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/*
* Pure Data Packet module. mesh implementation
* Copyright (c) by Tom Schouten <tom@zwizwa.be>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
/* a very naive approach to triangular meshes */
// $$TODO: some serious memory corruption in this file our the list implementation
#include <math.h>
#include "pdp.h"
#include "pdp_mesh.h"
/* VERTEX methods */
void vertex_add_triangle(t_vertex *v, t_triangle *t)
{
pdp_list_add_pointer(v->trilist, t);
}
void vertex_remove_triangle(t_vertex *v, t_triangle *t)
{
pdp_list_remove_pointer(v->trilist, t);
}
void vertex_add_neighbour(t_vertex *v, t_vertex *neighbour)
{
pdp_list_add_pointer_to_set(v->vertlist, neighbour);
};
/* constructor/destructors are "private"
they may only be called by the mesh object to ensure
the vector list stays sound (i.e. without duplicates) */
void _vertex_free(t_vertex *v)
{
if (!v->trilist) post("WARNING: vertex %x has empty trilist", v);
else{
pdp_list_free(v->trilist);
v->trilist = 0;
}
if (!v->vertlist) post("WARNING: vertex %x has empty vertlist", v);
{
pdp_list_free(v->vertlist);
v->vertlist = 0;
}
pdp_dealloc(v);
}
t_vertex *_vertex_new(float *c, float *n)
{
int k;
t_vertex *v = (t_vertex *) pdp_alloc(sizeof(t_vertex));
I3(k) v->c[k] = c[k];
I3(k) v->n[k] = n[k];
v->trilist = pdp_list_new(0);
v->vertlist = pdp_list_new(0);
return v;
}
void vertex_compute_normal_random(t_vertex *v){int k; I3(k) v->n[k] = _rand();}
void vertex_compute_normal_sphere(t_vertex *v){int k; I3(k) v->n[k] = v->c[k];}
void vertex_compute_normal_prism(t_vertex *v)
{
float scale = 0.0f;
float sum[] = {0.0f, 0.0f, 0.0f};
int k;
t_pdp_atom* i;
t_pdp_list *vl = v->vertlist;
t_vertex *vtx;
PDP_POINTER_IN(vl, i, vtx) {
I3(k) sum[k] += vtx->c[k];
scale = scale + 1.0f;
}
scale = 1.0f / scale;
I3(k) sum[k] *= scale;
I3(k) v->n[k] = v->c[k] - sum[k];
//post("computed normal (%f, %f, %f) of vertex (%f, %f, %f)", v->n[0], v->n[1], v->n[2], v->c[0], v->c[1], v->c[2]);
};
void vertex_compute_normal_average(t_vertex *v)
{
int triangles = pdp_list_size(v->trilist);
float scale = 1.0f / ((float)triangles);
t_pdp_atom* i;
int k;
t_triangle *t;
I3(k) v->n[k] = 0; //reset normal
PDP_POINTER_IN(v->trilist, i, t){
I3(k) v->n[k] += t->n[k];
}
_vector3_scale(v->n, scale);
}
float vertex_normalize(t_vertex *v)
{
return _vector3_normalize(v->c);
}
/* TRIANGLE methods */
/* create triangle (a connection between 3 vertices):
counterclockwize with facing front
this method is "private"
you can only create triangles as part of a mesh */
t_triangle *_triangle_new(t_vertex *v0, t_vertex *v1, t_vertex *v2)
{
int k;
t_triangle *t = (t_triangle *)pdp_alloc(sizeof(t_triangle));
/* store vertex references */
t->v[0] = v0;
t->v[1] = v1;
t->v[2] = v2;
/* reset median vertices */
I3(k) t->m[k] = 0;
/* connect triangle to vertices */
vertex_add_triangle(v0, t);
vertex_add_triangle(v1, t);
vertex_add_triangle(v2, t);
