Add an a* pathfinder (tgstation#113)

Returns the shortest path in a static node map. That is made for TGMC wich uses manually placed nodes for pathfinding.

Benchmark :
image
That's the average number of path computed in one second, out of 30 runs with random nodes. Size of the node map is roughly 800

On average 32 times faster than tgmc a* implementation.
Another possible comparison is with TG's JPS system, and according to the benchmark done here it's 7000 times faster (tgstation/tgstation#56780). Not exactly the same use cases though

Author: BraveMole

Cargo.lock

@@ -46,6 +46,8 @@ toml-dep = { version = "0.5.8", package="toml", optional = true }
 aho-corasick = { version = "0.7.18", optional = true}
 rayon = { version = "1.5", optional = true}
 dbpnoise = { version = "0.1.2", optional = true}
+pathfinding = { version = "3.0.13", optional = true }
+num = { version = "0.4.0", optional = true }
 
 [features]
 default = ["acreplace", "cellularnoise", "dmi", "file", "git", "http", "json", "log", "noise", "sql", "time", "toml", "url"]
@@ -67,6 +69,7 @@ url = ["url-dep", "percent-encoding"]
 # additional features
 batchnoise = ["dbpnoise"]
 hash = ["base64", "const-random", "md-5", "hex", "sha-1", "sha2",  "twox-hash", "serde", "serde_json"]
+pathfinder = [ "num", "pathfinding", "serde", "serde_json"]
 redis_pubsub = ["flume", "redis", "serde", "serde_json"]
 unzip = ["zip", "jobs"]
 worleynoise = ["rand","rayon"]

Cargo.toml

@@ -0,0 +1,32 @@
+/**
+ * Register a list of nodes into a rust library. This list of nodes must have been serialized in a json.
+ * Node {// Index of this node in the list of nodes
+ *  	  unique_id: usize,
+ *  	  // Position of the node in byond
+ *  	  x: usize,
+ *  	  y: usize,
+ *  	  z: usize,
+ *  	  // Indexes of nodes connected to this one
+ *  	  connected_nodes_id: Vec<usize>}
+ * It is important that the node with the unique_id 0 is the first in the json, unique_id 1 right after that, etc.
+ * It is also important that all unique ids follow. {0, 1, 2, 4} is not a correct list and the registering will fail
+ * Nodes should not link across z levels.
+ * A node cannot link twice to the same node and shouldn't link itself either
+ */
+#define rustg_register_nodes_astar(json) call(RUST_G, "register_nodes_astar")(json)
+
+/**
+ * Add a new node to the static list of nodes. Same rule as registering_nodes applies.
+ * This node unique_id must be equal to the current length of the static list of nodes
+ */
+#define rustg_add_node_astar(json) call(RUST_G, "add_node_astar")(json)
+
+/**²
+ * Remove every link to the node with unique_id. Replace that node by null
+ */
+#define rustg_remove_node_astart(unique_id) call(RUST_G, "remove_node_astar")(unique_id)
+
+/**
+ * Compute the shortest path between start_node and goal_node using A*. Heuristic used is simple geometric distance
+ */
+#define rustg_generate_path_astar(start_node_id, goal_node_id) call(RUST_G, "generate_path_astar")(start_node_id, goal_node_id)

dmsrc/pathfinder.dm

@@ -30,6 +30,8 @@ pub mod json;
 pub mod log;
 #[cfg(feature = "noise")]
 pub mod noise_gen;
+#[cfg(feature = "pathfinder")]
+pub mod pathfinder;
 #[cfg(feature = "redis_pubsub")]
 pub mod redis_pubsub;
 #[cfg(feature = "sql")]