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[carveJwlIkooP6JGAAIwe30JlM.git] / rigidbody.h
1 /*
2 * Copyright (C) 2021-2022 Mt.ZERO Software, Harry Godden - All Rights Reserved
3 */
4
5 /*
6 * Resources: Box2D - Erin Catto
7 * qu3e - Randy Gaul
8 */
9
10 #include "common.h"
11 #include "bvh.h"
12 #include "scene.h"
13
14 #include <math.h>
15
16 VG_STATIC void rb_tangent_basis( v3f n, v3f tx, v3f ty );
17 VG_STATIC bh_system bh_system_rigidbodies;
18
19 #ifndef RIGIDBODY_H
20 #define RIGIDBODY_H
21
22 /*
23 * -----------------------------------------------------------------------------
24 * (K)onstants
25 * -----------------------------------------------------------------------------
26 */
27
28 VG_STATIC const float
29 k_rb_rate = (1.0/VG_TIMESTEP_FIXED),
30 k_rb_delta = (1.0/k_rb_rate),
31 k_friction = 0.4f,
32 k_damp_linear = 0.1f, /* scale velocity 1/(1+x) */
33 k_damp_angular = 0.1f, /* scale angular 1/(1+x) */
34 k_penetration_slop = 0.01f,
35 k_inertia_scale = 8.0f,
36 k_phys_baumgarte = 0.2f,
37 k_gravity = 9.6f;
38
39 VG_STATIC float
40 k_limit_bias = 0.02f,
41 k_joint_correction = 0.01f,
42 k_joint_impulse = 1.0f,
43 k_joint_bias = 0.08f; /* positional joints */
44
45 VG_STATIC void rb_register_cvar(void)
46 {
47 VG_VAR_F32( k_limit_bias, flags=VG_VAR_CHEAT );
48 VG_VAR_F32( k_joint_bias, flags=VG_VAR_CHEAT );
49 VG_VAR_F32( k_joint_correction, flags=VG_VAR_CHEAT );
50 VG_VAR_F32( k_joint_impulse, flags=VG_VAR_CHEAT );
51 }
52
53 /*
54 * -----------------------------------------------------------------------------
55 * structure definitions
56 * -----------------------------------------------------------------------------
57 */
58
59 typedef struct rigidbody rigidbody;
60 typedef struct rb_object rb_object;
61 typedef struct contact rb_ct;
62 typedef struct rb_sphere rb_sphere;
63 typedef struct rb_capsule rb_capsule;
64 typedef struct rb_scene rb_scene;
65
66 struct rb_sphere{
67 float radius;
68 };
69
70 struct rb_capsule{
71 float height, radius;
72 };
73
74 struct rb_scene{
75 bh_tree *bh_scene;
76 };
77
78 struct rigidbody{
79 v3f co, v, w;
80 v4f q;
81
82 boxf bbx, bbx_world;
83 float inv_mass;
84
85 /* inertia model and inverse world tensor */
86 v3f I;
87 m3x3f iI, iIw;
88 m4x3f to_world, to_local;
89 };
90
91 /* simple objects */
92 struct rb_object{
93 rigidbody rb;
94 enum rb_shape{
95 k_rb_shape_box = 0,
96 k_rb_shape_sphere = 1,
97 k_rb_shape_capsule = 2,
98 k_rb_shape_scene = 3
99 }
100 type;
101
102 union{
103 struct rb_sphere sphere;
104 struct rb_capsule capsule;
105 struct rb_scene scene;
106 }
107 inf;
108 };
109
110 VG_STATIC struct contact{
111 rigidbody *rba, *rbb;
112 v3f co, n;
113 v3f t[2];
114 float p, bias, norm_impulse, tangent_impulse[2],
115 normal_mass, tangent_mass[2];
116
117 u32 element_id;
118
119 enum contact_type type;
120 }
121 rb_contact_buffer[256];
122 VG_STATIC int rb_contact_count = 0;
123
124 typedef struct rb_constr_pos rb_constr_pos;
125 typedef struct rb_constr_swingtwist rb_constr_swingtwist;
126
127 struct rb_constr_pos{
128 rigidbody *rba, *rbb;
129 v3f lca, lcb;
130 };
131
132 struct rb_constr_swingtwist{
133 rigidbody *rba, *rbb;
134
135 v4f conevx, conevy; /* relative to rba */
136 v3f view_offset, /* relative to rba */
137 coneva, conevxb;/* relative to rbb */
138
139 int tangent_violation, axis_violation;
140 v3f axis, tangent_axis, tangent_target, axis_target;
141
142 float conet;
143 float tangent_mass, axis_mass;
144 };
145
146 struct rb_constr_spring{
147 int nothing;
148 };
149
150 /*
151 * -----------------------------------------------------------------------------
152 * Math Utils
153 * -----------------------------------------------------------------------------
154 */
155
156 VG_STATIC float sphere_volume( float radius )
157 {
158 float r3 = radius*radius*radius;
159 return (4.0f/3.0f) * VG_PIf * r3;
160 }
161
162 VG_STATIC void rb_tangent_basis( v3f n, v3f tx, v3f ty )
163 {
164 /* Compute tangent basis (box2d) */
165 if( fabsf( n[0] ) >= 0.57735027f ){
166 tx[0] = n[1];
167 tx[1] = -n[0];
168 tx[2] = 0.0f;
169 }
170 else{
171 tx[0] = 0.0f;
172 tx[1] = n[2];
173 tx[2] = -n[1];
174 }
175
176 v3_normalize( tx );
177 v3_cross( n, tx, ty );
178 }
179
180 /*
181 * -----------------------------------------------------------------------------
182 * Debugging
183 * -----------------------------------------------------------------------------
184 */
185
186 VG_STATIC void rb_debug_contact( rb_ct *ct )
187 {
188 v3f p1;
189 v3_muladds( ct->co, ct->n, 0.05f, p1 );
190
191 if( ct->type == k_contact_type_default ){
192 vg_line_pt3( ct->co, 0.0125f, 0xff0000ff );
193 vg_line( ct->co, p1, 0xffffffff );
194 }
195 else if( ct->type == k_contact_type_edge ){
196 vg_line_pt3( ct->co, 0.0125f, 0xff00ffc0 );
197 vg_line( ct->co, p1, 0xffffffff );
198 }
199 }
200
201 VG_STATIC void debug_sphere( m4x3f m, float radius, u32 colour )
202 {
203 v3f ly = { 0.0f, 0.0f, radius },
204 lx = { 0.0f, radius, 0.0f },
205 lz = { 0.0f, 0.0f, radius };
206
207 for( int i=0; i<16; i++ ){
208 float t = ((float)(i+1) * (1.0f/16.0f)) * VG_PIf * 2.0f,
209 s = sinf(t),
210 c = cosf(t);
211
212 v3f py = { s*radius, 0.0f, c*radius },
213 px = { s*radius, c*radius, 0.0f },
214 pz = { 0.0f, s*radius, c*radius };
215
216 v3f p0, p1, p2, p3, p4, p5;
217 m4x3_mulv( m, py, p0 );
218 m4x3_mulv( m, ly, p1 );
219 m4x3_mulv( m, px, p2 );
220 m4x3_mulv( m, lx, p3 );
221 m4x3_mulv( m, pz, p4 );
222 m4x3_mulv( m, lz, p5 );
223
224 vg_line( p0, p1, colour == 0x00? 0xff00ff00: colour );
225 vg_line( p2, p3, colour == 0x00? 0xff0000ff: colour );
226 vg_line( p4, p5, colour == 0x00? 0xffff0000: colour );
227
228 v3_copy( py, ly );
229 v3_copy( px, lx );
230 v3_copy( pz, lz );
231 }
232 }
233
234 VG_STATIC void debug_capsule( m4x3f m, float radius, float h, u32 colour )
235 {
236 v3f ly = { 0.0f, 0.0f, radius },
237 lx = { 0.0f, radius, 0.0f },
238 lz = { 0.0f, 0.0f, radius };
239
240 float s0 = sinf(0.0f)*radius,
241 c0 = cosf(0.0f)*radius;
242
243 v3f p0, p1, up, right, forward;
244 m3x3_mulv( m, (v3f){0.0f,1.0f,0.0f}, up );
245 m3x3_mulv( m, (v3f){1.0f,0.0f,0.0f}, right );
246 m3x3_mulv( m, (v3f){0.0f,0.0f,-1.0f}, forward );
247 v3_muladds( m[3], up, -h*0.5f+radius, p0 );
248 v3_muladds( m[3], up, h*0.5f-radius, p1 );
249
250 v3f a0, a1, b0, b1;
251 v3_muladds( p0, right, radius, a0 );
252 v3_muladds( p1, right, radius, a1 );
253 v3_muladds( p0, forward, radius, b0 );
254 v3_muladds( p1, forward, radius, b1 );
255 vg_line( a0, a1, colour );
256 vg_line( b0, b1, colour );
257
258 v3_muladds( p0, right, -radius, a0 );
259 v3_muladds( p1, right, -radius, a1 );
260 v3_muladds( p0, forward, -radius, b0 );
261 v3_muladds( p1, forward, -radius, b1 );
262 vg_line( a0, a1, colour );
263 vg_line( b0, b1, colour );
264
265 for( int i=0; i<16; i++ ){
266 float t = ((float)(i+1) * (1.0f/16.0f)) * VG_PIf * 2.0f,
267 s1 = sinf(t)*radius,
268 c1 = cosf(t)*radius;
269
270 v3f e0 = { s0, 0.0f, c0 },
271 e1 = { s1, 0.0f, c1 },
272 e2 = { s0, c0, 0.0f },
273 e3 = { s1, c1, 0.0f },
274 e4 = { 0.0f, c0, s0 },
275 e5 = { 0.0f, c1, s1 };
276
277 m3x3_mulv( m, e0, e0 );
278 m3x3_mulv( m, e1, e1 );
279 m3x3_mulv( m, e2, e2 );
280 m3x3_mulv( m, e3, e3 );
281 m3x3_mulv( m, e4, e4 );
282 m3x3_mulv( m, e5, e5 );
283
284 v3_add( p0, e0, a0 );
285 v3_add( p0, e1, a1 );
286 v3_add( p1, e0, b0 );
287 v3_add( p1, e1, b1 );
288
289 vg_line( a0, a1, colour );
290 vg_line( b0, b1, colour );
291
292 if( c0 < 0.0f ){
293 v3_add( p0, e2, a0 );
294 v3_add( p0, e3, a1 );
295 v3_add( p0, e4, b0 );
296 v3_add( p0, e5, b1 );
297 }
298 else{
299 v3_add( p1, e2, a0 );
300 v3_add( p1, e3, a1 );
301 v3_add( p1, e4, b0 );
302 v3_add( p1, e5, b1 );
303 }
304
305 vg_line( a0, a1, colour );
306 vg_line( b0, b1, colour );
307
308 s0 = s1;
309 c0 = c1;
310 }
311 }
312
313 VG_STATIC void rb_object_debug( rb_object *obj, u32 colour )
314 {
315 if( obj->type == k_rb_shape_box ){
316 v3f *box = obj->rb.bbx;
317 vg_line_boxf_transformed( obj->rb.to_world, obj->rb.bbx, colour );
318 }
319 else if( obj->type == k_rb_shape_sphere ){
320 debug_sphere( obj->rb.to_world, obj->inf.sphere.radius, colour );
321 }
322 else if( obj->type == k_rb_shape_capsule ){
323 m4x3f m0, m1;
324 float h = obj->inf.capsule.height,
325 r = obj->inf.capsule.radius;
326
327 debug_capsule( obj->rb.to_world, r, h, colour );
328 }
329 else if( obj->type == k_rb_shape_scene ){
330 vg_line_boxf( obj->rb.bbx, colour );
331 }
332 }
333
334 /*
335 * -----------------------------------------------------------------------------
336 * Integration
337 * -----------------------------------------------------------------------------
338 */
339
340 /*
341 * Update world space bounding box based on local one
342 */
343 VG_STATIC void rb_update_bounds( rigidbody *rb )
344 {
345 box_copy( rb->bbx, rb->bbx_world );
346 m4x3_transform_aabb( rb->to_world, rb->bbx_world );
347 }
348
349 /*
350 * Commit transform to rigidbody. Updates matrices
351 */
352 VG_STATIC void rb_update_transform( rigidbody *rb )
353 {
354 q_normalize( rb->q );
355 q_m3x3( rb->q, rb->to_world );
356 v3_copy( rb->co, rb->to_world[3] );
357
358 m4x3_invert_affine( rb->to_world, rb->to_local );
359
360 #if 0
361 m3x3_mulv( rb->to_world, (v3f){1.0f,0.0f, 0.0f}, rb->right );
362 m3x3_mulv( rb->to_world, (v3f){0.0f,1.0f, 0.0f}, rb->up );
363 m3x3_mulv( rb->to_world, (v3f){0.0f,0.0f,-1.0f}, rb->forward );
364 #endif
365
366 m3x3_mul( rb->iI, rb->to_local, rb->iIw );
367 m3x3_mul( rb->to_world, rb->iIw, rb->iIw );
368
369 rb_update_bounds( rb );
370 }
371
372 /*
373 * Extrapolate rigidbody into a transform based on vg accumulator.
