2 * Copyright (C) 2021-2022 Mt.ZERO Software, Harry Godden - All Rights Reserved
34 u32 lower
, upper
, target
, pole
;
43 struct mdl_keyframe
*anim_data
;
52 bindable_count
; /* TODO: try to place IK last in the rig from export
53 so that we dont always upload transforms for
54 useless cpu IK bones. */
57 static u32
skeleton_bone_id( struct skeleton
*skele
, const char *name
)
59 for( u32 i
=0; i
<skele
->bone_count
; i
++ )
61 if( !strcmp( skele
->bones
[i
].name
, name
))
68 static void keyframe_copy_pose( mdl_keyframe
*kfa
, mdl_keyframe
*kfb
, int num
)
70 for( int i
=0; i
<num
; i
++ )
75 * Lerp between two sets of keyframes and store in dest. Rotations use Nlerp.
77 static void keyframe_lerp_pose( mdl_keyframe
*kfa
, mdl_keyframe
*kfb
, float t
,
78 mdl_keyframe
*kfd
, int count
)
82 keyframe_copy_pose( kfa
, kfd
, count
);
87 keyframe_copy_pose( kfb
, kfd
, count
);
91 for( int i
=0; i
<count
; i
++ )
93 v3_lerp( kfa
[i
].co
, kfb
[i
].co
, t
, kfd
[i
].co
);
94 q_nlerp( kfa
[i
].q
, kfb
[i
].q
, t
, kfd
[i
].q
);
95 v3_lerp( kfa
[i
].s
, kfb
[i
].s
, t
, kfd
[i
].s
);
99 static void skeleton_lerp_pose( struct skeleton
*skele
,
100 mdl_keyframe
*kfa
, mdl_keyframe
*kfb
, float t
,
103 keyframe_lerp_pose( kfa
, kfb
, t
, kfd
, skele
->bone_count
-1 );
107 * Sample animation between 2 closest frames using time value. Output is a
108 * keyframe buffer that is allocated with an appropriate size
110 static void skeleton_sample_anim( struct skeleton
*skele
,
111 struct skeleton_anim
*anim
,
113 mdl_keyframe
*output
)
115 float animtime
= time
*anim
->rate
;
117 u32 frame
= ((u32
)animtime
) % anim
->length
,
118 next
= (frame
+1) % anim
->length
;
120 float t
= vg_fractf( animtime
);
122 mdl_keyframe
*base
= anim
->anim_data
+ (skele
->bone_count
-1)*frame
,
123 *nbase
= anim
->anim_data
+ (skele
->bone_count
-1)*next
;
125 skeleton_lerp_pose( skele
, base
, nbase
, t
, output
);
128 static int skeleton_sample_anim_clamped( struct skeleton
*skele
,
129 struct skeleton_anim
*anim
,
131 mdl_keyframe
*output
)
133 float end
= (float)(anim
->length
-1) / anim
->rate
;
134 skeleton_sample_anim( skele
, anim
, vg_minf( end
, time
), output
);
142 typedef enum anim_apply
145 k_anim_apply_defer_ik
,
146 k_anim_apply_deffered_only
150 static int should_apply_bone( struct skeleton
*skele
, u32 id
, anim_apply type
)
152 struct skeleton_bone
*sb
= &skele
->bones
[ id
],
153 *sp
= &skele
->bones
[ sb
->parent
];
155 if( type
== k_anim_apply_defer_ik
)
157 if( (sp
->ik
&& !sb
->ik
) || sp
->defer
)
168 else if( type
== k_anim_apply_deffered_only
)
180 * Apply block of keyframes to skeletons final pose
182 static void skeleton_apply_pose( struct skeleton
*skele
, mdl_keyframe
*pose
,
183 anim_apply passtype
)
185 m4x3_identity( skele
->final_mtx
[0] );
186 skele
->bones
[0].defer
= 0;
187 skele
->bones
[0].ik
= 0;
189 for( int i
=1; i
<skele
->bone_count
; i
++ )
191 struct skeleton_bone
*sb
= &skele
->bones
[i
],
192 *sp
= &skele
->bones
[ sb
->parent
];
194 if( !should_apply_bone( skele
, i
, passtype
) )
203 v3_sub( skele
->bones
[i
].co
, skele
->bones
[sb
->parent
].co
, temp_delta
);
206 mdl_keyframe
*kf
= &pose
[i
-1];
207 q_m3x3( kf
->q
, posemtx
);
208 v3_copy( kf
->co
, posemtx
[3] );
209 v3_add( temp_delta
, posemtx
[3], posemtx
[3] );
212 m4x3_mul( skele
->final_mtx
[ sb
->parent
], posemtx
, skele
->final_mtx
[i
] );
217 * creates the reference inverse matrix for an IK bone, as it has an initial
218 * intrisic rotation based on the direction that the IK is setup..
