forked from bartvdbraak/blender
Fixed numerical issues, hardened it again.
This commit is contained in:
Daniel Genrich
parent
4cb5470f82
commit
83c1dd78a6
@ -72,8 +72,8 @@ typedef struct ClothSpring {
|
||||
int matrix_index; /* needed for implicit solver (fast lookup) */
|
||||
int type; /* types defined in BKE_cloth.h ("springType") */
|
||||
int flags; /* defined in BKE_cloth.h, e.g. deactivated due to tearing */
|
||||
float dfdx[3][4];
|
||||
float dfdv[3][4];
|
||||
float dfdx[3][3];
|
||||
float dfdv[3][3];
|
||||
float f[3];
|
||||
} ClothSpring;
|
||||
|
||||
@ -91,13 +91,13 @@ typedef struct Cloth {
|
||||
unsigned int numothersprings;
|
||||
unsigned int numspringssave;
|
||||
unsigned int old_solver_type;
|
||||
float (*x)[4]; /* The current position of all vertices.*/
|
||||
float (*xold)[4]; /* The previous position of all vertices.*/
|
||||
float (*current_x)[4]; /* The TEMPORARY current position of all vertices.*/
|
||||
float (*current_xold)[4]; /* The TEMPORARY previous position of all vertices.*/
|
||||
float (*x)[3]; /* The current position of all vertices.*/
|
||||
float (*xold)[3]; /* The previous position of all vertices.*/
|
||||
float (*current_x)[3]; /* The TEMPORARY current position of all vertices.*/
|
||||
float (*current_xold)[3]; /* The TEMPORARY previous position of all vertices.*/
|
||||
float (*v)[4]; /* the current velocity of all vertices */
|
||||
float (*current_v)[4];
|
||||
float (*xconst)[4];
|
||||
float (*current_v)[3];
|
||||
float (*xconst)[3];
|
||||
} Cloth;
|
||||
|
||||
/* goal defines */
|
||||
|
||||
@ -90,9 +90,9 @@ double tval()
|
||||
}
|
||||
#else
|
||||
#include <sys/time.h>
|
||||
static struct timeval _tstart, _tend;
|
||||
static struct timezone tz;
|
||||
void tstart ( void )
|
||||
static struct timeval _tstart, _tend;
|
||||
static struct timezone tz;
|
||||
void tstart ( void )
|
||||
{
|
||||
gettimeofday ( &_tstart, &tz );
|
||||
}
|
||||
@ -133,11 +133,11 @@ static void cloth_apply_vgroup(ClothModifierData *clmd, DerivedMesh *dm, short v
|
||||
*
|
||||
******************************************************************************/
|
||||
/**
|
||||
* cloth_init - creates a new cloth simulation.
|
||||
*
|
||||
* 1. create object
|
||||
* 2. fill object with standard values or with the GUI settings if given
|
||||
*/
|
||||
* cloth_init - creates a new cloth simulation.
|
||||
*
|
||||
* 1. create object
|
||||
* 2. fill object with standard values or with the GUI settings if given
|
||||
*/
|
||||
void cloth_init (ClothModifierData *clmd)
|
||||
{
|
||||
/* Initialize our new data structure to reasonable values. */
|
||||
@ -202,38 +202,38 @@ DerivedMesh *CDDM_convert_to_triangle(DerivedMesh *dm)
|
||||
|
||||
for(i = 0; i < numfaces; i++)
|
||||
{
|
||||
if(mface[i].v4)
|
||||
numquads++;
|
||||
else
|
||||
numtris++;
|
||||
}
|
||||
if(mface[i].v4)
|
||||
numquads++;
