2 * Copyright (C) 2021-2022 Mt.ZERO Software, Harry Godden - All Rights Reserved
36 mdl_keyframe
*anim_data
;
45 u32 lower
, upper
, target
, pole
;
56 VG_STATIC u32
skeleton_bone_id( struct skeleton
*skele
, const char *name
)
58 for( u32 i
=1; i
<skele
->bone_count
; i
++ ){
59 if( !strcmp( skele
->bones
[i
].name
, name
))
63 vg_error( "skeleton_bone_id( *, \"%s\" );\n", name
);
64 vg_fatal_error( "Bone does not exist\n" );
69 VG_STATIC
void keyframe_copy_pose( mdl_keyframe
*kfa
, mdl_keyframe
*kfb
,
72 for( int i
=0; i
<num
; i
++ )
77 /* apply a rotation from the perspective of root */
78 VG_STATIC
void keyframe_rotate_around( mdl_keyframe
*kf
,
79 v3f origin
, v3f offset
, v4f q
)
82 v3_add( kf
->co
, offset
, co
);
83 v3_sub( co
, origin
, v0
);
85 v3_add( v0
, origin
, co
);
86 v3_sub( co
, offset
, kf
->co
);
88 q_mul( q
, kf
->q
, kf
->q
);
93 * Lerp between two sets of keyframes and store in dest. Rotations use Nlerp.
95 VG_STATIC
void keyframe_lerp_pose( mdl_keyframe
*kfa
, mdl_keyframe
*kfb
,
96 float t
, mdl_keyframe
*kfd
, int count
)
99 keyframe_copy_pose( kfa
, kfd
, count
);
102 else if( t
>= 0.9999f
){
103 keyframe_copy_pose( kfb
, kfd
, count
);
107 for( int i
=0; i
<count
; i
++ ){
108 v3_lerp( kfa
[i
].co
, kfb
[i
].co
, t
, kfd
[i
].co
);
109 q_nlerp( kfa
[i
].q
, kfb
[i
].q
, t
, kfd
[i
].q
);
110 v3_lerp( kfa
[i
].s
, kfb
[i
].s
, t
, kfd
[i
].s
);
115 void skeleton_lerp_pose( struct skeleton
*skele
,
116 mdl_keyframe
*kfa
, mdl_keyframe
*kfb
, float t
,
119 keyframe_lerp_pose( kfa
, kfb
, t
, kfd
, skele
->bone_count
-1 );
122 VG_STATIC
void skeleton_copy_pose( struct skeleton
*skele
,
123 mdl_keyframe
*kfa
, mdl_keyframe
*kfd
)
125 keyframe_copy_pose( kfa
, kfd
, skele
->bone_count
-1 );
129 * Sample animation between 2 closest frames using time value. Output is a
130 * keyframe buffer that is allocated with an appropriate size
132 VG_STATIC
void skeleton_sample_anim( struct skeleton
*skele
,
133 struct skeleton_anim
*anim
,
135 mdl_keyframe
*output
)
137 float animtime
= time
*anim
->rate
;
139 u32 frame
= ((u32
)animtime
) % anim
->length
,
140 next
= (frame
+1) % anim
->length
;
142 float t
= vg_fractf( animtime
);
144 mdl_keyframe
*base
= anim
->anim_data
+ (skele
->bone_count
-1)*frame
,
145 *nbase
= anim
->anim_data
+ (skele
->bone_count
-1)*next
;
147 skeleton_lerp_pose( skele
, base
, nbase
, t
, output
);
150 VG_STATIC
int skeleton_sample_anim_clamped( struct skeleton
*skele
,
151 struct skeleton_anim
*anim
,
153 mdl_keyframe
*output
)
155 float end
= (float)(anim
->length
-1) / anim
->rate
;
156 skeleton_sample_anim( skele
, anim
, vg_minf( end
, time
), output
);
164 typedef enum anim_apply
167 k_anim_apply_defer_ik
,
168 k_anim_apply_deffered_only
173 int should_apply_bone( struct skeleton
*skele
, u32 id
, anim_apply type
)
175 struct skeleton_bone
*sb
= &skele
->bones
[ id
],
176 *sp
= &skele
->bones
[ sb
->parent
];
178 if( type
== k_anim_apply_defer_ik
){
179 if( ((sp
->flags
& k_bone_flag_ik
) && !(sb
->flags
& k_bone_flag_ik
))
190 else if( type
== k_anim_apply_deffered_only
){
201 * Apply block of keyframes to skeletons final pose
203 VG_STATIC
void skeleton_apply_pose( struct skeleton
*skele
, mdl_keyframe
*pose
,
204 anim_apply passtype
)
206 m4x3_identity( skele
->final_mtx
[0] );
207 skele
->bones
[0].defer
= 0;
208 skele
->bones
[0].flags
&= ~k_bone_flag_ik
;
210 for( u32 i
=1; i
<skele
->bone_count
; i
++ ){
211 struct skeleton_bone
*sb
= &skele
->bones
[i
],
212 *sp
= &skele
->bones
[sb
->parent
];
214 if( !should_apply_bone( skele
, i
, passtype
) )
223 v3_sub( skele
->bones
[i
].co
, skele
->bones
[sb
->parent
].co
, temp_delta
);
226 mdl_keyframe
*kf
= &pose
[i
-1];
227 q_m3x3( kf
->q
, posemtx
);
228 v3_copy( kf
->co
, posemtx
[3] );
229 v3_add( temp_delta
, posemtx
[3], posemtx
[3] );
232 m4x3_mul( skele
->final_mtx
[ sb
->parent
], posemtx
, skele
->final_mtx
[i
] );
237 * creates the reference inverse matrix for an IK bone, as it has an initial
238 * intrisic rotation based on the direction that the IK is setup..
