copy( tri[0], dest );
563 v3_copy( (v3f){INFINITY,INFINITY,INFINITY}, dest );
564 return;
565 }
566
567 /* Region outside B */
568 v3f bp;
569 float d3, d4;
570
571 v3_sub( p, tri[1], bp );
572 d3 = v3_dot( ab, bp );
573 d4 = v3_dot( ac, bp );
574
575 if( d3 >= 0.0f && d4 <= d3 )
576 {
577 v3_copy( tri[1], dest );
578 v3_copy( (v3f){INFINITY,INFINITY,INFINITY}, dest );
579 return;
580 }
581
582 /* Edge region of AB */
583 float vc = d1*d4 - d3*d2;
584 if( vc <= 0.0f && d1 >= 0.0f && d3 <= 0.0f )
585 {
586 float v = d1 / (d1-d3);
587 v3_muladds( tri[0], ab, v, dest );
588 v3_copy( (v3f){INFINITY,INFINITY,INFINITY}, dest );
589 return;
590 }
591
592 /* Region outside C */
593 v3f cp;
594 float d5, d6;
595 v3_sub( p, tri[2], cp );
596 d5 = v3_dot(ab, cp);
597 d6 = v3_dot(ac, cp);
598
599 if( d6 >= 0.0f && d5 <= d6 )
600 {
601 v3_copy( tri[2], dest );
602 v3_copy( (v3f){INFINITY,INFINITY,INFINITY}, dest );
603 return;
604 }
605
606 /* Region of AC */
607 float vb = d5*d2 - d1*d6;
608 if( vb <= 0.0f && d2 >= 0.0f && d6 <= 0.0f )
609 {
610 float w = d2 / (d2-d6);
611 v3_muladds( tri[0], ac, w, dest );
612 v3_copy( (v3f){INFINITY,INFINITY,INFINITY}, dest );
613 return;
614 }
615
616 /* Region of BC */
617 float va = d3*d6 - d5*d4;
618 if( va <= 0.0f && (d4-d3) >= 0.0f && (d5-d6) >= 0.0f )
619 {
620 float w = (d4-d3) / ((d4-d3) + (d5-d6));
621 v3f bc;
622 v3_sub( tri[2], tri[1], bc );
623 v3_muladds( tri[1], bc, w, dest );
624 v3_copy( (v3f){INFINITY,INFINITY,INFINITY}, dest );
625 return;
626 }
627
628 /* P inside region, Q via barycentric coordinates uvw */
629 float d = 1.0f/(va+vb+vc),
630 v = vb*d,
631 w = vc*d;
632
633 v3_muladds( tri[0], ab, v, dest );
634 v3_muladds( dest, ac, w, dest );
635 }
636
637 /* TODO */
638 static void closest_on_triangle_1( v3f p, v3f tri[3], v3f dest )
639 {
640 v3f ab, ac, ap;
641 float d1, d2;
642
643 /* Region outside A */
644 v3_sub( tri[1], tri[0], ab );
645 v3_sub( tri[2], tri[0], ac );
646 v3_sub( p, tri[0], ap );
647
648 d1 = v3_dot(ab,ap);
649 d2 = v3_dot(ac,ap);
650 if( d1 <= 0.0f && d2 <= 0.0f )
651 {
652 v3_copy( tri[0], dest );
653 return;
654 }
655
656 /* Region outside B */
657 v3f bp;
658 float d3, d4;
659
660 v3_sub( p, tri[1], bp );
661 d3 = v3_dot( ab, bp );
662 d4 = v3_dot( ac, bp );
663
664 if( d3 >= 0.0f && d4 <= d3 )
665 {
666 v3_copy( tri[1], dest );
667 return;
668 }
669
670 /* Edge region of AB */
671 float vc = d1*d4 - d3*d2;
672 if( vc <= 0.0f && d1 >= 0.0f && d3 <= 0.0f )
673 {
674 float v = d1 / (d1-d3);
675 v3_muladds( tri[0], ab, v, dest );
676 return;
677 }
678
679 /* Region outside C */
680 v3f cp;
681 float d5, d6;
682 v3_sub( p, tri[2], cp );
683 d5 = v3_dot(ab, cp);
684 d6 = v3_dot(ac, cp);
685
686 if( d6 >= 0.0f && d5 <= d6 )
687 {
688 v3_copy( tri[2], dest );
689 return;
690 }
691
692 /* Region of AC */
693 float vb = d5*d2 - d1*d6;
694 if( vb <= 0.0f && d2 >= 0.0f && d6 <= 0.0f )
695 {
696 float w = d2 / (d2-d6);
697 v3_muladds( tri[0], ac, w, dest );
698 return;
699 }
700
701 /* Region of BC */
702 float va = d3*d6 - d5*d4;
703 if( va <= 0.0f && (d4-d3) >= 0.0f && (d5-d6) >= 0.0f )
704 {
705 float w = (d4-d3) / ((d4-d3) + (d5-d6));
706 v3f bc;
707 v3_sub( tri[2], tri[1], bc );
708 v3_muladds( tri[1], bc, w, dest );
709 return;
710 }
711
712 /* P inside region, Q via barycentric coordinates uvw */
713 float d = 1.0f/(va+vb+vc),
714 v = vb*d,
715 w = vc*d;
716
717 v3_muladds( tri[0], ab, v, dest );
718 v3_muladds( dest, ac, w, dest );
719 }
720
721 /*
722 * -----------------------------------------------------------------------------
723 * Boolean shape overlap functions
724 * -----------------------------------------------------------------------------
725 */
726
727 /*
728 * Project AABB, and triangle interval onto axis to check if they overlap
729 */
730 static int rb_box_triangle_interval( v3f extent, v3f axis, v3f tri[3] )
731 {
732 float
733
734 r = extent[0] * fabsf(axis[0]) +
735 extent[1] * fabsf(axis[1]) +
736 extent[2] * fabsf(axis[2]),
737
738 p0 = v3_dot( axis, tri[0] ),
739 p1 = v3_dot( axis, tri[1] ),
740 p2 = v3_dot( axis, tri[2] ),
741
742 e = vg_maxf(-vg_maxf(p0,vg_maxf(p1,p2)), vg_minf(p0,vg_minf(p1,p2)));
743
744 if( e > r ) return 0;
745 else return 1;
746 }
747
748 /*
749 * Seperating axis test box vs triangle
750 */
751 static int rb_box_triangle_sat( rigidbody *rba, v3f tri_src[3] )
752 {
753 v3f tri[3];
754
755 v3f extent, c;
756 v3_sub( rba->bbx[1], rba->bbx[0], extent );
757 v3_muls( extent, 0.5f, extent );
758 v3_add( rba->bbx[0], extent, c );
759
760 for( int i=0; i<3; i++ )
761 {
762 m4x3_mulv( rba->to_local, tri_src[i], tri[i] );
763 v3_sub( tri[i], c, tri[i] );
764 }
765
766 /* u0, u1, u2 */
767 if(!rb_box_triangle_interval( extent, (v3f){1.0f,0.0f,0.0f}, tri )) return 0;
