Fix T62408: Cycles viewport adaptive subdivision hangs after updates

Backporting fix from the master branch.

intern/cycles/app/cycles_xml.cpp

@@ -516,8 +516,6 @@ static void xml_read_mesh(const XMLReadState& state, xml_node node)
 		xml_read_float(&sdparams.dicing_rate, node, "dicing_rate");
 		sdparams.dicing_rate = std::max(0.1f, sdparams.dicing_rate);
 
-		state.scene->camera->update(state.scene);
-		sdparams.camera = state.scene->camera;
 		sdparams.objecttoworld = state.tfm;
 	}
 

intern/cycles/blender/blender_mesh.cpp

@@ -1027,8 +1027,6 @@ static void create_subd_mesh(Scene *scene,
 	sdparams.dicing_rate = max(0.1f, RNA_float_get(&cobj, "dicing_rate") * dicing_rate);
 	sdparams.max_level = max_subdivisions;
 
-	scene->dicing_camera->update(scene);
-	sdparams.camera = scene->dicing_camera;
 	sdparams.objecttoworld = get_transform(b_ob.matrix_world());
 }
 

intern/cycles/blender/blender_sync.cpp

@@ -104,10 +104,10 @@ bool BlenderSync::sync_recalc()
 		if(b_lamp->is_updated() || (b_lamp->node_tree() && b_lamp->node_tree().is_updated()))
 			shader_map.set_recalc(*b_lamp);
 
-	bool dicing_prop_changed = false;
-
 	if(experimental) {
+		/* Mark all meshes as needing to be exported again if dicing changed. */
 		PointerRNA cscene = RNA_pointer_get(&b_scene.ptr, "cycles");
+		bool dicing_prop_changed = false;
 
 		float updated_dicing_rate = preview ? RNA_float_get(&cscene, "preview_dicing_rate")
 		                                    : RNA_float_get(&cscene, "dicing_rate");
@@ -123,6 +123,15 @@ bool BlenderSync::sync_recalc()
 			max_subdivisions = updated_max_subdivisions;
 			dicing_prop_changed = true;
 		}
+
+		if(dicing_prop_changed) {
+			for(const pair<void*, Mesh*>& iter: mesh_map.key_to_scene_data()) {
+				Mesh *mesh = iter.second;
+				if(mesh->subdivision_type != Mesh::SUBDIVISION_NONE) {
+					mesh_map.set_recalc(iter.first);
+				}
+			}
+		}
 	}
 
 	BL::BlendData::objects_iterator b_ob;
@@ -134,9 +143,7 @@ bool BlenderSync::sync_recalc()
 		}
 
 		if(object_is_mesh(*b_ob)) {
-			if(b_ob->is_updated_data() || b_ob->data().is_updated() ||
+			if(b_ob->is_updated_data() || b_ob->data().is_updated()) {
-			   (dicing_prop_changed && object_subdivision_type(*b_ob, preview, experimental) != Mesh::SUBDIVISION_NONE))
-			{
 				BL::ID key = BKE_object_is_modified(*b_ob)? *b_ob: b_ob->data();
 				mesh_map.set_recalc(key);
 			}

intern/cycles/blender/blender_util.h

@@ -644,6 +644,11 @@ public:
 		b_recalc.insert(id.ptr.data);
 	}
 
+	void set_recalc(void *id_ptr)
+	{
+		b_recalc.insert(id_ptr);
+	}
+
 	bool has_recalc()
 	{
 		return !(b_recalc.empty());
@@ -739,6 +744,11 @@ public:
 		return deleted;
 	}
 
+	const map<K, T*>& key_to_scene_data()
+	{
+		return b_map;
+	}
+
 protected:
 	vector<T*> *scene_data;
 	map<K, T*> b_map;

intern/cycles/render/camera.cpp

@@ -169,6 +169,8 @@ Camera::Camera()
 	cameratoworld = transform_identity();
 	worldtoraster = projection_identity();
 
+	full_rastertocamera = projection_identity();
+
 	dx = make_float3(0.0f, 0.0f, 0.0f);
 	dy = make_float3(0.0f, 0.0f, 0.0f);
 
