1 // userdata.hxx -- two classes for populating ssg user data slots in association
2 // with our implimenation of random surface objects.
4 // Written by David Megginson, started December 2001.
6 // Copyright (C) 2001 - 2003 Curtis L. Olson - http://www.flightgear.org/~curt
8 // This program is free software; you can redistribute it and/or
9 // modify it under the terms of the GNU General Public License as
10 // published by the Free Software Foundation; either version 2 of the
11 // License, or (at your option) any later version.
13 // This program is distributed in the hope that it will be useful, but
14 // WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 // General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
25 # include <simgear_config.h>
28 #include <simgear/sg_inlines.h>
29 #include <simgear/math/point3d.hxx>
30 #include <simgear/math/sg_geodesy.hxx>
31 #include <simgear/math/sg_random.h>
32 #include <simgear/scene/material/mat.hxx>
33 #include <simgear/scene/material/matmodel.hxx>
35 #include "userdata.hxx"
38 // the following are static values needed by the runtime object
39 // loader. However, the loading is done via a call back so these
40 // values cannot be passed as parameters. The calling application
41 // needs to call sgUserDataInit() with the appropriate values before
42 // building / drawing any scenery.
44 static bool _inited = false;
45 static SGModelLib *modellib = NULL;
46 static string model_root = "";
47 static SGPropertyNode *root_props = NULL;
48 static double sim_time_sec = 0.0;
50 void sgUserDataInit( SGModelLib *m, const string &r,
51 SGPropertyNode *p, double t ) {
60 static void random_pt_inside_tri( float *res,
61 float *n1, float *n2, float *n3 )
63 double a = sg_random();
64 double b = sg_random();
71 res[0] = n1[0]*a + n2[0]*b + n3[0]*c;
72 res[1] = n1[1]*a + n2[1]*b + n3[1]*c;
73 res[2] = n1[2]*a + n2[2]*b + n3[2]*c;
78 * Fill in a triangle with randomly-placed objects.
80 * This method is invoked by a callback when the triangle is in range
81 * but not yet populated.
85 void SGTriUserData::fill_in_triangle ()
87 // generate a repeatable random seed
90 int nObjects = object_group->get_object_count();
92 for (int i = 0; i < nObjects; i++) {
93 SGMatModel * object = object_group->get_object(i);
94 double num = area / object->get_coverage_m2();
96 // place an object each unit of area
98 add_object_to_triangle(object);
101 // for partial units of area, use a zombie door method to
102 // create the proper random chance of an object being created
105 if ( sg_random() <= num ) {
106 // a zombie made it through our door
107 add_object_to_triangle(object);
113 void SGTriUserData::add_object_to_triangle (SGMatModel * object)
115 // Set up the random heading if required.
117 if (object->get_heading_type() == SGMatModel::HEADING_RANDOM)
118 hdg_deg = sg_random() * 360;
123 makeWorldMatrix(mat, hdg_deg);
125 ssgTransform * pos = new ssgTransform;
126 pos->setTransform(mat);
127 // the parameters to get_random_model() are set in local static
128 // data via the ssgUserDataInit() function. This function must be
129 // called before any scenery is drawn.
130 pos->addKid( object->get_random_model( modellib, model_root,
131 root_props, sim_time_sec )
137 void SGTriUserData::makeWorldMatrix (sgMat4 mat, double hdg_deg )
140 // if (hdg_deg == 0) {
141 // mat[0][0] = leafData->sin_lat * leafData->cos_lon;
142 // mat[0][1] = leafData->sin_lat * leafData->sin_lon;
143 // mat[0][2] = -leafData->cos_lat;
144 // mat[0][3] = SG_ZERO;
146 // mat[1][0] = -leafData->sin_lon;
147 // mat[1][1] = leafData->cos_lon;
148 // mat[1][2] = SG_ZERO;
149 // mat[1][3] = SG_ZERO;
151 // float sin_hdg = sin( hdg_deg * SGD_DEGREES_TO_RADIANS ) ;
152 // float cos_hdg = cos( hdg_deg * SGD_DEGREES_TO_RADIANS ) ;
153 // mat[0][0] = cos_hdg * leafData->sin_lat * leafData->cos_lon - sin_hdg * leafData->sin_lon;
154 // mat[0][1] = cos_hdg * leafData->sin_lat * leafData->sin_lon + sin_hdg * leafData->cos_lon;
155 // mat[0][2] = -cos_hdg * leafData->cos_lat;
156 // mat[0][3] = SG_ZERO;
158 // mat[1][0] = -sin_hdg * leafData->sin_lat * leafData->cos_lon - cos_hdg * leafData->sin_lon;
159 // mat[1][1] = -sin_hdg * leafData->sin_lat * leafData->sin_lon + cos_hdg * leafData->cos_lon;
160 // mat[1][2] = sin_hdg * leafData->cos_lat;
161 // mat[1][3] = SG_ZERO;
164 // mat[2][0] = leafData->cos_lat * leafData->cos_lon;
165 // mat[2][1] = leafData->cos_lat * leafData->sin_lon;
166 // mat[2][2] = leafData->sin_lat;
167 // mat[2][3] = SG_ZERO;
169 // // translate to random point in triangle
171 // random_pt_inside_tri(result, p1, p2, p3);
172 // sgSubVec3(mat[3], result, center);
174 // mat[3][3] = SG_ONE ;
178 * SSG callback for an in-range triangle of randomly-placed objects.
