Files
test2/source/blender/blenkernel/intern/node_runtime.cc
Jacques Lucke 0de54b84c6 Geometry Nodes: add simulation support
This adds support for building simulations with geometry nodes. A new
`Simulation Input` and `Simulation Output` node allow maintaining a
simulation state across multiple frames. Together these two nodes form
a `simulation zone` which contains all the nodes that update the simulation
state from one frame to the next.

A new simulation zone can be added via the menu
(`Simulation > Simulation Zone`) or with the node add search.

The simulation state contains a geometry by default. However, it is possible
to add multiple geometry sockets as well as other socket types. Currently,
field inputs are evaluated and stored for the preceding geometry socket in
the order that the sockets are shown. Simulation state items can be added
by linking one of the empty sockets to something else. In the sidebar, there
is a new panel that allows adding, removing and reordering these sockets.

The simulation nodes behave as follows:
* On the first frame, the inputs of the `Simulation Input` node are evaluated
  to initialize the simulation state. In later frames these sockets are not
  evaluated anymore. The `Delta Time` at the first frame is zero, but the
  simulation zone is still evaluated.
* On every next frame, the `Simulation Input` node outputs the simulation
  state of the previous frame. Nodes in the simulation zone can edit that
  data in arbitrary ways, also taking into account the `Delta Time`. The new
  simulation state has to be passed to the `Simulation Output` node where it
  is cached and forwarded.
* On a frame that is already cached or baked, the nodes in the simulation
  zone are not evaluated, because the `Simulation Output` node can return
  the previously cached data directly.

It is not allowed to connect sockets from inside the simulation zone to the
outside without going through the `Simulation Output` node. This is a necessary
restriction to make caching and sub-frame interpolation work. Links can go into
the simulation zone without problems though.

Anonymous attributes are not propagated by the simulation nodes unless they
are explicitly stored in the simulation state. This is unfortunate, but
currently there is no practical and reliable alternative. The core problem
is detecting which anonymous attributes will be required for the simulation
and afterwards. While we can detect this for the current evaluation, we can't
look into the future in time to see what data will be necessary. We intend to
make it easier to explicitly pass data through a simulation in the future,
even if the simulation is in a nested node group.

There is a new `Simulation Nodes` panel in the physics tab in the properties
editor. It allows baking all simulation zones on the selected objects. The
baking options are intentially kept at a minimum for this MVP. More features
for simulation baking as well as baking in general can be expected to be added
separately.

All baked data is stored on disk in a folder next to the .blend file. #106937
describes how baking is implemented in more detail. Volumes can not be baked
yet and materials are lost during baking for now. Packing the baked data into
the .blend file is not yet supported.

The timeline indicates which frames are currently cached, baked or cached but
invalidated by user-changes.

Simulation input and output nodes are internally linked together by their
`bNode.identifier` which stays the same even if the node name changes. They
are generally added and removed together. However, there are still cases where
"dangling" simulation nodes can be created currently. Those generally don't
cause harm, but would be nice to avoid this in more cases in the future.

Co-authored-by: Hans Goudey <h.goudey@me.com>
Co-authored-by: Lukas Tönne <lukas@blender.org>

Pull Request: https://projects.blender.org/blender/blender/pulls/104924
2023-05-03 13:18:59 +02:00