768 if(!rb_box_triangle_interval( extent, (v3f){0.0f,1.0f,0.0f}, tri )) return 0;
769 if(!rb_box_triangle_interval( extent, (v3f){0.0f,0.0f,1.0f}, tri )) return 0;
770
771 v3f v0,v1,v2,n, e0,e1,e2;
772 v3_sub( tri[1], tri[0], v0 );
773 v3_sub( tri[2], tri[0], v1 );
774 v3_sub( tri[2], tri[1], v2 );
775 v3_normalize( v0 );
776 v3_normalize( v1 );
777 v3_normalize( v2 );
778 v3_cross( v0, v1, n );
779 v3_cross( v0, n, e0 );
780 v3_cross( n, v1, e1 );
781 v3_cross( v2, n, e2 );
782
783 /* normal */
784 if(!rb_box_triangle_interval( extent, n, tri )) return 0;
785
786 v3f axis[9];
787 v3_cross( e0, (v3f){1.0f,0.0f,0.0f}, axis[0] );
788 v3_cross( e0, (v3f){0.0f,1.0f,0.0f}, axis[1] );
789 v3_cross( e0, (v3f){0.0f,0.0f,1.0f}, axis[2] );
790 v3_cross( e1, (v3f){1.0f,0.0f,0.0f}, axis[3] );
791 v3_cross( e1, (v3f){0.0f,1.0f,0.0f}, axis[4] );
792 v3_cross( e1, (v3f){0.0f,0.0f,1.0f}, axis[5] );
793 v3_cross( e2, (v3f){1.0f,0.0f,0.0f}, axis[6] );
794 v3_cross( e2, (v3f){0.0f,1.0f,0.0f}, axis[7] );
795 v3_cross( e2, (v3f){0.0f,0.0f,1.0f}, axis[8] );
796
797 for( int i=0; i<9; i++ )
798 if(!rb_box_triangle_interval( extent, axis[i], tri )) return 0;
799
800 return 1;
801 }
802
803 /*
804 * -----------------------------------------------------------------------------
805 * Collision matrix
806 * -----------------------------------------------------------------------------
807 */
808
809 /*
810 * Contact generators
811 *
812 * These do not automatically allocate contacts, an appropriately sized
813 * buffer must be supplied. The function returns the size of the manifold
814 * which was generated.
815 *
816 * The values set on the contacts are: n, co, p, rba, rbb
817 */
818
819 /*
820 * By collecting the minimum(time) and maximum(time) pairs of points, we
821 * build a reduced and stable exact manifold.
822 *
823 * tx: time at point
824 * rx: minimum distance of these points
825 * dx: the delta between the two points
826 *
827 * pairs will only ammend these if they are creating a collision
828 */
829 typedef struct capsule_manifold capsule_manifold;
830 struct capsule_manifold
831 {
832 float t0, t1;
833 float r0, r1;
834 v3f d0, d1;
835 };
836
837 /*
838 * Expand a line manifold with a new pair. t value is the time along segment
839 * on the oriented object which created this pair.
840 */
841 static void rb_capsule_manifold( v3f pa, v3f pb, float t, float r,
842 capsule_manifold *manifold )
843 {
844 v3f delta;
845 v3_sub( pa, pb, delta );
846
847 if( v3_length2(delta) < r*r )
848 {
849 if( t < manifold->t0 )
850 {
851 v3_copy( delta, manifold->d0 );
852 manifold->t0 = t;
853 manifold->r0 = r;
854 }
855
856 if( t > manifold->t1 )
857 {
858 v3_copy( delta, manifold->d1 );
859 manifold->t1 = t;
860 manifold->r1 = r;
861 }
862 }
863 }
864
865 static void rb_capsule_manifold_init( capsule_manifold *manifold )
866 {
867 manifold->t0 = INFINITY;
868 manifold->t1 = -INFINITY;
869 }
870
871 static int rb_capsule_manifold_done( rigidbody *rba, rigidbody *rbb,
872 capsule_manifold *manifold, rb_ct *buf )
873 {
874 float h = rba->inf.capsule.height,
875 ra = rba->inf.capsule.radius;
876
877 v3f p0, p1;
878 v3_muladds( rba->co, rba->up, -h*0.5f+ra, p0 );
879 v3_muladds( rba->co, rba->up, h*0.5f-ra, p1 );
880
881 int count = 0;
882 if( manifold->t0 <= 1.0f )
883 {
884 rb_ct *ct = buf;
885
886 v3f pa;
887 v3_muls( p0, 1.0f-manifold->t0, pa );
888 v3_muladds( pa, p1, manifold->t0, pa );
889
890 float d = v3_length( manifold->d0 );
891 v3_muls( manifold->d0, 1.0f/d, ct->n );
892 v3_muladds( pa, ct->n, -ra, ct->co );
893
894 ct->p = manifold->r0 - d;
895 ct->rba = rba;
896 ct->rbb = rbb;
897
898 count ++;
899 }
900
901 if( (manifold->t1 >= 0.0f) && (manifold->t0 != manifold->t1) )
902 {
903 rb_ct *ct = buf+count;
904
905 v3f pa;
906 v3_muls( p0, 1.0f-manifold->t1, pa );
907 v3_muladds( pa, p1, manifold->t1, pa );
908
909 float d = v3_length( manifold->d1 );
910 v3_muls( manifold->d1, 1.0f/d, ct->n );
911 v3_muladds( pa, ct->n, -ra, ct->co );
912
913 ct->p = manifold->r1 - d;
914 ct->rba = rba;
915 ct->rbb = rbb;
916
917 count ++;
918 }
919
920 /*
921 * Debugging
922 */
923
924 if( count == 2 )
925 vg_line( buf[0].co, buf[1].co, 0xff0000ff );
926
927 return count;
928 }
929
930 static int rb_capsule_sphere( rigidbody *rba, rigidbody *rbb, rb_ct *buf )
931 {
932 float h = rba->inf.capsule.height,
933 ra = rba->inf.capsule.radius,
934 rb = rbb->inf.sphere.radius;
935
936 v3f p0, p1;
937 v3_muladds( rba->co, rba->up, -h*0.5f+ra, p0 );
938 v3_muladds( rba->co, rba->up, h*0.5f-ra, p1 );
939
940 v3f c, delta;
941 closest_point_segment( p0, p1, rbb->co, c );
942 v3_sub( c, rbb->co, delta );
943
944 float d2 = v3_length2(delta),
945 r = ra + rb;
