Add Blender blend asset processor

src/blend_asset.rs

@@ -0,0 +1,340 @@
+//! Blender `.blend` source processing.
+//!
+//! Blender is used as an offline importer. The processed result is a normal
+//! GLB, so the runtime continues to use Bevy's built-in glTF loader.
+
+use bevy::{
+    asset::{
+        AssetLoader, AssetPath, AsyncWriteExt, LoadContext,
+        io::{Reader, Writer},
+        processor::LoadTransformAndSave,
+        saver::{AssetSaver, SavedAsset},
+        transformer::{AssetTransformer, TransformedAsset},
+    },
+    gltf::GltfLoader,
+    prelude::*,
+    reflect::TypePath,
+};
+use serde::Deserialize;
+use std::{
+    fs, io,
+    path::{Path, PathBuf},
+    process::Command,
+    time::{SystemTime, UNIX_EPOCH},
+};
+
+const EXPORT_SCRIPT: &str = include_str!("blend_asset/export.py");
+
+#[derive(Asset, TypePath)]
+struct BlendSource {
+    glb: Vec<u8>,
+}
+
+#[derive(Default, TypePath)]
+struct BlendSourceLoader;
+
+#[derive(Debug, Deserialize)]
+struct ExportManifest {
+    dependencies: Vec<String>,
+}
+
+impl AssetLoader for BlendSourceLoader {
+    type Asset = BlendSource;
+    type Settings = ();
+    type Error = io::Error;
+
+    async fn load(
+        &self,
+        reader: &mut dyn Reader,
+        _: &Self::Settings,
+        load_context: &mut LoadContext<'_>,
+    ) -> Result<Self::Asset, Self::Error> {
+        let mut source_bytes = Vec::new();
+        reader.read_to_end(&mut source_bytes).await?;
+
+        let temp = TempDir::new()?;
+        let source_path = locate_source(load_context.path().path());
+        let blend_path = if let Some(path) = source_path.as_deref() {
+            path.to_path_buf()
+        } else {
+            let path = temp.path().join("source.blend");
+            fs::write(&path, source_bytes)?;
+            path
+        };
+        let output = temp.path().join("export.gltf");
+        let script = temp.path().join("export.py");
+        fs::write(&script, EXPORT_SCRIPT)?;
+
+        let result = Command::new(std::env::var_os("BLENDER").unwrap_or_else(|| "blender".into()))
+            .arg("--background")
+            .arg(&blend_path)
+            .arg("--python")
+            .arg(&script)
+            .arg("--")
+            .arg(&output)
+            .output()
+            .map_err(|error| io::Error::other(format!("failed to start Blender: {error}")))?;
+        if !result.status.success() {
+            return Err(io::Error::other(format!(
+                "Blender export failed with {}:\n{}\n{}",
+                result.status,
+                String::from_utf8_lossy(&result.stdout),
+                String::from_utf8_lossy(&result.stderr)
+            )));
+        }
+
+        let manifest: ExportManifest =
+            serde_json::from_slice(&fs::read(temp.path().join("export-manifest.json"))?)
+                .map_err(|error| io::Error::new(io::ErrorKind::InvalidData, error))?;
+
+        let asset_root = asset_root();
+        let mut dependencies = manifest.dependencies;
+        let document: serde_json::Value = serde_json::from_slice(&fs::read(&output)?)
+            .map_err(|error| io::Error::new(io::ErrorKind::InvalidData, error))?;
+        if let Some(images) = document.get("images").and_then(serde_json::Value::as_array) {
+            for image in images {
+                if let Some(uri) = image.get("uri").and_then(serde_json::Value::as_str) {
+                    let path = temp.path().join(uri);
+                    dependencies.push(path.to_string_lossy().into_owned());
+                }
+            }
+        }
+
+        let mut seen = std::collections::HashSet::new();
+        for dependency in dependencies {
+            let physical = PathBuf::from(&dependency);
+            let Some(asset_path) = physical_to_asset_path(&physical, &asset_root) else {
+                continue;
+            };
+            if seen.insert(asset_path.clone()) {
+                // This read is intentionally discarded: it registers the file and
+                // its processed hash as a processor dependency.
+                load_context
+                    .read_asset_bytes(asset_path)
+                    .await
+                    .map_err(|error| {
+                        io::Error::other(format!("failed to read blend dependency: {error}"))
+                    })?;
+            }
+        }
+
+        let glb = make_glb(&output, &temp, load_context.path().path(), &asset_root)?;
+        Ok(BlendSource { glb })
+    }
+
+    fn extensions(&self) -> &[&str] {
+        &["blend"]
+    }
+}
+
+#[derive(Asset, TypePath)]
+struct ProcessedBlend {
+    bytes: Vec<u8>,
+}
+
+#[derive(Default, TypePath)]
+struct BlendTransformer;
+
+impl AssetTransformer for BlendTransformer {
+    type AssetInput = BlendSource;
+    type AssetOutput = ProcessedBlend;
+    type Settings = ();
+    type Error = io::Error;
+
+    async fn transform<'a>(
+        &'a self,
+        source: TransformedAsset<Self::AssetInput>,
+        _: &'a Self::Settings,
+    ) -> Result<TransformedAsset<Self::AssetOutput>, Self::Error> {
+        let bytes = source.glb.clone();
+        Ok(source.replace_asset(ProcessedBlend { bytes }))
+    }
+}
+
+#[derive(Default, TypePath)]
+struct BlendSaver;
+
+impl AssetSaver for BlendSaver {
+    type Asset = ProcessedBlend;
+    type Settings = ();
+    type OutputLoader = GltfLoader;
+    type Error = io::Error;
+
+    async fn save(
+        &self,
+        writer: &mut Writer,
+        asset: SavedAsset<'_, '_, Self::Asset>,
+        _: &Self::Settings,
+        _: AssetPath<'_>,
+    ) -> Result<<Self::OutputLoader as AssetLoader>::Settings, Self::Error> {
+        writer.write_all(&asset.bytes).await?;
+        Ok(default())
+    }
+}
+
+type BlendProcessor = LoadTransformAndSave<BlendSourceLoader, BlendTransformer, BlendSaver>;
+