374 * Useful for rendering
375 */
376 VG_STATIC void rb_extrapolate( rigidbody *rb, v3f co, v4f q )
377 {
378 float substep = vg_clampf( vg.accumulator / k_rb_delta, 0.0f, 1.0f );
379
380 v3_muladds( rb->co, rb->v, k_rb_delta*substep, co );
381
382 if( v3_length2( rb->w ) > 0.0f ){
383 v4f rotation;
384 v3f axis;
385 v3_copy( rb->w, axis );
386
387 float mag = v3_length( axis );
388 v3_divs( axis, mag, axis );
389 q_axis_angle( rotation, axis, mag*k_rb_delta*substep );
390 q_mul( rotation, rb->q, q );
391 q_normalize( q );
392 }
393 else{
394 v4_copy( rb->q, q );
395 }
396 }
397
398 /*
399 * Initialize rigidbody and calculate masses, inertia
400 */
401 VG_STATIC void rb_init_object( rb_object *obj )
402 {
403 float volume = 1.0f;
404 int inert = 0;
405
406 if( obj->type == k_rb_shape_box ){
407 v3f dims;
408 v3_sub( obj->rb.bbx[1], obj->rb.bbx[0], dims );
409 volume = dims[0]*dims[1]*dims[2];
410 }
411 else if( obj->type == k_rb_shape_sphere ){
412 volume = sphere_volume( obj->inf.sphere.radius );
413 v3_fill( obj->rb.bbx[0], -obj->inf.sphere.radius );
414 v3_fill( obj->rb.bbx[1], obj->inf.sphere.radius );
415 }
416 else if( obj->type == k_rb_shape_capsule ){
417 float r = obj->inf.capsule.radius,
418 h = obj->inf.capsule.height;
419 volume = sphere_volume( r ) + VG_PIf * r*r * (h - r*2.0f);
420
421 v3_fill( obj->rb.bbx[0], -r );
422 v3_fill( obj->rb.bbx[1], r );
423 obj->rb.bbx[0][1] = -h;
424 obj->rb.bbx[1][1] = h;
425 }
426 else if( obj->type == k_rb_shape_scene ){
427 inert = 1;
428 box_copy( obj->inf.scene.bh_scene->nodes[0].bbx, obj->rb.bbx );
429 }
430
431 if( inert ){
432 obj->rb.inv_mass = 0.0f;
433 v3_zero( obj->rb.I );
434 m3x3_zero( obj->rb.iI );
435 }
436 else{
437 float mass = 2.0f*volume;
438 obj->rb.inv_mass = 1.0f/mass;
439
440 v3f extent;
441 v3_sub( obj->rb.bbx[1], obj->rb.bbx[0], extent );
442 v3_muls( extent, 0.5f, extent );
443
444 /* local intertia tensor */
445 float scale = k_inertia_scale;
446 float ex2 = scale*extent[0]*extent[0],
447 ey2 = scale*extent[1]*extent[1],
448 ez2 = scale*extent[2]*extent[2];
449
450 obj->rb.I[0] = ((1.0f/12.0f) * mass * (ey2+ez2));
451 obj->rb.I[1] = ((1.0f/12.0f) * mass * (ex2+ez2));
452 obj->rb.I[2] = ((1.0f/12.0f) * mass * (ex2+ey2));
453
454 m3x3_identity( obj->rb.iI );
455 obj->rb.iI[0][0] = obj->rb.I[0];
456 obj->rb.iI[1][1] = obj->rb.I[1];
457 obj->rb.iI[2][2] = obj->rb.I[2];
458 m3x3_inv( obj->rb.iI, obj->rb.iI );
459 }
460
461 rb_update_transform( &obj->rb );
462 }
463
464 VG_STATIC void rb_iter( rigidbody *rb )
465 {
466 if( !vg_validf( rb->v[0] ) ||
467 !vg_validf( rb->v[1] ) ||
468 !vg_validf( rb->v[2] ) )
469 {
470 vg_fatal_exit_loop( "NaN velocity" );
471 }
472
473 v3f gravity = { 0.0f, -9.8f, 0.0f };
474 v3_muladds( rb->v, gravity, k_rb_delta, rb->v );
475
476 /* intergrate velocity */
477 v3_muladds( rb->co, rb->v, k_rb_delta, rb->co );
478 v3_lerp( rb->w, (v3f){0.0f,0.0f,0.0f}, 0.0025f, rb->w );
479
480 /* inegrate inertia */
481 if( v3_length2( rb->w ) > 0.0f )
482 {
483 v4f rotation;
484 v3f axis;
485 v3_copy( rb->w, axis );
486
487 float mag = v3_length( axis );
488 v3_divs( axis, mag, axis );
489 q_axis_angle( rotation, axis, mag*k_rb_delta );
490 q_mul( rotation, rb->q, rb->q );
491 }
492
493 /* damping */
494 v3_muls( rb->v, 1.0f/(1.0f+k_rb_delta*k_damp_linear), rb->v );
495 v3_muls( rb->w, 1.0f/(1.0f+k_rb_delta*k_damp_angular), rb->w );
496 }
497
498
499 /*
500 * -----------------------------------------------------------------------------
501 * Boolean shape overlap functions
502 * -----------------------------------------------------------------------------
503 */
504
505 /*
506 * Project AABB, and triangle interval onto axis to check if they overlap
507 */
508 VG_STATIC int rb_box_triangle_interval( v3f extent, v3f axis, v3f tri[3] )
509 {
510 float
511
512 r = extent[0] * fabsf(axis[0]) +
513 extent[1] * fabsf(axis[1]) +
514 extent[2] * fabsf(axis[2]),
515
516 p0 = v3_dot( axis, tri[0] ),
517 p1 = v3_dot( axis, tri[1] ),
518 p2 = v3_dot( axis, tri[2] ),
519
520 e = vg_maxf(-vg_maxf(p0,vg_maxf(p1,p2)), vg_minf(p0,vg_minf(p1,p2)));
521
522 if( e > r ) return 0;
523 else return 1;
524 }
525
526 /*
527 * Seperating axis test box vs triangle
528 */
529 VG_STATIC int rb_box_triangle_sat( v3f extent, v3f center,
530 m4x3f to_local, v3f tri_src[3] )
531 {
532 v3f tri[3];
533
534 for( int i=0; i<3; i++ ){
535 m4x3_mulv( to_local, tri_src[i], tri[i] );
536 v3_sub( tri[i], center, tri[i] );
537 }
538
539 v3f f0,f1,f2,n;
540 v3_sub( tri[1], tri[0], f0 );
541 v3_sub( tri[2], tri[1], f1 );
542 v3_sub( tri[0], tri[2], f2 );
543
544
545 v3f axis[9];
546 v3_cross( (v3f){1.0f,0.0f,0.0f}, f0, axis[0] );
547 v3_cross( (v3f){1.0f,0.0f,0.0f}, f1, axis[1] );
548 v3_cross( (v3f){1.0f,0.0f,0.0f}, f2, axis[2] );
549 v3_cross( (v3f){0.0f,1.0f,0.0f}, f0, axis[3] );
550 v3_cross( (v3f){0.0f,1.0f,0.0f}, f1, axis[4] );
551 v3_cross( (v3f){0.0f,1.0f,0.0f}, f2, axis[5] );
552 v3_cross( (v3f){0.0f,0.0f,1.0f}, f0, axis[6] );
553 v3_cross( (v3f){0.0f,0.0f,1.0f}, f1, axis[7] );
554 v3_cross( (v3f){0.0f,0.0f,1.0f}, f2, axis[8] );
555
556 for( int i=0; i<9; i++ )
557 if(!rb_box_triangle_interval( extent, axis[i], tri )) return 0;
558
559 /* u0, u1, u2 */
560 if(!rb_box_triangle_interval( extent, (v3f){1.0f,0.0f,0.0f}, tri )) return 0;
561 if(!rb_box_triangle_interval( extent, (v3f){0.0f,1.0f,0.0f}, tri )) return 0;
562 if(!rb_box_triangle_interval( extent, (v3f){0.0f,0.0f,1.0f}, tri )) return 0;
563
564 /* normal */
565 v3_cross( f0, f1, n );
566 if(!rb_box_triangle_interval( extent, n, tri )) return 0;
567
568 return 1;
569 }
570
571 /*
572 * -----------------------------------------------------------------------------
573 * Manifold
574 * -----------------------------------------------------------------------------
575 */
576
577 VG_STATIC int rb_manifold_apply_filtered( rb_ct *man, int len )
578 {
579 int k = 0;
580
581 for( int i=0; i<len; i++ ){
582 rb_ct *ct = &man[i];
583
584 if( ct->type == k_contact_type_disabled )
585 continue;
586
587 man[k ++] = man[i];
588 }
589
590 return k;
591 }
592
593 /*
594 * Merge two contacts if they are within radius(r) of eachother
595 */
596 VG_STATIC void rb_manifold_contact_weld( rb_ct *ci, rb_ct *cj, float r )
597 {
598 if( v3_dist2( ci->co, cj->co ) < r*r ){
599 cj->type = k_contact_type_disabled;
600 ci->p = (ci->p + cj->p) * 0.5f;
601
602 v3_add( ci->co, cj->co, ci->co );
603 v3_muls( ci->co, 0.5f, ci->co );
604
605 v3f delta;
606 v3_sub( ci->rba->co, ci->co, delta );
607
608 float c0 = v3_dot( ci->n, delta ),
609 c1 = v3_dot( cj->n, delta );
610
611 if( c0 < 0.0f || c1 < 0.0f ){
612 /* error */
613 ci->type = k_contact_type_disabled;
614 }
615 else{
616 v3f n;
617 v3_muls( ci->n, c0, n );
618 v3_muladds( n, cj->n, c1, n );
619 v3_normalize( n );
620 v3_copy( n, ci->n );
621 }
622 }
623 }
624
625 /*
626 *
627 */
628 VG_STATIC void rb_manifold_filter_joint_edges( rb_ct *man, int len, float r )
629 {
630 for( int i=0; i<len-1; i++ ){
631 rb_ct *ci = &man[i];
632 if( ci->type != k_contact_type_edge )
633 continue;
634
635 for( int j=i+1; j<len; j++ ){
636 rb_ct *cj = &man[j];
637 if( cj->type != k_contact_type_edge )
638 continue;
639
640 rb_manifold_contact_weld( ci, cj, r );
641 }
642 }
643 }
644
645 /*
646 * Resolve overlapping pairs
647 *
648 * TODO: Remove?