946
947 if( d2 < r*r )
948 {
949 float d = sqrtf(d2);
950
951 rb_ct *ct = buf;
952 v3_muls( delta, 1.0f/d, ct->n );
953 ct->p = r-d;
954
955 v3f p0, p1;
956 v3_muladds( c, ct->n, -ra, p0 );
957 v3_muladds( rbb->co, ct->n, rb, p1 );
958 v3_add( p0, p1, ct->co );
959 v3_muls( ct->co, 0.5f, ct->co );
960
961 ct->rba = rba;
962 ct->rbb = rbb;
963
964 return 1;
965 }
966
967 return 0;
968 }
969
970 static int rb_capsule_capsule( rigidbody *rba, rigidbody *rbb, rb_ct *buf )
971 {
972 float ha = rba->inf.capsule.height,
973 hb = rbb->inf.capsule.height,
974 ra = rba->inf.capsule.radius,
975 rb = rbb->inf.capsule.radius,
976 r = ra+rb;
977
978 v3f p0, p1, p2, p3;
979 v3_muladds( rba->co, rba->up, -ha*0.5f+ra, p0 );
980 v3_muladds( rba->co, rba->up, ha*0.5f-ra, p1 );
981 v3_muladds( rbb->co, rbb->up, -hb*0.5f+rb, p2 );
982 v3_muladds( rbb->co, rbb->up, hb*0.5f-rb, p3 );
983
984 capsule_manifold manifold;
985 rb_capsule_manifold_init( &manifold );
986
987 v3f pa, pb;
988 float ta, tb;
989 closest_segment_segment( p0, p1, p2, p3, &ta, &tb, pa, pb );
990 rb_capsule_manifold( pa, pb, ta, r, &manifold );
991
992 ta = closest_point_segment( p0, p1, p2, pa );
993 tb = closest_point_segment( p0, p1, p3, pb );
994 rb_capsule_manifold( pa, p2, ta, r, &manifold );
995 rb_capsule_manifold( pb, p3, tb, r, &manifold );
996
997 closest_point_segment( p2, p3, p0, pa );
998 closest_point_segment( p2, p3, p1, pb );
999 rb_capsule_manifold( p0, pa, 0.0f, r, &manifold );
1000 rb_capsule_manifold( p1, pb, 1.0f, r, &manifold );
1001
1002 return rb_capsule_manifold_done( rba, rbb, &manifold, buf );
1003 }
1004
1005 /*
1006 * Generates up to two contacts; optimised for the most stable manifold
1007 */
1008 static int rb_capsule_box( rigidbody *rba, rigidbody *rbb, rb_ct *buf )
1009 {
1010 float h = rba->inf.capsule.height,
1011 r = rba->inf.capsule.radius;
1012
1013 /*
1014 * Solving this in symetric local space of the cube saves us some time and a
1015 * couple branches when it comes to the quad stage.
1016 */
1017 v3f centroid;
1018 v3_add( rbb->bbx[0], rbb->bbx[1], centroid );
1019 v3_muls( centroid, 0.5f, centroid );
1020
1021 boxf bbx;
1022 v3_sub( rbb->bbx[0], centroid, bbx[0] );
1023 v3_sub( rbb->bbx[1], centroid, bbx[1] );
1024
1025 v3f pc, p0w, p1w, p0, p1;
1026 v3_muladds( rba->co, rba->up, -h*0.5f+r, p0w );
1027 v3_muladds( rba->co, rba->up, h*0.5f-r, p1w );
1028
1029 m4x3_mulv( rbb->to_local, p0w, p0 );
1030 m4x3_mulv( rbb->to_local, p1w, p1 );
1031 v3_sub( p0, centroid, p0 );
1032 v3_sub( p1, centroid, p1 );
1033 v3_add( p0, p1, pc );
1034 v3_muls( pc, 0.5f, pc );
1035
1036 /*
1037 * Finding an appropriate quad to collide lines with
1038 */
1039 v3f region;
1040 v3_div( pc, bbx[1], region );
1041
1042 v3f quad[4];
1043 if( (fabsf(region[0]) > fabsf(region[1])) &&
1044 (fabsf(region[0]) > fabsf(region[2])) )
1045 {
1046 float px = vg_signf(region[0]) * bbx[1][0];
1047 v3_copy( (v3f){ px, bbx[0][1], bbx[0][2] }, quad[0] );
1048 v3_copy( (v3f){ px, bbx[1][1], bbx[0][2] }, quad[1] );
1049 v3_copy( (v3f){ px, bbx[1][1], bbx[1][2] }, quad[2] );
1050 v3_copy( (v3f){ px, bbx[0][1], bbx[1][2] }, quad[3] );
1051 }
1052 else if( fabsf(region[1]) > fabsf(region[2]) )
1053 {
1054 float py = vg_signf(region[1]) * bbx[1][1];
1055 v3_copy( (v3f){ bbx[0][0], py, bbx[0][2] }, quad[0] );
1056 v3_copy( (v3f){ bbx[1][0], py, bbx[0][2] }, quad[1] );
1057 v3_copy( (v3f){ bbx[1][0], py, bbx[1][2] }, quad[2] );
1058 v3_copy( (v3f){ bbx[0][0], py, bbx[1][2] }, quad[3] );
1059 }
1060 else
1061 {
1062 float pz = vg_signf(region[2]) * bbx[1][2];
1063 v3_copy( (v3f){ bbx[0][0], bbx[0][1], pz }, quad[0] );
1064 v3_copy( (v3f){ bbx[1][0], bbx[0][1], pz }, quad[1] );
1065 v3_copy( (v3f){ bbx[1][0], bbx[1][1], pz }, quad[2] );
1066 v3_copy( (v3f){ bbx[0][0], bbx[1][1], pz }, quad[3] );
1067 }
1068
1069 capsule_manifold manifold;
1070 rb_capsule_manifold_init( &manifold );
1071
1072 v3f c0, c1;
1073 closest_point_aabb( p0, bbx, c0 );
1074 closest_point_aabb( p1, bbx, c1 );
1075
1076 v3f d0, d1, da;
1077 v3_sub( c0, p0, d0 );
1078 v3_sub( c1, p1, d1 );
1079 v3_sub( p1, p0, da );
1080
1081 /* TODO: ? */
1082 v3_normalize(d0);
1083 v3_normalize(d1);
1084 v3_normalize(da);
1085
1086 if( v3_dot( da, d0 ) <= 0.01f )
1087 rb_capsule_manifold( p0, c0, 0.0f, r, &manifold );
1088
1089 if( v3_dot( da, d1 ) >= -0.01f )
1090 rb_capsule_manifold( p1, c1, 1.0f, r, &manifold );
1091
1092 for( int i=0; i<4; i++ )
1093 {
1094 int i0 = i,
1095 i1 = (i+1)%4;
1096
1097 v3f ca, cb;
1098 float ta, tb;
1099 closest_segment_segment( p0, p1, quad[i0], quad[i1], &ta, &tb, ca, cb );
1100 rb_capsule_manifold( ca, cb, ta, r, &manifold );
1101 }
1102
1103 /*
1104 * Create final contacts based on line manifold
1105 */
