From e7e576055fec7218f77310652530fdf0aa0d98cb Mon Sep 17 00:00:00 2001
From: david <david>
Date: Thu, 25 Jul 2002 17:32:31 +0000
Subject: [PATCH] Added a new range-selector layer above each tile. That way,
by default, each tile has only 3 extra SSG nodes unless it falls into range.
---
src/Objects/obj.cxx | 191 ++++++++++++++++++++++++++++++++------------
1 file changed, 142 insertions(+), 49 deletions(-)
diff --git a/src/Objects/obj.cxx b/src/Objects/obj.cxx
index 017c755df..bef13c199 100644
--- a/src/Objects/obj.cxx
+++ b/src/Objects/obj.cxx
@@ -402,7 +402,11 @@ add_object_to_triangle (sgVec3 p1, sgVec3 p2, sgVec3 p3, sgVec3 center,
branch->addKid(pos);
}
-class RandomObjectUserData : public ssgBase
+
+/**
+ * User data for populating triangles when they come in range.
+ */
+class TriUserData : public ssgBase
{
public:
bool is_filled_in;
@@ -436,6 +440,9 @@ fill_in_triangle (float * p1, float * p2, float * p3,
FGNewMat::ObjectGroup * object_group, ssgBranch * branch,
double lon_deg, double lat_deg)
{
+ // generate a repeatable random seed
+ sg_srandom((unsigned int)(p1[0]));
+
int nObjects = object_group->get_object_count();
for (int i = 0; i < nObjects; i++) {
FGNewMat::Object * object = object_group->get_object(i);
@@ -466,7 +473,6 @@ fill_in_triangle (float * p1, float * p2, float * p3,
}
}
-
/**
* SSG callback for an in-range triangle of randomly-placed objects.
*
@@ -480,9 +486,9 @@ fill_in_triangle (float * p1, float * p2, float * p3,
* @return Always 1, to allow traversal and culling to continue.
*/
static int
-in_range_callback (ssgEntity * entity, int mask)
+tri_in_range_callback (ssgEntity * entity, int mask)
{
- RandomObjectUserData * data = (RandomObjectUserData *)entity->getUserData();
+ TriUserData * data = (TriUserData *)entity->getUserData();
if (!data->is_filled_in) {
fill_in_triangle(data->p1, data->p2, data->p3, data->object_group,
data->branch, data->lon_deg, data->lat_deg);
@@ -505,9 +511,9 @@ in_range_callback (ssgEntity * entity, int mask)
* @return Always 0, to prevent any further traversal or culling.
*/
static int
-out_of_range_callback (ssgEntity * entity, int mask)
+tri_out_of_range_callback (ssgEntity * entity, int mask)
{
- RandomObjectUserData * data = (RandomObjectUserData *)entity->getUserData();
+ TriUserData * data = (TriUserData *)entity->getUserData();
if (data->is_filled_in) {
data->branch->removeAllKids();
data->is_filled_in = false;
@@ -630,7 +636,7 @@ setup_triangle (float * p1, float * p2, float * p3,
// allow for objects far from the center.
float ranges[] = {0,
group->get_range_m() + bounding_radius,
- 500000};
+ SG_MAX};
ssgRangeSelector * lod = new ssgRangeSelector;
lod->setRanges(ranges, 3);
location->addKid(lod);
@@ -643,7 +649,7 @@ setup_triangle (float * p1, float * p2, float * p3,
// Set up the user data for if/when
// the random objects in this triangle
// are filled in.
- RandomObjectUserData * data = new RandomObjectUserData;
+ TriUserData * data = new TriUserData;
data->is_filled_in = false;
data->p1 = p1;
data->p2 = p2;
@@ -656,29 +662,107 @@ setup_triangle (float * p1, float * p2, float * p3,
// Set up the in-range node.
in_range->setUserData(data);
in_range->setTravCallback(SSG_CALLBACK_PRETRAV,
- in_range_callback);
+ tri_in_range_callback);
lod->addKid(in_range);
// Set up the out-of-range node.
out_of_range->setUserData(data);
out_of_range->setTravCallback(SSG_CALLBACK_PRETRAV,
- out_of_range_callback);
+ tri_out_of_range_callback);
out_of_range->addKid(DummyBSphereEntity::get_entity());
lod->addKid(out_of_range);
}
}
+/**
+ * User data for populating tiles when they come in range.
