Convert from xyz to lle as the main roam coordinates

This keeps splits along latitude lines instead of along great circles.
It is a little less accurate, but makes texture mapping much simpler, at
least with Mercator projections.

If we ever manage to get lle->xyz conversions done in an OpenGL shader,
this should make the transition a little easier as well.

     Old Way           New Way
    .-''/'''-.        .-''/'''-.
   / __/_____ \      /.__/____..\
  /''  |     ''\    /    |       \
  *..__*_____..*    *..__*_____..*
  \    |       /    \    |       /
   \   \      /      \   \      /
    '-..\...-'        '-..\...-'

diff --git a/src/gis-util.c b/src/gis-util.c
index 3bd5246002e134843c7c8c2a13726dbc8e05c653..19604feb35e21b6e0f917c42df607d4b964de5b0 100644 (file)
--- a/src/gis-util.c
+++ b/src/gis-util.c
@@ -65,3 +65,16 @@ gdouble distd(gdouble *a, gdouble *b)
                    (a[1]-b[1])*(a[1]-b[1]) +
                    (a[2]-b[2])*(a[2]-b[2]));
 }
+
+gdouble lon_avg(gdouble a, gdouble b)
+{
+       gdouble diff = ABS(a-b);
+       gdouble avg  = (a+b)/2;
+       if (diff > 180) {
+               if (avg >= 0)
+                       avg -= 180;
+               else
+                       avg += 180;
+       }
+       return avg;
+}

diff --git a/src/gis-util.h b/src/gis-util.h
index a9f288a35b85f2554813355d6abfdeb770d65737..c7e1f69c497a4881a4696d040f980e79a84f713e 100644 (file)
--- a/src/gis-util.h
+++ b/src/gis-util.h
@@ -91,4 +91,6 @@ gdouble ll2m(gdouble lon_dist, gdouble lat);
 
 gdouble distd(gdouble *a, gdouble *b);
 
+gdouble lon_avg(gdouble a, gdouble b);
+
 #endif

diff --git a/src/roam.c b/src/roam.c
index 4bc294c08097c644ab0fa771e9e25c0b60c13218..7f131825d4735bb57fc95ffda639325705e3b486 100644 (file)
--- a/src/roam.c
+++ b/src/roam.c
@@ -46,17 +46,18 @@ static gint dia_cmp(RoamDiamond *a, RoamDiamond *b, gpointer data)
        else                          return  0;
 }
 
+
 /*************
  * RoamPoint *
  *************/
-RoamPoint *roam_point_new(gdouble x, gdouble y, gdouble z)
+RoamPoint *roam_point_new(gdouble lat, gdouble lon, gdouble elev)
 {
        RoamPoint *self = g_new0(RoamPoint, 1);
-       self->x = x;
-       self->y = y;
-       self->z = z;
+       self->lat  = lat;
+       self->lon  = lon;
+       self->elev = elev;
        /* For get_intersect */
-       xyz2ll(x, y, z, &self->lat, &self->lon);
+       lle2xyz(lat, lon, elev, &self->x, &self->y, &self->z);
        return self;
 }
 RoamPoint *roam_point_dup(RoamPoint *self)
@@ -93,13 +94,6 @@ void roam_point_update_height(RoamPoint *self)
                                self->lat, self->lon, self->height_data);
                lle2xyz(self->lat, self->lon, elev,
                                &self->x, &self->y, &self->z);
-       } else {
-               gdouble dist = sqrt(self->x * self->x +
-                                   self->y * self->y +
-                                   self->z * self->z);
-               self->x = self->x/dist * EARTH_R;
-               self->y = self->y/dist * EARTH_R;
-               self->z = self->z/dist * EARTH_R;
        }
 }
 void roam_point_update_projection(RoamPoint *self, RoamSphere *sphere)
@@ -134,9 +128,11 @@ RoamTriangle *roam_triangle_new(RoamPoint *l, RoamPoint *m, RoamPoint *r)
        self->p.m = m;
        self->p.r = r;
        self->split = roam_point_new(
-               (l->x + r->x)/2,
-               (l->y + r->y)/2,
-               (l->z + r->z)/2);
+               (l->lat + r->lat)/2,
+               (ABS(l->lat) == 90 ? r->lon :
+                ABS(r->lat) == 90 ? l->lon :
+                lon_avg(l->lon, r->lon)),
+               (l->elev + r->elev)/2);
        /* TODO: Move this back to sphere, or actually use the nesting */
        self->split->height_func = m->height_func;
        self->split->height_data = m->height_data;
@@ -173,10 +169,7 @@ RoamTriangle *roam_triangle_new(RoamPoint *l, RoamPoint *m, RoamPoint *r)
        self->norm[2] /= total;
 