1106 m3x3_mulv( rbb->to_world, manifold.d0, manifold.d0 );
1107 m3x3_mulv( rbb->to_world, manifold.d1, manifold.d1 );
1108
1109 /*
1110 * Debugging
1111 */
1112
1113 #if 0
1114 for( int i=0; i<4; i++ )
1115 {
1116 v3f q0, q1;
1117 int i0 = i,
1118 i1 = (i+1)%4;
1119
1120 v3_add( quad[i0], centroid, q0 );
1121 v3_add( quad[i1], centroid, q1 );
1122
1123 m4x3_mulv( rbb->to_world, q0, q0 );
1124 m4x3_mulv( rbb->to_world, q1, q1 );
1125
1126 vg_line( q0, q1, 0xffffffff );
1127 }
1128 #endif
1129
1130 return rb_capsule_manifold_done( rba, rbb, &manifold, buf );
1131 }
1132
1133 static int rb_sphere_box( rigidbody *rba, rigidbody *rbb, rb_ct *buf )
1134 {
1135 v3f co, delta;
1136
1137 closest_point_obb( rba->co, rbb, co );
1138 v3_sub( rba->co, co, delta );
1139
1140 float d2 = v3_length2(delta),
1141 r = rba->inf.sphere.radius;
1142
1143 if( d2 <= r*r )
1144 {
1145 float d;
1146
1147 rb_ct *ct = buf;
1148 if( d2 <= 0.0001f )
1149 {
1150 v3_sub( rba->co, rbb->co, delta );
1151
1152 /*
1153 * some extra testing is required to find the best axis to push the
1154 * object back outside the box. Since there isnt a clear seperating
1155 * vector already, especially on really high aspect boxes.
1156 */
1157 float lx = v3_dot( rbb->right, delta ),
1158 ly = v3_dot( rbb->up, delta ),
1159 lz = v3_dot( rbb->forward, delta ),
1160 px = rbb->bbx[1][0] - fabsf(lx),
1161 py = rbb->bbx[1][1] - fabsf(ly),
1162 pz = rbb->bbx[1][2] - fabsf(lz);
1163
1164 if( px < py && px < pz )
1165 v3_muls( rbb->right, vg_signf(lx), ct->n );
1166 else if( py < pz )
1167 v3_muls( rbb->up, vg_signf(ly), ct->n );
1168 else
1169 v3_muls( rbb->forward, vg_signf(lz), ct->n );
1170
1171 v3_muladds( rba->co, ct->n, -r, ct->co );
1172 ct->p = r;
1173 }
1174 else
1175 {
1176 d = sqrtf(d2);
1177 v3_muls( delta, 1.0f/d, ct->n );
1178 ct->p = r-d;
1179 v3_copy( co, ct->co );
1180 }
1181
1182 ct->rba = rba;
1183 ct->rbb = rbb;
1184 return 1;
1185 }
1186
1187 return 0;
1188 }
1189
1190 static int rb_sphere_sphere( rigidbody *rba, rigidbody *rbb, rb_ct *buf )
1191 {
1192 v3f delta;
1193 v3_sub( rba->co, rbb->co, delta );
1194
1195 float d2 = v3_length2(delta),
1196 r = rba->inf.sphere.radius + rbb->inf.sphere.radius;
1197
1198 if( d2 < r*r )
1199 {
1200 float d = sqrtf(d2);
1201
1202 rb_ct *ct = buf;
1203 v3_muls( delta, 1.0f/d, ct->n );
1204
1205 v3f p0, p1;
1206 v3_muladds( rba->co, ct->n,-rba->inf.sphere.radius, p0 );
1207 v3_muladds( rbb->co, ct->n, rbb->inf.sphere.radius, p1 );
1208 v3_add( p0, p1, ct->co );
1209 v3_muls( ct->co, 0.5f, ct->co );
1210 ct->p = r-d;
1211 ct->rba = rba;
1212 ct->rbb = rbb;
1213 return 1;
1214 }
1215
1216 return 0;
1217 }
1218
1219 static int rb_sphere_triangle( rigidbody *rba, rigidbody *rbb,
1220 v3f tri[3], rb_ct *buf )
1221 {
1222 v3f delta, co;
1223
1224 closest_on_triangle( rba->co, tri, co );
1225 v3_sub( rba->co, co, delta );
1226
1227 vg_line( rba->co, co, 0xffff0000 );
1228 vg_line_pt3( rba->co, 0.1f, 0xff00ffff );
1229
1230 float d2 = v3_length2( delta ),
1231 r = rba->inf.sphere.radius;
1232
1233 if( d2 < r*r )
1234 {
1235 rb_ct *ct = buf;
1236
1237 v3f ab, ac, tn;
1238 v3_sub( tri[2], tri[0], ab );
1239 v3_sub( tri[1], tri[0], ac );
1240 v3_cross( ac, ab, tn );
1241 v3_copy( tn, ct->n );
1242 v3_normalize( ct->n );
1243
1244 float d = sqrtf(d2);
1245
1246 v3_copy( co, ct->co );
1247 ct->p = r-d;
1248 ct->rba = rba;
1249 ct->rbb = rbb;
1250 return 1;
1251 }
1252
1253 return 0;
1254 }
1255
1256 static int rb_sphere_scene( rigidbody *rba, rigidbody *rbb, rb_ct *buf )
1257 {
1258 scene *sc = rbb->inf.scene.pscene;
1259
1260 u32 geo[128];
1261 v3f tri[3];
1262 int len = bh_select( &sc->bhtris, rba->bbx_world, geo, 128 );
1263
1264 int count = 0;
1265
1266 for( int i=0; i<len; i++ )
1267 {
1268 u32 *ptri = &sc->indices[ geo[i]*3 ];
1269
1270 for( int j=0; j<3; j++ )
1271 v3_copy( sc->verts[ptri[j]].co, tri[j] );
1272
1273 vg_line(tri[0],tri[1],0xff00ff00 );
1274 vg_line(tri[1],tri[2],0xff00ff00 );
1275 vg_line(tri[2],tri[0],0xff00ff00 );
1276
1277 buf[count].element_id = ptri[0];
1278 count += rb_sphere_triangle( rba, rbb, tri, buf+count );
1279
1280 if( count == 12 )
1281 {
1282 vg_warn( "Exceeding sphere_vs_scene capacity. Geometry too dense!\n" );
1283 return count;
1284 }
1285 }
1286
1287 return count;
1288 }
1289
1290 static int rb_box_scene( rigidbody *rba, rigidbody *rbb, rb_ct *buf )
1291 {
1292 scene *sc = rbb->inf.scene.pscene;
1293
1294 u32 geo[128];
1295 v3f tri[3];
1296 int len = bh_select( &sc->bhtris, rba->bbx_world, geo, 128 );
1297
1298 int count = 0;
1299
1300 for( int i=0; i<len; i++ )
1301 {
1302 u32 *ptri = &sc->indices[ geo[i]*3 ];
1303
1304 for( int j=0; j<3; j++ )
1305 v3_copy( sc->verts[ptri[j]].co, tri[j] );
1306
