Fix RNG so it is passed in from above rather than generating the same

seed continuously.

diff --git a/simgear/scene/sky/newcloud.cxx b/simgear/scene/sky/newcloud.cxx
index 503e1de740e83e9e23386d4312374460e0d2b957..18b7710c20115ca4f07f42584fdce8f678066997 100644 (file)
--- a/simgear/scene/sky/newcloud.cxx
+++ b/simgear/scene/sky/newcloud.cxx
@@ -70,11 +70,11 @@ EffectMap effectMap;
 
 float SGNewCloud::sprite_density = 1.0;
 
-SGNewCloud::SGNewCloud(const SGPath &texture_root, const SGPropertyNode *cld_def)
+SGNewCloud::SGNewCloud(const SGPath &texture_root, const SGPropertyNode *cld_def, mt* s)
 {
-    // Set up a RNG that is repeatable within 10 minutes to ensure that clouds
-    // are synced up in multi-process deployments.
-    mt_init_time_10(&seed);
+    // Set up the RNG with the passed in seed. This allows us to make the RNG repeatable
+    // if required.
+    seed = s;
   
     min_width = cld_def->getFloatValue("min-cloud-width-m", 500.0);
     max_width = cld_def->getFloatValue("max-cloud-width-m", min_width*2);
@@ -135,7 +135,7 @@ SGNewCloud::~SGNewCloud() {
 #if 0
 // return a random number between -n/2 and n/2, tending to 0
 static float Rnd(float n) {
-    return n * (-0.5f + (mt_rand(&seed) + mt_rand(&seed)) / 2.0f);
+    return n * (-0.5f + (mt_rand(seed) + mt_rand(seed)) / 2.0f);
 }
 #endif
 
@@ -146,17 +146,17 @@ osg::ref_ptr<EffectGeode> SGNewCloud::genCloud() {
     // Determine how big this specific cloud instance is. Note that we subtract
     // the sprite size because the width/height is used to define the limits of
     // the center of the sprites, not their edges.
-    float width = min_width + mt_rand(&seed) * (max_width - min_width) - min_sprite_width;
-    float height = min_height + mt_rand(&seed) * (max_height - min_height) - min_sprite_height;
+    float width = min_width + mt_rand(seed) * (max_width - min_width) - min_sprite_width;
+    float height = min_height + mt_rand(seed) * (max_height - min_height) - min_sprite_height;
     
     if (width  < 0.0) { width  = 0.0; }
     if (height < 0.0) { height = 0.0; }
     
     // Determine appropriate shading factors
-    float top_factor = min_top_lighting_factor + mt_rand(&seed) * (max_top_lighting_factor - min_top_lighting_factor);
-    float middle_factor = min_middle_lighting_factor + mt_rand(&seed) * (max_middle_lighting_factor - min_middle_lighting_factor);
-    float bottom_factor = min_bottom_lighting_factor + mt_rand(&seed) * (max_bottom_lighting_factor - min_bottom_lighting_factor);
-    float shade_factor = min_shade_lighting_factor + mt_rand(&seed) * (max_shade_lighting_factor - min_shade_lighting_factor);
+    float top_factor = min_top_lighting_factor + mt_rand(seed) * (max_top_lighting_factor - min_top_lighting_factor);
+    float middle_factor = min_middle_lighting_factor + mt_rand(seed) * (max_middle_lighting_factor - min_middle_lighting_factor);
+    float bottom_factor = min_bottom_lighting_factor + mt_rand(seed) * (max_bottom_lighting_factor - min_bottom_lighting_factor);
+    float shade_factor = min_shade_lighting_factor + mt_rand(seed) * (max_shade_lighting_factor - min_shade_lighting_factor);
     
     //printf("Cloud: %2f, %2f, %2f, %2f\n", top_factor, middle_factor, bottom_factor, shade_factor); 
     
@@ -176,7 +176,7 @@ osg::ref_ptr<EffectGeode> SGNewCloud::genCloud() {
     float cull_distance_squared = min_sprite_height * min_sprite_height * 0.1f;
     
     // The number of sprites we actually use is a function of the (user-controlled) density
-    int n_sprites = num_sprites * sprite_density * (0.5f + mt_rand(&seed));
+    int n_sprites = num_sprites * sprite_density * (0.5f + mt_rand(seed));
     
     for (int i = 0; i < n_sprites; i++)
     {
@@ -194,16 +194,16 @@ osg::ref_ptr<EffectGeode> SGNewCloud::genCloud() {
             y = 0;
             z = height * 0.5;
         } else {
-            float theta = mt_rand(&seed) * SGD_2PI;
-            float elev  = mt_rand(&seed) * SGD_PI;
+            float theta = mt_rand(seed) * SGD_2PI;
+            float elev  = mt_rand(seed) * SGD_PI;
             x = width * cos(theta) * 0.5f * sin(elev);
             y = width * sin(theta) * 0.5f * sin(elev);
             z = height * cos(elev) * 0.5f + height * 0.5f;
         }
         
         // Determine the height and width
-        float sprite_width = min_sprite_width + mt_rand(&seed) * (max_sprite_width - min_sprite_width);
-        float sprite_height = min_sprite_height + mt_rand(&seed) * (max_sprite_height - min_sprite_height);
+        float sprite_width = min_sprite_width + mt_rand(seed) * (max_sprite_width - min_sprite_width);
+        float sprite_height = min_sprite_height + mt_rand(seed) * (max_sprite_height - min_sprite_height);
         
         // Sprites are never taller than square.
         if (sprite_height > sprite_width )
@@ -226,10 +226,10 @@ osg::ref_ptr<EffectGeode> SGNewCloud::genCloud() {
         }        
 
         // Determine the sprite texture indexes.
-        int index_x = (int) floor(mt_rand(&seed) * num_textures_x);
+        int index_x = (int) floor(mt_rand(seed) * num_textures_x);
         if (index_x >= num_textures_x) { index_x = num_textures_x - 1; }
                 
-        int index_y = (int) floor(mt_rand(&seed) * num_textures_y);
+        int index_y = (int) floor(mt_rand(seed) * num_textures_y);
         
         if (height_map_texture) {
           // The y index depends on the position of the sprite within the cloud.

diff --git a/simgear/scene/sky/newcloud.hxx b/simgear/scene/sky/newcloud.hxx
index fd7c905a295359f2d5ec5886c77397334aa64d77..88edf19c4bba181683b57d8f16cf449733db3494 100644 (file)
--- a/simgear/scene/sky/newcloud.hxx
+++ b/simgear/scene/sky/newcloud.hxx
@@ -41,7 +41,7 @@ using std::vector;
 class SGNewCloud {
 
 public:
-        SGNewCloud(const SGPath &texture_root, const SGPropertyNode *cld_def);
+        SGNewCloud(const SGPath &texture_root, const SGPropertyNode *cld_def, mt* s);
 
         ~SGNewCloud();
 
@@ -103,7 +103,7 @@ private:
         static float sprite_density;
         
         // RNG seed for this cloud
-        mt seed;
+        mt* seed;
 
         osg::Geometry* createOrthQuad(float w, float h, int varieties_x, int varieties_y);
 };