|
||||
else
|
||||
numtris++;
|
||||
}
|
||||
|
||||
result = CDDM_from_template(dm, numverts, 0, numtris + 2*numquads);
|
||||
|
||||
if(!result)
|
||||
return NULL;
|
||||
return NULL;
|
||||
|
||||
// do verts
|
||||
mvert2 = CDDM_get_verts(result);
|
||||
for(a=0; a<numverts; a++)
|
||||
{
|
||||
MVert *inMV;
|
||||
MVert *mv = &mvert2[a];
|
||||
MVert *inMV;
|
||||
MVert *mv = &mvert2[a];
|
||||
|
||||
inMV = &mvert[a];
|
||||
inMV = &mvert[a];
|
||||
|
||||
DM_copy_vert_data(dm, result, a, a, 1);
|
||||
*mv = *inMV;
|
||||
}
|
||||
DM_copy_vert_data(dm, result, a, a, 1);
|
||||
*mv = *inMV;
|
||||
}
|
||||
|
||||
|
||||
// do faces
|
||||
mface2 = CDDM_get_faces(result);
|
||||
for(a=0, i=0; a<numfaces; a++)
|
||||
{
|
||||
MFace *mf = &mface2[i];
|
||||
MFace *inMF;
|
||||
inMF = &mface[a];
|
||||
MFace *mf = &mface2[i];
|
||||
MFace *inMF;
|
||||
inMF = &mface[a];
|
||||
|
||||
|
||||
// DM_copy_face_data(dm, result, a, i, 1);
|
||||
@ -241,57 +241,57 @@ DerivedMesh *CDDM_convert_to_triangle(DerivedMesh *dm)
|
||||
// *mf = *inMF;
|
||||
|
||||
|
||||
if(mface[a].v4 && random==1)
|
||||
{
|
||||
mf->v1 = mface[a].v2;
|
||||
mf->v2 = mface[a].v3;
|
||||
mf->v3 = mface[a].v4;
|
||||
}
|
||||
else
|
||||
{
|
||||
mf->v1 = mface[a].v1;
|
||||
mf->v2 = mface[a].v2;
|
||||
mf->v3 = mface[a].v3;
|
||||
}
|
||||
if(mface[a].v4 && random==1)
|
||||
{
|
||||
mf->v1 = mface[a].v2;
|
||||
mf->v2 = mface[a].v3;
|
||||
mf->v3 = mface[a].v4;
|
||||
}
|
||||
else
|
||||
{
|
||||
mf->v1 = mface[a].v1;
|
||||
mf->v2 = mface[a].v2;
|
||||
mf->v3 = mface[a].v3;
|
||||
}
|
||||
|
||||
mf->v4 = 0;
|
||||
mf->flag |= ME_SMOOTH;
|
||||
mf->v4 = 0;
|
||||
mf->flag |= ME_SMOOTH;
|
||||
|
||||
test_index_face(mf, NULL, 0, 3);
|
||||
test_index_face(mf, NULL, 0, 3);
|
||||
|
||||
if(mface[a].v4)
|
||||
{
|
||||
MFace *mf2;
|
||||
if(mface[a].v4)
|
||||
{
|
||||
MFace *mf2;
|
||||
|
||||
i++;
|
||||
i++;
|
||||
|
||||
mf2 = &mface2[i];
|
||||
mf2 = &mface2[i];
|
||||
|
||||
// DM_copy_face_data(dm, result, a, i, 1);
|
||||
|
||||
// *mf2 = *inMF;
|
||||
|
||||
|
||||
if(random==1)
|
||||
{
|
||||
mf2->v1 = mface[a].v1;
|
||||
mf2->v2 = mface[a].v2;
|
||||
mf2->v3 = mface[a].v4;
|
||||
}
|
||||
else
|
||||
{
|
||||
mf2->v1 = mface[a].v4;
|
||||
mf2->v2 = mface[a].v1;
|
||||
mf2->v3 = mface[a].v3;
|
||||
}
|
||||
mf2->v4 = 0;
|
||||
mf2->flag |= ME_SMOOTH;
|
||||
if(random==1)
|
||||
{
|
||||
mf2->v1 = mface[a].v1;
|
||||
mf2->v2 = mface[a].v2;
|
||||
mf2->v3 = mface[a].v4;
|
||||
}
|
||||
else
|
||||
{
|
||||
mf2->v1 = mface[a].v4;
|
||||
mf2->v2 = mface[a].v1;
|
||||
mf2->v3 = mface[a].v3;
|
||||
}
|
||||
mf2->v4 = 0;
|
||||
mf2->flag |= ME_SMOOTH;
|
||||
|
||||
test_index_face(mf2, NULL, 0, 3);
|
||||
}
|
||||
test_index_face(mf2, NULL, 0, 3);
|
||||
}
|
||||
|
||||
i++;
|
||||
}
|
||||
i++;
|
||||
}
|
||||
|
||||
CDDM_calc_edges(result);
|
||||