1307 if( rb_box_triangle_sat( rba, tri ) )
1308 {
1309 vg_line(tri[0],tri[1],0xff50ff00 );
1310 vg_line(tri[1],tri[2],0xff50ff00 );
1311 vg_line(tri[2],tri[0],0xff50ff00 );
1312 }
1313 else
1314 {
1315 vg_line(tri[0],tri[1],0xff0000ff );
1316 vg_line(tri[1],tri[2],0xff0000ff );
1317 vg_line(tri[2],tri[0],0xff0000ff );
1318
1319 continue;
1320 }
1321
1322 v3f v0,v1,n;
1323 v3_sub( tri[1], tri[0], v0 );
1324 v3_sub( tri[2], tri[0], v1 );
1325 v3_cross( v0, v1, n );
1326 v3_normalize( n );
1327
1328 /* find best feature */
1329 float best = v3_dot( rba->right, n );
1330 int axis = 0;
1331
1332 float cy = v3_dot( rba->up, n );
1333 if( fabsf(cy) > fabsf(best) )
1334 {
1335 best = cy;
1336 axis = 1;
1337 }
1338
1339 /* TODO: THIS IS WRONG DIRECTION */
1340 float cz = -v3_dot( rba->forward, n );
1341 if( fabsf(cz) > fabsf(best) )
1342 {
1343 best = cz;
1344 axis = 2;
1345 }
1346
1347 v3f manifold[4];
1348
1349 if( axis == 0 )
1350 {
1351 float px = best > 0.0f? rba->bbx[0][0]: rba->bbx[1][0];
1352 manifold[0][0] = px;
1353 manifold[0][1] = rba->bbx[0][1];
1354 manifold[0][2] = rba->bbx[0][2];
1355 manifold[1][0] = px;
1356 manifold[1][1] = rba->bbx[1][1];
1357 manifold[1][2] = rba->bbx[0][2];
1358 manifold[2][0] = px;
1359 manifold[2][1] = rba->bbx[1][1];
1360 manifold[2][2] = rba->bbx[1][2];
1361 manifold[3][0] = px;
1362 manifold[3][1] = rba->bbx[0][1];
1363 manifold[3][2] = rba->bbx[1][2];
1364 }
1365 else if( axis == 1 )
1366 {
1367 float py = best > 0.0f? rba->bbx[0][1]: rba->bbx[1][1];
1368 manifold[0][0] = rba->bbx[0][0];
1369 manifold[0][1] = py;
1370 manifold[0][2] = rba->bbx[0][2];
1371 manifold[1][0] = rba->bbx[1][0];
1372 manifold[1][1] = py;
1373 manifold[1][2] = rba->bbx[0][2];
1374 manifold[2][0] = rba->bbx[1][0];
1375 manifold[2][1] = py;
1376 manifold[2][2] = rba->bbx[1][2];
1377 manifold[3][0] = rba->bbx[0][0];
1378 manifold[3][1] = py;
1379 manifold[3][2] = rba->bbx[1][2];
1380 }
1381 else
1382 {
1383 float pz = best > 0.0f? rba->bbx[0][2]: rba->bbx[1][2];
1384 manifold[0][0] = rba->bbx[0][0];
1385 manifold[0][1] = rba->bbx[0][1];
1386 manifold[0][2] = pz;
1387 manifold[1][0] = rba->bbx[1][0];
1388 manifold[1][1] = rba->bbx[0][1];
1389 manifold[1][2] = pz;
1390 manifold[2][0] = rba->bbx[1][0];
1391 manifold[2][1] = rba->bbx[1][1];
1392 manifold[2][2] = pz;
1393 manifold[3][0] = rba->bbx[0][0];
1394 manifold[3][1] = rba->bbx[1][1];
1395 manifold[3][2] = pz;
1396 }
1397
1398 for( int j=0; j<4; j++ )
1399 m4x3_mulv( rba->to_world, manifold[j], manifold[j] );
1400
1401 vg_line( manifold[0], manifold[1], 0xffffffff );
1402 vg_line( manifold[1], manifold[2], 0xffffffff );
1403 vg_line( manifold[2], manifold[3], 0xffffffff );
1404 vg_line( manifold[3], manifold[0], 0xffffffff );
1405
1406 for( int j=0; j<4; j++ )
1407 {
1408 rb_ct *ct = buf+count;
1409
1410 v3_copy( manifold[j], ct->co );
1411 v3_copy( n, ct->n );
1412
1413 float l0 = v3_dot( tri[0], n ),
1414 l1 = v3_dot( manifold[j], n );
1415
1416 ct->p = (l0-l1)*0.5f;
1417 if( ct->p < 0.0f )
1418 continue;
1419
1420 ct->rba = rba;
1421 ct->rbb = rbb;
1422 count ++;
1423
1424 if( count >= 12 )
1425 return count;
1426 }
1427 }
1428 return count;
1429 }
1430
1431 static int RB_MATRIX_ERROR( rigidbody *rba, rigidbody *rbb, rb_ct *buf )
1432 {
1433 vg_error( "Collision type is unimplemented between types %d and %d\n",
1434 rba->type, rbb->type );
1435
1436 return 0;
1437 }
1438
1439 static int rb_sphere_capsule( rigidbody *rba, rigidbody *rbb, rb_ct *buf )
1440 {
1441 return rb_capsule_sphere( rbb, rba, buf );
1442 }
1443
1444 static int rb_box_capsule( rigidbody *rba, rigidbody *rbb, rb_ct *buf )
1445 {
1446 return rb_capsule_box( rbb, rba, buf );
1447 }
1448
1449 static int rb_box_sphere( rigidbody *rba, rigidbody *rbb, rb_ct *buf )
1450 {
1451 return rb_sphere_box( rbb, rba, buf );
1452 }
1453
1454 static int rb_scene_box( rigidbody *rba, rigidbody *rbb, rb_ct *buf )
1455 {
1456 return rb_box_scene( rbb, rba, buf );
1457 }
1458
1459 static int (*rb_jump_table[4][4])( rigidbody *a, rigidbody *b, rb_ct *buf ) =
1460 {
1461 /* box */ /* Sphere */ /* Capsule */ /* Mesh */
1462 { RB_MATRIX_ERROR, rb_box_sphere, rb_box_capsule, rb_box_scene },
1463 { rb_sphere_box, rb_sphere_sphere, rb_sphere_capsule, rb_sphere_scene },
1464 { rb_capsule_box, rb_capsule_sphere, rb_capsule_capsule, RB_MATRIX_ERROR },
1465 { rb_scene_box, RB_MATRIX_ERROR, RB_MATRIX_ERROR, RB_MATRIX_ERROR }
1466 };
1467
1468 static int rb_collide( rigidbody *rba, rigidbody *rbb )
1469 {
1470 int (*collider_jump)(rigidbody *rba, rigidbody *rbb, rb_ct *buf )
1471 = rb_jump_table[rba->type][rbb->type];
1472
1473 /*
1474 * 12 is the maximum manifold size we can generate, so we are forced to abort
1475 * potentially checking any more.
