Add support for binary glTF (.glb) (bevyengine#271)

Add support for binary glTF (.glb)

crates/bevy_gltf/src/loader.rs

@@ -5,7 +5,7 @@ use bevy_render::{
 
 use anyhow::Result;
 use bevy_asset::AssetLoader;
-use gltf::{buffer::Source, iter, mesh::Mode};
+use gltf::{buffer::Source, mesh::Mode};
 use std::{fs, io, path::Path};
 use thiserror::Error;
 
@@ -22,7 +22,7 @@ impl AssetLoader<Mesh> for GltfLoader {
     }
 
     fn extensions(&self) -> &[&str] {
-        static EXTENSIONS: &[&str] = &["gltf"];
+        static EXTENSIONS: &[&str] = &["gltf", "glb"];
         EXTENSIONS
     }
 }
@@ -36,8 +36,8 @@ pub enum GltfError {
     Gltf(#[from] gltf::Error),
     #[error("Failed to load file.")]
     Io(#[from] io::Error),
-    #[error("Binary buffers not supported yet.")]
-    BinaryBuffersUnsupported,
+    #[error("Binary blob is missing.")]
+    MissingBlob,
     #[error("Failed to decode base64 mesh data.")]
     Base64Decode(#[from] base64::DecodeError),
     #[error("Unsupported buffer format.")]
@@ -58,7 +58,7 @@ fn get_primitive_topology(mode: Mode) -> Result<PrimitiveTopology, GltfError> {
 // TODO: this should return a scene
 pub fn load_gltf(asset_path: &Path, bytes: Vec<u8>) -> Result<Mesh, GltfError> {
     let gltf = gltf::Gltf::from_slice(&bytes)?;
-    let buffer_data = load_buffers(gltf.buffers(), asset_path)?;
+    let buffer_data = load_buffers(&gltf, asset_path)?;
     for scene in gltf.scenes() {
         if let Some(node) = scene.nodes().next() {
             return Ok(load_node(&buffer_data, &node, 1)?);
@@ -112,11 +112,11 @@ fn load_node(buffer_data: &[Vec<u8>], node: &gltf::Node, depth: i32) -> Result<M
     panic!("failed to find mesh")
 }
 
-fn load_buffers(buffers: iter::Buffers, asset_path: &Path) -> Result<Vec<Vec<u8>>, GltfError> {
+fn load_buffers(gltf: &gltf::Gltf, asset_path: &Path) -> Result<Vec<Vec<u8>>, GltfError> {
     const OCTET_STREAM_URI: &str = "data:application/octet-stream;base64,";
 
     let mut buffer_data = Vec::new();
-    for buffer in buffers {
+    for buffer in gltf.buffers() {
         match buffer.source() {
             Source::Uri(uri) => {
                 if uri.starts_with("data:") {
@@ -131,7 +131,13 @@ fn load_buffers(buffers: iter::Buffers, asset_path: &Path) -> Result<Vec<Vec<u8>
                     buffer_data.push(buffer_bytes);
                 }
             }
-            Source::Bin => return Err(GltfError::BinaryBuffersUnsupported),
+            Source::Bin => {
+                if let Some(blob) = gltf.blob.as_deref() {
+                    buffer_data.push(blob.into());
+                } else {
+                    return Err(GltfError::MissingBlob);
+                }
+            }
         }
     }
 

examples/3d/load_model.rs

@@ -17,12 +17,24 @@ fn setup(
     commands
         // mesh
         .spawn(PbrComponents {
-            // load the mesh
+            // load a mesh from glTF
             mesh: asset_server
                 .load("assets/models/monkey/Monkey.gltf")
                 .unwrap(),
             // create a material for the mesh
             material: materials.add(Color::rgb(0.5, 0.4, 0.3).into()),
+            translation: Translation::new(-1.5, 0.0, 0.0),
+            ..Default::default()
+        })
+        // mesh
+        .spawn(PbrComponents {
+            // load a mesh from binary glTF
+            mesh: asset_server
+                .load("assets/models/monkey/Monkey.glb")
+                .unwrap(),
+            // create a material for the mesh
+            material: materials.add(Color::rgb(0.5, 0.4, 0.3).into()),
+            translation: Translation::new(1.5, 0.0, 0.0),
             ..Default::default()
         })
         // light