649 */
650 VG_STATIC void rb_manifold_filter_pairs( rb_ct *man, int len, float r )
651 {
652 for( int i=0; i<len-1; i++ ){
653 rb_ct *ci = &man[i];
654 int similar = 0;
655
656 if( ci->type == k_contact_type_disabled ) continue;
657
658 for( int j=i+1; j<len; j++ ){
659 rb_ct *cj = &man[j];
660
661 if( cj->type == k_contact_type_disabled ) continue;
662
663 if( v3_dist2( ci->co, cj->co ) < r*r ){
664 cj->type = k_contact_type_disabled;
665 v3_add( cj->n, ci->n, ci->n );
666 ci->p += cj->p;
667 similar ++;
668 }
669 }
670
671 if( similar ){
672 float n = 1.0f/((float)similar+1.0f);
673 v3_muls( ci->n, n, ci->n );
674 ci->p *= n;
675
676 if( v3_length2(ci->n) < 0.1f*0.1f )
677 ci->type = k_contact_type_disabled;
678 else
679 v3_normalize( ci->n );
680 }
681 }
682 }
683
684 /*
685 * Remove contacts that are facing away from A
686 */
687 VG_STATIC void rb_manifold_filter_backface( rb_ct *man, int len )
688 {
689 for( int i=0; i<len; i++ ){
690 rb_ct *ct = &man[i];
691 if( ct->type == k_contact_type_disabled )
692 continue;
693
694 v3f delta;
695 v3_sub( ct->co, ct->rba->co, delta );
696
697 if( v3_dot( delta, ct->n ) > -0.001f )
698 ct->type = k_contact_type_disabled;
699 }
700 }
701
702 /*
703 * Filter out duplicate coplanar results. Good for spheres.
704 */
705 VG_STATIC void rb_manifold_filter_coplanar( rb_ct *man, int len, float w )
706 {
707 for( int i=0; i<len; i++ ){
708 rb_ct *ci = &man[i];
709 if( ci->type == k_contact_type_disabled ||
710 ci->type == k_contact_type_edge )
711 continue;
712
713 float d1 = v3_dot( ci->co, ci->n );
714
715 for( int j=0; j<len; j++ ){
716 if( j == i )
717 continue;
718
719 rb_ct *cj = &man[j];
720 if( cj->type == k_contact_type_disabled )
721 continue;
722
723 float d2 = v3_dot( cj->co, ci->n ),
724 d = d2-d1;
725
726 if( fabsf( d ) <= w ){
727 cj->type = k_contact_type_disabled;
728 }
729 }
730 }
731 }
732
733 /*
734 * -----------------------------------------------------------------------------
735 * Collision matrix
736 * -----------------------------------------------------------------------------
737 */
738
739 /*
740 * Contact generators
741 *
742 * These do not automatically allocate contacts, an appropriately sized
743 * buffer must be supplied. The function returns the size of the manifold
744 * which was generated.
745 *
746 * The values set on the contacts are: n, co, p, rba, rbb
747 */
748
749 /*
750 * By collecting the minimum(time) and maximum(time) pairs of points, we
751 * build a reduced and stable exact manifold.
752 *
753 * tx: time at point
754 * rx: minimum distance of these points
755 * dx: the delta between the two points
756 *
757 * pairs will only ammend these if they are creating a collision
758 */
759 typedef struct capsule_manifold capsule_manifold;
760 struct capsule_manifold
761 {
762 float t0, t1;
763 float r0, r1;
764 v3f d0, d1;
765 };
766
767 /*
768 * Expand a line manifold with a new pair. t value is the time along segment
769 * on the oriented object which created this pair.
770 */
771 VG_STATIC void rb_capsule_manifold( v3f pa, v3f pb, float t, float r,
772 capsule_manifold *manifold )
773 {
774 v3f delta;
775 v3_sub( pa, pb, delta );
776
777 if( v3_length2(delta) < r*r ){
778 if( t < manifold->t0 ){
779 v3_copy( delta, manifold->d0 );
780 manifold->t0 = t;
781 manifold->r0 = r;
782 }
783
784 if( t > manifold->t1 ){
785 v3_copy( delta, manifold->d1 );
786 manifold->t1 = t;
787 manifold->r1 = r;
788 }
789 }
790 }
791
792 VG_STATIC void rb_capsule_manifold_init( capsule_manifold *manifold )
793 {
794 manifold->t0 = INFINITY;
795 manifold->t1 = -INFINITY;
796 }
797
798 VG_STATIC int rb_capsule__manifold_done( m4x3f mtx, rb_capsule *c,
799 capsule_manifold *manifold,
800 rb_ct *buf )
801 {
802 v3f p0, p1;
803 v3_muladds( mtx[3], mtx[1], -c->height*0.5f+c->radius, p0 );
804 v3_muladds( mtx[3], mtx[1], c->height*0.5f-c->radius, p1 );
805
806 int count = 0;
807 if( manifold->t0 <= 1.0f ){
808 rb_ct *ct = buf;
809
810 v3f pa;
811 v3_muls( p0, 1.0f-manifold->t0, pa );
812 v3_muladds( pa, p1, manifold->t0, pa );
813
814 float d = v3_length( manifold->d0 );
815 v3_muls( manifold->d0, 1.0f/d, ct->n );
816 v3_muladds( pa, ct->n, -c->radius, ct->co );
817
818 ct->p = manifold->r0 - d;
819 ct->type = k_contact_type_default;
820 count ++;
821 }
822
823 if( (manifold->t1 >= 0.0f) && (manifold->t0 != manifold->t1) ){
824 rb_ct *ct = buf+count;
825
826 v3f pa;
827 v3_muls( p0, 1.0f-manifold->t1, pa );
828 v3_muladds( pa, p1, manifold->t1, pa );
829
830 float d = v3_length( manifold->d1 );
831 v3_muls( manifold->d1, 1.0f/d, ct->n );
832 v3_muladds( pa, ct->n, -c->radius, ct->co );
833
834 ct->p = manifold->r1 - d;
835 ct->type = k_contact_type_default;
836
837 count ++;
838 }
839
840 /*
841 * Debugging
842 */
843
844 if( count == 2 )
845 vg_line( buf[0].co, buf[1].co, 0xff0000ff );
846
847 return count;
848 }
849
850 VG_STATIC int rb_capsule_sphere( rb_object *obja, rb_object *objb, rb_ct *buf )
851 {
852 rigidbody *rba = &obja->rb, *rbb = &objb->rb;
853 float h = obja->inf.capsule.height,
854 ra = obja->inf.capsule.radius,
855 rb = objb->inf.sphere.radius;
856
857 v3f p0, p1;
858 v3_muladds( rba->co, rba->to_world[1], -h*0.5f+ra, p0 );
859 v3_muladds( rba->co, rba->to_world[1], h*0.5f-ra, p1 );
860
861 v3f c, delta;
862 closest_point_segment( p0, p1, rbb->co, c );
863 v3_sub( c, rbb->co, delta );
864
865 float d2 = v3_length2(delta),
866 r = ra + rb;
867
868 if( d2 < r*r ){
869 float d = sqrtf(d2);
870
871 rb_ct *ct = buf;
872 v3_muls( delta, 1.0f/d, ct->n );
873 ct->p = r-d;
874
875 v3f p0, p1;
876 v3_muladds( c, ct->n, -ra, p0 );
877 v3_muladds( rbb->co, ct->n, rb, p1 );
878 v3_add( p0, p1, ct->co );
879 v3_muls( ct->co, 0.5f, ct->co );
880
881 ct->rba = rba;
882 ct->rbb = rbb;
883 ct->type = k_contact_type_default;
884
885 return 1;
886 }
887
888 return 0;
889 }
890
891 VG_STATIC int rb_capsule__capsule( m4x3f mtxA, rb_capsule *ca,
892 m4x3f mtxB, rb_capsule *cb, rb_ct *buf )
893 {
894 float ha = ca->height,
895 hb = cb->height,
896 ra = ca->radius,
897 rb = cb->radius,
898 r = ra+rb;
899
900 v3f p0, p1, p2, p3;
901 v3_muladds( mtxA[3], mtxA[1], -ha*0.5f+ra, p0 );
902 v3_muladds( mtxA[3], mtxA[1], ha*0.5f-ra, p1 );
903 v3_muladds( mtxB[3], mtxB[1], -hb*0.5f+rb, p2 );
904 v3_muladds( mtxB[3], mtxB[1], hb*0.5f-rb, p3 );
905
906 capsule_manifold manifold;
907 rb_capsule_manifold_init( &manifold );
908
909 v3f pa, pb;
910 float ta, tb;
911 closest_segment_segment( p0, p1, p2, p3, &ta, &tb, pa, pb );
912 rb_capsule_manifold( pa, pb, ta, r, &manifold );
913
914 ta = closest_point_segment( p0, p1, p2, pa );
915 tb = closest_point_segment( p0, p1, p3, pb );
916 rb_capsule_manifold( pa, p2, ta, r, &manifold );
917 rb_capsule_manifold( pb, p3, tb, r, &manifold );
918
919 closest_point_segment( p2, p3, p0, pa );
920 closest_point_segment( p2, p3, p1, pb );
921 rb_capsule_manifold( p0, pa, 0.0f, r, &manifold );
922 rb_capsule_manifold( p1, pb, 1.0f, r, &manifold );
923
924 return rb_capsule__manifold_done( mtxA, ca, &manifold, buf );
925 }
926
927 #if 0
928 /*
929 * Generates up to two contacts; optimised for the most stable manifold
930 */
931 VG_STATIC int rb_capsule_box( rigidbody *rba, rigidbody *rbb, rb_ct *buf )
932 {
933 float h = rba->inf.capsule.height,
934 r = rba->inf.capsule.radius;
935
936 /*
937 * Solving this in symetric local space of the cube saves us some time and a
938 * couple branches when it comes to the quad stage.
