fix memory leaks in random object code

Don't allocate mt structures (for the random number generator) on the heap.

simgear/scene/tgdb/SGTexturedTriangleBin.hxx

@@ -98,8 +98,7 @@ class SGTexturedTriangleBin : public SGTriangleBin<SGVertNormTex> {
 public:
   SGTexturedTriangleBin()
   {
-    seed = new mt;
-    mt_init(seed, 123);
+    mt_init(&seed, 123);
   }
 
   // Computes and adds random surface points to the points list.
@@ -107,7 +106,7 @@ public:
   // The points are offsetted away from the triangles in
   // offset * positive normal direction.
   void addRandomSurfacePoints(float coverage, float offset,
-                              std::vector<SGVec3f>& points) const
+                              std::vector<SGVec3f>& points)
   {
     unsigned num = getNumTriangles();
     for (unsigned i = 0; i < num; ++i) {
@@ -125,13 +124,13 @@ public:
       // For partial units of area, use a zombie door method to
       // create the proper random chance of a light being created
       // for this triangle
-      float unit = area + mt_rand(seed)*coverage;
+      float unit = area + mt_rand(&seed)*coverage;
       
       SGVec3f offsetVector = offset*normalize(normal);
       // generate a light point for each unit of area
       while ( coverage < unit ) {
-        float a = mt_rand(seed);
-        float b = mt_rand(seed);
+        float a = mt_rand(&seed);
+        float b = mt_rand(&seed);
         if ( a + b > 1 ) {
           a = 1 - a;
           b = 1 - b;
@@ -145,7 +144,7 @@ public:
   }
   
    void addRandomPoints(float coverage, 
-                        std::vector<SGVec3f>& points) const
+                        std::vector<SGVec3f>& points)
   {
     unsigned num = getNumTriangles();
     for (unsigned i = 0; i < num; ++i) {
@@ -163,12 +162,12 @@ public:
       // for partial units of area, use a zombie door method to
       // create the proper random chance of an object being created
       // for this triangle.
-      double num = area / coverage + mt_rand(seed);
+      double num = area / coverage + mt_rand(&seed);
 
       // place an object each unit of area
       while ( num > 1.0 ) {
-        float a = mt_rand(seed);
-        float b = mt_rand(seed);
+        float a = mt_rand(&seed);
+        float b = mt_rand(&seed);
         if ( a + b > 1 ) {
           a = 1 - a;
           b = 1 - b;
@@ -243,7 +242,7 @@ public:
 
 private:
   // Random seed for the triangle.
-  mt* seed;
+  mt seed;
 };
 
 #endif

simgear/scene/tgdb/obj.cxx

@@ -400,11 +400,11 @@ struct SGTileGeometryBin {
 
   void computeRandomSurfaceLights(SGMaterialLib* matlib)
   {
-    SGMaterialTriangleMap::const_iterator i;
+    SGMaterialTriangleMap::iterator i;
         
     // generate a repeatable random seed
-    mt* seed = new mt;
-    mt_init(seed, unsigned(123));
+    mt seed;
+    mt_init(&seed, unsigned(123));
     
     for (i = materialTriangleMap.begin(); i != materialTriangleMap.end(); ++i) {
       SGMaterial *mat = matlib->find(i->first);
@@ -424,9 +424,9 @@ struct SGTileGeometryBin {
       i->second.addRandomSurfacePoints(coverage, 3, randomPoints);
       std::vector<SGVec3f>::iterator j;
       for (j = randomPoints.begin(); j != randomPoints.end(); ++j) {
-        float zombie = mt_rand(seed);
+        float zombie = mt_rand(&seed);
         // factor = sg_random() ^ 2, range = 0 .. 1 concentrated towards 0
-        float factor = mt_rand(seed);
+        float factor = mt_rand(&seed);
         factor *= factor;
 
         float bright = 1;
@@ -451,7 +451,7 @@ struct SGTileGeometryBin {
   
   void computeRandomObjects(SGMaterialLib* matlib)
   {
-    SGMaterialTriangleMap::const_iterator i;
+    SGMaterialTriangleMap::iterator i;
     for (i = materialTriangleMap.begin(); i != materialTriangleMap.end(); ++i) {
       SGMaterial *mat = matlib->find(i->first);
       if (!mat)
@@ -528,8 +528,8 @@ SGLoadBTG(const std::string& path, SGMaterialLib *matlib, bool calc_lights, bool
     
     if (tileGeometryBin.randomModels.getNumModels() > 0) {
       // Generate a repeatable random seed
-      mt* seed = new mt;
-      mt_init(seed, unsigned(123));
+      mt seed;
+      mt_init(&seed, unsigned(123));
     
       // Determine an rotation matrix for the models to place them 
       // perpendicular to the earth's surface. We use the same matrix, 
@@ -555,7 +555,7 @@ SGLoadBTG(const std::string& path, SGMaterialLib *matlib, bool calc_lights, bool
         
         if (obj.model->get_heading_type() == SGMatModel::HEADING_RANDOM) {
           // Rotate the object around the z axis.
-          double hdg = mt_rand(seed) * M_PI * 2;
+          double hdg = mt_rand(&seed) * M_PI * 2;
           osg::Matrix rot(cos(hdg), -sin(hdg), 0, 0,
                           sin(hdg),  cos(hdg), 0, 0,
                           0,         0, 1, 0,