        /* Store bounding box, for get_intersect */
-       RoamPoint *m1 = roam_point_new((l->x+m->x)/2, (l->y+m->y)/2, (l->z+m->z)/2);
-       RoamPoint *m2 = roam_point_new((m->x+r->x)/2, (m->y+r->y)/2, (m->z+r->z)/2);
-       RoamPoint *m3 = roam_point_new((r->x+l->x)/2, (r->y+l->y)/2, (r->z+l->z)/2);
-       RoamPoint *p[] = {l,m,r,m1,m2,m3};
+       RoamPoint *p[] = {l,m,r};
        self->edge.n =  -90; self->edge.s =  90;
        self->edge.e = -180; self->edge.w = 180;
        gboolean maxed = FALSE;
@@ -198,9 +191,6 @@ RoamTriangle *roam_triangle_new(RoamPoint *l, RoamPoint *m, RoamPoint *r)
                else
                        self->edge.e =  180;
        }
-       g_free(m1);
-       g_free(m2);
-       g_free(m3);
 
        //g_message("roam_triangle_new: %p", self);
        return self;
@@ -479,12 +469,12 @@ RoamSphere *roam_sphere_new()
        self->diamonds    = g_pqueue_new((GCompareDataFunc)dia_cmp, NULL);
 
        RoamPoint *vertexes[] = {
-               roam_point_new( 0, 1, 0), // 0
-               roam_point_new( 0,-1, 0), // 1
-               roam_point_new( 0, 0, 1), // 2
-               roam_point_new( 1, 0, 0), // 3
-               roam_point_new( 0, 0,-1), // 4
-               roam_point_new(-1, 0, 0), // 5
+               roam_point_new( 90,   0,  0), // 0 (North)
+               roam_point_new(-90,   0,  0), // 1 (South)
+               roam_point_new(  0,   0,  0), // 2 (Europe/Africa)
+               roam_point_new(  0,  90,  0), // 3 (Asia,East)
+               roam_point_new(  0, 180,  0), // 4 (Pacific)
+               roam_point_new(  0, -90,  0), // 5 (Americas,West)
        };
        int _triangles[][2][3] = {
                /*lv mv rv   ln, bn, rn */
@@ -610,7 +600,7 @@ void roam_sphere_draw_normals(RoamSphere *self)
        g_debug("RoamSphere: draw_normal");
        g_pqueue_foreach(self->triangles, (GFunc)roam_triangle_draw_normal, NULL);
 }
-GList *_roam_sphere_get_leaves(RoamTriangle *tri, GList *list)
+static GList *_roam_sphere_get_leaves(RoamTriangle *tri, GList *list)
 {
        if (tri->kids[0] && tri->kids[1]) {
                list = _roam_sphere_get_leaves(tri->kids[0], list);
@@ -620,7 +610,7 @@ GList *_roam_sphere_get_leaves(RoamTriangle *tri, GList *list)
                return g_list_append(list, tri);
        }
 }
-GList *_roam_sphere_get_intersect_rec(RoamTriangle *tri, GList *list,
+static GList *_roam_sphere_get_intersect_rec(RoamTriangle *tri, GList *list,
                gdouble n, gdouble s, gdouble e, gdouble w)
 {
        gdouble tn = tri->edge.n;

diff --git a/src/roam.h b/src/roam.h
index 38457005f735e8ec1dd3231221d35158308371af..815390f2d4616f17816ad684c71962e6d1bc1fae 100644 (file)
--- a/src/roam.h
+++ b/src/roam.h
@@ -48,7 +48,7 @@ struct _RoamPoint {
        gdouble  norm[3];   // Vertex normal
 
        /* For get_intersect */
-       gdouble  lat, lon;
+       gdouble  lat, lon, elev;
 
        /* For terrain */
        RoamHeightFunc height_func;