lib: Compute BVHs asynchronously

A new cr_mesh_finalize() API function starts the BVH build task while
other meshes are still being loaded to reduce initialization time.

bindings/blender_init.py

@@ -323,6 +323,7 @@ def sync_scene(self, depsgraph):
 			facebuf = (c_ray.cr_face * len(faces))(*faces)
 			cr_mesh.bind_faces(bytearray(facebuf), len(faces))
 			cr_mesh.bind_vertex_buf(me)
+			cr_mesh.finalize()
 
 		# Set background shader
 		bl_nodetree = bpy.data.worlds[0].node_tree

bindings/c_ray.py

@@ -264,6 +264,8 @@ def bind_vertex_buf(self, me):
 		_lib.mesh_bind_vertex_buf(self.scene_ptr, self.cr_idx, self.v, self.vn, self.n, self.nn, self.t, self.tn)
 	def bind_faces(self, faces, face_count):
 		_lib.mesh_bind_faces(self.scene_ptr, self.cr_idx, faces, face_count)
+	def finalize(self):
+		_lib.mesh_finalize(self.scene_ptr, self.cr_idx)
 	def instance_new(self):
 		self.instances.append(instance(self.scene_ptr, self, 0))
 		return self.instances[-1]

bindings/cray_wrap.c

@@ -424,6 +424,19 @@ static PyObject *py_cr_mesh_bind_faces(PyObject *self, PyObject *args) {
 	Py_RETURN_NONE;
 }
 
+static PyObject *py_cr_mesh_finalize(PyObject *self, PyObject *args) {
+	(void)self; (void)args;
+	PyObject *s_ext;
+	cr_mesh mesh;
+	if (!PyArg_ParseTuple(args, "Ol", &s_ext, &mesh)) {
+		return NULL;
+	}
+
+	struct cr_scene *s = PyCapsule_GetPointer(s_ext, "cray.cr_scene");
+	cr_mesh_finalize(s, mesh);
+	Py_RETURN_NONE;
+}
+
 static PyObject *py_cr_scene_mesh_new(PyObject *self, PyObject *args) {
 	(void)self; (void)args;
 	PyObject *s_ext;
@@ -732,6 +745,7 @@ static PyMethodDef cray_methods[] = {
 	{ "scene_add_sphere", py_cr_scene_add_sphere, METH_VARARGS, "" },
 	{ "mesh_bind_vertex_buf", py_cr_mesh_bind_vertex_buf, METH_VARARGS, "" },
 	{ "mesh_bind_faces", py_cr_mesh_bind_faces, METH_VARARGS, "" },
+	{ "mesh_finalize", py_cr_mesh_finalize, METH_VARARGS, "" },
 	{ "scene_mesh_new", py_cr_scene_mesh_new, METH_VARARGS, "" },
 	{ "scene_get_mesh", py_cr_scene_get_mesh, METH_VARARGS, "" },
 	{ "camera_new", py_cr_camera_new, METH_VARARGS, "" },

include/c-ray/c-ray.h

@@ -198,6 +198,7 @@ CR_EXPORT cr_mesh cr_scene_get_mesh(struct cr_scene *s_ext, const char *name);
 
 CR_EXPORT void cr_mesh_bind_vertex_buf(struct cr_scene *s_ext, cr_mesh mesh, struct cr_vertex_buf_param buf);
 CR_EXPORT void cr_mesh_bind_faces(struct cr_scene *s_ext, cr_mesh mesh, struct cr_face *faces, size_t face_count);
+CR_EXPORT void cr_mesh_finalize(struct cr_scene *s_ext, cr_mesh mesh);
 
 // -- Camera --
 // FIXME: Use cr_vector

src/lib/accelerators/bvh.c

@@ -16,9 +16,6 @@
 #include "../datatypes/poly.h"
 #include "../renderer/instance.h"
 #include "../../common/vector.h"
-#include "../../common/platform/thread.h"
-#include "../../common/platform/thread_pool.h"
-#include "../../common/platform/capabilities.h"
 #include "../../common/platform/signal.h"
 #include "../../common/timer.h"
 