CDDM_calc_normals(result);
|
||||
@ -330,43 +330,43 @@ DerivedMesh *CDDM_create_tearing(ClothModifierData *clmd, DerivedMesh *dm)
|
||||
|
||||
for(i = 0; i < numsprings; i++)
|
||||
{
|
||||
if((springs[i].flags & CSPRING_FLAG_DEACTIVATE)
|
||||
&&(!BLI_edgehash_haskey(edgehash, springs[i].ij, springs[i].kl)))
|
||||
{
|
||||
BLI_edgehash_insert(edgehash, springs[i].ij, springs[i].kl, NULL);
|
||||
BLI_edgehash_insert(edgehash, springs[i].kl, springs[i].ij, NULL);
|
||||
j++;
|
||||
}
|
||||
}
|
||||
if((springs[i].flags & CSPRING_FLAG_DEACTIVATE)
|
||||
&&(!BLI_edgehash_haskey(edgehash, springs[i].ij, springs[i].kl)))
|
||||
{
|
||||
BLI_edgehash_insert(edgehash, springs[i].ij, springs[i].kl, NULL);
|
||||
BLI_edgehash_insert(edgehash, springs[i].kl, springs[i].ij, NULL);
|
||||
j++;
|
||||
}
|
||||
}
|
||||
|
||||
// printf("found %d tears\n", j);
|
||||
|
||||
result = CDDM_from_template(dm, numverts, 0, numfaces);
|
||||
|
||||
if(!result)
|
||||
return NULL;
|
||||
return NULL;
|
||||
|
||||
// do verts
|
||||
mvert2 = CDDM_get_verts(result);
|
||||
for(a=0; a<numverts; a++)
|
||||
{
|
||||
MVert *inMV;
|
||||
MVert *mv = &mvert2[a];
|
||||
MVert *inMV;
|
||||
MVert *mv = &mvert2[a];
|
||||
|
||||
inMV = &mvert[a];
|
||||
inMV = &mvert[a];
|
||||
|
||||
DM_copy_vert_data(dm, result, a, a, 1);
|
||||
*mv = *inMV;
|
||||
}
|
||||
DM_copy_vert_data(dm, result, a, a, 1);
|
||||
*mv = *inMV;
|
||||
}
|
||||
|
||||
|
||||
// do faces
|
||||
mface2 = CDDM_get_faces(result);
|
||||
for(a=0, i=0; a<numfaces; a++)
|
||||
{
|
||||
MFace *mf = &mface2[i];
|
||||
MFace *inMF;
|
||||
inMF = &mface[a];
|
||||
MFace *mf = &mface2[i];
|
||||
MFace *inMF;
|
||||
inMF = &mface[a];
|
||||
|
||||
|
||||
// DM_copy_face_data(dm, result, a, i, 1);
|
||||
@ -374,21 +374,21 @@ DerivedMesh *CDDM_create_tearing(ClothModifierData *clmd, DerivedMesh *dm)
|
||||
// *mf = *inMF;
|
||||
|
||||
|
||||
if((!BLI_edgehash_haskey(edgehash, mface[a].v1, mface[a].v2))
|
||||
&&(!BLI_edgehash_haskey(edgehash, mface[a].v2, mface[a].v3))
|
||||
&&(!BLI_edgehash_haskey(edgehash, mface[a].v3, mface[a].v4))
|
||||
&&(!BLI_edgehash_haskey(edgehash, mface[a].v4, mface[a].v1)))
|
||||
{
|
||||
mf->v1 = mface[a].v1;
|
||||
mf->v2 = mface[a].v2;
|
||||
mf->v3 = mface[a].v3;
|
||||
mf->v4 = mface[a].v4;
|
||||
if((!BLI_edgehash_haskey(edgehash, mface[a].v1, mface[a].v2))
|
||||
&&(!BLI_edgehash_haskey(edgehash, mface[a].v2, mface[a].v3))
|
||||
&&(!BLI_edgehash_haskey(edgehash, mface[a].v3, mface[a].v4))
|
||||
&&(!BLI_edgehash_haskey(edgehash, mface[a].v4, mface[a].v1)))
|
||||
{
|
||||
mf->v1 = mface[a].v1;
|
||||
mf->v2 = mface[a].v2;
|
||||
mf->v3 = mface[a].v3;
|
||||
mf->v4 = mface[a].v4;
|
||||
|
||||
test_index_face(mf, NULL, 0, 4);
|
||||
test_index_face(mf, NULL, 0, 4);
|
||||
|
||||
i++;
|
||||
}
|
||||
}
|
||||
i++;
|
||||
}
|
||||
}
|
||||
|
||||
CDDM_lower_num_faces(result, i);