+pub struct BlendAssetProcessingPlugin;
+
+impl Plugin for BlendAssetProcessingPlugin {
+    fn build(&self, app: &mut App) {
+        app.init_asset::<BlendSource>()
+            .init_asset::<ProcessedBlend>()
+            .register_asset_loader(BlendSourceLoader)
+            .register_asset_processor(BlendProcessor::new(BlendTransformer, BlendSaver))
+            .set_default_asset_processor::<BlendProcessor>("blend");
+    }
+}
+
+struct TempDir(PathBuf);
+
+impl TempDir {
+    fn new() -> io::Result<Self> {
+        let stamp = SystemTime::now()
+            .duration_since(UNIX_EPOCH)
+            .unwrap_or_default()
+            .as_nanos();
+        let path =
+            std::env::temp_dir().join(format!("shinespark-blend-{}-{stamp}", std::process::id()));
+        fs::create_dir_all(&path)?;
+        Ok(Self(path))
+    }
+    fn path(&self) -> &Path {
+        &self.0
+    }
+}
+
+impl Drop for TempDir {
+    fn drop(&mut self) {
+        let _ = fs::remove_dir_all(&self.0);
+    }
+}
+
+fn asset_root() -> PathBuf {
+    std::env::var_os("BEVY_ASSET_ROOT")
+        .map(PathBuf::from)
+        .unwrap_or_else(|| std::env::current_dir().unwrap_or_default().join("assets"))
+}
+
+fn locate_source(path: &Path) -> Option<PathBuf> {
+    let root = asset_root();
+    [root.join(path), PathBuf::from(path)]
+        .into_iter()
+        .find(|candidate| candidate.is_file())
+}
+
+fn physical_to_asset_path(path: &Path, root: &Path) -> Option<String> {
+    let canonical = fs::canonicalize(path).ok()?;
+    let root = fs::canonicalize(root).ok()?;
+    let relative = canonical.strip_prefix(root).ok()?;
+    Some(relative.to_string_lossy().replace('\\', "/"))
+}
+
+fn make_glb(
+    gltf_path: &Path,
+    temp: &TempDir,
+    model_asset_path: &Path,
+    asset_root: &Path,
+) -> io::Result<Vec<u8>> {
+    let mut json: serde_json::Value = serde_json::from_slice(&fs::read(gltf_path)?)
+        .map_err(|error| io::Error::new(io::ErrorKind::InvalidData, error))?;
+    let bin_name = json["buffers"][0]["uri"].as_str().ok_or_else(|| {
+        io::Error::new(io::ErrorKind::InvalidData, "glTF has no binary buffer URI")
+    })?;
+    let mut bin = fs::read(temp.path().join(bin_name))?;
+    let model_parent = model_asset_path.parent().unwrap_or_else(|| Path::new(""));
+    let image_count = json["images"]
+        .as_array()
+        .ok_or_else(|| io::Error::new(io::ErrorKind::InvalidData, "glTF images are not an array"))?
+        .len();
+    if !json["bufferViews"].is_array() {
+        return Err(io::Error::new(
+            io::ErrorKind::InvalidData,
+            "glTF bufferViews are not an array",
+        ));
+    }
+    for index in 0..image_count {
+        let uri = json["images"][index]
+            .get("uri")
+            .and_then(serde_json::Value::as_str)
+            .map(str::to_owned);
+        let Some(uri) = uri else { continue };
+        if uri.starts_with("data:") {
+            continue;
+        }
+        let uri_path = temp.path().join(uri);
+        if let Some(asset_path) = physical_to_asset_path(&uri_path, asset_root) {
+            json["images"][index]["uri"] =
+                serde_json::Value::String(relative_uri(model_parent, Path::new(&asset_path)));
+        } else {
+            let bytes = fs::read(&uri_path)?;
+            while bin.len() % 4 != 0 {
+                bin.push(0);
+            }
+            let offset = bin.len();
+            bin.extend_from_slice(&bytes);
+            let mime = mime_type(&uri_path);
+            let view = json["bufferViews"].as_array().unwrap().len();
+            json["bufferViews"]
+                .as_array_mut()
+                .unwrap()
+                .push(serde_json::json!({
+                    "buffer": 0,
+                    "byteOffset": offset,
+                    "byteLength": bytes.len(),
+                }));
+            json["images"][index].as_object_mut().unwrap().remove("uri");
+            json["images"][index]["bufferView"] = serde_json::Value::from(view);
+            json["images"][index]["mimeType"] = serde_json::Value::String(mime.to_owned());
+        }
+    }
+    json["buffers"][0]["byteLength"] = serde_json::Value::from(bin.len());
+    json["buffers"][0].as_object_mut().unwrap().remove("uri");
+    let mut json_bytes = serde_json::to_vec(&json).map_err(io::Error::other)?;
+    while json_bytes.len() % 4 != 0 {
+        json_bytes.push(b' ');
+    }
+    while bin.len() % 4 != 0 {
+        bin.push(0);
+    }
+    let length = 12 + 8 + json_bytes.len() + 8 + bin.len();
+    let mut glb = Vec::with_capacity(length);
+    glb.extend_from_slice(b"glTF");
+    glb.extend_from_slice(&2u32.to_le_bytes());
+    glb.extend_from_slice(&(length as u32).to_le_bytes());
+    glb.extend_from_slice(&(json_bytes.len() as u32).to_le_bytes());
+    glb.extend_from_slice(b"JSON");
+    glb.extend_from_slice(&json_bytes);
+    glb.extend_from_slice(&(bin.len() as u32).to_le_bytes());
+    glb.extend_from_slice(b"BIN\0");
+    glb.extend_from_slice(&bin);
+    Ok(glb)
+}
+
+fn relative_uri(from: &Path, to: &Path) -> String {
+    let from: Vec<_> = from.components().collect();
+    let to: Vec<_> = to.components().collect();
+    let common = from.iter().zip(&to).take_while(|(a, b)| a == b).count();
+    let mut result = PathBuf::new();
+    for _ in common..from.len() {
+        result.push("..");
+    }
+    for component in &to[common..] {
+        result.push(component.as_os_str());
+    }
+    result.to_string_lossy().replace('\\', "/")
+}
+
+fn mime_type(path: &Path) -> &'static str {
+    match path
+        .extension()
+        .and_then(|e| e.to_str())
+        .unwrap_or_default()
+        .to_ascii_lowercase()
+        .as_str()
+    {
+        "jpg" | "jpeg" => "image/jpeg",
+        "webp" => "image/webp",
+        _ => "image/png",
+    }
+}