220 static void skeleton_inverse_for_ik( struct skeleton
*skele
,
222 u32 id
, m3x3f inverse
)
224 v3_copy( ivaxis
, inverse
[0] );
225 v3_copy( skele
->bones
[id
].end
, inverse
[1] );
226 v3_normalize( inverse
[1] );
227 v3_cross( inverse
[0], inverse
[1], inverse
[2] );
228 m3x3_transpose( inverse
, inverse
);
232 * Creates inverse rotation matrices which the IK system uses.
234 static void skeleton_create_inverses( struct skeleton
*skele
)
236 /* IK: inverse 'plane-bone space' axis '(^axis,^bone,...)[base] */
237 for( int i
=0; i
<skele
->ik_count
; i
++ )
239 struct skeleton_ik
*ik
= &skele
->ik
[i
];
242 v3f iv0
, iv1
, ivaxis
;
243 v3_sub( skele
->bones
[ik
->target
].co
, skele
->bones
[ik
->lower
].co
, iv0
);
244 v3_sub( skele
->bones
[ik
->pole
].co
, skele
->bones
[ik
->lower
].co
, iv1
);
245 v3_cross( iv0
, iv1
, ivaxis
);
246 v3_normalize( ivaxis
);
248 skeleton_inverse_for_ik( skele
, ivaxis
, ik
->lower
, ik
->ia
);
249 skeleton_inverse_for_ik( skele
, ivaxis
, ik
->upper
, ik
->ib
);
254 * Apply a model matrix to all bones, should be done last
256 static void skeleton_apply_transform( struct skeleton
*skele
, m4x3f transform
)
258 for( int i
=0; i
<skele
->bone_count
; i
++ )
260 struct skeleton_bone
*sb
= &skele
->bones
[i
];
261 m4x3_mul( transform
, skele
->final_mtx
[i
], skele
->final_mtx
[i
] );
266 * Apply an inverse matrix to all bones which maps vertices from bind space into
267 * bone relative positions
269 static void skeleton_apply_inverses( struct skeleton
*skele
)
271 for( int i
=0; i
<skele
->bone_count
; i
++ )
273 struct skeleton_bone
*sb
= &skele
->bones
[i
];
275 m3x3_identity( inverse
);
276 v3_negate( sb
->co
, inverse
[3] );
278 m4x3_mul( skele
->final_mtx
[i
], inverse
, skele
->final_mtx
[i
] );
283 * Apply all IK modifiers (2 bone ik reference from blender is supported)
285 static void skeleton_apply_ik_pass( struct skeleton
*skele
)
287 for( int i
=0; i
<skele
->ik_count
; i
++ )
289 struct skeleton_ik
*ik
= &skele
->ik
[i
];
291 v3f v0
, /* base -> target */
292 v1
, /* base -> pole */
299 v3_copy( skele
->final_mtx
[ik
->lower
][3], co_base
);
300 v3_copy( skele
->final_mtx
[ik
->target
][3], co_target
);
301 v3_copy( skele
->final_mtx
[ik
->pole
][3], co_pole
);
303 v3_sub( co_target
, co_base
, v0
);
304 v3_sub( co_pole
, co_base
, v1
);
305 v3_cross( v0
, v1
, vaxis
);
306 v3_normalize( vaxis
);
308 v3_cross( vaxis
, v0
, v1
);
310 /* localize problem into [x:v0,y:v1] 2d plane */
311 v2f base
= { v3_dot( v0
, co_base
), v3_dot( v1
, co_base
) },
312 end
= { v3_dot( v0
, co_target
), v3_dot( v1
, co_target
) },
315 /* Compute angles (basic trig)*/
317 v2_sub( end
, base
, delta
);
320 l1
= v3_length( skele
->bones
[ik
->lower
].end
),
321 l2
= v3_length( skele
->bones
[ik
->upper
].end
),
322 d
= vg_clampf( v2_length(delta
), fabsf(l1
- l2
), l1
+l2
-0.00001f
),
323 c
= acosf( (l1
*l1
+ d
*d
- l2
*l2
) / (2.0f
*l1
*d
) ),
324 rot
= atan2f( delta
[1], delta
[0] ) + c
- VG_PIf
/2.0f
;
326 knee
[0] = sinf(-rot
) * l1
;
327 knee
[1] = cosf(-rot
