static int cloth_build_springs ( ClothModifierData *clmd, DerivedMesh *dm )
{
Cloth *cloth = clmd->clothObject;
ClothSpring *spring = NULL, *tspring = NULL, *tspring2 = NULL;
unsigned int struct_springs = 0, shear_springs=0, bend_springs = 0;
unsigned int i = 0;
unsigned int numverts = (unsigned int)dm->getNumVerts ( dm );
unsigned int numedges = (unsigned int)dm->getNumEdges ( dm );
unsigned int numfaces = (unsigned int)dm->getNumFaces ( dm );
MEdge *medge = dm->getEdgeArray ( dm );
MFace *mface = dm->getFaceArray ( dm );
int index2 = 0; // our second vertex index
LinkNode **edgelist = NULL;
EdgeHash *edgehash = NULL;
LinkNode *search = NULL, *search2 = NULL;
// error handling
if ( numedges==0 )
return 0;
cloth->springs = NULL;
edgelist = MEM_callocN ( sizeof ( LinkNode * ) * numverts, "cloth_edgelist_alloc" );
if(!edgelist)
return 0;
for ( i = 0; i < numverts; i++ )
{
edgelist[i] = NULL;
}
if ( cloth->springs )
MEM_freeN ( cloth->springs );
// create spring network hash
edgehash = BLI_edgehash_new();
// structural springs
for ( i = 0; i < numedges; i++ )
{
spring = ( ClothSpring * ) MEM_callocN ( sizeof ( ClothSpring ), "cloth spring" );
if ( spring )
{
spring->ij = MIN2(medge[i].v1, medge[i].v2);
spring->kl = MAX2(medge[i].v2, medge[i].v1);
spring->restlen = len_v3v3(cloth->verts[spring->kl].xrest, cloth->verts[spring->ij].xrest);
clmd->sim_parms->avg_spring_len += spring->restlen;
cloth->verts[spring->ij].avg_spring_len += spring->restlen;
cloth->verts[spring->kl].avg_spring_len += spring->restlen;
cloth->verts[spring->ij].spring_count++;
cloth->verts[spring->kl].spring_count++;
spring->type = CLOTH_SPRING_TYPE_STRUCTURAL;
spring->flags = 0;
spring->stiffness = (cloth->verts[spring->kl].struct_stiff + cloth->verts[spring->ij].struct_stiff) / 2.0f;
struct_springs++;
BLI_linklist_prepend ( &cloth->springs, spring );
}
else
{
cloth_free_errorsprings(cloth, edgehash, edgelist);
return 0;
}
}
if(struct_springs > 0)
clmd->sim_parms->avg_spring_len /= struct_springs;
for(i = 0; i < numverts; i++)
{
cloth->verts[i].avg_spring_len = cloth->verts[i].avg_spring_len * 0.49f / ((float)cloth->verts[i].spring_count);
}
// shear springs
for ( i = 0; i < numfaces; i++ )
{
// triangle faces already have shear springs due to structural geometry
if ( !mface[i].v4 )
continue;
spring = ( ClothSpring *) MEM_callocN ( sizeof ( ClothSpring ), "cloth spring" );
if(!spring)
{
cloth_free_errorsprings(cloth, edgehash, edgelist);
return 0;
}
spring->ij = MIN2(mface[i].v1, mface[i].v3);
spring->kl = MAX2(mface[i].v3, mface[i].v1);
spring->restlen = len_v3v3(cloth->verts[spring->kl].xrest, cloth->verts[spring->ij].xrest);
spring->type = CLOTH_SPRING_TYPE_SHEAR;
spring->stiffness = (cloth->verts[spring->kl].shear_stiff + cloth->verts[spring->ij].shear_stiff) / 2.0f;
BLI_linklist_append ( &edgelist[spring->ij], spring );
BLI_linklist_append ( &edgelist[spring->kl], spring );
shear_springs++;
BLI_linklist_prepend ( &cloth->springs, spring );
// if ( mface[i].v4 ) --> Quad face
spring = ( ClothSpring * ) MEM_callocN ( sizeof ( ClothSpring ), "cloth spring" );
if(!spring)
{
cloth_free_errorsprings(cloth, edgehash, edgelist);
return 0;
}
spring->ij = MIN2(mface[i].v2, mface[i].v4);
spring->kl = MAX2(mface[i].v4, mface[i].v2);
spring->restlen = len_v3v3(cloth->verts[spring->kl].xrest, cloth->verts[spring->ij].xrest);
spring->type = CLOTH_SPRING_TYPE_SHEAR;
spring->stiffness = (cloth->verts[spring->kl].shear_stiff + cloth->verts[spring->ij].shear_stiff) / 2.0;
BLI_linklist_append ( &edgelist[spring->ij], spring );
BLI_linklist_append ( &edgelist[spring->kl], spring );
shear_springs++;
BLI_linklist_prepend ( &cloth->springs, spring );
}