939 */
940 v3f centroid;
941 v3_add( rbb->bbx[0], rbb->bbx[1], centroid );
942 v3_muls( centroid, 0.5f, centroid );
943
944 boxf bbx;
945 v3_sub( rbb->bbx[0], centroid, bbx[0] );
946 v3_sub( rbb->bbx[1], centroid, bbx[1] );
947
948 v3f pc, p0w, p1w, p0, p1;
949 v3_muladds( rba->co, rba->up, -h*0.5f+r, p0w );
950 v3_muladds( rba->co, rba->up, h*0.5f-r, p1w );
951
952 m4x3_mulv( rbb->to_local, p0w, p0 );
953 m4x3_mulv( rbb->to_local, p1w, p1 );
954 v3_sub( p0, centroid, p0 );
955 v3_sub( p1, centroid, p1 );
956 v3_add( p0, p1, pc );
957 v3_muls( pc, 0.5f, pc );
958
959 /*
960 * Finding an appropriate quad to collide lines with
961 */
962 v3f region;
963 v3_div( pc, bbx[1], region );
964
965 v3f quad[4];
966 if( (fabsf(region[0]) > fabsf(region[1])) &&
967 (fabsf(region[0]) > fabsf(region[2])) )
968 {
969 float px = vg_signf(region[0]) * bbx[1][0];
970 v3_copy( (v3f){ px, bbx[0][1], bbx[0][2] }, quad[0] );
971 v3_copy( (v3f){ px, bbx[1][1], bbx[0][2] }, quad[1] );
972 v3_copy( (v3f){ px, bbx[1][1], bbx[1][2] }, quad[2] );
973 v3_copy( (v3f){ px, bbx[0][1], bbx[1][2] }, quad[3] );
974 }
975 else if( fabsf(region[1]) > fabsf(region[2]) )
976 {
977 float py = vg_signf(region[1]) * bbx[1][1];
978 v3_copy( (v3f){ bbx[0][0], py, bbx[0][2] }, quad[0] );
979 v3_copy( (v3f){ bbx[1][0], py, bbx[0][2] }, quad[1] );
980 v3_copy( (v3f){ bbx[1][0], py, bbx[1][2] }, quad[2] );
981 v3_copy( (v3f){ bbx[0][0], py, bbx[1][2] }, quad[3] );
982 }
983 else
984 {
985 float pz = vg_signf(region[2]) * bbx[1][2];
986 v3_copy( (v3f){ bbx[0][0], bbx[0][1], pz }, quad[0] );
987 v3_copy( (v3f){ bbx[1][0], bbx[0][1], pz }, quad[1] );
988 v3_copy( (v3f){ bbx[1][0], bbx[1][1], pz }, quad[2] );
989 v3_copy( (v3f){ bbx[0][0], bbx[1][1], pz }, quad[3] );
990 }
991
992 capsule_manifold manifold;
993 rb_capsule_manifold_init( &manifold );
994
995 v3f c0, c1;
996 closest_point_aabb( p0, bbx, c0 );
997 closest_point_aabb( p1, bbx, c1 );
998
999 v3f d0, d1, da;
1000 v3_sub( c0, p0, d0 );
1001 v3_sub( c1, p1, d1 );
1002 v3_sub( p1, p0, da );
1003
1004 v3_normalize(d0);
1005 v3_normalize(d1);
1006 v3_normalize(da);
1007
1008 if( v3_dot( da, d0 ) <= 0.01f )
1009 rb_capsule_manifold( p0, c0, 0.0f, r, &manifold );
1010
1011 if( v3_dot( da, d1 ) >= -0.01f )
1012 rb_capsule_manifold( p1, c1, 1.0f, r, &manifold );
1013
1014 for( int i=0; i<4; i++ )
1015 {
1016 int i0 = i,
1017 i1 = (i+1)%4;
1018
1019 v3f ca, cb;
1020 float ta, tb;
1021 closest_segment_segment( p0, p1, quad[i0], quad[i1], &ta, &tb, ca, cb );
1022 rb_capsule_manifold( ca, cb, ta, r, &manifold );
1023 }
1024
1025 /*
1026 * Create final contacts based on line manifold
1027 */
1028 m3x3_mulv( rbb->to_world, manifold.d0, manifold.d0 );
1029 m3x3_mulv( rbb->to_world, manifold.d1, manifold.d1 );
1030
1031 /*
1032 * Debugging
1033 */
1034
1035 #if 0
1036 for( int i=0; i<4; i++ )
1037 {
1038 v3f q0, q1;
1039 int i0 = i,
1040 i1 = (i+1)%4;
1041
1042 v3_add( quad[i0], centroid, q0 );
1043 v3_add( quad[i1], centroid, q1 );
1044
1045 m4x3_mulv( rbb->to_world, q0, q0 );
1046 m4x3_mulv( rbb->to_world, q1, q1 );
1047
1048 vg_line( q0, q1, 0xffffffff );
1049 }
1050 #endif
1051
1052 return rb_capsule_manifold_done( rba, rbb, &manifold, buf );
1053 }
1054 #endif
1055
1056 VG_STATIC int rb_sphere_box( rb_object *obja, rb_object *objb, rb_ct *buf )
1057 {
1058 v3f co, delta;
1059 rigidbody *rba = &obja->rb, *rbb = &objb->rb;
1060
1061 closest_point_obb( rba->co, rbb->bbx, rbb->to_world, rbb->to_local, co );
1062 v3_sub( rba->co, co, delta );
1063
1064 float d2 = v3_length2(delta),
1065 r = obja->inf.sphere.radius;
1066
1067 if( d2 <= r*r ){
1068 float d;
1069
1070 rb_ct *ct = buf;
1071 if( d2 <= 0.0001f ){
1072 v3_sub( rba->co, rbb->co, delta );
1073
1074 /*
1075 * some extra testing is required to find the best axis to push the
1076 * object back outside the box. Since there isnt a clear seperating
1077 * vector already, especially on really high aspect boxes.
1078 */
1079 float lx = v3_dot( rbb->to_world[0], delta ),
1080 ly = v3_dot( rbb->to_world[1], delta ),
1081 lz = v3_dot( rbb->to_world[2], delta ),
1082 px = rbb->bbx[1][0] - fabsf(lx),
1083 py = rbb->bbx[1][1] - fabsf(ly),
1084 pz = rbb->bbx[1][2] - fabsf(lz);
1085
1086 if( px < py && px < pz )
1087 v3_muls( rbb->to_world[0], vg_signf(lx), ct->n );
1088 else if( py < pz )
1089 v3_muls( rbb->to_world[1], vg_signf(ly), ct->n );
1090 else
1091 v3_muls( rbb->to_world[2], vg_signf(lz), ct->n );
1092
1093 v3_muladds( rba->co, ct->n, -r, ct->co );
1094 ct->p = r;
1095 }
1096 else{
1097 d = sqrtf(d2);
1098 v3_muls( delta, 1.0f/d, ct->n );
1099 ct->p = r-d;
1100 v3_copy( co, ct->co );
1101 }
1102
1103 ct->rba = rba;
1104 ct->rbb = rbb;
1105 ct->type = k_contact_type_default;
1106 return 1;
1107 }
1108
1109 return 0;
1110 }
1111
1112 VG_STATIC int rb_sphere_sphere( rb_object *obja, rb_object *objb, rb_ct *buf )
1113 {
1114 rigidbody *rba = &obja->rb, *rbb = &objb->rb;
1115 v3f delta;
1116 v3_sub( rba->co, rbb->co, delta );
1117
1118 float d2 = v3_length2(delta),
1119 r = obja->inf.sphere.radius + objb->inf.sphere.radius;
1120
1121 if( d2 < r*r ){
1122 float d = sqrtf(d2);
1123
1124 rb_ct *ct = buf;
1125 v3_muls( delta, 1.0f/d, ct->n );
1126
1127 v3f p0, p1;
1128 v3_muladds( rba->co, ct->n,-obja->inf.sphere.radius, p0 );
1129 v3_muladds( rbb->co, ct->n, objb->inf.sphere.radius, p1 );
1130 v3_add( p0, p1, ct->co );
1131 v3_muls( ct->co, 0.5f, ct->co );
1132 ct->type = k_contact_type_default;
1133 ct->p = r-d;
1134 ct->rba = rba;
1135 ct->rbb = rbb;
1136 return 1;
1137 }
1138
1139 return 0;
1140 }
1141
1142 //#define RIGIDBODY_DYNAMIC_MESH_EDGES
1143
1144 #if 0
1145 __attribute__ ((deprecated))
1146 VG_STATIC int rb_sphere_triangle( rigidbody *rba, rigidbody *rbb,
1147 v3f tri[3], rb_ct *buf )
1148 {
1149 v3f delta, co;
1150
1151 #ifdef RIGIDBODY_DYNAMIC_MESH_EDGES
1152 closest_on_triangle_1( rba->co, tri, co );
1153 #else
1154 enum contact_type type = closest_on_triangle_1( rba->co, tri, co );
1155 #endif
1156
1157 v3_sub( rba->co, co, delta );
1158
1159 float d2 = v3_length2( delta ),
1160 r = rba->inf.sphere.radius;
1161
1162 if( d2 < r*r )
1163 {
1164 rb_ct *ct = buf;
1165
1166 v3f ab, ac, tn;
1167 v3_sub( tri[2], tri[0], ab );
1168 v3_sub( tri[1], tri[0], ac );
1169 v3_cross( ac, ab, tn );
1170 v3_copy( tn, ct->n );
1171
1172 if( v3_length2( ct->n ) <= 0.00001f )
1173 {
1174 vg_error( "Zero area triangle!\n" );
1175 return 0;
1176 }
1177
1178 v3_normalize( ct->n );
1179
1180 float d = sqrtf(d2);
1181
1182 v3_copy( co, ct->co );
1183 ct->type = type;
1184 ct->p = r-d;
1185 ct->rba = rba;
1186 ct->rbb = rbb;
1187 return 1;
1188 }
1189
1190 return 0;
1191 }
1192 #endif
1193
1194 VG_STATIC int rb_sphere__triangle( m4x3f mtxA, rb_sphere *b,
1195 v3f tri[3], rb_ct *buf )
1196 {
1197 v3f delta, co;
1198 enum contact_type type = closest_on_triangle_1( mtxA[3], tri, co );
1199
1200 v3_sub( mtxA[3], co, delta );
1201
1202 float d2 = v3_length2( delta ),
1203 r = b->radius;
1204
1205 if( d2 <= r*r ){
1206 rb_ct *ct = buf;
1207
1208 v3f ab, ac, tn;
1209 v3_sub( tri[2], tri[0], ab );
1210 v3_sub( tri[1], tri[0], ac );
1211 v3_cross( ac, ab, tn );