1476 */
1477 if( rb_contact_count + 12 > vg_list_size(rb_contact_buffer) )
1478 {
1479 vg_warn( "Too many contacts made in global collider buffer (%d of %d\n)",
1480 rb_contact_count, vg_list_size(rb_contact_buffer) );
1481 return 0;
1482 }
1483
1484 /*
1485 * TODO: Replace this with a more dedicated broad phase pass
1486 */
1487 if( box_overlap( rba->bbx_world, rbb->bbx_world ) )
1488 {
1489 int count = collider_jump( rba, rbb, rb_contact_buffer+rb_contact_count);
1490 rb_contact_count += count;
1491 return count;
1492 }
1493 else
1494 return 0;
1495 }
1496
1497 /*
1498 * -----------------------------------------------------------------------------
1499 * Dynamics
1500 * -----------------------------------------------------------------------------
1501 */
1502
1503 static void rb_solver_reset(void)
1504 {
1505 rb_contact_count = 0;
1506 }
1507
1508 static rb_ct *rb_global_ct(void)
1509 {
1510 return rb_contact_buffer + rb_contact_count;
1511 }
1512
1513 /*
1514 * Initializing things like tangent vectors
1515 */
1516 static void rb_presolve_contacts( rb_ct *buffer, int len )
1517 {
1518 for( int i=0; i<len; i++ )
1519 {
1520 rb_ct *ct = &buffer[i];
1521 ct->bias = -0.2f * k_rb_rate * vg_minf( 0.0f, -ct->p+k_penetration_slop );
1522 rb_tangent_basis( ct->n, ct->t[0], ct->t[1] );
1523
1524 ct->norm_impulse = 0.0f;
1525 ct->tangent_impulse[0] = 0.0f;
1526 ct->tangent_impulse[1] = 0.0f;
1527
1528 v3f ra, rb, raCn, rbCn, raCt, rbCt;
1529 v3_sub( ct->co, ct->rba->co, ra );
1530 v3_sub( ct->co, ct->rbb->co, rb );
1531 v3_cross( ra, ct->n, raCn );
1532 v3_cross( rb, ct->n, rbCn );
1533
1534 /* orient inverse inertia tensors */
1535 v3f raCnI, rbCnI;
1536 m3x3_mulv( ct->rba->iIw, raCn, raCnI );
1537 m3x3_mulv( ct->rbb->iIw, rbCn, rbCnI );
1538
1539 ct->normal_mass = ct->rba->inv_mass + ct->rbb->inv_mass;
1540 ct->normal_mass += v3_dot( raCn, raCnI );
1541 ct->normal_mass += v3_dot( rbCn, rbCnI );
1542 ct->normal_mass = 1.0f/ct->normal_mass;
1543
1544 for( int j=0; j<2; j++ )
1545 {
1546 v3f raCtI, rbCtI;
1547 v3_cross( ct->t[j], ra, raCt );
1548 v3_cross( ct->t[j], rb, rbCt );
1549 m3x3_mulv( ct->rba->iIw, raCt, raCtI );
1550 m3x3_mulv( ct->rbb->iIw, rbCt, rbCtI );
1551
1552 ct->tangent_mass[j] = ct->rba->inv_mass + ct->rbb->inv_mass;
1553 ct->tangent_mass[j] += v3_dot( raCt, raCtI );
1554 ct->tangent_mass[j] += v3_dot( rbCt, rbCtI );
1555 ct->tangent_mass[j] = 1.0f/ct->tangent_mass[j];
1556 }
1557
1558 rb_debug_contact( ct );
1559 }
1560 }
1561
1562 /*
1563 * Creates relative contact velocity vector, and offsets between each body
1564 */
1565 static void rb_rcv( rb_ct *ct, v3f rv, v3f da, v3f db )
1566 {
1567 rigidbody *rba = ct->rba,
1568 *rbb = ct->rbb;
1569
1570 v3_sub( ct->co, rba->co, da );
1571 v3_sub( ct->co, rbb->co, db );
1572
1573 v3f rva, rvb;
1574 v3_cross( rba->w, da, rva );
1575 v3_add( rba->v, rva, rva );
1576 v3_cross( rbb->w, db, rvb );
1577 v3_add( rbb->v, rvb, rvb );
1578
1579 v3_sub( rva, rvb, rv );
1580 }
1581
1582 /*
1583 * Apply impulse to object
1584 */
1585 static void rb_linear_impulse( rigidbody *rb, v3f delta, v3f impulse )
1586 {
1587 /* linear */
1588 v3_muladds( rb->v, impulse, rb->inv_mass, rb->v );
1589
1590 /* Angular velocity */
1591 v3f wa;
1592 v3_cross( delta, impulse, wa );
1593
1594 m3x3_mulv( rb->iIw, wa, wa );
1595 v3_add( rb->w, wa, rb->w );
1596 }
1597
1598 /*
1599 * One iteration to solve the contact constraint
1600 */
1601 static void rb_solve_contacts( rb_ct *buf, int len )
1602 {
1603 for( int i=0; i<len; i++ )
1604 {
1605 struct contact *ct = &buf[i];
1606 rigidbody *rb = ct->rba;
1607
1608 v3f rv, da, db;
1609 rb_rcv( ct, rv, da, db );
1610
1611 /* Friction */
1612 for( int j=0; j<2; j++ )
1613 {
1614 float f = k_friction * ct->norm_impulse,
1615 vt = v3_dot( rv, ct->t[j] ),
1616 lambda = ct->tangent_mass[j] * -vt;
1617
1618 float temp = ct->tangent_impulse[j];
1619 ct->tangent_impulse[j] = vg_clampf( temp + lambda, -f, f );
1620 lambda = ct->tangent_impulse[j] - temp;
1621
1622 v3f impulse;
1623 v3_muls( ct->t[j], lambda, impulse );
1624 rb_linear_impulse( ct->rba, da, impulse );
1625
1626 v3_muls( ct->t[j], -lambda, impulse );
1627 rb_linear_impulse( ct->rbb, db, impulse );
1628 }
1629