240 VG_STATIC
void skeleton_inverse_for_ik( struct skeleton
*skele
,
242 u32 id
, m3x3f inverse
)
244 v3_copy( ivaxis
, inverse
[0] );
245 v3_copy( skele
->bones
[id
].end
, inverse
[1] );
246 v3_normalize( inverse
[1] );
247 v3_cross( inverse
[0], inverse
[1], inverse
[2] );
248 m3x3_transpose( inverse
, inverse
);
252 * Creates inverse rotation matrices which the IK system uses.
254 VG_STATIC
void skeleton_create_inverses( struct skeleton
*skele
)
256 /* IK: inverse 'plane-bone space' axis '(^axis,^bone,...)[base] */
257 for( u32 i
=0; i
<skele
->ik_count
; i
++ ){
258 struct skeleton_ik
*ik
= &skele
->ik
[i
];
261 v3f iv0
, iv1
, ivaxis
;
262 v3_sub( skele
->bones
[ik
->target
].co
, skele
->bones
[ik
->lower
].co
, iv0
);
263 v3_sub( skele
->bones
[ik
->pole
].co
, skele
->bones
[ik
->lower
].co
, iv1
);
264 v3_cross( iv0
, iv1
, ivaxis
);
265 v3_normalize( ivaxis
);
267 skeleton_inverse_for_ik( skele
, ivaxis
, ik
->lower
, ik
->ia
);
268 skeleton_inverse_for_ik( skele
, ivaxis
, ik
->upper
, ik
->ib
);
273 * Apply a model matrix to all bones, should be done last
276 void skeleton_apply_transform( struct skeleton
*skele
, m4x3f transform
)
278 for( u32 i
=0; i
<skele
->bone_count
; i
++ ){
279 struct skeleton_bone
*sb
= &skele
->bones
[i
];
280 m4x3_mul( transform
, skele
->final_mtx
[i
], skele
->final_mtx
[i
] );
285 * Apply an inverse matrix to all bones which maps vertices from bind space into
286 * bone relative positions
288 VG_STATIC
void skeleton_apply_inverses( struct skeleton
*skele
)
290 for( u32 i
=0; i
<skele
->bone_count
; i
++ ){
291 struct skeleton_bone
*sb
= &skele
->bones
[i
];
293 m3x3_identity( inverse
);
294 v3_negate( sb
->co
, inverse
[3] );
296 m4x3_mul( skele
->final_mtx
[i
], inverse
, skele
->final_mtx
[i
] );
301 * Apply all IK modifiers (2 bone ik reference from blender is supported)
303 VG_STATIC
void skeleton_apply_ik_pass( struct skeleton
*skele
)
305 for( u32 i
=0; i
<skele
->ik_count
; i
++ ){
306 struct skeleton_ik
*ik
= &skele
->ik
[i
];
308 v3f v0
, /* base -> target */
309 v1
, /* base -> pole */
316 v3_copy( skele
->final_mtx
[ik
->lower
][3], co_base
);
317 v3_copy( skele
->final_mtx
[ik
->target
][3], co_target
);
318 v3_copy( skele
->final_mtx
[ik
->pole
][3], co_pole
);
320 v3_sub( co_target
, co_base
, v0
);
321 v3_sub( co_pole
, co_base
, v1
);
322 v3_cross( v0
, v1
, vaxis
);
323 v3_normalize( vaxis
);
325 v3_cross( vaxis
, v0
, v1
);
327 /* localize problem into [x:v0,y:v1] 2d plane */
328 v2f base
= { v3_dot( v0
, co_base
), v3_dot( v1
, co_base
) },
329 end
= { v3_dot( v0
, co_target
), v3_dot( v1
, co_target
) },
332 /* Compute angles (basic trig)*/
334 v2_sub( end
, base
, delta
);
337 l1
= v3_length( skele
->bones
[ik
->lower
].end
),
338 l2
= v3_length( skele
->bones
[ik
->upper
].end
),
339 d
= vg_clampf( v2_length(delta
), fabsf(l1
- l2
), l1
+l2
-0.00001f
),
340 c
= acosf( (l1
*l1
+ d
*d
- l2
*l2
) / (2.0f
*l1
*d
) ),
341 rot
= atan2f( delta
[1], delta
[0] ) + c
- VG_PIf
/2.0f
;