+ */
+class TileUserData : public ssgBase
+{
+public:
+ bool is_filled_in;
+ ssgLeaf * leaf;
+ FGNewMat * mat;
+ ssgBranch * branch;
+ double lon_deg;
+ double lat_deg;
+};
+
+
+/**
+ * SSG callback for an in-range tile of randomly-placed objects.
+ *
+ * This pretraversal callback is attached to a branch that is
+ * traversed only when a tile is in range. If the tile is not
+ * currently prepared to be populated with randomly-placed objects,
+ * this callback will prepare it (actual population is handled by
+ * the tri_in_range_callback for individual triangles).
+ *
+ * @param entity The entity to which the callback is attached (not used).
+ * @param mask The entity's traversal mask (not used).
+ * @return Always 1, to allow traversal and culling to continue.
+ */
+static int
+tile_in_range_callback (ssgEntity * entity, int mask)
+{
+ TileUserData * data = (TileUserData *)entity->getUserData();
+
+ if (!data->is_filled_in) {
+ // Iterate through all the triangles
+ // and populate them.
+ int num_tris = data->leaf->getNumTriangles();
+ for ( int i = 0; i < num_tris; ++i ) {
+ short n1, n2, n3;
+ data->leaf->getTriangle(i, &n1, &n2, &n3);
+ setup_triangle(data->leaf->getVertex(n1),
+ data->leaf->getVertex(n2),
+ data->leaf->getVertex(n3),
+ data->mat, data->branch, data->lon_deg, data->lat_deg);
+ }
+ data->is_filled_in = true;
+ }
+ return 1;
+}
+
+
+/**
+ * SSG callback for an out-of-range tile of randomly-placed objects.
+ *
+ * This pretraversal callback is attached to a branch that is
+ * traversed only when a tile is out of range. If the tile is
+ * currently prepared to be populated with randomly-placed objects (or
+ * is actually populated), the objects will be removed.
+ *
+ * @param entity The entity to which the callback is attached (not used).
+ * @param mask The entity's traversal mask (not used).
+ * @return Always 0, to prevent any further traversal or culling.
+ */
+static int
+tile_out_of_range_callback (ssgEntity * entity, int mask)
+{
+ TileUserData * data = (TileUserData *)entity->getUserData();
+ if (data->is_filled_in) {
+ data->branch->removeAllKids();
+ data->is_filled_in = false;
+ }
+ return 0;
+}
+
+
/**
* Randomly place objects on a surface.
*
* The leaf node provides the geometry of the surface, while the
* material provides the objects and placement density. Latitude
* and longitude are required so that the objects can be rotated
- * to the world-up vector.
+ * to the world-up vector. This function does not actually add
+ * any objects; instead, it attaches an ssgRangeSelector to the
+ * branch with callbacks to generate the objects when needed.
*
* @param leaf The surface where the objects should be placed.
* @param branch The branch that will hold the randomly-placed objects.
+ * @param center The center of the tile in FlightGear coordinates.
* @param lon_deg The longitude of the surface center, in degrees.
* @param lat_deg The latitude of the surface center, in degrees.
* @param material_name The name of the surface's material.
@@ -686,12 +770,16 @@ setup_triangle (float * p1, float * p2, float * p3,
static void
gen_random_surface_objects (ssgLeaf *leaf,
ssgBranch *branch,
- float lon_deg,
- float lat_deg,
+ Point3D * center,
const string &material_name)
{
- // First, look up the material
- // for this surface.
+ // If the surface has no triangles, return
+ // now.
+ int num_tris = leaf->getNumTriangles();
+ if (num_tris < 1)
+ return;
+
+ // Get the material for this surface.
FGNewMat * mat = material_lib.find(material_name);
if (mat == 0) {
SG_LOG(SG_INPUT, SG_ALERT, "Unknown material " << material_name);
@@ -703,25 +791,44 @@ gen_random_surface_objects (ssgLeaf *leaf,
if (mat->get_object_group_count() < 1)
return;
- // If the surface has no triangles, return
- // now.
- int num_tris = leaf->getNumTriangles();
- if (num_tris < 1)
- return;
+ // Calculate the geodetic centre of
+ // the tile, for aligning automatic
+ // objects.
