Data commit

Task/Catmull-Clark-subdivision-surface/C/catmull-clark-subdivision-surface.c

@@ -0,0 +1,93 @@
+vertex face_point(face f)
+{
+	int i;
+	vertex v;
+
+	if (!f->avg) {
+		f->avg = vertex_new();
+		foreach(i, v, f->v)
+			if (!i) f->avg->pos = v->pos;
+			else    vadd(f->avg->pos, v->pos);
+
+		vdiv(f->avg->pos, len(f->v));
+	}
+	return f->avg;
+}
+
+#define hole_edge(e) (len(e->f)==1)
+vertex edge_point(edge e)
+{
+	int i;
+	face f;
+
+	if (!e->e_pt) {
+		e->e_pt = vertex_new();
+		e->avg = e->v[0]->pos;
+		vadd(e->avg, e->v[1]->pos);
+		e->e_pt->pos = e->avg;
+
+		if (!hole_edge(e)) {
+			foreach (i, f, e->f)
+				vadd(e->e_pt->pos, face_point(f)->pos);
+			vdiv(e->e_pt->pos, 4);
+		} else
+			vdiv(e->e_pt->pos, 2);
+
+		vdiv(e->avg, 2);
+	}
+
+	return e->e_pt;
+}
+
+#define hole_vertex(v) (len((v)->f) != len((v)->e))
+vertex updated_point(vertex v)
+{
+	int i, n = 0;
+	edge e;
+	face f;
+	coord_t sum = {0, 0, 0};
+
+	if (v->v_new) return v->v_new;
+
+	v->v_new = vertex_new();
+	if (hole_vertex(v)) {
+		v->v_new->pos = v->pos;
+		foreach(i, e, v->e) {
+			if (!hole_edge(e)) continue;
+			vadd(v->v_new->pos, edge_point(e)->pos);
+			n++;
+		}
+		vdiv(v->v_new->pos, n + 1);
+	} else {
+		n = len(v->f);
+		foreach(i, f, v->f)
+			vadd(sum, face_point(f)->pos);
+		foreach(i, e, v->e)
+			vmadd(sum, edge_point(e)->pos, 2, sum);
+		vdiv(sum, n);
+		vmadd(sum, v->pos, n - 3, sum);
+		vdiv(sum, n);
+		v->v_new->pos = sum;
+	}
+
+	return v->v_new;
+}
+
+model catmull(model m)
+{
+	int i, j, a, b, c, d;
+	face f;
+	vertex v, x;
+
+	model nm = model_new();
+	foreach (i, f, m->f) {
+		foreach(j, v, f->v) {
+			_get_idx(a, updated_point(v));
+			_get_idx(b, edge_point(elem(f->e, (j + 1) % len(f->e))));
+			_get_idx(c, face_point(f));
+			_get_idx(d, edge_point(elem(f->e, j)));
+			model_add_face(nm, 4, a, b, c, d);
+		}
+	}
+	return nm;
+}