/* connect vertices to vertices */
vertex_add_neighbour(v0, v1);
vertex_add_neighbour(v0, v2);
vertex_add_neighbour(v1, v0);
vertex_add_neighbour(v1, v2);
vertex_add_neighbour(v2, v0);
vertex_add_neighbour(v2, v1);
return t;
}
/* delete a triangle, disconnecting the vertices */
void _triangle_free(t_triangle *t)
{
int k;
/* remove the triangle reference of the vertices */
I3(k) vertex_remove_triangle(t->v[k], t);
/* set references to zero (bug catcher) */
I3(k) t->v[k] = 0;
I3(k) t->m[k] = 0;
/* free struct */
pdp_dealloc(t);
}
/* get triangle that shares the link between v0 and v1 */
t_triangle *triangle_neighbour(t_triangle *t, t_vertex *v0, t_vertex *v1)
{
t_pdp_atom* it;
t_triangle *tri;
PDP_POINTER_IN(v1->trilist, it, tri){
if (tri != t && pdp_list_contains_pointer(v0->trilist, tri)) return tri;
}
return 0;
}
/* add a median vector to a link in a triangle
note: vertices must be in triangle, or behaviour is undefined */
void triangle_add_median(t_triangle *t, t_vertex *v0, t_vertex *v1, t_vertex *median)
{
/* link 0 1 */
if (!((v0 == t->v[2]) || (v1 == t->v[2]))) t->m[0] = median;
/* link 1 2 */
else if (!((v0 == t->v[0]) || (v1 == t->v[0]))) t->m[1] = median;
/* link 2 0 */
else t->m[2] = median;
}
void triangle_compute_normal(t_triangle *t)
{
int k;
float v0[3];
float v1[3];
I3(k) v0[k] = t->v[1]->c[k] - t->v[0]->c[k];
I3(k) v1[k] = t->v[2]->c[k] - t->v[0]->c[k];
_vector3_cross(v0,v1,t->n);
}
void triangle_compute_unit_normal(t_triangle *t)
{
triangle_compute_normal(t);
_vector3_normalize(t->n);
}
/* MESH methods */
/* add and remove methods for vertices and triangles */
t_vertex *mesh_vertex_add(t_mesh *m, float *c, float *n)
{
t_vertex *v = _vertex_new(c, n);
pdp_list_add_pointer(m->vertices, v);
return v;
}
void mesh_vertex_remove(t_mesh *m, t_vertex *v)
{
pdp_list_remove_pointer(m->vertices, v);
_vertex_free(v);
}
t_triangle *mesh_triangle_add(t_mesh *m, t_vertex *v0, t_vertex *v1, t_vertex *v2)
{
t_triangle *t = _triangle_new(v0,v1,v2);
pdp_list_add_pointer(m->triangles, t);
return t;
}
void mesh_triangle_remove(t_mesh *m, t_triangle *t)
{
pdp_list_remove_pointer(m->triangles, t);
_triangle_free(t);
}
/* calculate normals */
void mesh_calculate_normals(t_mesh *m)
{
t_pdp_atom* it;
t_pdp_atom* it_tri;
t_pdp_list *l = m->vertices;
t_pdp_list *l_tri = m->triangles;
t_vertex *v;
t_triangle *t;
//while (v = pdp_list_getnext_pointer(l, &it)) vertex_compute_normal_sphere(v);
switch(m->normal_type){
default:
case MESH_NORMAL_SPHERE: PDP_POINTER_IN(l, it, v) vertex_compute_normal_sphere(v); break;
case MESH_NORMAL_PRISM: PDP_POINTER_IN(l, it, v) vertex_compute_normal_prism(v); break;
case MESH_NORMAL_RANDOM: PDP_POINTER_IN(l, it, v) vertex_compute_normal_random(v); break;
case MESH_NORMAL_AVERAGE:
PDP_POINTER_IN(l_tri, it_tri, t) triangle_compute_unit_normal(t);
PDP_POINTER_IN(l, it, v) vertex_compute_normal_average(v);
break;
}
}
/* split a triangle in 4, using the intermedia median vertex storage */