+ double lon_deg, lat_rad, lat_deg, alt_m, sl_radius_m;
+ Point3D geoc = sgCartToPolar3d(*center);
+ lon_deg = geoc.lon() * SGD_RADIANS_TO_DEGREES;
+ sgGeocToGeod(geoc.lat(), geoc.radius(),
+ &lat_rad, &alt_m, &sl_radius_m);
+ lat_deg = lat_rad * SGD_RADIANS_TO_DEGREES;
- // generate a repeatable random seed
- sg_srandom((unsigned int)(leaf->getVertex(0)[0]));
+ // LOD for the tile
+ // max random object range: 20000m
+ float ranges[] = {0, 20000, 1000000};
+ ssgRangeSelector * lod = new ssgRangeSelector;
+ lod->setRanges(ranges, 3);
+ branch->addKid(lod);
- // Iterate through all the triangles
- // and populate them.
- for ( int i = 0; i < num_tris; ++i ) {
- short n1, n2, n3;
- leaf->getTriangle(i, &n1, &n2, &n3);
- setup_triangle(leaf->getVertex(n1),
- leaf->getVertex(n2),
- leaf->getVertex(n3),
- mat, branch, lon_deg, lat_deg);
- }
+ // Create the in-range and out-of-range
+ // branches.
+ ssgBranch * in_range = new ssgBranch;
+ ssgBranch * out_of_range = new ssgBranch;
+ lod->addKid(in_range);
+ lod->addKid(out_of_range);
+
+ TileUserData * data = new TileUserData;
+ data->is_filled_in = false;
+ data->leaf = leaf;
+ data->mat = mat;
+ data->branch = in_range;
+ data->lon_deg = lon_deg;
+ data->lat_deg = lat_deg;
+
+ in_range->setUserData(data);
+ in_range->setTravCallback(SSG_CALLBACK_PRETRAV, tile_in_range_callback);
+ out_of_range->setUserData(data);
+ out_of_range->setTravCallback(SSG_CALLBACK_PRETRAV,
+ tile_out_of_range_callback);
+ out_of_range->addKid(DummyBSphereEntity::get_entity());
}
@@ -1339,22 +1446,11 @@ bool fgBinObjLoad( const string& path, const bool is_base,
geometry->setName( (char *)path.c_str() );
- double geod_lon = 0.0, geod_lat = 0.0, geod_alt = 0.0,
- geod_sl_radius = 0.0;
if ( is_base ) {
// reference point (center offset/bounding sphere)
*center = obj.get_gbs_center();
*bounding_radius = obj.get_gbs_radius();
- // Calculate the geodetic centre of
- // the tile, for aligning automatic
- // objects.
- Point3D geoc = sgCartToPolar3d(*center);
- geod_lon = geoc.lon();
- sgGeocToGeod(geoc.lat(), geoc.radius(),
- &geod_lat, &geod_alt, &geod_sl_radius);
- geod_lon *= SGD_RADIANS_TO_DEGREES;
- geod_lat *= SGD_RADIANS_TO_DEGREES;
}
point_list nodes = obj.get_wgs84_nodes();
@@ -1419,8 +1515,7 @@ bool fgBinObjLoad( const string& path, const bool is_base,
is_base, ground_lights );
if (use_random_objects)
- gen_random_surface_objects(leaf, geometry, geod_lon, geod_lat,
- material);
+ gen_random_surface_objects(leaf, geometry, center, material);
geometry->addKid( leaf );
}
@@ -1440,8 +1535,7 @@ bool fgBinObjLoad( const string& path, const bool is_base,
is_base, ground_lights );
if (use_random_objects)
- gen_random_surface_objects(leaf, geometry, geod_lon, geod_lat,
- material);
+ gen_random_surface_objects(leaf, geometry, center, material);
geometry->addKid( leaf );
}
@@ -1460,8 +1554,7 @@ bool fgBinObjLoad( const string& path, const bool is_base,
vertex_index, normal_index, tex_index,
is_base, ground_lights );
if (use_random_objects)
- gen_random_surface_objects(leaf, geometry, geod_lon, geod_lat,
- material);
+ gen_random_surface_objects(leaf, geometry, center, material);
geometry->addKid( leaf );
}