1212 v3_copy( tn, ct->n );
1213
1214 if( v3_length2( ct->n ) <= 0.00001f ){
1215 vg_error( "Zero area triangle!\n" );
1216 return 0;
1217 }
1218
1219 v3_normalize( ct->n );
1220
1221 float d = sqrtf(d2);
1222
1223 v3_copy( co, ct->co );
1224 ct->type = type;
1225 ct->p = r-d;
1226 return 1;
1227 }
1228
1229 return 0;
1230 }
1231
1232 VG_STATIC int rb_sphere__scene( m4x3f mtxA, rb_sphere *b,
1233 m4x3f mtxB, rb_scene *s, rb_ct *buf )
1234 {
1235 scene *sc = s->bh_scene->user;
1236
1237 bh_iter it;
1238 bh_iter_init( 0, &it );
1239 int idx;
1240
1241 int count = 0;
1242
1243 float r = b->radius + 0.1f;
1244 boxf box;
1245 v3_sub( mtxA[3], (v3f){ r,r,r }, box[0] );
1246 v3_add( mtxA[3], (v3f){ r,r,r }, box[1] );
1247
1248 while( bh_next( s->bh_scene, &it, box, &idx ) ){
1249 u32 *ptri = &sc->arrindices[ idx*3 ];
1250 v3f tri[3];
1251
1252 for( int j=0; j<3; j++ )
1253 v3_copy( sc->arrvertices[ptri[j]].co, tri[j] );
1254
1255 buf[ count ].element_id = ptri[0];
1256
1257 vg_line( tri[0],tri[1],0x70ff6000 );
1258 vg_line( tri[1],tri[2],0x70ff6000 );
1259 vg_line( tri[2],tri[0],0x70ff6000 );
1260
1261 int contact = rb_sphere__triangle( mtxA, b, tri, &buf[count] );
1262 count += contact;
1263
1264 if( count == 16 ){
1265 vg_warn( "Exceeding sphere_vs_scene capacity. Geometry too dense!\n" );
1266 return count;
1267 }
1268 }
1269
1270 return count;
1271 }
1272
1273 VG_STATIC int rb_box__scene( m4x3f mtxA, boxf bbx,
1274 m4x3f mtxB, rb_scene *s, rb_ct *buf )
1275 {
1276 #if 1
1277 scene *sc = s->bh_scene->user;
1278 v3f tri[3];
1279
1280 v3f extent, center;
1281 v3_sub( bbx[1], bbx[0], extent );
1282 v3_muls( extent, 0.5f, extent );
1283 v3_add( bbx[0], extent, center );
1284
1285 float r = v3_length(extent);
1286 boxf world_bbx;
1287 v3_fill( world_bbx[0], -r );
1288 v3_fill( world_bbx[1], r );
1289 for( int i=0; i<2; i++ ){
1290 v3_add( center, world_bbx[i], world_bbx[i] );
1291 v3_add( mtxA[3], world_bbx[i], world_bbx[i] );
1292 }
1293
1294 m4x3f to_local;
1295 m4x3_invert_affine( mtxA, to_local );
1296
1297 bh_iter it;
1298 bh_iter_init( 0, &it );
1299 int idx;
1300 int count = 0;
1301
1302 vg_line_boxf( world_bbx, VG__RED );
1303
1304 while( bh_next( s->bh_scene, &it, world_bbx, &idx ) ){
1305 u32 *ptri = &sc->arrindices[ idx*3 ];
1306
1307 for( int j=0; j<3; j++ )
1308 v3_copy( sc->arrvertices[ptri[j]].co, tri[j] );
1309
1310 if( rb_box_triangle_sat( extent, center, to_local, tri ) ){
1311 vg_line(tri[0],tri[1],0xff50ff00 );
1312 vg_line(tri[1],tri[2],0xff50ff00 );
1313 vg_line(tri[2],tri[0],0xff50ff00 );
1314 }
1315 else{
1316 vg_line(tri[0],tri[1],0xff0000ff );
1317 vg_line(tri[1],tri[2],0xff0000ff );
1318 vg_line(tri[2],tri[0],0xff0000ff );
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( mtxA[0], n );
1330 int axis = 0;
1331
1332 for( int i=1; i<3; i++ ){
1333 float c = v3_dot( mtxA[i], n );
1334
1335 if( fabsf(c) > fabsf(best) ){
1336 best = c;
1337 axis = i;
1338 }
1339 }
1340
1341 v3f manifold[4];
1342
1343 if( axis == 0 ){
1344 float px = best > 0.0f? bbx[0][0]: bbx[1][0];
1345 manifold[0][0] = px;
1346 manifold[0][1] = bbx[0][1];
1347 manifold[0][2] = bbx[0][2];
1348 manifold[1][0] = px;
1349 manifold[1][1] = bbx[1][1];
1350 manifold[1][2] = bbx[0][2];
1351 manifold[2][0] = px;
1352 manifold[2][1] = bbx[1][1];
1353 manifold[2][2] = bbx[1][2];
1354 manifold[3][0] = px;
1355 manifold[3][1] = bbx[0][1];
1356 manifold[3][2] = bbx[1][2];
1357 }
1358 else if( axis == 1 ){
1359 float py = best > 0.0f? bbx[0][1]: bbx[1][1];
1360 manifold[0][0] = bbx[0][0];
1361 manifold[0][1] = py;
1362 manifold[0][2] = bbx[0][2];
1363 manifold[1][0] = bbx[1][0];
1364 manifold[1][1] = py;
1365 manifold[1][2] = bbx[0][2];
1366 manifold[2][0] = bbx[1][0];
1367 manifold[2][1] = py;
1368 manifold[2][2] = bbx[1][2];
1369 manifold[3][0] = bbx[0][0];
1370 manifold[3][1] = py;
1371 manifold[3][2] = bbx[1][2];
1372 }
1373 else{
1374 float pz = best > 0.0f? bbx[0][2]: bbx[1][2];
1375 manifold[0][0] = bbx[0][0];
1376 manifold[0][1] = bbx[0][1];
1377 manifold[0][2] = pz;
1378 manifold[1][0] = bbx[1][0];
1379 manifold[1][1] = bbx[0][1];
1380 manifold[1][2] = pz;
1381 manifold[2][0] = bbx[1][0];
1382 manifold[2][1] = bbx[1][1];
1383 manifold[2][2] = pz;
1384 manifold[3][0] = bbx[0][0];
1385 manifold[3][1] = bbx[1][1];
1386 manifold[3][2] = pz;
1387 }
1388
1389 for( int j=0; j<4; j++ )
1390 m4x3_mulv( mtxA, manifold[j], manifold[j] );
1391
1392 vg_line( manifold[0], manifold[1], 0xffffffff );
1393 vg_line( manifold[1], manifold[2], 0xffffffff );
1394 vg_line( manifold[2], manifold[3], 0xffffffff );
1395 vg_line( manifold[3], manifold[0], 0xffffffff );
1396
1397 for( int j=0; j<4; j++ ){
1398 rb_ct *ct = buf+count;
1399
1400 v3_copy( manifold[j], ct->co );
1401 v3_copy( n, ct->n );
1402
1403 float l0 = v3_dot( tri[0], n ),
1404 l1 = v3_dot( manifold[j], n );
1405
1406 ct->p = (l0-l1)*0.5f;
1407 if( ct->p < 0.0f )
1408 continue;
1409
1410 ct->type = k_contact_type_default;
1411 count ++;
1412
1413 if( count >= 12 )
1414 return count;
1415 }
1416 }
1417 return count;
1418 #else
1419
1420 scene *sc = s->bh_scene->user;
1421 v3f tri[3];
1422
1423 v3f extent, center;
1424 v3_sub( bbx[1], bbx[0], extent );
1425 v3_muls( extent, 0.5f, extent );
1426 v3_add( bbx[0], extent, center );
1427
1428 float r = v3_length(extent);
1429 boxf world_bbx;
1430 v3_fill( world_bbx[0], -r );
1431 v3_fill( world_bbx[1], r );
1432 for( int i=0; i<2; i++ ){
1433 v3_add( center, world_bbx[i], world_bbx[i] );
1434 v3_add( mtxA[3], world_bbx[i], world_bbx[i] );
1435 }
1436
1437 m4x3f to_local;
1438 m4x3_invert_affine( mtxA, to_local );
1439
1440 bh_iter it;
1441 bh_iter_init( 0, &it );
1442 int idx;
1443 int count = 0;
1444
1445 vg_line_boxf( world_bbx, VG__RED );
1446
1447 while( bh_next( s->bh_scene, &it, world_bbx, &idx ) ){
1448 u32 *ptri = &sc->arrindices[ idx*3 ];
1449
1450 for( int j=0; j<3; j++ )
1451 v3_copy( sc->arrvertices[ptri[j]].co, tri[j] );
1452
1453 vg_line( tri[0],tri[1],VG__BLACK );
1454 vg_line( tri[1],tri[2],VG__BLACK );
1455 vg_line( tri[2],tri[0],VG__BLACK );
1456
1457 v3f clip[2][8];
1458 u32 clip_length = 0;
1459 }
1460
1461 #endif
1462 }
1463
1464 VG_STATIC int rb_capsule__triangle( m4x3f mtxA, rb_capsule *c,
1465 v3f tri[3], rb_ct *buf )
1466 {
1467 v3f pc, p0w, p1w;
1468 v3_muladds( mtxA[3], mtxA[1], -c->height*0.5f+c->radius, p0w );
1469 v3_muladds( mtxA[3], mtxA[1], c->height*0.5f-c->radius, p1w );
1470
1471 capsule_manifold manifold;
1472 rb_capsule_manifold_init( &manifold );
1473
1474 v3f c0, c1;
1475 closest_on_triangle_1( p0w, tri, c0 );
1476 closest_on_triangle_1( p1w, tri, c1 );
1477
1478 v3f d0, d1, da;
1479 v3_sub( c0, p0w, d0 );
1480 v3_sub( c1, p1w, d1 );
1481 v3_sub( p1w, p0w, da );
1482
1483 v3_normalize(d0);
1484 v3_normalize(d1);
1485 v3_normalize(da);
1486
1487 if( v3_dot( da, d0 ) <= 0.01f )
1488 rb_capsule_manifold( p0w, c0, 0.0f, c->radius, &manifold );
1489
1490 if( v3_dot( da, d1 ) >= -0.01f )
1491 rb_capsule_manifold( p1w, c1, 1.0f, c->radius, &manifold );
1492
1493 for( int i=0; i<3; i++ ){
1494 int i0 = i,
1495 i1 = (i+1)%3;
1496
1497 v3f ca, cb;
1498 float ta, tb;
