"Edge" triangles are triangles where one of the edges of the triangle
makes up an edge off the mesh. For example, the triangle E below is an
edge triangle due to the top edge.
This helps prevent jagged "edges" on the tops of mountains, etc. It also
helps round out the edges of the globe when viewed from far away.
________________
\ ______ /
\ /\ E /\ /
\/__\ /__\/
\/
if (neigh->t.l == old) neigh->t.l = new;
else if (neigh->t.b == old) neigh->t.b = new;
else if (neigh->t.r == old) neigh->t.r = new;
if (neigh->t.l == old) neigh->t.l = new;
else if (neigh->t.b == old) neigh->t.b = new;
else if (neigh->t.r == old) neigh->t.r = new;
- else g_assert_not_reached();
}
static gboolean roam_triangle_visible(RoamTriangle *triangle, RoamSphere *sphere)
}
static gboolean roam_triangle_visible(RoamTriangle *triangle, RoamSphere *sphere)
l->pz < 1 && m->pz < 1 && r->pz < 1;
}
l->pz < 1 && m->pz < 1 && r->pz < 1;
}
+static gboolean roam_triangle_backface(RoamTriangle *triangle, RoamSphere *sphere)
+{
+ RoamPoint *l = triangle->p.l;
+ RoamPoint *m = triangle->p.m;
+ RoamPoint *r = triangle->p.r;
+ roam_point_update_projection(l, sphere->view);
+ roam_point_update_projection(m, sphere->view);
+ roam_point_update_projection(r, sphere->view);
+ double size = -( l->px * (m->py - r->py) +
+ m->px * (r->py - l->py) +
+ r->px * (l->py - m->py) ) / 2.0;
+ return size < 0;
+}
+
/**
* roam_triangle_update_errors:
* @triangle: the triangle
/**
* roam_triangle_update_errors:
* @triangle: the triangle
/* Size < 0 == backface */
triangle->error *= size;
/* Size < 0 == backface */
triangle->error *= size;
+
+ /* Give some preference to "edge" faces */
+ if (roam_triangle_backface(triangle->t.l, sphere) ||
+ roam_triangle_backface(triangle->t.b, sphere) ||
+ roam_triangle_backface(triangle->t.r, sphere))
+ triangle->error *= 500;
b->kids[0] = b->kids[1] = NULL;
/* Add original triangles */
b->kids[0] = b->kids[1] = NULL;
/* Add original triangles */
+ roam_triangle_sync_neighbors(s->t.l, sl, s);
+ roam_triangle_sync_neighbors(s->t.r, sr, s);
+ roam_triangle_sync_neighbors(b->t.l, bl, b);
+ roam_triangle_sync_neighbors(b->t.r, br, b);
+
roam_triangle_add(s, sl->t.b, b, sr->t.b, sphere);
roam_triangle_add(b, bl->t.b, s, br->t.b, sphere);
roam_triangle_add(s, sl->t.b, b, sr->t.b, sphere);
roam_triangle_add(b, bl->t.b, s, br->t.b, sphere);