|
||||
CDDM_calc_edges(result);
|
||||
@ -527,40 +527,40 @@ DerivedMesh *clothModifier_do(ClothModifierData *clmd,Object *ob, DerivedMesh *d
|
||||
/*
|
||||
if ( clmd->clothObject )
|
||||
{
|
||||
if ( clmd->sim_parms->cache )
|
||||
{
|
||||
if ( current_time < clmd->sim_parms->firstframe )
|
||||
{
|
||||
int frametime = cloth_cache_first_frame ( clmd );
|
||||
if ( cloth_cache_search_frame ( clmd, frametime ) )
|
||||
{
|
||||
cloth_cache_get_frame ( clmd, frametime );
|
||||
cloth_to_object ( ob, result, clmd );
|
||||
}
|
||||
return result;
|
||||
}
|
||||
else if ( current_time > clmd->sim_parms->lastframe )
|
||||
{
|
||||
int frametime = cloth_cache_last_frame ( clmd );
|
||||
if ( cloth_cache_search_frame ( clmd, frametime ) )
|
||||
{
|
||||
cloth_cache_get_frame ( clmd, frametime );
|
||||
cloth_to_object ( ob, result, clmd );
|
||||
}
|
||||
return result;
|
||||
}
|
||||
else if ( ABS ( deltaTime ) >= 2.0f ) // no timewarps allowed
|
||||
{
|
||||
if ( cloth_cache_search_frame ( clmd, framenr ) )
|
||||
{
|
||||
cloth_cache_get_frame ( clmd, framenr );
|
||||
cloth_to_object ( ob, result, clmd );
|
||||
}
|
||||
clmd->sim_parms->sim_time = current_time;
|
||||
return result;
|
||||
}
|
||||
}
|
||||
}
|
||||
if ( clmd->sim_parms->cache )
|
||||
{
|
||||
if ( current_time < clmd->sim_parms->firstframe )
|
||||
{
|
||||
int frametime = cloth_cache_first_frame ( clmd );
|
||||
if ( cloth_cache_search_frame ( clmd, frametime ) )
|
||||
{
|
||||
cloth_cache_get_frame ( clmd, frametime );
|
||||
cloth_to_object ( ob, result, clmd );
|
||||
}
|
||||
return result;
|
||||
}
|
||||
else if ( current_time > clmd->sim_parms->lastframe )
|
||||
{
|
||||
int frametime = cloth_cache_last_frame ( clmd );
|
||||
if ( cloth_cache_search_frame ( clmd, frametime ) )
|
||||
{
|
||||
cloth_cache_get_frame ( clmd, frametime );
|
||||
cloth_to_object ( ob, result, clmd );
|
||||
}
|
||||
return result;
|
||||
}
|
||||
else if ( ABS ( deltaTime ) >= 2.0f ) // no timewarps allowed
|
||||
{
|
||||
if ( cloth_cache_search_frame ( clmd, framenr ) )
|
||||
{
|
||||
cloth_cache_get_frame ( clmd, framenr );
|
||||
cloth_to_object ( ob, result, clmd );
|
||||
}
|
||||
clmd->sim_parms->sim_time = current_time;
|
||||
return result;
|
||||
}
|
||||
}
|
||||
}
|
||||
*/
|
||||
|
||||
if(deltaTime == 1.0f)
|
||||
@ -737,10 +737,10 @@ void cloth_free_modifier (ClothModifierData *clmd)
|
||||
******************************************************************************/
|
||||
|
||||
/**
|
||||
* cloth_to_object - copies the deformed vertices to the object.
|
||||
*
|
||||
* This function is a modified version of the softbody.c:softbody_to_object() function.
|
||||
**/
|
||||
* cloth_to_object - copies the deformed vertices to the object.
|
||||
*
|
||||
* This function is a modified version of the softbody.c:softbody_to_object() function.