524 lines
18 KiB
C++

/* SPDX-License-Identifier: GPL-2.0-or-later */
#include "BKE_node.h"
#include "BKE_node_runtime.hh"
#include "DNA_node_types.h"
#include "BLI_function_ref.hh"
#include "BLI_stack.hh"
#include "BLI_task.hh"
#include "BLI_timeit.hh"
#include "NOD_geometry_nodes_lazy_function.hh"
namespace blender::bke::node_tree_runtime {
void preprocess_geometry_node_tree_for_evaluation(bNodeTree &tree_cow)
{
BLI_assert(tree_cow.type == NTREE_GEOMETRY);
/* Rebuild geometry nodes lazy function graph. */
tree_cow.runtime->geometry_nodes_lazy_function_graph_info.reset();
blender::nodes::ensure_geometry_nodes_lazy_function_graph(tree_cow);
}
static void update_interface_sockets(const bNodeTree &ntree)
{
bNodeTreeRuntime &tree_runtime = *ntree.runtime;
tree_runtime.interface_inputs = ntree.inputs;
tree_runtime.interface_outputs = ntree.outputs;
}
static void update_node_vector(const bNodeTree &ntree)
{
bNodeTreeRuntime &tree_runtime = *ntree.runtime;
const Span<bNode *> nodes = tree_runtime.nodes_by_id;
tree_runtime.group_nodes.clear();
tree_runtime.has_undefined_nodes_or_sockets = false;
for (const int i : nodes.index_range()) {
bNode &node = *nodes[i];
node.runtime->index_in_tree = i;
node.runtime->owner_tree = const_cast<bNodeTree *>(&ntree);
tree_runtime.has_undefined_nodes_or_sockets |= node.typeinfo == &NodeTypeUndefined;
if (node.is_group()) {
tree_runtime.group_nodes.append(&node);
}
}
}
static void update_link_vector(const bNodeTree &ntree)
{
bNodeTreeRuntime &tree_runtime = *ntree.runtime;
tree_runtime.links.clear();
LISTBASE_FOREACH (bNodeLink *, link, &ntree.links) {
/* Check that the link connects nodes within this tree. */
BLI_assert(tree_runtime.nodes_by_id.contains(link->fromnode));
BLI_assert(tree_runtime.nodes_by_id.contains(link->tonode));
tree_runtime.links.append(link);
}
}
static void update_socket_vectors_and_owner_node(const bNodeTree &ntree)
{
bNodeTreeRuntime &tree_runtime = *ntree.runtime;
tree_runtime.sockets.clear();
tree_runtime.input_sockets.clear();
tree_runtime.output_sockets.clear();
for (bNode *node : tree_runtime.nodes_by_id) {
bNodeRuntime &node_runtime = *node->runtime;
node_runtime.inputs.clear();
node_runtime.outputs.clear();
LISTBASE_FOREACH (bNodeSocket *, socket, &node->inputs) {
socket->runtime->index_in_node = node_runtime.inputs.append_and_get_index(socket);
socket->runtime->index_in_all_sockets = tree_runtime.sockets.append_and_get_index(socket);
socket->runtime->index_in_inout_sockets = tree_runtime.input_sockets.append_and_get_index(
socket);
socket->runtime->owner_node = node;
tree_runtime.has_undefined_nodes_or_sockets |= socket->typeinfo == &NodeSocketTypeUndefined;
}
LISTBASE_FOREACH (bNodeSocket *, socket, &node->outputs) {
socket->runtime->index_in_node = node_runtime.outputs.append_and_get_index(socket);
socket->runtime->index_in_all_sockets = tree_runtime.sockets.append_and_get_index(socket);
socket->runtime->index_in_inout_sockets = tree_runtime.output_sockets.append_and_get_index(
socket);
socket->runtime->owner_node = node;
tree_runtime.has_undefined_nodes_or_sockets |= socket->typeinfo == &NodeSocketTypeUndefined;
}
}
}
static void update_internal_link_inputs(const bNodeTree &ntree)
{
bNodeTreeRuntime &tree_runtime = *ntree.runtime;
for (bNode *node : tree_runtime.nodes_by_id) {
for (bNodeSocket *socket : node->runtime->outputs) {
socket->runtime->internal_link_input = nullptr;
}
for (bNodeLink &link : node->runtime->internal_links) {
link.tosock->runtime->internal_link_input = link.fromsock;
}
}
}
static void update_directly_linked_links_and_sockets(const bNodeTree &ntree)
{
bNodeTreeRuntime &tree_runtime = *ntree.runtime;
for (bNode *node : tree_runtime.nodes_by_id) {
for (bNodeSocket *socket : node->runtime->inputs) {
socket->runtime->directly_linked_links.clear();
socket->runtime->directly_linked_sockets.clear();
}
for (bNodeSocket *socket : node->runtime->outputs) {
socket->runtime->directly_linked_links.clear();
socket->runtime->directly_linked_sockets.clear();
}
