From 19e5c38ea88c3ce6189d49c94f11b83631a45fac Mon Sep 17 00:00:00 2001
From: Joshua Goins <josh@redstrate.com>
Date: Wed, 9 Jul 2025 00:33:26 -0400
Subject: [PATCH] Initial support for PCB parsing

These files are collision meshes used in zones.
---
 src/lib.rs |   3 ++
 src/pcb.rs | 127 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 130 insertions(+)
 create mode 100644 src/pcb.rs

diff --git a/src/lib.rs b/src/lib.rs
index 36cfe6b..6f0b075 100755
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -149,6 +149,9 @@ pub mod svb;
 /// File resource handling.
 pub mod resource;
 
+/// Reading PCB files.
+pub mod pcb;
+
 mod bcn;
 
 mod error;
diff --git a/src/pcb.rs b/src/pcb.rs
new file mode 100644
index 0000000..9f7085d
--- /dev/null
+++ b/src/pcb.rs
@@ -0,0 +1,127 @@
+// SPDX-FileCopyrightText: 2025 Joshua Goins <josh@redstrate.com>
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+use std::io::Cursor;
+use std::io::SeekFrom;
+
+use crate::ByteSpan;
+use binrw::BinRead;
+use binrw::BinResult;
+use binrw::binrw;
+use binrw::helpers::until_eof;
+
+#[binrw]
+#[derive(Debug)]
+#[brw(little)]
+struct PcbResourceHeader {
+    magic: u32,   // pretty terrible magic if you ask me, lumina calls it so but it's just 0000
+    version: u32, // usually 0x1?
+    total_nodes: u32,
+    total_polygons: u32,
+}
+
+// TODO: this is adapted from lumina and could probably be implemented better
+#[binrw::parser(reader)]
+fn parse_resource_node_children(
+    group_length: u32,
+    header_skip: u32,
+) -> BinResult<Vec<ResourceNode>> {
+    if group_length == 0 {
+        return Ok(Vec::default());
+    }
+
+    assert!(header_skip > 0);
+
+    let mut children = Vec::new();
+    let initial_position = reader.stream_position().unwrap() - header_skip as u64;
+    let final_position = initial_position + group_length as u64;
+
+    while reader.stream_position().unwrap() + (header_skip as u64) < final_position {
+        children.push(ResourceNode::read_le(reader).unwrap());
+    }
+
+    reader.seek(SeekFrom::Start(final_position)).unwrap();
+
+    Ok(children)
+}
+
+#[binrw]
+#[derive(Debug)]
+#[brw(little)]
+pub struct ResourceNode {
+    magic: u32,   // pretty terrible magic if you ask me, lumina calls it so
+    version: u32, // usually 0x0, is this really a version?!
+    header_skip: u32,
+    group_length: u32,
+    pub bounding_box: BoundingBox,
+
+    num_vert_f16: u16,
+    num_polygons: u16,
+    #[brw(pad_after = 2)] // padding
+    num_vert_f32: u16,
+
+    #[br(parse_with = parse_resource_node_children, args(group_length, header_skip))]
+    pub children: Vec<ResourceNode>,
+
+    // TODO: combine these
+    #[br(count = num_vert_f32)]
+    pub f32_vertices: Vec<[f32; 3]>,
+    #[br(count = num_vert_f16)]
+    pub f16_vertices: Vec<[u16; 3]>,
+    #[br(count = num_polygons)]
+    pub polygons: Vec<Polygon>,
+}
+
+// TODO: de-duplicate with MDL?
+#[binrw]
+#[derive(Debug, Clone, PartialEq)]
+#[allow(dead_code)]
+pub struct BoundingBox {
+    pub min: [f32; 3],
+    pub max: [f32; 3],
+}
+
+#[binrw]
+#[derive(Debug, Clone, PartialEq)]
+#[allow(dead_code)]
+struct Polygon {
+    pub vertex_indices: [u8; 3],
+    #[brw(pad_before = 2, pad_after = 5)] // padding
+    unk1: u16,
+}
+
+#[binrw]
+#[derive(Debug)]
+#[brw(little)]
+pub struct Pcb {
+    header: PcbResourceHeader,
+    // NOTE: this is technically wrong, we should be counting each node until we get total_nodes but im lazy
+    #[br(parse_with = until_eof)]
+    pub children: Vec<ResourceNode>,
+}
+
+impl Pcb {
+    /// Reads an existing PCB file
+    pub fn from_existing(buffer: ByteSpan) -> Option<Self> {
+        let mut cursor = Cursor::new(buffer);
+        Pcb::read(&mut cursor).ok()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::fs::read;
+    use std::path::PathBuf;
+
+    use super::*;
+
+    #[test]
+    fn test_invalid() {
+        let mut d = PathBuf::from(env!("CARGO_MANIFEST_DIR"));
+        d.push("resources/tests");
+        d.push("random");
+
+        // Feeding it invalid data should not panic
+        Pcb::from_existing(&read(d).unwrap());
+    }
+}