343 knee
[0] = sinf(-rot
) * l1
;
344 knee
[1] = cosf(-rot
) * l1
;
346 m4x3_identity( skele
->final_mtx
[ik
->lower
] );
347 m4x3_identity( skele
->final_mtx
[ik
->upper
] );
349 /* create rotation matrix */
351 v3_muladds( co_base
, v0
, knee
[0], co_knee
);
352 v3_muladds( co_knee
, v1
, knee
[1], co_knee
);
353 vg_line( co_base
, co_knee
, 0xff00ff00 );
356 v3_copy( vaxis
, transform
[0] );
357 v3_muls( v0
, knee
[0], transform
[1] );
358 v3_muladds( transform
[1], v1
, knee
[1], transform
[1] );
359 v3_normalize( transform
[1] );
360 v3_cross( transform
[0], transform
[1], transform
[2] );
361 v3_copy( co_base
, transform
[3] );
363 m3x3_mul( transform
, ik
->ia
, transform
);
364 m4x3_copy( transform
, skele
->final_mtx
[ik
->lower
] );
366 /* upper/knee bone */
367 v3_copy( vaxis
, transform
[0] );
368 v3_sub( co_target
, co_knee
, transform
[1] );
369 v3_normalize( transform
[1] );
370 v3_cross( transform
[0], transform
[1], transform
[2] );
371 v3_copy( co_knee
, transform
[3] );
373 m3x3_mul( transform
, ik
->ib
, transform
);
374 m4x3_copy( transform
, skele
->final_mtx
[ik
->upper
] );
379 * Applies the typical operations that you want for an IK rig:
380 * Pose, IK, Pose(deferred), Inverses, Transform
382 VG_STATIC
void skeleton_apply_standard( struct skeleton
*skele
, mdl_keyframe
*pose
,
385 skeleton_apply_pose( skele
, pose
, k_anim_apply_defer_ik
);
386 skeleton_apply_ik_pass( skele
);
387 skeleton_apply_pose( skele
, pose
, k_anim_apply_deffered_only
);
388 skeleton_apply_inverses( skele
);
389 skeleton_apply_transform( skele
, transform
);
393 * Get an animation by name
395 VG_STATIC
struct skeleton_anim
*skeleton_get_anim( struct skeleton
*skele
,
398 for( u32 i
=0; i
<skele
->anim_count
; i
++ ){
399 struct skeleton_anim
*anim
= &skele
->anims
[i
];
401 if( !strcmp( anim
->name
, name
) )
405 vg_error( "skeleton_get_anim( *, \"%s\" )\n", name
);
406 vg_fatal_error( "Invalid animation name\n" );
411 VG_STATIC
void skeleton_alloc_from( struct skeleton
*skele
,
414 mdl_armature
*armature
)
416 skele
->bone_count
= armature
->bone_count
+1;
417 skele
->anim_count
= armature
->anim_count
;
419 skele
->collider_count
= 0;
421 for( u32 i
=0; i
<armature
->bone_count
; i
++ ){
422 mdl_bone
*bone
= mdl_arritm( &mdl
->bones
, armature
->bone_start
+i
);
424 if( bone
->flags
& k_bone_flag_ik
)
428 skele
->collider_count
++;
431 u32 bone_size
= sizeof(struct skeleton_bone
) * skele
->bone_count
,
432 ik_size
= sizeof(struct skeleton_ik
) * skele
->ik_count
,
433 mtx_size
= sizeof(m4x3f
) * skele
->bone_count
,
434 anim_size
= sizeof(struct skeleton_anim
) * skele
->anim_count
;
436 skele
->bones
= vg_linear_alloc( lin_alloc
, bone_size
);
437 skele
->ik
= vg_linear_alloc( lin_alloc
, ik_size
);
438 skele
->final_mtx
= vg_linear_alloc( lin_alloc
, mtx_size
);
439 skele
->anims
= vg_linear_alloc( lin_alloc
, anim_size
);
442 VG_STATIC
void skeleton_fatal_err(void)
444 vg_fatal_error( "Skeleton setup failed" );