node->runtime->has_available_linked_inputs = false;
node->runtime->has_available_linked_outputs = false;
}
for (bNodeLink *link : tree_runtime.links) {
link->fromsock->runtime->directly_linked_links.append(link);
link->fromsock->runtime->directly_linked_sockets.append(link->tosock);
link->tosock->runtime->directly_linked_links.append(link);
if (link->is_available()) {
link->fromnode->runtime->has_available_linked_outputs = true;
link->tonode->runtime->has_available_linked_inputs = true;
}
}
for (bNodeSocket *socket : tree_runtime.input_sockets) {
if (socket->flag & SOCK_MULTI_INPUT) {
std::sort(socket->runtime->directly_linked_links.begin(),
socket->runtime->directly_linked_links.end(),
[&](const bNodeLink *a, const bNodeLink *b) {
return a->multi_input_socket_index > b->multi_input_socket_index;
});
}
}
for (bNodeSocket *socket : tree_runtime.input_sockets) {
for (bNodeLink *link : socket->runtime->directly_linked_links) {
/* Do this after sorting the input links. */
socket->runtime->directly_linked_sockets.append(link->fromsock);
}
}
}
static void find_logical_origins_for_socket_recursive(
bNodeSocket &input_socket,
bool only_follow_first_input_link,
Vector<bNodeSocket *, 16> &sockets_in_current_chain,
Vector<bNodeSocket *> &r_logical_origins,
Vector<bNodeSocket *> &r_skipped_origins)
{
if (sockets_in_current_chain.contains(&input_socket)) {
/* Protect against reroute recursions. */
return;
}
sockets_in_current_chain.append(&input_socket);
Span<bNodeLink *> links_to_check = input_socket.runtime->directly_linked_links;
if (only_follow_first_input_link) {
links_to_check = links_to_check.take_front(1);
}
for (bNodeLink *link : links_to_check) {
if (link->is_muted()) {
continue;
}
if (!link->is_available()) {
continue;
}
bNodeSocket &origin_socket = *link->fromsock;
bNode &origin_node = *link->fromnode;
if (!origin_socket.is_available()) {
/* Non available sockets are ignored. */
continue;
}
if (origin_node.type == NODE_REROUTE) {
bNodeSocket &reroute_input = *origin_node.runtime->inputs[0];
bNodeSocket &reroute_output = *origin_node.runtime->outputs[0];
r_skipped_origins.append(&reroute_input);
r_skipped_origins.append(&reroute_output);
find_logical_origins_for_socket_recursive(
reroute_input, false, sockets_in_current_chain, r_logical_origins, r_skipped_origins);
continue;
}
if (origin_node.is_muted()) {
if (bNodeSocket *mute_input = origin_socket.runtime->internal_link_input) {
r_skipped_origins.append(&origin_socket);
r_skipped_origins.append(mute_input);
find_logical_origins_for_socket_recursive(
*mute_input, true, sockets_in_current_chain, r_logical_origins, r_skipped_origins);
}
continue;
}
r_logical_origins.append(&origin_socket);
}
sockets_in_current_chain.pop_last();
}
static void update_logical_origins(const bNodeTree &ntree)
{
bNodeTreeRuntime &tree_runtime = *ntree.runtime;
Span<bNode *> nodes = tree_runtime.nodes_by_id;
threading::parallel_for(nodes.index_range(), 128, [&](const IndexRange range) {
for (const int i : range) {
bNode &node = *nodes[i];
for (bNodeSocket *socket : node.runtime->inputs) {
Vector<bNodeSocket *, 16> sockets_in_current_chain;
socket->runtime->logically_linked_sockets.clear();
socket->runtime->logically_linked_skipped_sockets.clear();
find_logical_origins_for_socket_recursive(
*socket,
false,
sockets_in_current_chain,
socket->runtime->logically_linked_sockets,
socket->runtime->logically_linked_skipped_sockets);
}
}
});
}
static void update_nodes_by_type(const bNodeTree &ntree)
{
bNodeTreeRuntime &tree_runtime = *ntree.runtime;
tree_runtime.nodes_by_type.clear();
for (bNode *node : tree_runtime.nodes_by_id) {
tree_runtime.nodes_by_type.add(node->typeinfo, node);
}
}
static void update_sockets_by_identifier(const bNodeTree &ntree)
{
bNodeTreeRuntime &tree_runtime = *ntree.runtime;
Span<bNode *> nodes = tree_runtime.nodes_by_id;
threading::parallel_for(nodes.index_range(), 128, [&](const IndexRange range) {
for (bNode *node : nodes.slice(range)) {
node->runtime->inputs_by_identifier.clear();
