Moved trail diffusion algorithm to the diffuse_trail global function

The functions from fucking_shit.* will be rearranged someday, so the diffusion algorithm will most likely be moved somewhere again, but who knows...

src/fucking_shit.cu

@@ -37,6 +37,18 @@ namespace jc = jones_constants;
 }
 
 
+__host__ __device__ void diffuse_trail(MapNode *node)
+{
+    auto left = node->get_left(), top = node->get_top(), right = node->get_right(), bottom = node->get_bottom();
+
+    double sum = top->get_left()->trail + top->trail + top->get_right()->trail +
+                 left->trail + node->trail + right->trail +
+                 bottom->get_left()->trail + bottom->trail + bottom->get_right()->trail;
+
+    node->temp_trail = (1 - jc::diffdamp) * (sum / 9.0);
+}
+
+
 __host__ __device__ int count_particles_in_node_window(MapNode *node, int window_size)
 {
     for(int i = 0; i < window_size / 2; ++i)

src/main_logic.cuh

@@ -174,13 +174,7 @@ __device__ inline void run_iteration_diffuse_trail(SimulationMap *const simulati
     MapNode *self;
     RUN_ITERATION_SET_SELF(self, node_index)
 
-    auto left = self->get_left(), top = self->get_top(), right = self->get_right(), bottom = self->get_bottom();
-
-    double sum = top->get_left()->trail + top->trail + top->get_right()->trail +
-                 left->trail + self->trail + right->trail +
-                 bottom->get_left()->trail + bottom->trail + bottom->get_right()->trail;
-
-    self->temp_trail = (1 - jc::diffdamp) * (sum / 9.0);
+    diffuse_trail(self);
 }
 
 /**