From 36027c9a9f4945fceaeedac3d448339256a1956a Mon Sep 17 00:00:00 2001
From: Joshua Goins <josh@redstrate.com>
Date: Sun, 25 Feb 2024 09:01:59 -0500
Subject: [PATCH] Write out a proper end of stream vertex element

---
 src/model.rs                     |  3 ++-
 src/model_vertex_declarations.rs | 14 ++++++++++----
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/src/model.rs b/src/model.rs
index 082f63a..e102452 100755
--- a/src/model.rs
+++ b/src/model.rs
@@ -10,6 +10,8 @@ use binrw::BinReaderExt;
 use crate::{ByteBuffer, ByteSpan};
 use crate::model_vertex_declarations::{vertex_element_parser, VERTEX_ELEMENT_SIZE, vertex_element_writer, VertexDeclaration, VertexElement, VertexType, VertexUsage};
 
+pub const NUM_VERTICES: u32 = 17;
+
 #[binrw]
 #[derive(Debug)]
 #[brw(little)]
@@ -836,7 +838,6 @@ impl MDL {
 impl ModelFileHeader {
     pub fn calculate_stack_size(&self) -> u32 {
         // From https://github.com/Ottermandias/Penumbra.GameData/blob/44021b93e6901c84b739bbf4d1c6350f4486cdbf/Files/MdlFile.cs#L11
-        const NUM_VERTICES: u32 = 17;
         self.vertex_declaration_count as u32 * NUM_VERTICES * VERTEX_ELEMENT_SIZE as u32
     }
 }
diff --git a/src/model_vertex_declarations.rs b/src/model_vertex_declarations.rs
index 72010cf..352619b 100644
--- a/src/model_vertex_declarations.rs
+++ b/src/model_vertex_declarations.rs
@@ -3,6 +3,7 @@
 
 use std::io::SeekFrom;
 use binrw::{BinRead, BinResult, binrw, BinWrite};
+use crate::model::NUM_VERTICES;
 
 // Marker for end of stream (0xFF)
 const END_OF_STREAM: u8 = 0xFF;
@@ -75,7 +76,7 @@ pub(crate) fn vertex_element_parser(count: u16) -> BinResult<Vec<VertexDeclarati
             }
         }
 
-        let to_seek = 17 * 8 - (declaration.elements.len() + 1) * 8;
+        let to_seek = NUM_VERTICES as usize * 8 - (declaration.elements.len() + 1) * 8;
         reader.seek(SeekFrom::Current(to_seek as i64))?;
     }
 
@@ -92,10 +93,15 @@ pub(crate) fn vertex_element_writer(
             element.write_options(writer, endian, ())?;
         }
 
-        writer.write_all(&[END_OF_STREAM])?;
+        VertexElement {
+            stream: END_OF_STREAM,
+            offset: 0,
+            vertex_type: VertexType::Single1,
+            vertex_usage: VertexUsage::Position,
+            usage_index: 0
+        }.write_options(writer, endian, ())?;
 
-        // We have a -1 here like we do in read, because writing the EOF (255) pushes our cursor forward.
-        let to_seek = 17 * 8 - (declaration.elements.len()) * 8 - 1;
+        let to_seek = (NUM_VERTICES as usize - 1 - declaration.elements.len()) * 8;
         writer.seek(SeekFrom::Current(to_seek as i64))?;
     }