|
||||
**/
|
||||
static void cloth_to_object (Object *ob, DerivedMesh *dm, ClothModifierData *clmd)
|
||||
{
|
||||
unsigned int i = 0;
|
||||
@ -765,9 +765,9 @@ static void cloth_to_object (Object *ob, DerivedMesh *dm, ClothModifierData *cl
|
||||
|
||||
|
||||
/**
|
||||
* cloth_apply_vgroup - applies a vertex group as specified by type
|
||||
*
|
||||
**/
|
||||
* cloth_apply_vgroup - applies a vertex group as specified by type
|
||||
*
|
||||
**/
|
||||
static void cloth_apply_vgroup(ClothModifierData *clmd, DerivedMesh *dm, short vgroup)
|
||||
{
|
||||
unsigned int i = 0;
|
||||
@ -863,51 +863,50 @@ static int cloth_from_object(Object *ob, ClothModifierData *clmd, DerivedMesh *d
|
||||
clmd->clothObject->springs = NULL;
|
||||
clmd->clothObject->numsprings = -1;
|
||||
|
||||
/* set initial values */
|
||||
for (i = 0; i < numverts; ++i)
|
||||
{
|
||||
VECCOPY (clmd->clothObject->x[i], mvert[i].co);
|
||||
Mat4MulVecfl(ob->obmat, clmd->clothObject->x[i]);
|
||||
/* set initial values */
|
||||
for (i = 0; i < numverts; ++i)
|
||||
{
|
||||
VECCOPY (clmd->clothObject->x[i], mvert[i].co);
|
||||
Mat4MulVecfl(ob->obmat, clmd->clothObject->x[i]);
|
||||
|
||||
clmd->clothObject->verts [i].mass = clmd->sim_parms->mass;
|
||||
if ( clmd->sim_parms->flags & CLOTH_SIMSETTINGS_FLAG_GOAL )
|
||||
clmd->clothObject->verts [i].goal= clmd->sim_parms->defgoal;
|
||||
else
|
||||
clmd->clothObject->verts [i].goal= 0.0;
|
||||
clmd->clothObject->verts [i].flags = 0;
|
||||
VECCOPY(clmd->clothObject->xold[i], clmd->clothObject->x[i]);
|
||||
VECCOPY(clmd->clothObject->xconst[i], clmd->clothObject->x[i]);
|
||||
VECCOPY(clmd->clothObject->current_xold[i], clmd->clothObject->x[i]);
|
||||
VecMulf(clmd->clothObject->v[i], 0.0);
|
||||
clmd->clothObject->verts [i].mass = clmd->sim_parms->mass;
|
||||
if ( clmd->sim_parms->flags & CLOTH_SIMSETTINGS_FLAG_GOAL )
|
||||
clmd->clothObject->verts [i].goal= clmd->sim_parms->defgoal;
|
||||
else
|
||||
clmd->clothObject->verts [i].goal= 0.0;
|
||||
clmd->clothObject->verts [i].flags = 0;
|
||||
VECCOPY(clmd->clothObject->xold[i], clmd->clothObject->x[i]);
|
||||
VECCOPY(clmd->clothObject->xconst[i], clmd->clothObject->x[i]);
|
||||
VECCOPY(clmd->clothObject->current_xold[i], clmd->clothObject->x[i]);
|
||||
VecMulf(clmd->clothObject->v[i], 0.0);
|
||||
|
||||
clmd->clothObject->verts [i].impulse_count = 0;
|
||||
VECCOPY ( clmd->clothObject->verts [i].impulse, tnull );
|
||||
clmd->clothObject->verts [i].impulse_count = 0;
|
||||
VECCOPY ( clmd->clothObject->verts [i].impulse, tnull );
|
||||
}
|
||||
|
||||
if (!cloth_build_springs (clmd->clothObject, dm) )
|
||||
{
|
||||
modifier_setError (&(clmd->modifier), "Can't build springs.");
|
||||
return 0;
|
||||
}
|
||||
|
||||
/* apply / set vertex groups */
|
||||
if (clmd->sim_parms->vgroup_mass > 0)
|
||||
cloth_apply_vgroup (clmd, olddm, clmd->sim_parms->vgroup_mass);
|
||||
|
||||
/* init our solver */
|
||||
if (solvers [clmd->sim_parms->solver_type].init)
|
||||
solvers [clmd->sim_parms->solver_type].init (ob, clmd);
|
||||
|
||||