1499 closest_segment_segment( p0w, p1w, tri[i0], tri[i1], &ta, &tb, ca, cb );
1500 rb_capsule_manifold( ca, cb, ta, c->radius, &manifold );
1501 }
1502
1503 v3f v0, v1, n;
1504 v3_sub( tri[1], tri[0], v0 );
1505 v3_sub( tri[2], tri[0], v1 );
1506 v3_cross( v0, v1, n );
1507 v3_normalize( n );
1508
1509 int count = rb_capsule__manifold_done( mtxA, c, &manifold, buf );
1510 for( int i=0; i<count; i++ )
1511 v3_copy( n, buf[i].n );
1512
1513 return count;
1514 }
1515
1516 /* mtxB is defined only for tradition; it is not used currently */
1517 VG_STATIC int rb_capsule__scene( m4x3f mtxA, rb_capsule *c,
1518 m4x3f mtxB, rb_scene *s,
1519 rb_ct *buf )
1520 {
1521 bh_iter it;
1522 bh_iter_init( 0, &it );
1523 int idx;
1524 int count = 0;
1525
1526 boxf bbx;
1527 v3_sub( mtxA[3], (v3f){ c->height, c->height, c->height }, bbx[0] );
1528 v3_add( mtxA[3], (v3f){ c->height, c->height, c->height }, bbx[1] );
1529
1530 scene *sc = s->bh_scene->user;
1531
1532 while( bh_next( s->bh_scene, &it, bbx, &idx ) ){
1533 u32 *ptri = &sc->arrindices[ idx*3 ];
1534 v3f tri[3];
1535
1536 for( int j=0; j<3; j++ )
1537 v3_copy( sc->arrvertices[ptri[j]].co, tri[j] );
1538
1539 buf[ count ].element_id = ptri[0];
1540
1541 int contact = rb_capsule__triangle( mtxA, c, tri, &buf[count] );
1542 count += contact;
1543
1544 if( count >= 16 ){
1545 vg_warn("Exceeding capsule_vs_scene capacity. Geometry too dense!\n");
1546 return count;
1547 }
1548 }
1549
1550 return count;
1551 }
1552
1553 VG_STATIC int rb_global_has_space( void )
1554 {
1555 if( rb_contact_count + 16 > vg_list_size(rb_contact_buffer) )
1556 return 0;
1557
1558 return 1;
1559 }
1560
1561 VG_STATIC rb_ct *rb_global_buffer( void )
1562 {
1563 return &rb_contact_buffer[ rb_contact_count ];
1564 }
1565
1566 /*
1567 * -----------------------------------------------------------------------------
1568 * Dynamics
1569 * -----------------------------------------------------------------------------
1570 */
1571
1572 VG_STATIC void rb_solver_reset(void)
1573 {
1574 rb_contact_count = 0;
1575 }
1576
1577 VG_STATIC rb_ct *rb_global_ct(void)
1578 {
1579 return rb_contact_buffer + rb_contact_count;
1580 }
1581
1582 VG_STATIC void rb_prepare_contact( rb_ct *ct, float timestep )
1583 {
1584 ct->bias = -0.2f * (timestep*3600.0f)
1585 * vg_minf( 0.0f, -ct->p+k_penetration_slop );
1586
1587 rb_tangent_basis( ct->n, ct->t[0], ct->t[1] );
1588 ct->norm_impulse = 0.0f;
1589 ct->tangent_impulse[0] = 0.0f;
1590 ct->tangent_impulse[1] = 0.0f;
1591 }
1592
1593 /* calculate total move. manifold should belong to ONE object only */
1594 VG_STATIC void rb_depenetrate( rb_ct *manifold, int len, v3f dt )
1595 {
1596 v3_zero( dt );
1597
1598 for( int j=0; j<7; j++ )
1599 {
1600 for( int i=0; i<len; i++ )
1601 {
1602 struct contact *ct = &manifold[i];
1603
1604 float resolved_amt = v3_dot( ct->n, dt ),
1605 remaining = (ct->p-k_penetration_slop) - resolved_amt,
1606 apply = vg_maxf( remaining, 0.0f ) * 0.4f;
1607
1608 v3_muladds( dt, ct->n, apply, dt );
1609 }
1610 }
1611 }
1612
1613 /*
1614 * Initializing things like tangent vectors
1615 */
1616 VG_STATIC void rb_presolve_contacts( rb_ct *buffer, int len )
1617 {
1618 for( int i=0; i<len; i++ ){
1619 rb_ct *ct = &buffer[i];
1620 rb_prepare_contact( ct, k_rb_delta );
1621
1622 v3f ra, rb, raCn, rbCn, raCt, rbCt;
1623 v3_sub( ct->co, ct->rba->co, ra );
1624 v3_sub( ct->co, ct->rbb->co, rb );
1625 v3_cross( ra, ct->n, raCn );
1626 v3_cross( rb, ct->n, rbCn );
1627
1628 /* orient inverse inertia tensors */
1629 v3f raCnI, rbCnI;
1630 m3x3_mulv( ct->rba->iIw, raCn, raCnI );
1631 m3x3_mulv( ct->rbb->iIw, rbCn, rbCnI );
1632
1633 ct->normal_mass = ct->rba->inv_mass + ct->rbb->inv_mass;
1634 ct->normal_mass += v3_dot( raCn, raCnI );
1635 ct->normal_mass += v3_dot( rbCn, rbCnI );
1636 ct->normal_mass = 1.0f/ct->normal_mass;
1637
1638 for( int j=0; j<2; j++ ){
1639 v3f raCtI, rbCtI;
1640 v3_cross( ct->t[j], ra, raCt );
1641 v3_cross( ct->t[j], rb, rbCt );
1642 m3x3_mulv( ct->rba->iIw, raCt, raCtI );
1643 m3x3_mulv( ct->rbb->iIw, rbCt, rbCtI );
1644
1645 ct->tangent_mass[j] = ct->rba->inv_mass + ct->rbb->inv_mass;
1646 ct->tangent_mass[j] += v3_dot( raCt, raCtI );
1647 ct->tangent_mass[j] += v3_dot( rbCt, rbCtI );
1648 ct->tangent_mass[j] = 1.0f/ct->tangent_mass[j];
1649 }
1650
1651 rb_debug_contact( ct );
1652 }
1653 }
1654
1655 /*
1656 * Creates relative contact velocity vector
1657 */
1658 VG_STATIC void rb_rcv( rigidbody *rba, rigidbody *rbb, v3f ra, v3f rb, v3f rv )
1659 {
1660 v3f rva, rvb;
1661 v3_cross( rba->w, ra, rva );
1662 v3_add( rba->v, rva, rva );
1663 v3_cross( rbb->w, rb, rvb );
1664 v3_add( rbb->v, rvb, rvb );
1665
1666 v3_sub( rva, rvb, rv );
1667 }
1668
1669 VG_STATIC void rb_contact_restitution( rb_ct *ct, float cr )
1670 {
1671 v3f rv, ra, rb;
1672 v3_sub( ct->co, ct->rba->co, ra );
1673 v3_sub( ct->co, ct->rbb->co, rb );
1674 rb_rcv( ct->rba, ct->rbb, ra, rb, rv );
1675
1676 float v = v3_dot( rv, ct->n );
1677
1678 if( v < -1.0f ){
1679 ct->bias += -cr * v;
1680 }
1681 }
1682
1683 /*
1684 * Apply impulse to object
1685 */
1686 VG_STATIC void rb_linear_impulse( rigidbody *rb, v3f delta, v3f impulse )
1687 {
1688 /* linear */
1689 v3_muladds( rb->v, impulse, rb->inv_mass, rb->v );
1690
1691 /* Angular velocity */
1692 v3f wa;
1693 v3_cross( delta, impulse, wa );
1694
1695 m3x3_mulv( rb->iIw, wa, wa );
1696 v3_add( rb->w, wa, rb->w );
1697 }
1698
1699 /*
1700 * One iteration to solve the contact constraint
1701 */
1702 VG_STATIC void rb_solve_contacts( rb_ct *buf, int len )
1703 {
1704 for( int i=0; i<len; i++ ){
1705 struct contact *ct = &buf[i];
1706
1707 v3f rv, ra, rb;
1708 v3_sub( ct->co, ct->rba->co, ra );
1709 v3_sub( ct->co, ct->rbb->co, rb );
1710 rb_rcv( ct->rba, ct->rbb, ra, rb, rv );
1711
1712 /* Friction */
1713 for( int j=0; j<2; j++ ){
1714 float f = k_friction * ct->norm_impulse,
1715 vt = v3_dot( rv, ct->t[j] ),
1716 lambda = ct->tangent_mass[j] * -vt;
1717
1718 float temp = ct->tangent_impulse[j];
1719 ct->tangent_impulse[j] = vg_clampf( temp + lambda, -f, f );
1720 lambda = ct->tangent_impulse[j] - temp;
1721
1722 v3f impulse;
1723 v3_muls( ct->t[j], lambda, impulse );
1724 rb_linear_impulse( ct->rba, ra, impulse );
1725
1726 v3_muls( ct->t[j], -lambda, impulse );
1727 rb_linear_impulse( ct->rbb, rb, impulse );
1728 }
1729
1730 /* Normal */
1731 rb_rcv( ct->rba, ct->rbb, ra, rb, rv );
1732 float vn = v3_dot( rv, ct->n ),
1733 lambda = ct->normal_mass * (-vn + ct->bias);
1734
1735 float temp = ct->norm_impulse;
1736 ct->norm_impulse = vg_maxf( temp + lambda, 0.0f );
1737 lambda = ct->norm_impulse - temp;
1738
1739 v3f impulse;
1740 v3_muls( ct->n, lambda, impulse );
1741 rb_linear_impulse( ct->rba, ra, impulse );
1742
1743 v3_muls( ct->n, -lambda, impulse );
1744 rb_linear_impulse( ct->rbb, rb, impulse );
1745 }
1746 }
1747
1748 /*
1749 * -----------------------------------------------------------------------------
1750 * Constraints
1751 * -----------------------------------------------------------------------------
1752 */
1753
1754 VG_STATIC void rb_debug_position_constraints( rb_constr_pos *buffer, int len )