@@ -251,7 +253,7 @@ void Camera::update(Scene *scene)
 	ProjectionTransform screentocamera = projection_inverse(cameratoscreen);
 
 	rastertocamera = screentocamera * rastertoscreen;
-	ProjectionTransform full_rastertocamera = screentocamera * full_rastertoscreen;
+	full_rastertocamera = screentocamera * full_rastertoscreen;
 	cameratoraster = screentoraster * cameratoscreen;
 
 	cameratoworld = matrix;
@@ -627,7 +629,7 @@ float Camera::world_to_raster_size(float3 P)
 
 		if(offscreen_dicing_scale > 1.0f) {
 			float3 p = transform_point(&worldtocamera, P);
-			float3 v = transform_perspective(&rastertocamera, make_float3(width, height, 0.0f));
+			float3 v = transform_perspective(&full_rastertocamera, make_float3(full_width, full_height, 0.0f));
 
 			/* Create point clamped to frustum */
 			float3 c;
@@ -644,8 +646,8 @@ float Camera::world_to_raster_size(float3 P)
 	}
 	else if(type == CAMERA_PERSPECTIVE) {
 		/* Calculate as if point is directly ahead of the camera. */
-		float3 raster = make_float3(0.5f*width, 0.5f*height, 0.0f);
+		float3 raster = make_float3(0.5f*full_width, 0.5f*full_height, 0.0f);
-		float3 Pcamera = transform_perspective(&rastertocamera, raster);
+		float3 Pcamera = transform_perspective(&full_rastertocamera, raster);
 
 		/* dDdx */
 		float3 Ddiff = transform_direction(&cameratoworld, Pcamera);
@@ -728,22 +730,21 @@ float Camera::world_to_raster_size(float3 P)
 		 * point directly ahead seems to produce good enough results. */
 #if 0
 		float2 dir = direction_to_panorama(&kernel_camera, kernel_camera_motion.data(), normalize(D));
-		float3 raster = transform_perspective(&cameratoraster, make_float3(dir.x, dir.y, 0.0f));
+		float3 raster = transform_perspective(&full_cameratoraster, make_float3(dir.x, dir.y, 0.0f));
 
 		ray.t = 1.0f;
 		camera_sample_panorama(&kernel_camera, kernel_camera_motion.data(), raster.x, raster.y, 0.0f, 0.0f, &ray);
 		if(ray.t == 0.0f) {
 			/* No differentials, just use from directly ahead. */
-			camera_sample_panorama(&kernel_camera, kernel_camera_motion.data(), 0.5f*width, 0.5f*height, 0.0f, 0.0f, &ray);
+			camera_sample_panorama(&kernel_camera, kernel_camera_motion.data(), 0.5f*full_width, 0.5f*full_height, 0.0f, 0.0f, &ray);
 		}
 #else
-		camera_sample_panorama(&kernel_camera, kernel_camera_motion.data(), 0.5f*width, 0.5f*height, 0.0f, 0.0f, &ray);
+		camera_sample_panorama(&kernel_camera, kernel_camera_motion.data(), 0.5f*full_width, 0.5f*full_height, 0.0f, 0.0f, &ray);
 #endif
 
 		differential_transfer(&ray.dP, ray.dP, ray.D, ray.dD, ray.D, dist);
 
-		return max(len(ray.dP.dx) * (float(width)/float(full_width)),
+		return max(len(ray.dP.dx),len(ray.dP.dy));
-		           len(ray.dP.dy) * (float(height)/float(full_height)));
 	}
 
 	return res;

intern/cycles/render/camera.h

@@ -160,6 +160,8 @@ public:
 	ProjectionTransform rastertocamera;
 	ProjectionTransform cameratoraster;
 
+	ProjectionTransform full_rastertocamera;
+
 	float3 dx;
 	float3 dy;
 

intern/cycles/render/mesh.cpp

@@ -2168,6 +2168,9 @@ void MeshManager::device_update(Device *device, DeviceScene *dscene, Scene *scen
 
 	/* Tessellate meshes that are using subdivision */
 	if(total_tess_needed) {
+		Camera *dicing_camera = scene->dicing_camera;
+		dicing_camera->update(scene);
+
 		size_t i = 0;
 		foreach(Mesh *mesh, scene->meshes) {
 			if(mesh->need_update &&
@@ -2183,6 +2186,7 @@ void MeshManager::device_update(Device *device, DeviceScene *dscene, Scene *scen
 
 				progress.set_status("Updating Mesh", msg);
 
+				mesh->subd_params->camera = dicing_camera;
 				DiagSplit dsplit(*mesh->subd_params);
 				mesh->tessellate(&dsplit);