1630 /* Normal */
1631 rb_rcv( ct, rv, da, db );
1632 float vn = v3_dot( rv, ct->n ),
1633 lambda = ct->normal_mass * (-vn + ct->bias);
1634
1635 float temp = ct->norm_impulse;
1636 ct->norm_impulse = vg_maxf( temp + lambda, 0.0f );
1637 lambda = ct->norm_impulse - temp;
1638
1639 v3f impulse;
1640 v3_muls( ct->n, lambda, impulse );
1641 rb_linear_impulse( ct->rba, da, impulse );
1642
1643 v3_muls( ct->n, -lambda, impulse );
1644 rb_linear_impulse( ct->rbb, db, impulse );
1645 }
1646 }
1647
1648 /*
1649 * -----------------------------------------------------------------------------
1650 * Constraints
1651 * -----------------------------------------------------------------------------
1652 */
1653
1654 static void draw_angle_limit( v3f c, v3f major, v3f minor,
1655 float amin, float amax, float measured,
1656 u32 colour )
1657 {
1658 float f = 0.05f;
1659 v3f ay, ax;
1660 v3_muls( major, f, ay );
1661 v3_muls( minor, f, ax );
1662
1663 for( int x=0; x<16; x++ )
1664 {
1665 float t0 = (float)x / 16.0f,
1666 t1 = (float)(x+1) / 16.0f,
1667 a0 = vg_lerpf( amin, amax, t0 ),
1668 a1 = vg_lerpf( amin, amax, t1 );
1669
1670 v3f p0, p1;
1671 v3_muladds( c, ay, cosf(a0), p0 );
1672 v3_muladds( p0, ax, sinf(a0), p0 );
1673 v3_muladds( c, ay, cosf(a1), p1 );
1674 v3_muladds( p1, ax, sinf(a1), p1 );
1675
1676 vg_line( p0, p1, colour );
1677
1678 if( x == 0 )
1679 vg_line( c, p0, colour );
1680 if( x == 15 )
1681 vg_line( c, p1, colour );
1682 }
1683
1684 v3f p2;
1685 v3_muladds( c, ay, cosf(measured)*1.2f, p2 );
1686 v3_muladds( p2, ax, sinf(measured)*1.2f, p2 );
1687 vg_line( c, p2, colour );
1688 }
1689
1690 static void rb_debug_constraint_limits( rigidbody *ra, rigidbody *rb, v3f lca,
1691 v3f limits[2] )
1692 {
1693 v3f ax, ay, az, bx, by, bz;
1694 m3x3_mulv( ra->to_world, (v3f){1.0f,0.0f,0.0f}, ax );
1695 m3x3_mulv( ra->to_world, (v3f){0.0f,1.0f,0.0f}, ay );
1696 m3x3_mulv( ra->to_world, (v3f){0.0f,0.0f,1.0f}, az );
1697 m3x3_mulv( rb->to_world, (v3f){1.0f,0.0f,0.0f}, bx );
1698 m3x3_mulv( rb->to_world, (v3f){0.0f,1.0f,0.0f}, by );
1699 m3x3_mulv( rb->to_world, (v3f){0.0f,0.0f,1.0f}, bz );
1700
1701 v2f px, py, pz;
1702 px[0] = v3_dot( ay, by );
1703 px[1] = v3_dot( az, by );
1704
1705 py[0] = v3_dot( az, bz );
1706 py[1] = v3_dot( ax, bz );
1707
1708 pz[0] = v3_dot( ax, bx );
1709 pz[1] = v3_dot( ay, bx );
1710
1711 float r0 = atan2f( px[1], px[0] ),
1712 r1 = atan2f( py[1], py[0] ),
1713 r2 = atan2f( pz[1], pz[0] );
1714
1715 v3f c;
1716 m4x3_mulv( ra->to_world, lca, c );
1717 draw_angle_limit( c, ay, az, limits[0][0], limits[1][0], r0, 0xff0000ff );
1718 draw_angle_limit( c, az, ax, limits[0][1], limits[1][1], r1, 0xff00ff00 );
1719 draw_angle_limit( c, ax, ay, limits[0][2], limits[1][2], r2, 0xffff0000 );
1720 }
1721
1722 static void rb_limit_cure( rigidbody *ra, rigidbody *rb, v3f axis, float d )
1723 {
1724 if( d != 0.0f )
1725 {
1726 float avx = v3_dot( ra->w, axis ) - v3_dot( rb->w, axis );
1727 float joint_mass = rb->inv_mass + ra->inv_mass;
1728 joint_mass = 1.0f/joint_mass;
1729
1730 float bias = (k_limit_bias * k_rb_rate) * d,
1731 lambda = -(avx + bias) * joint_mass;
1732
1733 /* Angular velocity */
1734 v3f wa, wb;
1735 v3_muls( axis, lambda * ra->inv_mass, wa );
1736 v3_muls( axis, -lambda * rb->inv_mass, wb );
1737
1738 v3_add( ra->w, wa, ra->w );
1739 v3_add( rb->w, wb, rb->w );
1740 }
1741 }
1742
1743 static void rb_constraint_limits( rigidbody *ra, v3f lca,
1744 rigidbody *rb, v3f lcb, v3f limits[2] )
1745 {
1746 /* TODO: Code dupe remover */
1747 v3f ax, ay, az, bx, by, bz;
1748 m3x3_mulv( ra->to_world, (v3f){1.0f,0.0f,0.0f}, ax );
1749 m3x3_mulv( ra->to_world, (v3f){0.0f,1.0f,0.0f}, ay );
1750 m3x3_mulv( ra->to_world, (v3f){0.0f,0.0f,1.0f}, az );
1751 m3x3_mulv( rb->to_world, (v3f){1.0f,0.0f,0.0f}, bx );
1752 m3x3_mulv( rb->to_world, (v3f){0.0f,1.0f,0.0f}, by );
1753 m3x3_mulv( rb->to_world, (v3f){0.0f,0.0f,1.0f}, bz );
1754
1755 v2f px, py, pz;
1756 px[0] = v3_dot( ay, by );
1757 px[1] = v3_dot( az, by );
1758
1759 py[0] = v3_dot( az, bz );
1760 py[1] = v3_dot( ax, bz );
1761
1762 pz[0] = v3_dot( ax, bx );
1763 pz[1] = v3_dot( ay, bx );
1764
1765 float r0 = atan2f( px[1], px[0] ),
1766 r1 = atan2f( py[1], py[0] ),