void mesh_split_four(t_mesh *m, t_triangle *old_t)
{
int k;
t_vertex *v[6];
/* some intermediates */
t_triangle *neighbour;
t_float newv[] = {0,0,0};
t_float nullvect[] = {0,0,0};
/* get main vertices */
I3(k) v[k] = old_t->v[k];
/* get median vertices inserted by neighbouring triangles */
I3(k) v[k+3] = old_t->m[k];
#define GET_MEDIAN(v, v0, v1) \
if (!v){ \
I3(k) newv[k] = 0.5f * (v0->c[k] + v1->c[k]); \
v = mesh_vertex_add(m, newv, nullvect); \
/*vertex_normalize(v);*/ \
if (neighbour = triangle_neighbour(old_t, v0, v1)){ \
triangle_add_median(neighbour, v0, v1, v); \
} \
}
GET_MEDIAN(v[3], v[0], v[1])
GET_MEDIAN(v[4], v[1], v[2])
GET_MEDIAN(v[5], v[2], v[0])
#undef GET_MEDIAN
/* remove the old triangle */
mesh_triangle_remove(m, old_t);
/* create 4 new triangles */
mesh_triangle_add(m, v[0], v[3], v[5]);
mesh_triangle_add(m, v[1], v[4], v[3]);
mesh_triangle_add(m, v[2], v[5], v[4]);
mesh_triangle_add(m, v[3], v[4], v[5]);
}
/* split a triangle in 3 */
void mesh_split_three(t_mesh *m, t_triangle *old_t)
{
int k, l;
t_vertex *v[4];
t_float newv[] = {0,0,0};
t_float nullvect[] = {0,0,0};
/* get vertices */
I3(k) v[k] = old_t->v[k];
/* remove a triangle */
mesh_triangle_remove(m, old_t);
/* compute new vertex coordinates */
I3(k) I3(l) newv[k] += 0.33333f * v[l]->c[k];
/* create new vertex */
v[3] = mesh_vertex_add(m, newv, nullvect);
//vertex_normalize(v[3]);
/* create 3 new triangles */
mesh_triangle_add(m, v[0], v[1], v[3]);
mesh_triangle_add(m, v[1], v[2], v[3]);
mesh_triangle_add(m, v[2], v[0], v[3]);
}
void mesh_split_all_four(t_mesh *m)
{
t_triangle *t;
t_pdp_list *l = pdp_list_copy(m->triangles);
//post("split_all_four: nb triangles %d", pdp_list_size(m->triangles));
while (l->elements){
t = pdp_list_pop(l).w_pointer;
mesh_split_four(m, t);
}
mesh_calculate_normals(m);
pdp_list_free(l);
}
void mesh_split_all_three(t_mesh *m)
{
t_triangle *t;
t_pdp_list *l = pdp_list_copy(m->triangles);
//post("split_all_three: nb triangles %d", pdp_list_size(m->triangles));
while (l->elements){
t = pdp_list_pop(l).w_pointer;
mesh_split_three(m, t);
}
mesh_calculate_normals(m);
pdp_list_free(l);
}
void mesh_split_random_three(t_mesh *m)
{
int size = pdp_list_size(m->triangles);
t_triangle *t = pdp_list_index(m->triangles, (random() % size)).w_pointer;
mesh_split_three(m, t);
mesh_calculate_normals(m);
}
void mesh_free(t_mesh *m)
{
t_pdp_list *l;
t_triangle *t;
t_vertex *v;
/* delete all triangles */
while (m->triangles->elements){
t = pdp_list_pop(m->triangles).w_pointer;
//post("freeing triangle %x", t);
_triangle_free(t);
}
pdp_list_free(m->triangles);
m->triangles = 0;
/* delete all vertices */
while (m->vertices->elements){
v = pdp_list_pop(m->vertices).w_pointer;
//post("freeing vertex %x", v);
_vertex_free(v);
}
pdp_list_free(m->vertices);
m->vertices = 0;
pdp_dealloc(m);
}
t_mesh *_mesh_new(void)
{
t_mesh *m = (t_mesh *)pdp_alloc(sizeof(t_mesh));