1755 {
1756 for( int i=0; i<len; i++ ){
1757 rb_constr_pos *constr = &buffer[i];
1758 rigidbody *rba = constr->rba, *rbb = constr->rbb;
1759
1760 v3f wca, wcb;
1761 m3x3_mulv( rba->to_world, constr->lca, wca );
1762 m3x3_mulv( rbb->to_world, constr->lcb, wcb );
1763
1764 v3f p0, p1;
1765 v3_add( wca, rba->co, p0 );
1766 v3_add( wcb, rbb->co, p1 );
1767 vg_line_pt3( p0, 0.0025f, 0xff000000 );
1768 vg_line_pt3( p1, 0.0025f, 0xffffffff );
1769 vg_line2( p0, p1, 0xff000000, 0xffffffff );
1770 }
1771 }
1772
1773 VG_STATIC void rb_presolve_swingtwist_constraints( rb_constr_swingtwist *buf,
1774 int len )
1775 {
1776 float size = 0.12f;
1777
1778 for( int i=0; i<len; i++ ){
1779 rb_constr_swingtwist *st = &buf[ i ];
1780
1781 v3f vx, vy, va, vxb, axis, center;
1782
1783 m3x3_mulv( st->rba->to_world, st->conevx, vx );
1784 m3x3_mulv( st->rbb->to_world, st->conevxb, vxb );
1785 m3x3_mulv( st->rba->to_world, st->conevy, vy );
1786 m3x3_mulv( st->rbb->to_world, st->coneva, va );
1787 m4x3_mulv( st->rba->to_world, st->view_offset, center );
1788 v3_cross( vy, vx, axis );
1789
1790 /* Constraint violated ? */
1791 float fx = v3_dot( vx, va ), /* projection world */
1792 fy = v3_dot( vy, va ),
1793 fn = v3_dot( va, axis ),
1794
1795 rx = st->conevx[3], /* elipse radii */
1796 ry = st->conevy[3],
1797
1798 lx = fx/rx, /* projection local (fn==lz) */
1799 ly = fy/ry;
1800
1801 st->tangent_violation = ((lx*lx + ly*ly) > fn*fn) || (fn <= 0.0f);
1802 if( st->tangent_violation ){
1803 /* Calculate a good position and the axis to solve on */
1804 v2f closest, tangent,
1805 p = { fx/fabsf(fn), fy/fabsf(fn) };
1806
1807 closest_point_elipse( p, (v2f){rx,ry}, closest );
1808 tangent[0] = -closest[1] / (ry*ry);
1809 tangent[1] = closest[0] / (rx*rx);
1810 v2_normalize( tangent );
1811
1812 v3f v0, v1;
1813 v3_muladds( axis, vx, closest[0], v0 );
1814 v3_muladds( v0, vy, closest[1], v0 );
1815 v3_normalize( v0 );
1816
1817 v3_muls( vx, tangent[0], v1 );
1818 v3_muladds( v1, vy, tangent[1], v1 );
1819
1820 v3_copy( v0, st->tangent_target );
1821 v3_copy( v1, st->tangent_axis );
1822
1823 /* calculate mass */
1824 v3f aIw, bIw;
1825 m3x3_mulv( st->rba->iIw, st->tangent_axis, aIw );
1826 m3x3_mulv( st->rbb->iIw, st->tangent_axis, bIw );
1827 st->tangent_mass = 1.0f / (v3_dot( st->tangent_axis, aIw ) +
1828 v3_dot( st->tangent_axis, bIw ));
1829
1830 float angle = v3_dot( va, st->tangent_target );
1831 }
1832
1833 v3f refaxis;
1834 v3_cross( vy, va, refaxis ); /* our default rotation */
1835 v3_normalize( refaxis );
1836
1837 float angle = v3_dot( refaxis, vxb );
1838 st->axis_violation = fabsf(angle) < st->conet;
1839
1840 if( st->axis_violation ){
1841 v3f dir_test;
1842 v3_cross( refaxis, vxb, dir_test );
1843
1844 if( v3_dot(dir_test, va) < 0.0f )
1845 st->axis_violation = -st->axis_violation;
1846
1847 float newang = (float)st->axis_violation * acosf(st->conet-0.0001f);
1848
1849 v3f refaxis_up;
1850 v3_cross( va, refaxis, refaxis_up );
1851 v3_muls( refaxis_up, sinf(newang), st->axis_target );
1852 v3_muladds( st->axis_target, refaxis, -cosf(newang), st->axis_target );
1853
1854 /* calculate mass */
1855 v3_copy( va, st->axis );
1856 v3f aIw, bIw;
1857 m3x3_mulv( st->rba->iIw, st->axis, aIw );
1858 m3x3_mulv( st->rbb->iIw, st->axis, bIw );
1859 st->axis_mass = 1.0f / (v3_dot( st->axis, aIw ) +
1860 v3_dot( st->axis, bIw ));
1861 }
1862 }
1863 }
1864
1865 VG_STATIC void rb_debug_swingtwist_constraints( rb_constr_swingtwist *buf,
1866 int len )
1867 {
1868 float size = 0.12f;
1869
1870 for( int i=0; i<len; i++ ){
1871 rb_constr_swingtwist *st = &buf[ i ];
1872
1873 v3f vx, vxb, vy, va, axis, center;
1874
1875 m3x3_mulv( st->rba->to_world, st->conevx, vx );
1876 m3x3_mulv( st->rbb->to_world, st->conevxb, vxb );
1877 m3x3_mulv( st->rba->to_world, st->conevy, vy );
1878 m3x3_mulv( st->rbb->to_world, st->coneva, va );
1879 m4x3_mulv( st->rba->to_world, st->view_offset, center );
1880 v3_cross( vy, vx, axis );
1881
1882 float rx = st->conevx[3], /* elipse radii */
1883 ry = st->conevy[3];
1884
1885 v3f p0, p1;
1886 v3_muladds( center, va, size, p1 );
1887 vg_line( center, p1, 0xffffffff );
1888 vg_line_pt3( p1, 0.00025f, 0xffffffff );
1889
1890 if( st->tangent_violation ){
1891 v3_muladds( center, st->tangent_target, size, p0 );
1892
1893 vg_line( center, p0, 0xff00ff00 );
1894 vg_line_pt3( p0, 0.00025f, 0xff00ff00 );
1895 vg_line( p1, p0, 0xff000000 );
1896 }
1897
1898 for( int x=0; x<32; x++ ){
1899 float t0 = ((float)x * (1.0f/32.0f)) * VG_TAUf,
1900 t1 = (((float)x+1.0f) * (1.0f/32.0f)) * VG_TAUf,
1901 c0 = cosf( t0 ),
1902 s0 = sinf( t0 ),
1903 c1 = cosf( t1 ),
1904 s1 = sinf( t1 );
1905
1906 v3f v0, v1;
1907 v3_muladds( axis, vx, c0*rx, v0 );
1908 v3_muladds( v0, vy, s0*ry, v0 );
1909 v3_muladds( axis, vx, c1*rx, v1 );
1910 v3_muladds( v1, vy, s1*ry, v1 );
1911
1912 v3_normalize( v0 );
1913 v3_normalize( v1 );
1914
1915 v3_muladds( center, v0, size, p0 );
1916 v3_muladds( center, v1, size, p1 );
1917
1918 u32 col0r = fabsf(c0) * 255.0f,
1919 col0g = fabsf(s0) * 255.0f,
1920 col1r = fabsf(c1) * 255.0f,
1921 col1g = fabsf(s1) * 255.0f,
1922 col = st->tangent_violation? 0xff0000ff: 0xff000000,
1923 col0 = col | (col0r<<16) | (col0g << 8),
1924 col1 = col | (col1r<<16) | (col1g << 8);
1925
1926 vg_line2( center, p0, VG__NONE, col0 );
1927 vg_line2( p0, p1, col0, col1 );
1928 }
1929
1930 /* Draw twist */
1931 v3_muladds( center, va, size, p0 );
1932 v3_muladds( p0, vxb, size, p1 );
1933
1934 vg_line( p0, p1, 0xff0000ff );
1935
1936 if( st->axis_violation ){
1937 v3_muladds( p0, st->axis_target, size*1.25f, p1 );
1938 vg_line( p0, p1, 0xffffff00 );
1939 vg_line_pt3( p1, 0.0025f, 0xffffff80 );
1940 }
1941
1942 v3f refaxis;
1943 v3_cross( vy, va, refaxis ); /* our default rotation */
1944 v3_normalize( refaxis );
1945 v3f refaxis_up;
1946 v3_cross( va, refaxis, refaxis_up );
1947 float newang = acosf(st->conet-0.0001f);
1948
1949 v3_muladds( p0, refaxis_up, sinf(newang)*size, p1 );
1950 v3_muladds( p1, refaxis, -cosf(newang)*size, p1 );
1951 vg_line( p0, p1, 0xff000000 );
1952
1953 v3_muladds( p0, refaxis_up, sinf(-newang)*size, p1 );
1954 v3_muladds( p1, refaxis, -cosf(-newang)*size, p1 );
1955 vg_line( p0, p1, 0xff404040 );
1956 }
1957 }
1958
1959 /*
1960 * Solve a list of positional constraints
1961 */
1962 VG_STATIC void rb_solve_position_constraints( rb_constr_pos *buf, int len )
1963 {
1964 for( int i=0; i<len; i++ ){
1965 rb_constr_pos *constr = &buf[i];
1966 rigidbody *rba = constr->rba, *rbb = constr->rbb;
1967
1968 v3f wa, wb;
1969 m3x3_mulv( rba->to_world, constr->lca, wa );
1970 m3x3_mulv( rbb->to_world, constr->lcb, wb );
1971
1972 m3x3f ssra, ssrat, ssrb, ssrbt;
1973
1974 m3x3_skew_symetric( ssrat, wa );
1975 m3x3_skew_symetric( ssrbt, wb );
1976 m3x3_transpose( ssrat, ssra );
1977 m3x3_transpose( ssrbt, ssrb );
1978
1979 v3f b, b_wa, b_wb, b_a, b_b;
1980 m3x3_mulv( ssra, rba->w, b_wa );
1981 m3x3_mulv( ssrb, rbb->w, b_wb );
1982 v3_add( rba->v, b_wa, b );
1983 v3_sub( b, rbb->v, b );
1984 v3_sub( b, b_wb, b );
1985 v3_muls( b, -1.0f, b );
1986
1987 m3x3f invMa, invMb;
