Bugfix #2648

Thread render with  using Area lights was not fully thread safe yet. I
thought I had a smart method to trick threads, but apparently it can best
(and only) be done with Mutexes...

2 files changed, 31 insertions, 17 deletions

diff --git a/source/blender/render/intern/source/initrender.c b/source/blender/render/intern/source/initrender.c
index fba9593fbbf..23fbffa8861 100644
--- a/source/blender/render/intern/source/initrender.c
+++ b/source/blender/render/intern/source/initrender.c
@@ -872,7 +872,7 @@ static void yafrayRender(void)
 /* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
 
 // exported to other files, belongs in include... later
-SDL_mutex *render_abuf_lock=NULL, *load_ibuf_lock=NULL;
+SDL_mutex *render_abuf_lock=NULL, *load_ibuf_lock=NULL, *make_table_lock= NULL;
 
 
 static void renderloop_setblending(void)
@@ -916,7 +916,8 @@ static void mainRenderLoop(void)  /* here the PART and FIELD loops */
 	/* create mutexes for threaded render */
 	render_abuf_lock = SDL_CreateMutex();
 	load_ibuf_lock = SDL_CreateMutex();
-
+	make_table_lock = SDL_CreateMutex();
+	
 	if(R.rectz) MEM_freeN(R.rectz);
 	R.rectz = NULL;
 	if(R.rectftot) MEM_freeN(R.rectftot);
@@ -1170,8 +1171,10 @@ static void mainRenderLoop(void)  /* here the PART and FIELD loops */
 	/* mutexes free */
 	SDL_DestroyMutex(load_ibuf_lock);
 	SDL_DestroyMutex(render_abuf_lock);
+	SDL_DestroyMutex(make_table_lock);
 	load_ibuf_lock= NULL;
 	render_abuf_lock= NULL;
+	make_table_lock= NULL;
 }
 
 void render() {
diff --git a/source/blender/render/intern/source/ray.c b/source/blender/render/intern/source/ray.c
index 8a856883752..6aa157e8983 100644
--- a/source/blender/render/intern/source/ray.c
+++ b/source/blender/render/intern/source/ray.c
@@ -51,6 +51,8 @@
 #include "jitter.h"
 #include "texture.h"
 
+#include "SDL_thread.h"
+
 #define DDA_SHADOW 0
 #define DDA_MIRROR 1
 #define DDA_SHADOW_TRA 2
@@ -1636,25 +1638,34 @@ static float *jitter_plane(LampRen *lar, int xs, int ys)
 	tot= lar->ray_totsamp;
 	
 	if(lar->jitter==NULL) {
-		lar->jitter= (float *)4;	// mislead thread quickly (tsk!)
-		fp=lar->jitter= MEM_mallocN(4*tot*2*sizeof(float), "lamp jitter tab");
-		
-		/* fill table with random locations, area_size large */
-		for(x=0; x<tot; x++, fp+=2) {
-			fp[0]= (BLI_frand()-0.5)*lar->area_size;
-			fp[1]= (BLI_frand()-0.5)*lar->area_sizey;
-		}
+		extern SDL_mutex *make_table_lock; // initrender.c
+		if(make_table_lock) SDL_mutexP(make_table_lock);
 		
-		while(iter--) {
-			fp= lar->jitter;
-			for(x=tot; x>0; x--, fp+=2) {
-				DP_energy(lar->jitter, fp, tot, lar->area_size, lar->area_sizey);
+		/* check again, since other thread could have entered */
+		if(lar->jitter==NULL) {
+			
+			
+			fp=lar->jitter= MEM_mallocN(4*tot*2*sizeof(float), "lamp jitter tab");
+			
+			/* fill table with random locations, area_size large */
+			for(x=0; x<tot; x++, fp+=2) {
+				fp[0]= (BLI_frand()-0.5)*lar->area_size;
+				fp[1]= (BLI_frand()-0.5)*lar->area_sizey;
 			}
+			
+			while(iter--) {
+				fp= lar->jitter;
+				for(x=tot; x>0; x--, fp+=2) {
+					DP_energy(lar->jitter, fp, tot, lar->area_size, lar->area_sizey);
+				}
+			}
+			
+			jitter_plane_offset(lar->jitter, lar->jitter+2*tot, tot, lar->area_size, lar->area_sizey, 0.5, 0.0);
+			jitter_plane_offset(lar->jitter, lar->jitter+4*tot, tot, lar->area_size, lar->area_sizey, 0.5, 0.5);
+			jitter_plane_offset(lar->jitter, lar->jitter+6*tot, tot, lar->area_size, lar->area_sizey, 0.0, 0.5);
 		}
 		
-		jitter_plane_offset(lar->jitter, lar->jitter+2*tot, tot, lar->area_size, lar->area_sizey, 0.5, 0.0);
-		jitter_plane_offset(lar->jitter, lar->jitter+4*tot, tot, lar->area_size, lar->area_sizey, 0.5, 0.5);
-		jitter_plane_offset(lar->jitter, lar->jitter+6*tot, tot, lar->area_size, lar->area_sizey, 0.0, 0.5);
+		if(make_table_lock) SDL_mutexV(make_table_lock);
 	}
 		
 	if(lar->ray_samp_type & LA_SAMP_JITTER) {