/* create main vertex and triangle lists */
m->triangles = pdp_list_new(0);
m->vertices = pdp_list_new(0);
/* set normal type */
m->normal_type = MESH_NORMAL_PRISM;
return m;
}
/* init tetra */
t_mesh *mesh_new_tetra(void)
{
int k;
t_triangle *t[4];
t_vertex *v[4];
t_pdp_atom* it;
t_triangle *tri;
t_mesh *m = _mesh_new();
float n[] = {0,0,0};
float fv[4][3] = {{2,0,0},{0,2,0},{0,0,2}, {-1,-1,-1}};
/* add vertices */
I4(k) v[k] = mesh_vertex_add(m, &fv[k][0], n);
I4(k) vertex_normalize(v[k]);
/* add triangles */
mesh_triangle_add(m, v[0], v[1], v[2]);
mesh_triangle_add(m, v[1], v[0], v[3]);
mesh_triangle_add(m, v[0], v[2], v[3]);
mesh_triangle_add(m, v[1], v[3], v[2]);
/* compute normals */
mesh_calculate_normals(m);
return m;
}
void _mesh_relax_compute_resultant_spring(t_mesh *m, float *center, float d0, float r0)
{
int k;
t_pdp_atom *i, *j;
t_vertex *v, *w;
PDP_POINTER_IN(m->vertices, i, v){
float scale = 0.0f;
float r;
/* compute contribution of origin link */
I3(k) v->n[k] = v->c[k] - center[k];
r = _vector3_normalize(v->n);
I3(k) v->n[k] *= (r0 - r);
PDP_POINTER_IN(v->vertlist, j, w){
int k;
float f[3];
float d, l;
/* compute force contribution of one link (model: spring with rest length == d0) */
I3(k) f[k] = w->c[k] - v->c[k]; // PC: f == distance vector
d = _vector3_normalize(f); // PC: d == distance, vector == unit norm
I3(k) v->n[k] += (d - d0) * f[k]; // PC: n == n_prev + fource resultant
}
}
}
void _mesh_relax_apply_force(t_mesh *m, float k)
{
t_pdp_atom* it;
t_vertex *v;
PDP_POINTER_IN(m->vertices, it, v){
int i;
/* apply fource vector with step */
I3(i) v->c[i] += k * v->n[i];
}
}
void mesh_compute_center(t_mesh *m, float *c)
{
t_pdp_atom*(it);
t_vertex *v;
float scale;
int k;
I3(k) c[k] = 0;
PDP_POINTER_IN(m->vertices, it, v){
I3(k) c[k] += v->c[k];
}
scale = 1.0f / ((float)pdp_list_size(m->vertices));
I3(k) c[k] *= scale;
}
void mesh_translate(t_mesh *m, float *c)
{
t_pdp_atom *it;
t_vertex *v;
int k;
PDP_POINTER_IN(m->vertices, it, v){
I3(k) v->c[k] += c[k];
}
}
/* relax a mesh (move toward equal link length) */
void mesh_relax(t_mesh *m, float step, float d0, float r0)
{
int k;
float c[3];
mesh_compute_center(m, c);
I3(k) c[k] = -c[k];
mesh_translate(m, c);
I3(k) c[k] = 0;
_mesh_relax_compute_resultant_spring(m, c, d0, r0); /* compute force resultant */
_mesh_relax_apply_force(m, step); /* apply "time step towards desired distance" */
mesh_calculate_normals(m); /* restore normals */
}
/* print some debug information */
void mesh_debug(t_mesh *m)
{
int k;
int boundary_edges = 0;
t_pdp_atom* it;
t_triangle *t;
post("mesh info");
post("\tnumber of vertices = %d", pdp_list_size(m->vertices));
post("\tnumber of triangles = %d", pdp_list_size(m->triangles));
PDP_POINTER_IN(m->triangles, it, t){
I3(k) if (!triangle_neighbour(t, t->v[k], t->v[(k+1)%3])) boundary_edges++;
}
post("\tnumber of boundaray edges = %d", boundary_edges);
}
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