Tomato Cycles: experimental option to cancel rendering when doing initial synchronization

This required wrapping create and update pytohn callbacks as  into begin/end
allow threading macroses. From quick tests this seems to be stable enough,
but more tests would be needed before considering this stable.

intern/cycles/blender/blender_object.cpp

@@ -302,14 +302,17 @@ void BlenderSync::sync_objects(BL::SpaceView3D b_v3d, int motion)
 	BL::Scene b_sce = b_scene;
 	int particle_offset = 0;
 
-	for(; b_sce; b_sce = b_sce.background_set()) {
-		for(b_sce.objects.begin(b_ob); b_ob != b_sce.objects.end(); ++b_ob) {
+	bool cancel = false;
+
+	for(; b_sce && !cancel; b_sce = b_sce.background_set()) {
+		for(b_sce.objects.begin(b_ob); b_ob != b_sce.objects.end() && !cancel; ++b_ob) {
 			bool hide = (render_layer.use_viewport_visibility)? b_ob->hide(): b_ob->hide_render();
 			uint ob_layer = get_layer(b_ob->layers(), b_ob->layers_local_view(), object_is_light(*b_ob));
 			CYCLES_LOCAL_LAYER_HACK(render_layer.use_localview, ob_layer);
 			hide = hide || !(ob_layer & scene_layer);
 
 			if(!hide) {
+				progress.set_status("Synchronizing object", (*b_ob).name());
 
 				int num_particles = object_count_particles(*b_ob);
 
@@ -351,10 +354,12 @@ void BlenderSync::sync_objects(BL::SpaceView3D b_v3d, int motion)
 
 				particle_offset += num_particles;
 			}
+
+			cancel = progress.get_cancel();
 		}
 	}
 
-	if(!motion) {
+	if(!cancel && !motion) {
 		sync_background_light();
 
 		/* handle removed data and modified pointers */

intern/cycles/blender/blender_python.cpp

@@ -80,6 +80,8 @@ static PyObject *create_func(PyObject *self, PyObject *args)
 	/* create session */
 	BlenderSession *session;
 
+	Py_BEGIN_ALLOW_THREADS
+
 	if(rv3d) {
 		/* interactive session */
 		int width = region.width();
@@ -91,7 +93,9 @@ static PyObject *create_func(PyObject *self, PyObject *args)
 		/* offline session */
 		session = new BlenderSession(engine, userpref, data, scene);
 	}
-	
+
+	Py_END_ALLOW_THREADS
+
 	return PyLong_FromVoidPtr(session);
 }
 
@@ -136,9 +140,13 @@ static PyObject *draw_func(PyObject *self, PyObject *args)
 
 static PyObject *sync_func(PyObject *self, PyObject *value)
 {
+	Py_BEGIN_ALLOW_THREADS
+
 	BlenderSession *session = (BlenderSession*)PyLong_AsVoidPtr(value);
 	session->synchronize();
 
+	Py_END_ALLOW_THREADS
+
 	Py_RETURN_NONE;
 }
 

intern/cycles/blender/blender_session.cpp

@@ -88,15 +88,6 @@ void BlenderSession::create_session()
 	/* create scene */
 	scene = new Scene(scene_params, session_params.device);
 
-	/* create sync */
-	sync = new BlenderSync(b_engine, b_data, b_scene, scene, !background);
-	sync->sync_data(b_v3d, b_engine.camera_override());
-
-	if(b_rv3d)
-		sync->sync_view(b_v3d, b_rv3d, width, height);
-	else
-		sync->sync_camera(b_engine.camera_override(), width, height);
-
 	/* create session */
 	session = new Session(session_params);
 	session->scene = scene;
@@ -104,6 +95,15 @@ void BlenderSession::create_session()
 	session->progress.set_cancel_callback(function_bind(&BlenderSession::test_cancel, this));
 	session->set_pause(BlenderSync::get_session_pause(b_scene, background));
 
+	/* create sync */
+	sync = new BlenderSync(b_engine, b_data, b_scene, scene, !background, session->progress);
+	sync->sync_data(b_v3d, b_engine.camera_override());
+
+	if(b_rv3d)
+		sync->sync_view(b_v3d, b_rv3d, width, height);
+	else
+		sync->sync_camera(b_engine.camera_override(), width, height);
+
 	/* set buffer parameters */
 	BufferParams buffer_params = BlenderSync::get_buffer_params(b_scene, scene->camera, width, height);
 	session->reset(buffer_params, session_params.samples);

intern/cycles/blender/blender_sync.cpp

@@ -40,7 +40,7 @@ CCL_NAMESPACE_BEGIN
 
 /* Constructor */
 
-BlenderSync::BlenderSync(BL::RenderEngine b_engine_, BL::BlendData b_data_, BL::Scene b_scene_, Scene *scene_, bool preview_)
+BlenderSync::BlenderSync(BL::RenderEngine b_engine_, BL::BlendData b_data_, BL::Scene b_scene_, Scene *scene_, bool preview_, Progress &progress_)
 : b_engine(b_engine_),
   b_data(b_data_), b_scene(b_scene_),
   shader_map(&scene_->shaders),
@@ -49,7 +49,8 @@ BlenderSync::BlenderSync(BL::RenderEngine b_engine_, BL::BlendData b_data_, BL::
   light_map(&scene_->lights),
   world_map(NULL),
   world_recalc(false),
-  experimental(false)
+  experimental(false),
+  progress(progress_)
 {
 	scene = scene_;
 	preview = preview_;

intern/cycles/blender/blender_sync.h

@@ -49,7 +49,7 @@ class ShaderNode;
 
 class BlenderSync {
 public:
-	BlenderSync(BL::RenderEngine b_engine_, BL::BlendData b_data, BL::Scene b_scene, Scene *scene_, bool preview_);
+	BlenderSync(BL::RenderEngine b_engine_, BL::BlendData b_data, BL::Scene b_scene, Scene *scene_, bool preview_, Progress &progress_);
 	~BlenderSync();
 
 	/* sync */
@@ -131,6 +131,8 @@ private:
 		bool use_localview;
 		int samples;
 	} render_layer;
+
+	Progress &progress;
 };
 
 /* we don't have spare bits for localview (normally 20-28)