node->runtime->outputs_by_identifier.clear();
for (bNodeSocket *socket : node->runtime->inputs) {
node->runtime->inputs_by_identifier.add_new(socket->identifier, socket);
}
for (bNodeSocket *socket : node->runtime->outputs) {
node->runtime->outputs_by_identifier.add_new(socket->identifier, socket);
}
}
});
}
enum class ToposortDirection {
LeftToRight,
RightToLeft,
};
struct ToposortNodeState {
bool is_done = false;
bool is_in_stack = false;
};
static Vector<const bNode *> get_implicit_origin_nodes(const bNodeTree &ntree, bNode &node)
{
Vector<const bNode *> origin_nodes;
if (node.type == GEO_NODE_SIMULATION_OUTPUT) {
for (const bNode *sim_input_node :
ntree.runtime->nodes_by_type.lookup(nodeTypeFind("GeometryNodeSimulationInput")))
{
const auto &storage = *static_cast<const NodeGeometrySimulationInput *>(
sim_input_node->storage);
if (storage.output_node_id == node.identifier) {
origin_nodes.append(sim_input_node);
}
}
}
return origin_nodes;
}
static Vector<const bNode *> get_implicit_target_nodes(const bNodeTree &ntree, bNode &node)
{
Vector<const bNode *> target_nodes;
if (node.type == GEO_NODE_SIMULATION_INPUT) {
const auto &storage = *static_cast<const NodeGeometrySimulationInput *>(node.storage);
if (const bNode *sim_output_node = ntree.node_by_id(storage.output_node_id)) {
target_nodes.append(sim_output_node);
}
}
return target_nodes;
}
static void toposort_from_start_node(const bNodeTree &ntree,
const ToposortDirection direction,
bNode &start_node,
MutableSpan<ToposortNodeState> node_states,
Vector<bNode *> &r_sorted_nodes,
bool &r_cycle_detected)
{
struct Item {
bNode *node;
int socket_index = 0;
int link_index = 0;
int implicit_link_index = 0;
};
Stack<Item, 64> nodes_to_check;
nodes_to_check.push({&start_node});
node_states[start_node.index()].is_in_stack = true;
while (!nodes_to_check.is_empty()) {
Item &item = nodes_to_check.peek();
bNode &node = *item.node;
bool pushed_node = false;
auto handle_linked_node = [&](bNode &linked_node) {
ToposortNodeState &linked_node_state = node_states[linked_node.index()];
if (linked_node_state.is_done) {
/* The linked node has already been visited. */
return true;
}
if (linked_node_state.is_in_stack) {
r_cycle_detected = true;
}
else {
nodes_to_check.push({&linked_node});
linked_node_state.is_in_stack = true;
pushed_node = true;
}
return false;
};
const Span<bNodeSocket *> sockets = (direction == ToposortDirection::LeftToRight) ?
node.runtime->inputs :
node.runtime->outputs;
while (true) {
if (item.socket_index == sockets.size()) {
/* All sockets have already been visited. */
break;
}
bNodeSocket &socket = *sockets[item.socket_index];
const Span<bNodeLink *> linked_links = socket.runtime->directly_linked_links;
if (item.link_index == linked_links.size()) {
/* All links connected to this socket have already been visited. */
item.socket_index++;
item.link_index = 0;
continue;
}
bNodeLink &link = *linked_links[item.link_index];
if (!link.is_available()) {
/* Ignore unavailable links. */
item.link_index++;
continue;
}
bNodeSocket &linked_socket = *socket.runtime->directly_linked_sockets[item.link_index];
bNode &linked_node = *linked_socket.runtime->owner_node;
if (handle_linked_node(linked_node)) {
/* The linked node has already been visited. */
item.link_index++;
continue;
}
break;
}
if (!pushed_node) {
/* Some nodes are internally linked without an explicit `bNodeLink`. The toposort should
* still order them correctly and find cycles. */
const Vector<const bNode *> implicitly_linked_nodes =
(direction == ToposortDirection::LeftToRight) ? get_implicit_origin_nodes(ntree, node) :
get_implicit_target_nodes(ntree, node);
while (true) {
if (item.implicit_link_index == implicitly_linked_nodes.size()) {
/* All implicitly linked nodes have already been visited. */
break;
}
const bNode &linked_node = *implicitly_linked_nodes[item.implicit_link_index];
if (handle_linked_node(const_cast<bNode &>(linked_node))) {
/* The implicitly linked node has already been visited. */
item.implicit_link_index++;
continue;
}
break;
}
}
