From aa6840a27b3e313e9f9b0c4067355dfb25b717b2 Mon Sep 17 00:00:00 2001
From: Kayh <basedlainpilled@gmail.com>
Date: Thu, 9 Nov 2023 18:14:40 -0500
Subject: [PATCH] set up basic graph

---
 Cargo.lock            |   1 +
 README.md             |   2 +
 core/Cargo.toml       |   1 +
 core/examples/read.rs |  12 ++---
 core/src/graph.rs     |  36 +++++++++++++++
 core/src/lib.rs       | 100 +++++++++++++++++++++++++++++++++++++++++-
 6 files changed, 143 insertions(+), 9 deletions(-)
 create mode 100644 core/src/graph.rs

diff --git a/Cargo.lock b/Cargo.lock
index 0e7a53c..7bbe68c 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1863,6 +1863,7 @@ name = "gltf_kun"
 version = "0.0.0"
 dependencies = [
  "gltf",
+ "petgraph",
 ]
 
 [[package]]
diff --git a/README.md b/README.md
index 1b83b66..8993c98 100644
--- a/README.md
+++ b/README.md
@@ -6,3 +6,5 @@
 [![Documentation](https://docs.rs/gltf_kun/badge.svg)](https://docs.rs/gltf_kun)
 
 Extensible library for building [glTF](https://github.com/KhronosGroup/glTF) toolchains.
+
+Builds upon the lower level [`gltf`](https://github.com/gltf-rs/gltf) crate to create a traversable graph of the glTF document.
diff --git a/core/Cargo.toml b/core/Cargo.toml
index 1776240..7a74e3e 100644
--- a/core/Cargo.toml
+++ b/core/Cargo.toml
@@ -24,3 +24,4 @@ gltf = { version = "1.3.0", features = [
   "KHR_materials_specular",
   "KHR_materials_emissive_strength",
 ] }
+petgraph = "0.6.4"
diff --git a/core/examples/read.rs b/core/examples/read.rs
index 6b26cf6..2893f24 100644
--- a/core/examples/read.rs
+++ b/core/examples/read.rs
@@ -1,16 +1,12 @@
-use std::{fs, io};
-
 const CARGO_MANIFEST_DIR: &str = env!("CARGO_MANIFEST_DIR");
 const ASSETS_DIR: &str = "../assets";
-
 const MODEL: &str = "TriangleWithoutIndices/TriangleWithoutIndices.gltf";
 
 fn main() {
     let path = format!("{}/{}/{}", CARGO_MANIFEST_DIR, ASSETS_DIR, MODEL);
+    let gltf = gltf_kun::import(&path).unwrap();
 
-    let file = fs::File::open(path).unwrap();
-    let reader = io::BufReader::new(file);
-    let gltf = gltf_kun::Gltf::from_reader(reader).unwrap();
-
-    println!("{:#?}", gltf);
+    gltf.nodes().iter().for_each(|node| {
+        println!("{:#?}", node.data());
+    });
 }
diff --git a/core/src/graph.rs b/core/src/graph.rs
new file mode 100644
index 0000000..3cd91f4
--- /dev/null
+++ b/core/src/graph.rs
@@ -0,0 +1,36 @@
+pub struct AssetData {
+    pub version: String,
+    pub generator: Option<String>,
+    pub extensions_used: Vec<String>,
+    pub extensions_required: Vec<String>,
+}
+
+pub struct MeshData {
+    pub name: Option<String>,
+}
+
+#[derive(Debug)]
+pub struct NodeData {
+    pub name: Option<String>,
+    pub translation: [f32; 3],
+    pub rotation: [f32; 4],
+    pub scale: [f32; 3],
+}
+
+pub struct SceneData {
+    pub name: Option<String>,
+}
+
+pub enum GraphNode {
+    Asset(AssetData),
+    Mesh(MeshData),
+    Node(NodeData),
+    Scene(SceneData),
+}
+
+pub enum GraphEdge {
+    Parent,
+    Child,
+}
+
+pub type GltfGraph = petgraph::graph::DiGraph<GraphNode, GraphEdge>;
diff --git a/core/src/lib.rs b/core/src/lib.rs
index e23f481..6c9f4fb 100644
--- a/core/src/lib.rs
+++ b/core/src/lib.rs
@@ -1 +1,99 @@
-pub use gltf::*;
+use std::collections::HashMap;
+use std::sync::Arc;
+
+mod graph;
+
+use graph::*;
+use petgraph::graph::NodeIndex;
+use petgraph::visit::EdgeRef;
+
+pub struct Node {
+    graph: Arc<GltfGraph>,
+    index: NodeIndex,
+}
+
+impl Node {
+    pub fn data(&self) -> &NodeData {
+        match &self.graph[self.index] {
+            GraphNode::Node(node) => node,
+            _ => panic!("Node is not a NodeData"),
+        }
+    }
+
+    pub fn children(&self) -> Vec<Node> {
+        self.graph
+            .edges(self.index)
+            .filter_map(|edge| {
+                let index = match edge.weight() {
+                    GraphEdge::Child => edge.target(),
+                    _ => return None,
+                };
+
+                Some(Node {
+                    graph: self.graph.clone(),
+                    index,
+                })
+            })
+            .collect()
+    }
+}
+
+pub struct Gltf {
+    graph: Arc<GltfGraph>,
+}
+
+impl Gltf {
+    /// Create a new Gltf from json
+    pub fn from_json(json: &gltf::json::Root) -> Self {
+        let mut graph = GltfGraph::new();
+        let mut nodes = HashMap::new();
+
+        json.nodes.iter().enumerate().for_each(|(i, node)| {
+            let graph_node = graph.add_node(GraphNode::Node(NodeData {
+                name: node.name.clone(),
+                translation: node.translation.unwrap_or([0.0, 0.0, 0.0]),
+                rotation: node.rotation.unwrap_or_default().0,
+                scale: node.scale.unwrap_or([1.0, 1.0, 1.0]),
+            }));
+
+            nodes.insert(i, graph_node);
+        });
+
+        json.nodes.iter().enumerate().for_each(|(i, node)| {
+            let graph_node = nodes.get(&i).unwrap();
+
+            if let Some(children) = &node.children {
+                children.iter().for_each(|child| {
+                    let child_graph_node = nodes.get(&child.value()).unwrap();
+
+                    graph.add_edge(*graph_node, *child_graph_node, GraphEdge::Child);
+                    graph.add_edge(*child_graph_node, *graph_node, GraphEdge::Parent);
+                });
+            }
+        });
+
+        Gltf {
+            graph: Arc::new(graph),
+        }
+    }
+
+    /// Get all glTF nodes
+    pub fn nodes(&self) -> Vec<Node> {
+        self.graph
+            .node_indices()
+            .filter_map(|index| match self.graph[index] {
+                GraphNode::Node(_) => Some(Node {
+                    graph: self.graph.clone(),
+                    index,
+                }),
+                _ => None,
+            })
+            .collect()
+    }
+}
+
+/// Import a glTF from the file system
+pub fn import(path: &str) -> Result<Gltf, gltf::Error> {
+    let (doc, _, _) = gltf::import(path)?;
+    Ok(Gltf::from_json(&doc.into_json()))
+}