*
* A spherical version of the Realtime Optimally-Adapting Meshes (ROAM)
* algorithm is use for drawing the surface of the planet. ROAM provide a
- * continuous level-of-detail mesh of the planet which is used by #GisOpenGL
- * when drawing surface textures for GisTiles.
+ * continuous level-of-detail mesh of the planet which is used by #GritsOpenGL
+ * when drawing surface textures for GritsTiles.
*
* This implementation of the ROAM algorithm is based on an octahedron as the
* base model.
#include <GL/glu.h>
#include "gpqueue.h"
-#include "gis-util.h"
+#include "grits-util.h"
#include "roam.h"
/*
// triangle->split->lat, l->lat);
/* Update normal */
- double pa[3];
- double pb[3];
- pa[0] = triangle->p.l->x - triangle->p.m->x;
- pa[1] = triangle->p.l->y - triangle->p.m->y;
- pa[2] = triangle->p.l->z - triangle->p.m->z;
-
- pb[0] = triangle->p.r->x - triangle->p.m->x;
- pb[1] = triangle->p.r->y - triangle->p.m->y;
- pb[2] = triangle->p.r->z - triangle->p.m->z;
-
- triangle->norm[0] = pa[1] * pb[2] - pa[2] * pb[1];
- triangle->norm[1] = pa[2] * pb[0] - pa[0] * pb[2];
- triangle->norm[2] = pa[0] * pb[1] - pa[1] * pb[0];
-
- double total = sqrt(triangle->norm[0] * triangle->norm[0] +
- triangle->norm[1] * triangle->norm[1] +
- triangle->norm[2] * triangle->norm[2]);
-
- triangle->norm[0] /= total;
- triangle->norm[1] /= total;
- triangle->norm[2] /= total;
+ crossd3((gdouble*)triangle->p.l,
+ (gdouble*)triangle->p.m,
+ (gdouble*)triangle->p.r, triangle->norm);
+ normd(triangle->norm);
/* Store bounding box, for get_intersect */
RoamPoint *p[] = {l,m,r};
g_pqueue_remove(sphere->triangles, triangle->handle);
}
-static void roam_triangle_sync_neighbors(RoamTriangle *new, RoamTriangle *old, RoamTriangle *neigh)
+/* (neight->t.? == old) = new */
+static void roam_triangle_sync_neighbors(RoamTriangle *neigh, RoamTriangle *old, RoamTriangle *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)
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
/* 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;
}
}
roam_triangle_add(bl, br, b->t.l, sr, sphere);
roam_triangle_add(br, sl, b->t.r, bl, sphere);
- roam_triangle_sync_neighbors(sl, s, s->t.l);
- roam_triangle_sync_neighbors(sr, s, s->t.r);
- roam_triangle_sync_neighbors(bl, b, b->t.l);
- roam_triangle_sync_neighbors(br, b, b->t.r);
+ roam_triangle_sync_neighbors(s->t.l, s, sl);
+ roam_triangle_sync_neighbors(s->t.r, s, sr);
+ roam_triangle_sync_neighbors(b->t.l, b, bl);
+ roam_triangle_sync_neighbors(b->t.r, b, br);
/* Remove old triangles */
roam_triangle_remove(s, sphere);
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_sync_neighbors(s, sl, sl->t.b);
- roam_triangle_sync_neighbors(s, sr, sr->t.b);
- roam_triangle_sync_neighbors(b, bl, bl->t.b);
- roam_triangle_sync_neighbors(b, br, br->t.b);
+ roam_triangle_sync_neighbors(sl->t.b, sl, s);
+ roam_triangle_sync_neighbors(sr->t.b, sr, s);
+ roam_triangle_sync_neighbors(bl->t.b, bl, b);
+ roam_triangle_sync_neighbors(br->t.b, br, b);
/* Remove child triangles */
roam_triangle_remove(sl, sphere);