) * l1
;
329 m4x3_identity( skele
->final_mtx
[ik
->lower
] );
330 m4x3_identity( skele
->final_mtx
[ik
->upper
] );
332 /* create rotation matrix */
334 v3_muladds( co_base
, v0
, knee
[0], co_knee
);
335 v3_muladds( co_knee
, v1
, knee
[1], co_knee
);
336 vg_line( co_base
, co_knee
, 0xff00ff00 );
339 v3_copy( vaxis
, transform
[0] );
340 v3_muls( v0
, knee
[0], transform
[1] );
341 v3_muladds( transform
[1], v1
, knee
[1], transform
[1] );
342 v3_normalize( transform
[1] );
343 v3_cross( transform
[0], transform
[1], transform
[2] );
344 v3_copy( co_base
, transform
[3] );
346 m3x3_mul( transform
, ik
->ia
, transform
);
347 m4x3_copy( transform
, skele
->final_mtx
[ik
->lower
] );
349 /* upper/knee bone */
350 v3_copy( vaxis
, transform
[0] );
351 v3_sub( co_target
, co_knee
, transform
[1] );
352 v3_normalize( transform
[1] );
353 v3_cross( transform
[0], transform
[1], transform
[2] );
354 v3_copy( co_knee
, transform
[3] );
356 m3x3_mul( transform
, ik
->ib
, transform
);
357 m4x3_copy( transform
, skele
->final_mtx
[ik
->upper
] );
362 * Applies the typical operations that you want for an IK rig:
363 * Pose, IK, Pose(deferred), Inverses, Transform
365 static void skeleton_apply_standard( struct skeleton
*skele
, mdl_keyframe
*pose
,
368 skeleton_apply_pose( skele
, pose
, k_anim_apply_defer_ik
);
369 skeleton_apply_ik_pass( skele
);
370 skeleton_apply_pose( skele
, pose
, k_anim_apply_deffered_only
);
371 skeleton_apply_inverses( skele
);
372 skeleton_apply_transform( skele
, transform
);
376 * Get an animation by name
378 static struct skeleton_anim
*skeleton_get_anim( struct skeleton
*skele
,
381 for( int i
=0; i
<skele
->anim_count
; i
++ )
383 struct skeleton_anim
*anim
= &skele
->anims
[i
];
385 if( !strcmp( anim
->name
, name
) )
392 /* Setup an animated skeleton from model */
393 static int skeleton_setup( struct skeleton
*skele
, mdl_header
*mdl
)
395 u32 bone_count
= 1, skeleton_root
= 0, ik_count
= 0, collider_count
= 0;
396 skele
->bone_count
= 0;
398 skele
->final_mtx
= NULL
;
401 struct classtype_skeleton
*inf
= NULL
;
403 for( u32 i
=0; i
<mdl
->node_count
; i
++ )
405 mdl_node
*pnode
= mdl_node_from_id( mdl
, i
);
407 if( pnode
->classtype
== k_classtype_skeleton
)
409 inf
= mdl_get_entdata( mdl
, pnode
);
410 if( skele
->bone_count
)
412 vg_error( "Multiple skeletons in model file\n" );
416 skele
->bone_count
= inf
->channels
;
417 skele
->ik_count
= inf
->ik_count
;
418 skele
->collider_count
= inf
->collider_count
;
419 skele
->bones
=vg_alloc(sizeof(struct skeleton_bone
)*skele
->bone_count
);
420 skele
->ik
= vg_alloc(sizeof(struct skeleton_ik
)*skele
->ik_count
);
423 else if( skele
->bone_count
)
425 int is_bone
= pnode
->classtype
== k_classtype_bone
;
429 if( bone_count
== skele
->bone_count
)
431 vg_error( "too many bones (%u/%u) @%s!\n",
432 bone_count
, skele
->bone_count
,
433 mdl_pstr( mdl
, pnode
->pstr_name
));
438 struct skeleton_bone
*sb
= &skele
->bones
[bone_count
];
439 struct classtype_bone
*bone_inf
= mdl_get_entdata( mdl
, pnode