@@ -689,32 +686,3 @@ void destroy_bvh(struct bvh *bvh) {
 	free(bvh);
 }
 
-void bvh_build_task(void *arg) {
-	block_signals();
-	struct mesh *mesh = (struct mesh *)arg;
-	struct timeval timer = { 0 };
-	timer_start(&timer);
-	mesh->bvh = build_mesh_bvh(mesh);
-	if (mesh->bvh) {
-		logr(debug, "Built BVH for %s, took %lums\n", mesh->name, timer_get_ms(timer));
-	} else {
-		logr(debug, "BVH build FAILED for %s\n", mesh->name);
-	}
-}
-
-// FIXME: Add pthread_cancel() support
-void compute_accels(struct mesh_arr meshes) {
-	struct cr_thread_pool *pool = thread_pool_create(sys_get_cores());
-	logr(info, "Updating %zu BVHs: ", meshes.count);
-	struct timeval timer = { 0 };
-	timer_start(&timer);
-	for (size_t i = 0; i < meshes.count; ++i) {
-		if (!meshes.items[i].bvh) thread_pool_enqueue(pool, bvh_build_task, &meshes.items[i]);
-	}
-	thread_pool_wait(pool);
-
-	printSmartTime(timer_get_ms(timer));
-	logr(plain, "\n");
-	thread_pool_destroy(pool);
-}
-

src/lib/accelerators/bvh.h

@@ -55,5 +55,3 @@ bool traverse_bottom_level_bvh(
 
 /// Frees the memory allocated by the given BVH
 void destroy_bvh(struct bvh *);
-
-void compute_accels(struct mesh_arr meshes);

src/lib/api/c-ray.c

@@ -18,6 +18,7 @@
 #include "../../common/gitsha1.h"
 #include "../../common/fileio.h"
 #include "../../common/platform/terminal.h"
+#include "../../common/platform/signal.h"
 #include "../../common/assert.h"
 #include "../../common/texture.h"
 #include "../../common/string.h"
@@ -29,6 +30,8 @@
 #include "../../common/json_loader.h"
 #include "../protocol/protocol.h"
 #include "../../common/node_parse.h"
+#include "../../common/platform/thread_pool.h"
+#include "../accelerators/bvh.h"
 
 #ifdef CRAY_DEBUG_ENABLED
 #define DEBUG "D"
@@ -254,6 +257,20 @@ cr_sphere cr_scene_add_sphere(struct cr_scene *s_ext, float radius) {
 	return sphere_arr_add(&scene->spheres, (struct sphere){ .radius = radius });
 }
 
+void bvh_build_task(void *arg) {
+	block_signals();
+	struct mesh *mesh = (struct mesh *)arg;
+	if (mesh->bvh) destroy_bvh(mesh->bvh);
+	struct timeval timer = { 0 };
+	timer_start(&timer);
+	mesh->bvh = build_mesh_bvh(mesh);
+	if (mesh->bvh) {
+		logr(debug, "Built BVH for %s, took %lums\n", mesh->name, timer_get_ms(timer));
+	} else {
+		logr(debug, "BVH build FAILED for %s\n", mesh->name);
+	}
+}
+
 void cr_mesh_bind_vertex_buf(struct cr_scene *s_ext, cr_mesh mesh, struct cr_vertex_buf_param buf) {
 	if (!s_ext) return;
 	struct world *scene = (struct world *)s_ext;
@@ -290,6 +307,14 @@ void cr_mesh_bind_faces(struct cr_scene *s_ext, cr_mesh mesh, struct cr_face *fa
 	}
 }
 