if(numfaces) {
// bending springs
search2 = cloth->springs;
for ( i = struct_springs; i < struct_springs+shear_springs; i++ )
{
if ( !search2 )
break;
tspring2 = search2->link;
search = edgelist[tspring2->kl];
while ( search )
{
tspring = search->link;
index2 = ( ( tspring->ij==tspring2->kl ) ? ( tspring->kl ) : ( tspring->ij ) );
// check for existing spring
// check also if startpoint is equal to endpoint
if ( !BLI_edgehash_haskey ( edgehash, MIN2(tspring2->ij, index2), MAX2(tspring2->ij, index2) )
&& ( index2!=tspring2->ij ) )
{
spring = ( ClothSpring * ) MEM_callocN ( sizeof ( ClothSpring ), "cloth spring" );
if(!spring)
{
cloth_free_errorsprings(cloth, edgehash, edgelist);
return 0;
}
spring->ij = MIN2(tspring2->ij, index2);
spring->kl = MAX2(tspring2->ij, index2);
spring->restlen = len_v3v3(cloth->verts[spring->kl].xrest, cloth->verts[spring->ij].xrest);
spring->type = CLOTH_SPRING_TYPE_BENDING;
spring->stiffness = (cloth->verts[spring->kl].bend_stiff + cloth->verts[spring->ij].bend_stiff) / 2.0f;
BLI_edgehash_insert ( edgehash, spring->ij, spring->kl, NULL );
bend_springs++;
BLI_linklist_prepend ( &cloth->springs, spring );
}
search = search->next;
}
search2 = search2->next;
}
}
else if(struct_springs > 2) {
/* bending springs for hair strands */
/* The current algorightm only goes through the edges in order of the mesh edges list */
/* and makes springs between the outer vert of edges sharing a vertice. This works just */
/* fine for hair, but not for user generated string meshes. This could/should be later */
/* extended to work with non-ordered edges so that it can be used for general "rope */
/* dynamics" without the need for the vertices or edges to be ordered through the length*/
/* of the strands. -jahka */
search = cloth->springs;
search2 = search->next;
while(search && search2)
{
tspring = search->link;
tspring2 = search2->link;
if(tspring->ij == tspring2->kl) {
spring = ( ClothSpring * ) MEM_callocN ( sizeof ( ClothSpring ), "cloth spring" );
if(!spring)
{
cloth_free_errorsprings(cloth, edgehash, edgelist);
return 0;
}
spring->ij = tspring2->ij;
spring->kl = tspring->kl;
spring->restlen = len_v3v3(cloth->verts[spring->kl].xrest, cloth->verts[spring->ij].xrest);
spring->type = CLOTH_SPRING_TYPE_BENDING;
spring->stiffness = (cloth->verts[spring->kl].bend_stiff + cloth->verts[spring->ij].bend_stiff) / 2.0f;
bend_springs++;
BLI_linklist_prepend ( &cloth->springs, spring );
}
search = search->next;
search2 = search2->next;
}
}
/* insert other near springs in edgehash AFTER bending springs are calculated (for selfcolls) */
for ( i = 0; i < numedges; i++ ) // struct springs
BLI_edgehash_insert ( edgehash, MIN2(medge[i].v1, medge[i].v2), MAX2(medge[i].v2, medge[i].v1), NULL );
for ( i = 0; i < numfaces; i++ ) // edge springs
{
if(mface[i].v4)
{
BLI_edgehash_insert ( edgehash, MIN2(mface[i].v1, mface[i].v3), MAX2(mface[i].v3, mface[i].v1), NULL );
BLI_edgehash_insert ( edgehash, MIN2(mface[i].v2, mface[i].v4), MAX2(mface[i].v2, mface[i].v4), NULL );
}
}
cloth->numsprings = struct_springs + shear_springs + bend_springs;
if ( edgelist )
{
for ( i = 0; i < numverts; i++ )
{
BLI_linklist_free ( edgelist[i],NULL );
}
MEM_freeN ( edgelist );
}
cloth->edgehash = edgehash;
if(G.rt>0)
printf("avg_len: %f\n",clmd->sim_parms->avg_spring_len);
return 1;
} /* cloth_build_springs */
static int cloth_build_springs ( ClothModifierData *clmd, DerivedMesh *dm )
{
Cloth *cloth = clmd->clothObject;
ClothSpring *spring = NULL, *tspring = NULL, *tspring2 = NULL;
unsigned int struct_springs = 0, shear_springs=0, bend_springs = 0;
unsigned int i = 0;
unsigned int numverts = (unsigned int)dm->getNumVerts (dm);