1988 m3x3_diagonal( invMa, rba->inv_mass );
1989 m3x3_diagonal( invMb, rbb->inv_mass );
1990
1991 m3x3f ia, ib;
1992 m3x3_mul( ssra, rba->iIw, ia );
1993 m3x3_mul( ia, ssrat, ia );
1994 m3x3_mul( ssrb, rbb->iIw, ib );
1995 m3x3_mul( ib, ssrbt, ib );
1996
1997 m3x3f cma, cmb;
1998 m3x3_add( invMa, ia, cma );
1999 m3x3_add( invMb, ib, cmb );
2000
2001 m3x3f A;
2002 m3x3_add( cma, cmb, A );
2003
2004 /* Solve Ax = b ( A^-1*b = x ) */
2005 v3f impulse;
2006 m3x3f invA;
2007 m3x3_inv( A, invA );
2008 m3x3_mulv( invA, b, impulse );
2009
2010 v3f delta_va, delta_wa, delta_vb, delta_wb;
2011 m3x3f iwa, iwb;
2012 m3x3_mul( rba->iIw, ssrat, iwa );
2013 m3x3_mul( rbb->iIw, ssrbt, iwb );
2014
2015 m3x3_mulv( invMa, impulse, delta_va );
2016 m3x3_mulv( invMb, impulse, delta_vb );
2017 m3x3_mulv( iwa, impulse, delta_wa );
2018 m3x3_mulv( iwb, impulse, delta_wb );
2019
2020 v3_add( rba->v, delta_va, rba->v );
2021 v3_add( rba->w, delta_wa, rba->w );
2022 v3_sub( rbb->v, delta_vb, rbb->v );
2023 v3_sub( rbb->w, delta_wb, rbb->w );
2024 }
2025 }
2026
2027 VG_STATIC void rb_solve_swingtwist_constraints( rb_constr_swingtwist *buf,
2028 int len )
2029 {
2030 float size = 0.12f;
2031
2032 for( int i=0; i<len; i++ ){
2033 rb_constr_swingtwist *st = &buf[ i ];
2034
2035 if( !st->axis_violation )
2036 continue;
2037
2038 float rv = v3_dot( st->axis, st->rbb->w ) -
2039 v3_dot( st->axis, st->rba->w );
2040
2041 if( rv * (float)st->axis_violation > 0.0f )
2042 continue;
2043
2044 v3f impulse, wa, wb;
2045 v3_muls( st->axis, rv*st->axis_mass, impulse );
2046 m3x3_mulv( st->rba->iIw, impulse, wa );
2047 v3_add( st->rba->w, wa, st->rba->w );
2048
2049 v3_muls( impulse, -1.0f, impulse );
2050 m3x3_mulv( st->rbb->iIw, impulse, wb );
2051 v3_add( st->rbb->w, wb, st->rbb->w );
2052
2053 float rv2 = v3_dot( st->axis, st->rbb->w ) -
2054 v3_dot( st->axis, st->rba->w );
2055 }
2056
2057 for( int i=0; i<len; i++ ){
2058 rb_constr_swingtwist *st = &buf[ i ];
2059
2060 if( !st->tangent_violation )
2061 continue;
2062
2063 float rv = v3_dot( st->tangent_axis, st->rbb->w ) -
2064 v3_dot( st->tangent_axis, st->rba->w );
2065
2066 if( rv > 0.0f )
2067 continue;
2068
2069 v3f impulse, wa, wb;
2070 v3_muls( st->tangent_axis, rv*st->tangent_mass, impulse );
2071 m3x3_mulv( st->rba->iIw, impulse, wa );
2072 v3_add( st->rba->w, wa, st->rba->w );
2073
2074 v3_muls( impulse, -1.0f, impulse );
2075 m3x3_mulv( st->rbb->iIw, impulse, wb );
2076 v3_add( st->rbb->w, wb, st->rbb->w );
2077
2078 float rv2 = v3_dot( st->tangent_axis, st->rbb->w ) -
2079 v3_dot( st->tangent_axis, st->rba->w );
2080 }
2081 }
2082
2083 VG_STATIC void rb_solve_constr_angle( rigidbody *rba, rigidbody *rbb,
2084 v3f ra, v3f rb )
2085 {
2086 m3x3f ssra, ssrb, ssrat, ssrbt;
2087 m3x3f cma, cmb;
2088
2089 m3x3_skew_symetric( ssrat, ra );
2090 m3x3_skew_symetric( ssrbt, rb );
2091 m3x3_transpose( ssrat, ssra );
2092 m3x3_transpose( ssrbt, ssrb );
2093
2094 m3x3_mul( ssra, rba->iIw, cma );
2095 m3x3_mul( cma, ssrat, cma );
2096 m3x3_mul( ssrb, rbb->iIw, cmb );
2097 m3x3_mul( cmb, ssrbt, cmb );
2098
2099 m3x3f A, invA;
2100 m3x3_add( cma, cmb, A );
2101 m3x3_inv( A, invA );
2102
2103 v3f b_wa, b_wb, b;
2104 m3x3_mulv( ssra, rba->w, b_wa );
2105 m3x3_mulv( ssrb, rbb->w, b_wb );
2106 v3_add( b_wa, b_wb, b );
2107 v3_negate( b, b );
2108
2109 v3f impulse;
2110 m3x3_mulv( invA, b, impulse );
2111
2112 v3f delta_wa, delta_wb;
2113 m3x3f iwa, iwb;
2114 m3x3_mul( rba->iIw, ssrat, iwa );
2115 m3x3_mul( rbb->iIw, ssrbt, iwb );
2116 m3x3_mulv( iwa, impulse, delta_wa );
2117 m3x3_mulv( iwb, impulse, delta_wb );
2118 v3_add( rba->w, delta_wa, rba->w );
2119 v3_sub( rbb->w, delta_wb, rbb->w );
2120 }
2121
2122 /*
2123 * Correct position constraint drift errors
2124 * [ 0.0 <= amt <= 1.0 ]: the correction amount
2125 */
2126 VG_STATIC void rb_correct_position_constraints( rb_constr_pos *buf, int len,
2127 float amt )
2128 {
2129 for( int i=0; i<len; i++ ){
2130 rb_constr_pos *constr = &buf[i];
2131 rigidbody *rba = constr->rba, *rbb = constr->rbb;
2132
2133 v3f p0, p1, d;
2134 m3x3_mulv( rba->to_world, constr->lca, p0 );
2135 m3x3_mulv( rbb->to_world, constr->lcb, p1 );
2136 v3_add( rba->co, p0, p0 );
2137 v3_add( rbb->co, p1, p1 );
2138 v3_sub( p1, p0, d );
2139
2140 v3_muladds( rbb->co, d, -1.0f * amt, rbb->co );
2141 rb_update_transform( rbb );
2142 }
2143 }
2144
2145 VG_STATIC void rb_correct_swingtwist_constraints( rb_constr_swingtwist *buf,
2146 int len, float amt )
2147 {
2148 for( int i=0; i<len; i++ ){
2149 rb_constr_swingtwist *st = &buf[i];
2150
2151 if( !st->tangent_violation )
2152 continue;
2153
2154 v3f va;
2155 m3x3_mulv( st->rbb->to_world, st->coneva, va );
2156
2157 float angle = v3_dot( va, st->tangent_target );
2158
2159 if( fabsf(angle) < 0.9999f ){
2160 v3f axis;
2161 v3_cross( va, st->tangent_target, axis );
2162
2163 v4f correction;
2164 q_axis_angle( correction, axis, acosf(angle) * amt );
2165 q_mul( correction, st->rbb->q, st->rbb->q );
2166 rb_update_transform( st->rbb );
2167 }
2168 }
2169
2170 for( int i=0; i<len; i++ ){
2171 rb_constr_swingtwist *st = &buf[i];
2172
2173 if( !st->axis_violation )
2174 continue;
2175
2176 v3f vxb;
2177 m3x3_mulv( st->rbb->to_world, st->conevxb, vxb );
2178
2179 float angle = v3_dot( vxb, st->axis_target );
2180
2181 if( fabsf(angle) < 0.9999f ){
2182 v3f axis;
2183 v3_cross( vxb, st->axis_target, axis );
2184
2185 v4f correction;
2186 q_axis_angle( correction, axis, acosf(angle) * amt );
2187 q_mul( correction, st->rbb->q, st->rbb->q );
2188 rb_update_transform( st->rbb );
2189 }
2190 }
2191 }
2192
2193 VG_STATIC void rb_correct_contact_constraints( rb_ct *buf, int len, float amt )
2194 {
2195 for( int i=0; i<len; i++ ){
2196 rb_ct *ct = &buf[i];
2197 rigidbody *rba = ct->rba,
2198 *rbb = ct->rbb;
2199
2200 float mass_total = 1.0f / (rba->inv_mass + rbb->inv_mass);
2201
2202 v3_muladds( rba->co, ct->n, -mass_total * rba->inv_mass, rba->co );
2203 v3_muladds( rbb->co, ct->n, mass_total * rbb->inv_mass, rbb->co );
2204 }
2205 }
2206
2207
2208 /*
2209 * Effectors
2210 */
2211
2212 VG_STATIC void rb_effect_simple_bouyency( rigidbody *ra, v4f plane,
2213 float amt, float drag )
2214 {
2215 /* float */
2216 float depth = v3_dot( plane, ra->co ) - plane[3],
2217 lambda = vg_clampf( -depth, 0.0f, 1.0f ) * amt;
2218
2219 v3_muladds( ra->v, plane, lambda * k_rb_delta, ra->v );
2220
2221 if( depth < 0.0f )
2222 v3_muls( ra->v, 1.0f-(drag*k_rb_delta), ra->v );
2223 }
2224
2225 /* apply a spring&dampener force to match ra(worldspace) on rigidbody, to
2226 * rt(worldspace)
2227 */
2228 VG_STATIC void rb_effect_spring_target_vector( rigidbody *rba, v3f ra, v3f rt,
2229 float spring, float dampening,
2230 float timestep )
2231 {
2232 float d = v3_dot( rt, ra );
2233 float a = vg_signf( d ) * acosf( vg_clampf( d, -1.0f, 1.0f ) );
2234
2235 v3f axis;
2236 v3_cross( rt, ra, axis );
2237
2238 float Fs = -a * spring,
2239 Fd = -v3_dot( rba->w, axis ) * dampening;
2240
2241 v3_muladds( rba->w, axis, (Fs+Fd) * timestep, rba->w );
2242 }
2243
2244 #endif /* RIGIDBODY_H */
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