+void cr_mesh_finalize(struct cr_scene *s_ext, cr_mesh mesh) {
+	if (!s_ext) return;
+	struct world *scene = (struct world *)s_ext;
+	if ((size_t)mesh > scene->meshes.count - 1) return;
+	struct mesh *m = &scene->meshes.items[mesh];
+	thread_pool_enqueue(scene->bvh_builder, bvh_build_task, m);
+}
+
 cr_mesh cr_scene_mesh_new(struct cr_scene *s_ext, const char *name) {
 	if (!s_ext) return -1;
 	struct world *scene = (struct world *)s_ext;
@@ -844,6 +869,7 @@ void cr_renderer_restart_interactive(struct cr_renderer *ext) {
 		r->state.workers.items[i].totalSamples = 0;
 	}
 	update_toplevel_bvh(r->scene);
+	thread_pool_wait(r->scene->bvh_builder);
 	mutex_release(r->state.current_set->tile_mutex);
 }
 

src/lib/datatypes/scene.h

@@ -40,6 +40,8 @@ struct world {
 	struct cr_rwlock bvh_lock;
 	struct bvh *topLevel; // FIXME: Move to state?
 	bool top_level_dirty;
+	struct cr_thread_pool *bvh_builder;
+
 	struct sphere_arr spheres;
 	struct camera_arr cameras;
 	struct node_storage storage; // FIXME: Move to state?

src/lib/protocol/worker.c

@@ -27,6 +27,7 @@
 #include "../../common/texture.h"
 #include "../../common/platform/mutex.h"
 #include "../../common/platform/thread.h"
+#include "../../common/platform/thread_pool.h"
 #include "../../common/networking.h"
 #include "../../common/string.h"
 #include "../../common/gitsha1.h"
@@ -231,9 +232,8 @@ static cJSON *startRender(int connectionSocket, size_t thread_limit) {
 	struct tile_set set = tile_quantize(selected_cam.width, selected_cam.height, r->prefs.tileWidth, r->prefs.tileHeight, r->prefs.tileOrder);
 
 	logr(info, "%u x %u tiles\n", r->prefs.tileWidth, r->prefs.tileHeight);
-	// Do some pre-render preparations
-	// Compute BVH acceleration structures for all meshes in the scene
-	compute_accels(r->scene->meshes);
+	// Ensure BVHs are up to date
+	thread_pool_wait(r->scene->bvh_builder);
 
 	// And then compute a single top-level BVH that contains all the objects
 	logr(info, "Computing top-level BVH: ");

src/lib/renderer/renderer.c

@@ -15,6 +15,7 @@
 #include "../../common/timer.h"
 #include "../../common/texture.h"
 #include "../../common/platform/thread.h"
+#include "../../common/platform/thread_pool.h"
 #include "../../common/platform/mutex.h"
 #include "../../common/platform/capabilities.h"
 #include "../../common/platform/signal.h"
@@ -175,9 +176,10 @@ void renderer_render(struct renderer *r) {
 		inst->bbuf = &r->scene->shader_buffers.items[inst->bbuf_idx];
 	}
 
-	// Do some pre-render preparations
-	// Compute BVH acceleration structures for all meshes in the scene
-	compute_accels(r->scene->meshes);
+	// Ensure BVHs are up to date
+	logr(debug, "Waiting for BVH thread pool\n");
+	thread_pool_wait(r->scene->bvh_builder);
+	logr(debug, "Continuing\n");
 
 	// And compute an initial top-level BVH.
 	update_toplevel_bvh(r->scene);
@@ -479,11 +481,13 @@ struct renderer *renderer_new(void) {
 	r->scene->asset_path = stringCopy("./");
 	r->scene->storage.node_pool = newBlock(NULL, 1024);
 	r->scene->storage.node_table = newHashtable(compareNodes, &r->scene->storage.node_pool);
+	r->scene->bvh_builder = thread_pool_create(sys_get_cores());
 	return r;
 }
 
 void renderer_destroy(struct renderer *r) {
 	if (!r) return;
+	thread_pool_destroy(r->scene->bvh_builder);
 	scene_destroy(r->scene);
 	worker_arr_free(&r->state.workers);
 	render_client_arr_free(&r->state.clients);