Add external assets to .gitignore (#17388)

Added an external assets section to .gitignore. This prevents
contributors from accidentally adding or committing them.

I believe currently the only externel asset is the meshlet bunny.

Cargo.toml

@@ -1249,10 +1249,15 @@ description = "Meshlet rendering for dense high-poly scenes (experimental)"
 category = "3D Rendering"
 wasm = false
 setup = [
+  [
+    "mkdir",
+    "-p",
+    "assets/external/models",
+  ],
   [
     "curl",
     "-o",
-    "assets/models/bunny.meshlet_mesh",
+    "assets/external/models/bunny.meshlet_mesh",
     "https://raw.githubusercontent.com/JMS55/bevy_meshlet_asset/7a7c14138021f63904b584d5f7b73b695c7f4bbf/bunny.meshlet_mesh",
   ],
 ]

assets/external/.gitignore

@@ -0,0 +1,2 @@
+*
+!.gitignore

examples/3d/meshlet.rs

@@ -20,8 +20,8 @@ const ASSET_URL: &str =
     "https://raw.githubusercontent.com/JMS55/bevy_meshlet_asset/7a7c14138021f63904b584d5f7b73b695c7f4bbf/bunny.meshlet_mesh";
 
 fn main() -> ExitCode {
-    if !Path::new("./assets/models/bunny.meshlet_mesh").exists() {
-        eprintln!("ERROR: Asset at path <bevy>/assets/models/bunny.meshlet_mesh is missing. Please download it from {ASSET_URL}");
+    if !Path::new("./assets/external/models/bunny.meshlet_mesh").exists() {
+        eprintln!("ERROR: Asset at path <bevy>/assets/external/models/bunny.meshlet_mesh is missing. Please download it from {ASSET_URL}");
         return ExitCode::FAILURE;
     }
 
@@ -80,7 +80,7 @@ fn setup(
     // that has been converted to a [`bevy_pbr::meshlet::MeshletMesh`]
     // using [`bevy_pbr::meshlet::MeshletMesh::from_mesh`], which is
     // a function only available when the `meshlet_processor` cargo feature is enabled.
-    let meshlet_mesh_handle = asset_server.load("models/bunny.meshlet_mesh");
+    let meshlet_mesh_handle = asset_server.load("external/models/bunny.meshlet_mesh");
     let debug_material = debug_materials.add(MeshletDebugMaterial::default());
 
     for x in -2..=2 {