447 /* Setup an animated skeleton from model. mdl's metadata should stick around */
448 VG_STATIC
void skeleton_setup( struct skeleton
*skele
,
449 void *lin_alloc
, mdl_context
*mdl
)
451 u32 ik_count
= 0, collider_count
= 0;
452 skele
->bone_count
= 0;
454 skele
->final_mtx
= NULL
;
457 if( !mdl
->armatures
.count
){
458 vg_error( "No skeleton in model\n" );
459 skeleton_fatal_err();
462 mdl_armature
*armature
= mdl_arritm( &mdl
->armatures
, 0 );
463 skeleton_alloc_from( skele
, lin_alloc
, mdl
, armature
);
465 for( u32 i
=0; i
<armature
->bone_count
; i
++ ){
466 mdl_bone
*bone
= mdl_arritm( &mdl
->bones
, armature
->bone_start
+i
);
467 struct skeleton_bone
*sb
= &skele
->bones
[i
+1];
469 v3_copy( bone
->co
, sb
->co
);
470 v3_copy( bone
->end
, sb
->end
);
472 sb
->parent
= bone
->parent
;
473 sb
->name
= mdl_pstr( mdl
, bone
->pstr_name
);
474 sb
->flags
= bone
->flags
;
475 sb
->collider
= bone
->collider
;
476 sb
->orig_bone
= bone
;
478 if( sb
->flags
& k_bone_flag_ik
){
479 skele
->bones
[ sb
->parent
].flags
|= k_bone_flag_ik
;
481 if( ik_count
== skele
->ik_count
){
482 vg_error( "Too many ik bones, corrupt model file\n" );
483 skeleton_fatal_err();
486 struct skeleton_ik
*ik
= &skele
->ik
[ ik_count
++ ];
488 ik
->lower
= bone
->parent
;
489 ik
->target
= bone
->ik_target
;
490 ik
->pole
= bone
->ik_pole
;
493 box_copy( bone
->hitbox
, sb
->hitbox
);
495 if( bone
->collider
){
496 if( collider_count
== skele
->collider_count
){
497 vg_error( "Too many collider bones\n" );
498 skeleton_fatal_err();
505 /* fill in implicit root bone */
506 v3_zero( skele
->bones
[0].co
);
507 v3_copy( (v3f
){0.0f
,1.0f
,0.0f
}, skele
->bones
[0].end
);
508 skele
->bones
[0].parent
= 0xffffffff;
509 skele
->bones
[0].flags
= 0;
510 skele
->bones
[0].name
= "[root]";
512 /* process animation quick refs */
513 for( u32 i
=0; i
<skele
->anim_count
; i
++ ){
514 mdl_animation
*anim
=
515 mdl_arritm( &mdl
->animations
, armature
->anim_start
+i
);
517 skele
->anims
[i
].rate
= anim
->rate
;
518 skele
->anims
[i
].length
= anim
->length
;
519 skele
->anims
[i
].name
= mdl_pstr(mdl
, anim
->pstr_name
);
520 skele
->anims
[i
].anim_data
=
521 mdl_arritm( &mdl
->keyframes
, anim
->offset
);
523 vg_info( "animation[ %f, %u ] '%s'\n", anim
->rate
,
525 skele
->anims
[i
].name
);
528 skeleton_create_inverses( skele
);
529 vg_success( "Loaded skeleton with %u bones\n", skele
->bone_count
);
530 vg_success( " %u colliders\n", skele
->collider_count
);
533 VG_STATIC
void skeleton_debug( struct skeleton
*skele
)
535 for( u32 i
=1; i
<skele
->bone_count
; i
++ ){
536 struct skeleton_bone
*sb
= &skele
->bones
[i
];
539 v3_copy( sb
->co
, p0
);
540 v3_add( p0
, sb
->end
, p1
);
542 m4x3_mulv( skele
->final_mtx
[i
], p0
, p0
);
543 m4x3_mulv( skele
->final_mtx
[i
], p1
, p1
);
545 if( sb
->flags
& k_bone_flag_deform
){
546 if( sb
->flags
& k_bone_flag_ik
){
547 vg_line( p0
, p1
, 0xff0000ff );
550 vg_line( p0
, p1
, 0xffcccccc );
554 vg_line( p0
, p1
, 0xff00ffff );
558 #endif /* SKELETON_H */