1767 r2 = atan2f( pz[1], pz[0] );
1768
1769 /* calculate angle deltas */
1770 float dx = 0.0f, dy = 0.0f, dz = 0.0f;
1771
1772 if( r0 < limits[0][0] ) dx = limits[0][0] - r0;
1773 if( r0 > limits[1][0] ) dx = limits[1][0] - r0;
1774 if( r1 < limits[0][1] ) dy = limits[0][1] - r1;
1775 if( r1 > limits[1][1] ) dy = limits[1][1] - r1;
1776 if( r2 < limits[0][2] ) dz = limits[0][2] - r2;
1777 if( r2 > limits[1][2] ) dz = limits[1][2] - r2;
1778
1779 v3f wca, wcb;
1780 m3x3_mulv( ra->to_world, lca, wca );
1781 m3x3_mulv( rb->to_world, lcb, wcb );
1782
1783 rb_limit_cure( ra, rb, ax, dx );
1784 rb_limit_cure( ra, rb, ay, dy );
1785 rb_limit_cure( ra, rb, az, dz );
1786 }
1787
1788 static void rb_debug_constraint_position( rigidbody *ra, v3f lca,
1789 rigidbody *rb, v3f lcb )
1790 {
1791 v3f wca, wcb;
1792 m3x3_mulv( ra->to_world, lca, wca );
1793 m3x3_mulv( rb->to_world, lcb, wcb );
1794
1795 v3f p0, p1;
1796 v3_add( wca, ra->co, p0 );
1797 v3_add( wcb, rb->co, p1 );
1798 vg_line_pt3( p0, 0.005f, 0xffffff00 );
1799 vg_line_pt3( p1, 0.005f, 0xffffff00 );
1800 vg_line( p0, p1, 0xffffff00 );
1801 }
1802
1803 static void rb_constraint_position( rigidbody *ra, v3f lca,
1804 rigidbody *rb, v3f lcb )
1805 {
1806 /* C = (COa + Ra*LCa) - (COb + Rb*LCb) = 0 */
1807 v3f wca, wcb;
1808 m3x3_mulv( ra->to_world, lca, wca );
1809 m3x3_mulv( rb->to_world, lcb, wcb );
1810
1811 v3f rcv;
1812 v3_sub( ra->v, rb->v, rcv );
1813
1814 v3f rcv_Ra, rcv_Rb;
1815 v3_cross( ra->w, wca, rcv_Ra );
1816 v3_cross( rb->w, wcb, rcv_Rb );
1817 v3_add( rcv_Ra, rcv, rcv );
1818 v3_sub( rcv, rcv_Rb, rcv );
1819
1820 v3f delta;
1821 v3f p0, p1;
1822 v3_add( wca, ra->co, p0 );
1823 v3_add( wcb, rb->co, p1 );
1824 v3_sub( p1, p0, delta );
1825
1826 float dist2 = v3_length2( delta );
1827
1828 if( dist2 > 0.00001f )
1829 {
1830 float dist = sqrtf(dist2);
1831 v3_muls( delta, 1.0f/dist, delta );
1832
1833 float joint_mass = rb->inv_mass + ra->inv_mass;
1834
1835 v3f raCn, rbCn, raCt, rbCt;
1836 v3_cross( wca, delta, raCn );
1837 v3_cross( wcb, delta, rbCn );
1838
1839 /* orient inverse inertia tensors */
1840 v3f raCnI, rbCnI;
1841 m3x3_mulv( ra->iIw, raCn, raCnI );
1842 m3x3_mulv( rb->iIw, rbCn, rbCnI );
1843 joint_mass += v3_dot( raCn, raCnI );
1844 joint_mass += v3_dot( rbCn, rbCnI );
1845 joint_mass = 1.0f/joint_mass;
1846
1847 float vd = v3_dot( rcv, delta ),
1848 bias = -(k_joint_bias * k_rb_rate) * dist,
1849 lambda = -(vd + bias) * joint_mass;
1850
1851 v3f impulse;
1852 v3_muls( delta, lambda, impulse );
1853 rb_linear_impulse( ra, wca, impulse );
1854 v3_muls( delta, -lambda, impulse );
1855 rb_linear_impulse( rb, wcb, impulse );
1856
1857 /* 'fake' snap */
1858 v3_muladds( ra->co, delta, dist * k_joint_correction, ra->co );
1859 v3_muladds( rb->co, delta, -dist * k_joint_correction, rb->co );
1860 }
1861 }
1862
1863 /*
1864 * -----------------------------------------------------------------------------
1865 * BVH implementation, this is ONLY for static rigidbodies, its to slow for
1866 * realtime use.
1867 * -----------------------------------------------------------------------------
1868 */
1869
1870 static void rb_bh_expand_bound( void *user, boxf bound, u32 item_index )
1871 {
1872 rigidbody *rb = &((rigidbody *)user)[ item_index ];
1873 box_concat( bound, rb->bbx_world );
1874 }
1875
1876 static float rb_bh_centroid( void *user, u32 item_index, int axis )
1877 {
1878 rigidbody *rb = &((rigidbody *)user)[ item_index ];
1879 return (rb->bbx_world[axis][0] + rb->bbx_world[1][axis]) * 0.5f;
1880 }
1881
1882 static void rb_bh_swap( void *user, u32 ia, u32 ib )
1883 {
1884 rigidbody temp, *rba, *rbb;
1885 rba = &((rigidbody *)user)[ ia ];
1886 rbb = &((rigidbody *)user)[ ib ];
1887
1888 temp = *rba;
1889 *rba = *rbb;
1890 *rbb = temp;
1891 }
1892
1893 static void rb_bh_debug( void *user, u32 item_index )
1894 {
1895 rigidbody *rb = &((rigidbody *)user)[ item_index ];
1896 rb_debug( rb, 0xff00ffff );
1897 }
1898
1899 static bh_system bh_system_rigidbodies =
1900 {
1901 .expand_bound = rb_bh_expand_bound,
1902 .item_centroid = rb_bh_centroid,
1903 .item_swap = rb_bh_swap,
1904 .item_debug = rb_bh_debug,
1905 .cast_ray = NULL
1906 };
1907
1908 #endif /* RIGIDBODY_H */
Skaterift source tree