Vertex Loading

Added the ability to load vertex data from the vertexes lump for
a given level. This is to close issue #5 to get vertex data
loading working.

src/doomlevel.rs

@@ -0,0 +1,65 @@
+mod vertex;
+
+use std::{
+    fs::File,
+    io::{Read, Seek, SeekFrom},
+};
+
+use super::wadfile::WADFile;
+use vertex::Vertex;
+
+enum Lumps {
+    THINGS = 1,
+    LINEDEFS,
+    SIDEDEFS,
+    VERTEXES,
+    SEGS,
+    SSECTORS,
+    NODES,
+    SECTORS,
+    REJECT,
+    BLOCKMAP,
+    BEHAVIOR,
+}
+
+pub struct DoomLevel {
+    pub name: String,
+    pub vertexes: Vec<Vertex>,
+}
+
+impl DoomLevel {
+    pub fn load_level(wad_file: &WADFile, lvl_index: u32) -> Self {
+        Self {
+            name: wad_file.get_lump_name(lvl_index),
+            vertexes: load_vertexes(
+                wad_file,
+                wad_file.get_lump_offset(lvl_index + Lumps::VERTEXES as u32),
+                wad_file.get_lump_size(lvl_index + Lumps::VERTEXES as u32),
+            ),
+        }
+    }
+}
+
+fn load_vertexes(wad_file: &WADFile, offset: u32, size: u32) -> Vec<Vertex> {
+    let num_vertex: u32 = size / 4u32;
+
+    let mut vertex_list: Vec<Vertex> = Vec::with_capacity(num_vertex as usize);
+
+    let mut vertex_data = File::open(&wad_file.wad_path).unwrap();
+    vertex_data.seek(SeekFrom::Start(offset as u64)).unwrap();
+
+    for _ in 0..num_vertex {
+        let mut x = [0; 2];
+        let mut y = [0; 2];
+
+        vertex_data.read(&mut x).unwrap();
+        vertex_data.read(&mut y).unwrap();
+
+        vertex_list.push(Vertex {
+            x: i16::from_le_bytes(x),
+            y: i16::from_le_bytes(y),
+        });
+    }
+
+    vertex_list
+}