Index: blender/makesdna/DNA_scene_types.h
===================================================================
--- blender/makesdna/DNA_scene_types.h	(revision 12573)
+++ blender/makesdna/DNA_scene_types.h	(working copy)
@@ -498,6 +498,7 @@
 #define R_THREADS		0x80000
 #define R_SPEED			0x100000
 #define R_SSS			0x200000
+#define R_OSA_CLAMPHDR	0x400000
 
 /* filtertype */
 #define R_FILTER_BOX	0
@@ -528,7 +529,7 @@
 #define R_EXR_TILE_FILE		0x0400
 #define R_COMP_FREE			0x0800
 #define R_NO_IMAGE_LOAD		0x1000
-#define R_NO_TEX		0x2000
+#define R_NO_TEX			0x2000
 #define R_STAMP_INFO		0x4000
 
 /* r->stamp */
Index: blender/render/intern/source/pixelblending.c
===================================================================
--- blender/render/intern/source/pixelblending.c	(revision 12573)
+++ blender/render/intern/source/pixelblending.c	(working copy)
@@ -42,6 +42,7 @@
 #include "pixelblending.h"
 #include "gammaCorrectionTables.h"
 
+
 /* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
 /* defined in pipeline.c, is hardcopy of active dynamic allocated Render */
 /* only to be used here in this file, it's for speed */
@@ -169,6 +170,12 @@
 	b= col[2];
 	al= col[3];
 	
+	if (R.r.mode & R_OSA_CLAMPHDR) {
+		if (r> 1.0f) r = 1.0f;
+		if (g> 1.0f) g = 1.0f;
+		if (b> 1.0f) b = 1.0f;
+	}
+	
 	rb2= rowbuf-4;
 	rb3= rb2-4*row_w;
 	rb1= rb2+4*row_w;
Index: blender/src/buttons_scene.c
===================================================================
--- blender/src/buttons_scene.c	(revision 12573)
+++ blender/src/buttons_scene.c	(working copy)
@@ -1291,6 +1291,7 @@
 	uiDefButS(block, ROW,B_DIFF,"8",			400,88,29,20,&G.scene->r.osa,2.0,8.0, 0, 0, "Sets oversample level to 8 (Recommended)");
 	uiDefButS(block, ROW,B_DIFF,"11",			431,88,29,20,&G.scene->r.osa,2.0,11.0, 0, 0, "Sets oversample level to 11");
 	uiDefButS(block, ROW,B_DIFF,"16",			462,88,29,20,&G.scene->r.osa,2.0,16.0, 0, 0, "Sets oversample level to 16");
+	uiDefButBitI(block, TOG, R_OSA_CLAMPHDR, B_DIFF, "Clamp HDR",	369,68,122,20,&G.scene->r.mode, 0, 0, 0, 0, "Clamp high dynamic range colour channels to 1.0 before combining samples");
 	uiBlockEndAlign(block);
 
 	uiBlockBeginAlign(block);
@@ -1299,8 +1300,8 @@
 	uiBlockEndAlign(block);
 
 	uiBlockBeginAlign(block);
-	uiDefButS(block, NUM,B_DIFF,"Xparts:",		369,46,95,29,&G.scene->r.xparts,1.0, 512.0, 0, 0, "Sets the number of horizontal parts to render image in (For panorama sets number of camera slices)");
-	uiDefButS(block, NUM,B_DIFF,"Yparts:",		465,46,95,29,&G.scene->r.yparts,1.0, 64.0, 0, 0, "Sets the number of vertical parts to render image in");
+	uiDefButS(block, NUM,B_DIFF,"Xparts:",		369,40,95,24,&G.scene->r.xparts,1.0, 512.0, 0, 0, "Sets the number of horizontal parts to render image in (For panorama sets number of camera slices)");
+	uiDefButS(block, NUM,B_DIFF,"Yparts:",		465,40,95,24,&G.scene->r.yparts,1.0, 64.0, 0, 0, "Sets the number of vertical parts to render image in");
 	uiBlockEndAlign(block);
 
 	uiBlockBeginAlign(block);