Bugfix, own collection:

Random seeding is still not perfect in render, especially lack of good
thread support still.

- VectorBlur node was calling seed for each exec, causing other nodes to
  get fixed random too.
- added seed in non-OSA main loop for render
- use BLI_srandom, is better than BLI_srand

source/blender/render/intern/source/pipeline.c

@@ -1640,7 +1640,7 @@ static void do_render_composite_fields_blur_3d(Render *re)
 	bNodeTree *ntree= re->scene->nodetree;
 	
 	/* INIT seeding, compositor can use random texture */
-	BLI_srand(re->r.cfra);
+	BLI_srandom(re->r.cfra);
 	
 	if(composite_needs_render(re->scene)) {
 		/* save memory... free all cached images */

source/blender/render/intern/source/rendercore.c

@@ -3026,7 +3026,7 @@ static void shadeDA_tile(RenderPart *pa, RenderLayer *rl)
 		od= offs;
 		
 		for(x=pa->disprect.xmin+crop; x<pa->disprect.xmax-crop; x++, rd++, rf+=4, od++) {
-			BLI_thread_srandom(pa->thread, seed+x);
+			BLI_thread_srandom(pa->thread, seed++);
 			
 			ps= (PixStr *)(*rd);
 			mask= 0;
@@ -3098,7 +3098,6 @@ static void shadeDA_tile(RenderPart *pa, RenderLayer *rl)
 		rectf+= 4*pa->rectx;
 		rectdaps+= pa->rectx;
 		offs+= pa->rectx;
-		seed+= pa->rectx;
 		
 		if(y&1) if(R.test_break()) break; 
 	}
@@ -3368,7 +3367,10 @@ void zbufshade_tile(RenderPart *pa)
 			
 			if(rl->layflag & SCE_LAY_SOLID) {
 				float *fcol= rl->rectf;
-				int x, y, *rp= pa->rectp, *rz= pa->rectz, offs=0;
+				int x, y, *rp= pa->rectp, *rz= pa->rectz, offs=0, seed;
+				
+				/* we set per pixel a fixed seed, for random AO and shadow samples */
+				seed= pa->rectx*pa->disprect.ymin;
 				
 				/* irregular shadowb buffer creation */
 				if(R.r.mode & R_SHADOW)
@@ -3376,6 +3378,8 @@ void zbufshade_tile(RenderPart *pa)
 				
 				for(y=pa->disprect.ymin; y<pa->disprect.ymax; y++, rr->renrect.ymax++) {
 					for(x=pa->disprect.xmin; x<pa->disprect.xmax; x++, rz++, rp++, fcol+=4, offs++) {
+						BLI_thread_srandom(pa->thread, seed++);
+						
 						shadepixel_sky(&shpi, (float)x, (float)y, *rz, *rp, 0);
 						QUATCOPY(fcol, shpi.shr.combined);
 						

source/blender/render/intern/source/zbuf.c

@@ -2237,12 +2237,13 @@ void RE_zbuf_accumulate_vecblur(NodeBlurData *nbd, int xsize, int ysize, float *
 {
 	ZSpan zspan;
 	DrawBufPixel *rectdraw, *dr;
-	float jit[16][2];
+	static float jit[16][2];
 	float v1[3], v2[3], v3[3], v4[3], fx, fy;
 	float *rectvz, *dvz, *dimg, *dvec1, *dvec2, *dz1, *dz2, *rectz, *minvecbufrect= NULL;
 	float maxspeedsq= (float)nbd->maxspeed*nbd->maxspeed;
 	int y, x, step, maxspeed=nbd->maxspeed, samples= nbd->samples;
 	int tsktsk= 0;
+	static int firsttime= 1;
 	char *rectmove, *dm;
 	
 	zbuf_alloc_span(&zspan, xsize, ysize);
@@ -2420,8 +2421,11 @@ void RE_zbuf_accumulate_vecblur(NodeBlurData *nbd, int xsize, int ysize, float *
 	
 	antialias_tagbuf(xsize, ysize, rectmove);
 	
-	BLI_initjit(jit[0], 16);
-	
+	/* has to become static, the init-jit calls a random-seed, screwing up texture noise node */
+	if(firsttime) {
+		firsttime= 0;
+		BLI_initjit(jit[0], 16);
+	}
 	
 	/* accumulate */
 	samples/= 2;