180 * This pretraversal callback is attached to a branch that is traversed
181 * only when a triangle is in range. If the triangle is not currently
182 * populated with randomly-placed objects, this callback will populate
185 * @param entity The entity to which the callback is attached (not used).
186 * @param mask The entity's traversal mask (not used).
187 * @return Always 1, to allow traversal and culling to continue.
190 // tri_in_range_callback (ssgEntity * entity, int mask)
192 // SGTriUserData * data = (SGTriUserData *)entity->getUserData();
193 // if (!data->is_filled_in) {
194 // data->fill_in_triangle();
195 // data->is_filled_in = true;
202 * SSG callback for an out-of-range triangle of randomly-placed objects.
204 * This pretraversal callback is attached to a branch that is traversed
205 * only when a triangle is out of range. If the triangle is currently
206 * populated with randomly-placed objects, the objects will be removed.
209 * @param entity The entity to which the callback is attached (not used).
210 * @param mask The entity's traversal mask (not used).
211 * @return Always 0, to prevent any further traversal or culling.
214 // tri_out_of_range_callback (ssgEntity * entity, int mask)
216 // SGTriUserData * data = (SGTriUserData *)entity->getUserData();
217 // if (data->is_filled_in) {
218 // data->branch->removeAllKids();
219 // data->is_filled_in = false;
226 * Calculate the bounding radius of a triangle from its center.
228 * @param center The triangle center.
229 * @param p1 The first point in the triangle.
230 * @param p2 The second point in the triangle.
231 * @param p3 The third point in the triangle.
232 * @return The greatest distance any point lies from the center.
234 // static inline float
235 // get_bounding_radius( sgVec3 center, float *p1, float *p2, float *p3)
237 // return sqrt( SG_MAX3( sgDistanceSquaredVec3(center, p1),
238 // sgDistanceSquaredVec3(center, p2),
239 // sgDistanceSquaredVec3(center, p3) ) );
244 * Set up a triangle for randomly-placed objects.
246 * No objects will be added unless the triangle comes into range.
250 void SGLeafUserData::setup_triangle (int i )
253 // leaf->getTriangle(i, &n1, &n2, &n3);
255 // float * p1 = leaf->getVertex(n1);
256 // float * p2 = leaf->getVertex(n2);
257 // float * p3 = leaf->getVertex(n3);
259 // // Set up a single center point for LOD
262 // (p1[0] + p2[0] + p3[0]) / 3.0,
263 // (p1[1] + p2[1] + p3[1]) / 3.0,
264 // (p1[2] + p2[2] + p3[2]) / 3.0);
265 // double area = sgTriArea(p1, p2, p3);
267 // // maximum radius of an object from center.
268 // double bounding_radius = get_bounding_radius(center, p1, p2, p3);
270 // // Set up a transformation to the center
271 // // point, so that everything else can
272 // // be specified relative to it.
273 // ssgTransform * location = new ssgTransform;
275 // sgMakeTransMat4(TRANS, center);
276 // location->setTransform(TRANS);
277 // branch->addKid(location);
279 // // Iterate through all the object types.
280 // int num_groups = mat->get_object_group_count();
281 // for (int j = 0; j < num_groups; j++) {
282 // // Look up the random object.
283 // SGMatModelGroup * group = mat->get_object_group(j);
285 // // Set up the range selector for the entire
286 // // triangle; note that we use the object
287 // // range plus the bounding radius here, to
288 // // allow for objects far from the center.
289 // float ranges[] = { 0,
290 // group->get_range_m() + bounding_radius,
292 // ssgRangeSelector * lod = new ssgRangeSelector;
293 // lod->setRanges(ranges, 3);
294 // location->addKid(lod);
296 // // Create the in-range and out-of-range
298 // ssgBranch * in_range = new ssgBranch;
299 // ssgBranch * out_of_range = new ssgBranch;
301 // // Set up the user data for if/when
302 // // the random objects in this triangle
304 // SGTriUserData * data = new SGTriUserData;
305 // data->is_filled_in = false;
309 // sgCopyVec3 (data->center, center);
310 // data->area = area;
311 // data->object_group = group;
312 // data->branch = in_range;
313 // data->leafData = this;
314 // data->seed = (unsigned int)(p1[0] * j);
316 // // Set up the in-range node.
317 // in_range->setUserData(data);
318 // in_range->setTravCallback(SSG_CALLBACK_PRETRAV,
319 // tri_in_range_callback);
320 // lod->addKid(in_range);
322 // // Set up the out-of-range node.
323 // out_of_range->setUserData(data);
324 // out_of_range->setTravCallback(SSG_CALLBACK_PRETRAV,
325 // tri_out_of_range_callback);
326 // out_of_range->addKid(new SGDummyBSphereEntity(bounding_radius));
327 // lod->addKid(out_of_range);