/* If no other element has been pushed, the current node can be pushed to the sorted list.
*/
if (!pushed_node) {
ToposortNodeState &node_state = node_states[node.index()];
node_state.is_done = true;
node_state.is_in_stack = false;
r_sorted_nodes.append(&node);
nodes_to_check.pop();
}
}
}
static void update_toposort(const bNodeTree &ntree,
const ToposortDirection direction,
Vector<bNode *> &r_sorted_nodes,
bool &r_cycle_detected)
{
bNodeTreeRuntime &tree_runtime = *ntree.runtime;
r_sorted_nodes.clear();
r_sorted_nodes.reserve(tree_runtime.nodes_by_id.size());
r_cycle_detected = false;
Array<ToposortNodeState> node_states(tree_runtime.nodes_by_id.size());
for (bNode *node : tree_runtime.nodes_by_id) {
if (node_states[node->index()].is_done) {
/* Ignore nodes that are done already. */
continue;
}
if ((direction == ToposortDirection::LeftToRight) ?
node->runtime->has_available_linked_outputs :
node->runtime->has_available_linked_inputs)
{
/* Ignore non-start nodes. */
continue;
}
toposort_from_start_node(
ntree, direction, *node, node_states, r_sorted_nodes, r_cycle_detected);
}
if (r_sorted_nodes.size() < tree_runtime.nodes_by_id.size()) {
r_cycle_detected = true;
for (bNode *node : tree_runtime.nodes_by_id) {
if (node_states[node->index()].is_done) {
/* Ignore nodes that are done already. */
continue;
}
/* Start toposort at this node which is somewhere in the middle of a loop. */
toposort_from_start_node(
ntree, direction, *node, node_states, r_sorted_nodes, r_cycle_detected);
}
}
BLI_assert(tree_runtime.nodes_by_id.size() == r_sorted_nodes.size());
}
static void update_root_frames(const bNodeTree &ntree)
{
bNodeTreeRuntime &tree_runtime = *ntree.runtime;
Span<bNode *> nodes = tree_runtime.nodes_by_id;
tree_runtime.root_frames.clear();
for (bNode *node : nodes) {
if (!node->parent && node->is_frame()) {
tree_runtime.root_frames.append(node);
}
}
}
static void update_direct_frames_childrens(const bNodeTree &ntree)
{
bNodeTreeRuntime &tree_runtime = *ntree.runtime;
Span<bNode *> nodes = tree_runtime.nodes_by_id;
for (bNode *node : nodes) {
node->runtime->direct_children_in_frame.clear();
}
for (bNode *node : nodes) {
if (const bNode *frame = node->parent) {
frame->runtime->direct_children_in_frame.append(node);
}
}
}
static void update_group_output_node(const bNodeTree &ntree)
{
bNodeTreeRuntime &tree_runtime = *ntree.runtime;
const bNodeType *node_type = nodeTypeFind("NodeGroupOutput");
const Span<bNode *> group_output_nodes = tree_runtime.nodes_by_type.lookup(node_type);
if (group_output_nodes.is_empty()) {
tree_runtime.group_output_node = nullptr;
}
else if (group_output_nodes.size() == 1) {
tree_runtime.group_output_node = group_output_nodes[0];
}
else {
for (bNode *group_output : group_output_nodes) {
if (group_output->flag & NODE_DO_OUTPUT) {
tree_runtime.group_output_node = group_output;
break;
}
}
}
}
static void ensure_topology_cache(const bNodeTree &ntree)
{
bNodeTreeRuntime &tree_runtime = *ntree.runtime;
tree_runtime.topology_cache_mutex.ensure([&]() {
update_interface_sockets(ntree);
update_node_vector(ntree);
update_link_vector(ntree);
update_socket_vectors_and_owner_node(ntree);
update_internal_link_inputs(ntree);
update_directly_linked_links_and_sockets(ntree);
update_nodes_by_type(ntree);
threading::parallel_invoke(
tree_runtime.nodes_by_id.size() > 32,
[&]() { update_logical_origins(ntree); },
[&]() { update_sockets_by_identifier(ntree); },
[&]() {
update_toposort(ntree,
ToposortDirection::LeftToRight,
tree_runtime.toposort_left_to_right,
tree_runtime.has_available_link_cycle);
},
[&]() {
bool dummy;
update_toposort(
ntree, ToposortDirection::RightToLeft, tree_runtime.toposort_right_to_left, dummy);
},
[&]() { update_root_frames(ntree); },
[&]() { update_direct_frames_childrens(ntree); });
update_group_output_node(ntree);
tree_runtime.topology_cache_exists = true;
});
}
} // namespace blender::bke::node_tree_runtime
void bNodeTree::ensure_topology_cache() const
{
blender::bke::node_tree_runtime::ensure_topology_cache(*this);
}