);
440 int is_ik
= bone_inf
->ik_target
;
442 v3_copy( pnode
->co
, sb
->co
);
443 v3_copy( pnode
->s
, sb
->end
);
444 sb
->parent
= pnode
->parent
-skeleton_root
;
445 strncpy( sb
->name
, mdl_pstr(mdl
,pnode
->pstr_name
), 15 );
446 sb
->deform
= bone_inf
->deform
;
450 sb
->ik
= 1; /* TODO: place into new IK array */
451 skele
->bones
[ sb
->parent
].ik
= 1;
453 if( ik_count
== skele
->ik_count
)
455 vg_error( "Too many ik bones, corrupt model file\n" );
459 struct skeleton_ik
*ik
= &skele
->ik
[ ik_count
++ ];
460 ik
->upper
= bone_count
;
461 ik
->lower
= sb
->parent
;
462 ik
->target
= bone_inf
->ik_target
;
463 ik
->pole
= bone_inf
->ik_pole
;
470 sb
->collider
= bone_inf
->collider
;
472 box_copy( bone_inf
->hitbox
, sb
->hitbox
);
474 if( bone_inf
->collider
)
476 if( collider_count
== skele
->collider_count
)
478 vg_error( "Too many collider bones\n" );
496 vg_error( "No skeleton in model\n" );
500 if( collider_count
!= skele
->collider_count
)
502 vg_error( "Loaded %u colliders out of %u\n", collider_count
,
503 skele
->collider_count
);
507 if( bone_count
!= skele
->bone_count
)
509 vg_error( "Loaded %u bones out of %u\n", bone_count
, skele
->bone_count
);
513 if( ik_count
!= skele
->ik_count
)
515 vg_error( "Loaded %u ik bones out of %u\n", ik_count
, skele
->ik_count
);
519 /* fill in implicit root bone */
520 v3_zero( skele
->bones
[0].co
);
521 v3_copy( (v3f
){0.0f
,1.0f
,0.0f
}, skele
->bones
[0].end
);
522 skele
->bones
[0].parent
= 0xffffffff;
523 skele
->bones
[0].collider
= 0;
525 skele
->final_mtx
= vg_alloc( sizeof(m4x3f
) * skele
->bone_count
);
526 skele
->anim_count
= inf
->anim_count
;
527 skele
->anims
= vg_alloc( sizeof(struct skeleton_anim
) * inf
->anim_count
);
529 for( int i
=0; i
<inf
->anim_count
; i
++ )
531 mdl_animation
*anim
=
532 mdl_animation_from_id( mdl
, inf
->anim_start
+i
);
534 skele
->anims
[i
].rate
= anim
->rate
;
535 skele
->anims
[i
].length
= anim
->length
;
536 strncpy( skele
->anims
[i
].name
, mdl_pstr(mdl
, anim
->pstr_name
), 31 );
538 u32 total_keyframes
= (skele
->bone_count
-1)*anim
->length
;
539 size_t block_size
= sizeof(mdl_keyframe
) * total_keyframes
;
540 mdl_keyframe
*dst
= vg_alloc( block_size
);
542 skele
->anims
[i
].anim_data
= dst
;
543 memcpy( dst
, mdl_get_animdata( mdl
, anim
), block_size
);
546 skeleton_create_inverses( skele
);
547 vg_success( "Loaded skeleton with %u bones\n", skele
->bone_count
);
548 vg_success( " %u colliders\n", skele
->collider_count
);
552 vg_free( skele
->bones
);
553 vg_free( skele
->ik
);
557 static void skeleton_debug( struct skeleton
*skele
)
559 for( int i
=0; i
<skele
->bone_count
; i
++ )
561 struct skeleton_bone
*sb
= &skele
->bones
[i
];
564 v3_copy( sb
->co
, p0
);
565 v3_add( p0
, sb
->end
, p1
);
566 //vg_line( p0, p1, 0xffffffff );
568 m4x3_mulv( skele
->final_mtx
[i
], p0
, p0
);
569 m4x3_mulv( skele
->final_mtx
[i
], p1
, p1
);
575 vg_line( p0
, p1
, 0xff0000ff );
579 vg_line( p0
, p1
, 0xffcccccc );
583 vg_line( p0
, p1
, 0xff00ffff );
587 #endif /* SKELETON_H */