static gdouble interpolated_value (GtsSurface * s, FttVector * p)
{
GtsPoint q;
GtsFace * t;
q.x = p->x; q.y = p->y;
t = gts_point_locate (&q, s, NULL);
if (t == NULL) {
g_warning ("cannot locate point (%g,%g)", p->x, p->y);
return 0.;
}
gts_triangle_interpolate_height (GTS_TRIANGLE (t), &q);
return q.z;
}
static GtsSurface * happrox (gray ** g, gint width, gint height,
CostFunc cost_func,
gpointer cost_data,
GtsStopFunc stop_func,
gpointer stop_data)
{
GtsSurface * s = gts_surface_new (gts_surface_class (),
GTS_FACE_CLASS (list_face_class ()),
gts_edge_class (),
gts_vertex_class ());
GtsVertex * v1 = gts_vertex_new (s->vertex_class, 0., 0., g[0][0]);
GtsVertex * v2 = gts_vertex_new (s->vertex_class,
0., height - 1, g[height - 1][0]);
GtsVertex * v3 = gts_vertex_new (s->vertex_class,
width - 1, 0., g[0][width - 1]);
GtsVertex * v4 = gts_vertex_new (s->vertex_class,
width - 1, height - 1,
g[height - 1][width - 1]);
guint i, j;
GSList * corners = NULL;
GtsTriangle * t;
GtsVertex * w1, * w2, * w3;
GtsListFace * f;
/* creates enclosing triangle */
corners = g_slist_prepend (corners, v1);
corners = g_slist_prepend (corners, v2);
corners = g_slist_prepend (corners, v3);
corners = g_slist_prepend (corners, v4);
t = gts_triangle_enclosing (gts_triangle_class (), corners, 100.);
g_slist_free (corners);
gts_triangle_vertices (t, &w1, &w2, &w3);
f = GTS_LIST_FACE (gts_face_new (s->face_class, t->e1, t->e2, t->e3));
gts_surface_add_face (s, GTS_FACE (f));
/* add PGM vertices (corners excepted) to point list of f */
for (i = 1; i < width - 1; i++) {
for (j = 1; j < height - 1; j++)
prepend (f, g, i, j);
prepend (f, g, i, 0);
prepend (f, g, i, height - 1);
}
for (j = 1; j < height - 1; j++) {
prepend (f, g, 0, j);
prepend (f, g, width - 1, j);
}
pgm_freearray (g, height);
/* add four corners to initial triangulation */
g_assert (gts_delaunay_add_vertex_to_face (s, v1, GTS_FACE (f)) == NULL);
f = GTS_LIST_FACE (gts_point_locate (GTS_POINT (v2), s, NULL));
g_assert (gts_delaunay_add_vertex_to_face (s, v2, GTS_FACE (f)) == NULL);
f = GTS_LIST_FACE (gts_point_locate (GTS_POINT (v3), s, NULL));
g_assert (gts_delaunay_add_vertex_to_face (s, v3, GTS_FACE (f)) == NULL);
f = GTS_LIST_FACE (gts_point_locate (GTS_POINT (v4), s, NULL));
g_assert (gts_delaunay_add_vertex_to_face (s, v4, GTS_FACE (f)) == NULL);
/* refine surface */
surface_hf_refine (s, cost_func, cost_data, stop_func, stop_data);
/* destroy unused vertices */
gts_surface_foreach_face (s, (GtsFunc) destroy_unused, NULL);
/* destroy enclosing triangle */
gts_allow_floating_vertices = TRUE;
gts_object_destroy (GTS_OBJECT (w1));
gts_object_destroy (GTS_OBJECT (w2));
gts_object_destroy (GTS_OBJECT (w3));
gts_allow_floating_vertices = FALSE;
return s;
}
