- mat[1][0] = -leafData->sin_lon;
- mat[1][1] = leafData->cos_lon;
- mat[1][2] = SG_ZERO;
- mat[1][3] = SG_ZERO;
- } else {
- float sin_hdg = sin( hdg_deg * SGD_DEGREES_TO_RADIANS ) ;
- float cos_hdg = cos( hdg_deg * SGD_DEGREES_TO_RADIANS ) ;
- mat[0][0] = cos_hdg * leafData->sin_lat * leafData->cos_lon - sin_hdg * leafData->sin_lon;
- mat[0][1] = cos_hdg * leafData->sin_lat * leafData->sin_lon + sin_hdg * leafData->cos_lon;
- mat[0][2] = -cos_hdg * leafData->cos_lat;
- mat[0][3] = SG_ZERO;
-
- mat[1][0] = -sin_hdg * leafData->sin_lat * leafData->cos_lon - cos_hdg * leafData->sin_lon;
- mat[1][1] = -sin_hdg * leafData->sin_lat * leafData->sin_lon + cos_hdg * leafData->cos_lon;
- mat[1][2] = sin_hdg * leafData->cos_lat;
- mat[1][3] = SG_ZERO;
- }
-
- mat[2][0] = leafData->cos_lat * leafData->cos_lon;
- mat[2][1] = leafData->cos_lat * leafData->sin_lon;
- mat[2][2] = leafData->sin_lat;
- mat[2][3] = SG_ZERO;
-
- // translate to random point in triangle
- sgVec3 result;
- random_pt_inside_tri(result, p1, p2, p3);
- sgSubVec3(mat[3], result, center);
-
- mat[3][3] = SG_ONE ;
-}
-
-/**
- * SSG callback for an in-range triangle of randomly-placed objects.
- *
- * This pretraversal callback is attached to a branch that is traversed
- * only when a triangle is in range. If the triangle is not currently
- * populated with randomly-placed objects, this callback will populate
- * it.
- *
- * @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
-tri_in_range_callback (ssgEntity * entity, int mask)
-{
- SGTriUserData * data = (SGTriUserData *)entity->getUserData();
- if (!data->is_filled_in) {
- data->fill_in_triangle();
- data->is_filled_in = true;
- }
- return 1;
-}
-
-
-/**
- * SSG callback for an out-of-range triangle of randomly-placed objects.
- *
- * This pretraversal callback is attached to a branch that is traversed
- * only when a triangle is out of range. If the triangle is currently
- * populated with randomly-placed objects, 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
-tri_out_of_range_callback (ssgEntity * entity, int mask)
-{
- SGTriUserData * data = (SGTriUserData *)entity->getUserData();
- if (data->is_filled_in) {
- data->branch->removeAllKids();
- data->is_filled_in = false;
- }
- return 0;
-}
-
-
-/**
- * Calculate the bounding radius of a triangle from its center.
- *
- * @param center The triangle center.
- * @param p1 The first point in the triangle.
- * @param p2 The second point in the triangle.
- * @param p3 The third point in the triangle.
- * @return The greatest distance any point lies from the center.
- */
-static inline float
-get_bounding_radius( sgVec3 center, float *p1, float *p2, float *p3)
-{
- return sqrt( SG_MAX3( sgDistanceSquaredVec3(center, p1),
- sgDistanceSquaredVec3(center, p2),
- sgDistanceSquaredVec3(center, p3) ) );
-}
-
-
-/**
- * Set up a triangle for randomly-placed objects.
- *
- * No objects will be added unless the triangle comes into range.
- *
- */
-
-void SGLeafUserData::setup_triangle (int i )
-{
- short n1, n2, n3;
- leaf->getTriangle(i, &n1, &n2, &n3);
-
- float * p1 = leaf->getVertex(n1);
- float * p2 = leaf->getVertex(n2);
- float * p3 = leaf->getVertex(n3);
-
- // Set up a single center point for LOD
- sgVec3 center;
- sgSetVec3(center,
- (p1[0] + p2[0] + p3[0]) / 3.0,
- (p1[1] + p2[1] + p3[1]) / 3.0,
- (p1[2] + p2[2] + p3[2]) / 3.0);
- double area = sgTriArea(p1, p2, p3);
-
- // maximum radius of an object from center.
- double bounding_radius = get_bounding_radius(center, p1, p2, p3);
-
- // Set up a transformation to the center
- // point, so that everything else can
- // be specified relative to it.
- ssgTransform * location = new ssgTransform;
- sgMat4 TRANS;
- sgMakeTransMat4(TRANS, center);
- location->setTransform(TRANS);
- branch->addKid(location);
-
- // Iterate through all the object types.
- int num_groups = mat->get_object_group_count();
- for (int j = 0; j < num_groups; j++) {
- // Look up the random object.
- SGMatModelGroup * group = mat->get_object_group(j);
-
- // Set up the range selector for the entire
- // triangle; note that we use the object
- // range plus the bounding radius here, to
- // allow for objects far from the center.
- float ranges[] = { 0,
- group->get_range_m() + bounding_radius,
- SG_MAX };
- ssgRangeSelector * lod = new ssgRangeSelector;
- lod->setRanges(ranges, 3);
- location->addKid(lod);
-
- // Create the in-range and out-of-range
- // branches.
- ssgBranch * in_range = new ssgBranch;
- ssgBranch * out_of_range = new ssgBranch;
-
- // Set up the user data for if/when
- // the random objects in this triangle
- // are filled in.
- SGTriUserData * data = new SGTriUserData;
- data->is_filled_in = false;
- data->p1 = p1;
- data->p2 = p2;
- data->p3 = p3;
- sgCopyVec3 (data->center, center);
- data->area = area;
- data->object_group = group;
- data->branch = in_range;
- data->leafData = this;
- data->seed = (unsigned int)(p1[0] * j);
-
- // Set up the in-range node.
- in_range->setUserData(data);
- in_range->setTravCallback(SSG_CALLBACK_PRETRAV,
- 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,
- tri_out_of_range_callback);
- out_of_range->addKid(new SGDummyBSphereEntity(bounding_radius));
- lod->addKid(out_of_range);
- }
-}