when setting the subframe for large frames (250,000+) the precision was very poor.

now use double precision when combining the frame+subframe.

4 files changed, 21 insertions, 9 deletions

diff --git a/source/blender/blenkernel/BKE_scene.h b/source/blender/blenkernel/BKE_scene.h
index 74a847a01d4..34f34bb9951 100644
--- a/source/blender/blenkernel/BKE_scene.h
+++ b/source/blender/blenkernel/BKE_scene.h
@@ -99,6 +99,7 @@ int BKE_scene_validate_setscene(struct Main *bmain, struct Scene *sce);
 
 float BKE_scene_frame_get(struct Scene *scene);
 float BKE_scene_frame_get_from_ctime(struct Scene *scene, const float frame);
+void  BKE_scene_frame_set(struct Scene *scene, double cfra);
 
 void BKE_scene_update_tagged(struct Main *bmain, struct Scene *sce);
 
diff --git a/source/blender/blenkernel/intern/scene.c b/source/blender/blenkernel/intern/scene.c
index 9c376f9ea04..26563afa65b 100644
--- a/source/blender/blenkernel/intern/scene.c
+++ b/source/blender/blenkernel/intern/scene.c
@@ -1045,6 +1045,21 @@ float BKE_scene_frame_get_from_ctime(Scene *scene, const float frame)
 	return ctime;
 }
 
+/**
+ * Sets the frame int/float components.
+ */
+void BKE_scene_frame_set(struct Scene *scene, double cfra)
+{
+	double intpart;
+	scene->r.subframe = modf(cfra, &intpart);
+	scene->r.cfra = (int)intpart;
+
+	if (cfra < 0.0) {
+		scene->r.cfra -= 1;
+		scene->r.subframe = 1.0f + scene->r.subframe;
+	}
+}
+
 /* drivers support/hacks 
  *  - this method is called from scene_update_tagged_recursive(), so gets included in viewport + render
  *	- these are always run since the depsgraph can't handle non-object data
diff --git a/source/blender/makesrna/intern/rna_scene_api.c b/source/blender/makesrna/intern/rna_scene_api.c
index 1f4622ff7f4..375b31e0586 100644
--- a/source/blender/makesrna/intern/rna_scene_api.c
+++ b/source/blender/makesrna/intern/rna_scene_api.c
@@ -56,12 +56,11 @@
 
 static void rna_Scene_frame_set(Scene *scene, int frame, float subframe)
 {
-	float cfra = (float)frame + subframe;
+	double cfra = (double)frame + (double)subframe;
+
+	CLAMP(cfra, MINAFRAME, MAXFRAME);
+	BKE_scene_frame_set(scene, cfra);
 
-	scene->r.cfra = floorf(cfra);
-	scene->r.subframe = cfra - floorf(cfra);
-	
-	CLAMP(scene->r.cfra, MINAFRAME, MAXFRAME);
 	BKE_scene_update_for_newframe(G.main, scene, (1 << 20) - 1);
 	BKE_scene_camera_switch_update(scene);
 
diff --git a/source/blender/render/intern/source/pipeline.c b/source/blender/render/intern/source/pipeline.c
index 068df215edb..91244e95d3b 100644
--- a/source/blender/render/intern/source/pipeline.c
+++ b/source/blender/render/intern/source/pipeline.c
@@ -1113,7 +1113,6 @@ void RE_TileProcessor(Render *re)
 
 static void do_render_3d(Render *re)
 {
-	float cfra;
 	int cfra_backup;
 
 	/* try external */
@@ -1126,9 +1125,7 @@ static void do_render_3d(Render *re)
 	/* add motion blur and fields offset to frames */
 	cfra_backup = re->scene->r.cfra;
 
-	cfra = re->scene->r.cfra + re->mblur_offs + re->field_offs;
-	re->scene->r.cfra = floorf(cfra);
-	re->scene->r.subframe = cfra - floorf(cfra);
+	BKE_scene_frame_set(re->scene, (double)re->scene->r.cfra + (double)re->mblur_offs + (double)re->field_offs);
 
 	/* lock drawing in UI during data phase */
 	if (re->draw_lock)