unsigned int numedges = (unsigned int)dm->getNumEdges (dm);
unsigned int numfaces = (unsigned int)dm->getNumTessFaces (dm);
float shrink_factor;
MEdge *medge = dm->getEdgeArray (dm);
MFace *mface = dm->getTessFaceArray (dm);
int index2 = 0; // our second vertex index
LinkNode **edgelist = NULL;
EdgeSet *edgeset = NULL;
LinkNode *search = NULL, *search2 = NULL;
// error handling
if ( numedges==0 )
return 0;
/* NOTE: handling ownership of springs and edgeset is quite sloppy
* currently they are never initialized but assert just to be sure */
BLI_assert(cloth->springs == NULL);
BLI_assert(cloth->edgeset == NULL);
cloth->springs = NULL;
cloth->edgeset = NULL;
edgelist = MEM_callocN ( sizeof (LinkNode *) * numverts, "cloth_edgelist_alloc" );
if (!edgelist)
return 0;
// structural springs
for ( i = 0; i < numedges; i++ ) {
spring = (ClothSpring *)MEM_callocN ( sizeof ( ClothSpring ), "cloth spring" );
if ( spring ) {
spring_verts_ordered_set(spring, medge[i].v1, medge[i].v2);
if (clmd->sim_parms->flags & CLOTH_SIMSETTINGS_FLAG_SEW && medge[i].flag & ME_LOOSEEDGE) {
// handle sewing (loose edges will be pulled together)
spring->restlen = 0.0f;
spring->stiffness = 1.0f;
spring->type = CLOTH_SPRING_TYPE_SEWING;
}
else {
if (clmd->sim_parms->vgroup_shrink > 0)
shrink_factor = 1.0f - ((cloth->verts[spring->ij].shrink_factor + cloth->verts[spring->kl].shrink_factor) / 2.0f);
else
shrink_factor = 1.0f - clmd->sim_parms->shrink_min;
spring->restlen = len_v3v3(cloth->verts[spring->kl].xrest, cloth->verts[spring->ij].xrest) * shrink_factor;
spring->stiffness = (cloth->verts[spring->kl].struct_stiff + cloth->verts[spring->ij].struct_stiff) / 2.0f;
spring->type = CLOTH_SPRING_TYPE_STRUCTURAL;
}
clmd->sim_parms->avg_spring_len += spring->restlen;
cloth->verts[spring->ij].avg_spring_len += spring->restlen;
cloth->verts[spring->kl].avg_spring_len += spring->restlen;
cloth->verts[spring->ij].spring_count++;
cloth->verts[spring->kl].spring_count++;
spring->flags = 0;
struct_springs++;
BLI_linklist_prepend ( &cloth->springs, spring );
}
else {
cloth_free_errorsprings(cloth, edgelist);
return 0;
}
}
if (struct_springs > 0)
clmd->sim_parms->avg_spring_len /= struct_springs;
for (i = 0; i < numverts; i++) {
cloth->verts[i].avg_spring_len = cloth->verts[i].avg_spring_len * 0.49f / ((float)cloth->verts[i].spring_count);
}
// shear springs
for ( i = 0; i < numfaces; i++ ) {
// triangle faces already have shear springs due to structural geometry
if ( !mface[i].v4 )
continue;
spring = (ClothSpring *)MEM_callocN(sizeof(ClothSpring), "cloth spring");
if (!spring) {
cloth_free_errorsprings(cloth, edgelist);
return 0;
}
spring_verts_ordered_set(spring, mface[i].v1, mface[i].v3);
if (clmd->sim_parms->vgroup_shrink > 0)
shrink_factor = 1.0f - ((cloth->verts[spring->ij].shrink_factor + cloth->verts[spring->kl].shrink_factor) / 2.0f);
else
shrink_factor = 1.0f - clmd->sim_parms->shrink_min;
spring->restlen = len_v3v3(cloth->verts[spring->kl].xrest, cloth->verts[spring->ij].xrest) * shrink_factor;
spring->type = CLOTH_SPRING_TYPE_SHEAR;
spring->stiffness = (cloth->verts[spring->kl].shear_stiff + cloth->verts[spring->ij].shear_stiff) / 2.0f;
BLI_linklist_append ( &edgelist[spring->ij], spring );
BLI_linklist_append ( &edgelist[spring->kl], spring );
shear_springs++;
BLI_linklist_prepend ( &cloth->springs, spring );
// if ( mface[i].v4 ) --> Quad face
spring = (ClothSpring *)MEM_callocN ( sizeof ( ClothSpring ), "cloth spring" );
if (!spring) {
cloth_free_errorsprings(cloth, edgelist);
return 0;
}
spring_verts_ordered_set(spring, mface[i].v2, mface[i].v4);
if (clmd->sim_parms->vgroup_shrink > 0)
shrink_factor = 1.0f - ((cloth->verts[spring->ij].shrink_factor + cloth->verts[spring->kl].shrink_factor) / 2.0f);