clmd->clothObject->tree = bvh_build_from_float3(CDDM_get_faces(dm), dm->getNumFaces(dm), clmd->clothObject->x, numverts, clmd->coll_parms->epsilon);
|
||||
|
||||
clmd->clothObject->selftree = bvh_build_from_float3(NULL, 0, clmd->clothObject->x, numverts, clmd->coll_parms->selfepsilon);
|
||||
|
||||
// save initial state
|
||||
cloth_write_cache(ob, clmd, framenr-1);
|
||||
}
|
||||
|
||||
if (!cloth_build_springs (clmd->clothObject, dm) )
|
||||
{
|
||||
modifier_setError (&(clmd->modifier), "Can't build springs.");
|
||||
return 0;
|
||||
}
|
||||
|
||||
/* apply / set vertex groups */
|
||||
if (clmd->sim_parms->vgroup_mass > 0)
|
||||
cloth_apply_vgroup (clmd, olddm, clmd->sim_parms->vgroup_mass);
|
||||
|
||||
/* init our solver */
|
||||
if (solvers [clmd->sim_parms->solver_type].init)
|
||||
solvers [clmd->sim_parms->solver_type].init (ob, clmd);
|
||||
|
||||
clmd->clothObject->tree = bvh_build_from_float4(CDDM_get_faces(dm), dm->getNumFaces(dm), clmd->clothObject->x, numverts, clmd->coll_parms->epsilon);
|
||||
|
||||
clmd->clothObject->selftree = bvh_build_from_float4(NULL, 0, clmd->clothObject->x, numverts, clmd->coll_parms->selfepsilon);
|
||||
|
||||
// save initial state
|
||||
cloth_write_cache(ob, clmd, framenr-1);
|
||||
}
|
||||
|
||||
return 1;
|
||||
default: return 0; // TODO - we do not support changing meshes
|
||||
return 1;
|
||||
default: return 0; // TODO - we do not support changing meshes
|
||||
}
|
||||
|
||||
return 0;
|
||||
@ -1119,15 +1118,15 @@ int cloth_build_springs ( Cloth *cloth, DerivedMesh *dm )
|
||||
spring->ij = mface[i].v2;
|
||||
spring->kl = mface[i].v4;
|
||||
VECSUB ( temp, cloth->x[spring->kl], cloth->x[spring->ij] );
|
||||
spring->restlen = sqrt ( INPR ( temp, temp ) );
|
||||
spring->type = CLOTH_SPRING_TYPE_SHEAR;
|
||||
spring->restlen = sqrt ( INPR ( temp, temp ) );
|
||||
spring->type = CLOTH_SPRING_TYPE_SHEAR;
|
||||
|
||||
BLI_linklist_append ( &edgelist[spring->ij], spring );
|
||||
BLI_linklist_append ( &edgelist[spring->kl], spring );
|
||||
shear_springs++;
|
||||
BLI_linklist_append ( &edgelist[spring->ij], spring );
|
||||
BLI_linklist_append ( &edgelist[spring->kl], spring );
|
||||
shear_springs++;
|
||||
|
||||
node2 = BLI_linklist_append_fast ( &node->next, spring );
|
||||
node = node2;
|
||||
node2 = BLI_linklist_append_fast ( &node->next, spring );
|
||||
node = node2;
|
||||
}
|
||||
}
|
||||
|
||||
@ -1148,8 +1147,8 @@ int cloth_build_springs ( Cloth *cloth, DerivedMesh *dm )
|
||||
// check for existing spring
|
||||
// check also if startpoint is equal to endpoint
|
||||
if ( !BLI_edgehash_haskey ( edgehash, index2, tspring2->ij )
|
||||
&& !BLI_edgehash_haskey ( edgehash, tspring2->ij, index2 )
|
||||
&& ( index2!=tspring2->ij ) )
|
||||
&& !BLI_edgehash_haskey ( edgehash, tspring2->ij, index2 )
|
||||
&& ( index2!=tspring2->ij ) )
|
||||
{
|
||||
spring = ( ClothSpring * ) MEM_callocN ( sizeof ( ClothSpring ), "cloth spring" );
|
||||
|
||||
|
||||
File diff suppressed because it is too large
Load Diff
Loading…
Reference in New Issue
Block a user