X-Git-Url: https://git.ucc.asn.au/?a=blobdiff_plain;f=course%2Fsemester2%2Fpprog%2Fassignment1%2Fmthread%2Fnbody.c;h=f59b451228e37359697159a50204760395774ddc;hb=83cf58f62ddc5ce9fe44de27327fde27f767ebb6;hp=4acf28f2c9cd382d8298b7e10f2ac59e9773fcb3;hpb=19e590cc4f7dbc186cad9418bf5a2321bfa3fe1a;p=matches%2Fhonours.git

diff --git a/course/semester2/pprog/assignment1/mthread/nbody.c b/course/semester2/pprog/assignment1/mthread/nbody.c
index 4acf28f2..f59b4512 100644
--- a/course/semester2/pprog/assignment1/mthread/nbody.c
+++ b/course/semester2/pprog/assignment1/mthread/nbody.c
@@ -21,7 +21,9 @@ unsigned workers_busy; // Number of workers currently doing something
 
 pthread_mutex_t mutex_runstate; // Mutex around the runstate
 
-
+pthread_mutex_t mutex_graphics; //Mutex between graphics and computation
+pthread_cond_t graphics_cv; //Condition used to start graphics or computation thread from the other
+bool graphics_busy = false; // Indicate if graphics is currently drawing
 
 /**
  * @function Compute_Thread
@@ -94,8 +96,7 @@ void * Compute_Thread(void * arg)
 			pthread_exit(NULL);
 		}
 
-		if (options.draw_graphics == false && options.verbosity != 0 
-			&& universe.steps % options.verbosity == 1)
+		if (options.verbosity != 0 && universe.steps % options.verbosity == 1)
 		{
 			DisplayStatistics();
 		}
@@ -134,6 +135,15 @@ void * Compute_Thread(void * arg)
 		pthread_mutex_unlock(&mutex_workers);
 
 		//All the forces are now computed
+
+		// Wait for graphics to finish drawing the last step
+		if (options.pedantic_graphics && options.draw_graphics)
+		{
+			pthread_mutex_lock(&mutex_graphics);
+			while (graphics_busy)
+				pthread_cond_wait(&graphics_cv, &mutex_graphics);
+			pthread_mutex_unlock(&mutex_graphics);
+		}
 		
 		workers_busy = options.num_threads; //All threads working
 
@@ -158,10 +168,51 @@ void * Compute_Thread(void * arg)
 		universe.steps += 1;
 
 
+		// Signal graphics thread to draw bodies
+		if (options.pedantic_graphics && options.draw_graphics)
+		{
+			pthread_mutex_lock(&mutex_graphics);
+			graphics_busy = true;
+			pthread_cond_signal(&graphics_cv);
+			pthread_mutex_unlock(&mutex_graphics);
+		}
 
 	}
 }
 
+/**
+ * @function BeforeDraw
+ * @purpose Called in graphics thread before the draw loop
+ * 	When --pedantic-graphics enabled, will wait for position computations to finish before drawing
+ *	Otherwise does nothing
+ */
+void BeforeDraw()
+{
+	if (!options.pedantic_graphics)
+		return;
+	pthread_mutex_lock(&mutex_graphics);
+	while (!graphics_busy)
+		pthread_cond_wait(&graphics_cv, &mutex_graphics);
+	pthread_mutex_unlock(&mutex_graphics);
+}
+
+/**
+ * @function AfterDraw
+ * @purpose Called in graphics thread after the draw loop
+ *	When --pedantic-graphics is supplied, will signal computation thread that drawing is finished
+ *		So that positions can be safely altered
+ *	Otherwise does nothing
+ */
+void AfterDraw()
+{
+	if (!options.pedantic_graphics)
+		return;
+	pthread_mutex_lock(&mutex_graphics);
+	graphics_busy = false;
+	pthread_cond_signal(&graphics_cv);
+	pthread_mutex_unlock(&mutex_graphics);
+}
+
 /**
  * @function Force_Thread
  * @purpose Thread - Calculates the forces on objects in a System