else
shrink_factor = 1.0f - clmd->sim_parms->shrink_min;
spring->restlen = len_v3v3(cloth->verts[spring->kl].xrest, cloth->verts[spring->ij].xrest) * shrink_factor;
spring->type = CLOTH_SPRING_TYPE_SHEAR;
spring->stiffness = (cloth->verts[spring->kl].shear_stiff + cloth->verts[spring->ij].shear_stiff) / 2.0f;
BLI_linklist_append ( &edgelist[spring->ij], spring );
BLI_linklist_append ( &edgelist[spring->kl], spring );
shear_springs++;
BLI_linklist_prepend ( &cloth->springs, spring );
}
edgeset = BLI_edgeset_new_ex(__func__, numedges);
cloth->edgeset = edgeset;
if (numfaces) {
// bending springs
search2 = cloth->springs;
for ( i = struct_springs; i < struct_springs+shear_springs; i++ ) {
if ( !search2 )
break;
tspring2 = search2->link;
search = edgelist[tspring2->kl];
while ( search ) {
tspring = search->link;
index2 = ( ( tspring->ij==tspring2->kl ) ? ( tspring->kl ) : ( tspring->ij ) );
// check for existing spring
// check also if startpoint is equal to endpoint
if ((index2 != tspring2->ij) &&
!BLI_edgeset_haskey(edgeset, tspring2->ij, index2))
{
spring = (ClothSpring *)MEM_callocN ( sizeof ( ClothSpring ), "cloth spring" );
if (!spring) {
cloth_free_errorsprings(cloth, edgelist);
return 0;
}
spring_verts_ordered_set(spring, tspring2->ij, index2);
spring->restlen = len_v3v3(cloth->verts[spring->kl].xrest, cloth->verts[spring->ij].xrest);
spring->type = CLOTH_SPRING_TYPE_BENDING;
spring->stiffness = (cloth->verts[spring->kl].bend_stiff + cloth->verts[spring->ij].bend_stiff) / 2.0f;
BLI_edgeset_insert(edgeset, spring->ij, spring->kl);
bend_springs++;
BLI_linklist_prepend ( &cloth->springs, spring );
}
search = search->next;
}
search2 = search2->next;
}
}
else if (struct_springs > 2) {
/* bending springs for hair strands */
/* The current algorightm only goes through the edges in order of the mesh edges list */
/* and makes springs between the outer vert of edges sharing a vertice. This works just */
/* fine for hair, but not for user generated string meshes. This could/should be later */
/* extended to work with non-ordered edges so that it can be used for general "rope */
/* dynamics" without the need for the vertices or edges to be ordered through the length*/
/* of the strands. -jahka */
search = cloth->springs;
search2 = search->next;
while (search && search2) {
tspring = search->link;
tspring2 = search2->link;
if (tspring->ij == tspring2->kl) {
spring = (ClothSpring *)MEM_callocN ( sizeof ( ClothSpring ), "cloth spring" );
if (!spring) {
cloth_free_errorsprings(cloth, edgelist);
return 0;
}
spring->ij = tspring2->ij;
spring->kl = tspring->kl;
spring->restlen = len_v3v3(cloth->verts[spring->kl].xrest, cloth->verts[spring->ij].xrest);
spring->type = CLOTH_SPRING_TYPE_BENDING;
spring->stiffness = (cloth->verts[spring->kl].bend_stiff + cloth->verts[spring->ij].bend_stiff) / 2.0f;
bend_springs++;
BLI_linklist_prepend ( &cloth->springs, spring );
}
search = search->next;
search2 = search2->next;
}
}
/* note: the edges may already exist so run reinsert */
/* insert other near springs in edgeset AFTER bending springs are calculated (for selfcolls) */
for (i = 0; i < numedges; i++) { /* struct springs */
BLI_edgeset_add(edgeset, medge[i].v1, medge[i].v2);
}
for (i = 0; i < numfaces; i++) { /* edge springs */
if (mface[i].v4) {
BLI_edgeset_add(edgeset, mface[i].v1, mface[i].v3);
BLI_edgeset_add(edgeset, mface[i].v2, mface[i].v4);
}
}
cloth->numsprings = struct_springs + shear_springs + bend_springs;
cloth_free_edgelist(edgelist, numverts);
#if 0
if (G.debug_value > 0)
printf("avg_len: %f\n", clmd->sim_parms->avg_spring_len);
#endif
return 1;
} /* cloth_build_springs */