src/blend_asset/export.py

@@ -0,0 +1,33 @@
+import bpy
+import json
+import os
+import sys
+
+
+def main():
+    output = sys.argv[sys.argv.index("--") + 1]
+    bpy.ops.export_scene.gltf(
+        filepath=output,
+        export_format="GLTF_SEPARATE",
+        export_keep_originals=True,
+        export_extras=True,
+        export_animations=True,
+        export_skins=True,
+        export_morph=True,
+        export_yup=True,
+    )
+
+    dependencies = []
+    for image in bpy.data.images:
+        if image.source not in {"FILE", "TILED"}:
+            continue
+        path = image.filepath_raw or image.filepath
+        if path and not image.packed_file:
+            dependencies.append(bpy.path.abspath(path))
+
+    with open(os.path.join(os.path.dirname(output), "export-manifest.json"), "w") as file:
+        json.dump({"dependencies": sorted(set(dependencies))}, file)
+
+
+if __name__ == "__main__":
+    main()

src/fighter/baked_animation/asset_baking.rs

@@ -2,8 +2,8 @@ use super::{
     BAKED_ANIMATION_FPS,
     runtime::{BakedAnimationClip, BakedFighterAnimations},
 };
-use crate::math::fixed_transform::FixedMat4;
 use crate::fighter::{animation::AnimKind, manifest::FighterManifest};
+use crate::math::fixed_transform::FixedMat4;
 use bevy::{
     asset::{
         AssetLoader, AssetPath, AsyncWriteExt, LoadContext,
@@ -51,6 +51,9 @@ impl AssetLoader for FighterBakeSourceLoader {
             .map_err(|error| io::Error::other(error.to_string()))?;
         let manifest: FighterManifest = ron::de::from_bytes(&manifest_bytes)
             .map_err(|error| io::Error::new(io::ErrorKind::InvalidData, error))?;
+        // `read_asset_bytes` uses the processor's processed asset source. This
+        // deliberately allows `model_path` to point at a `.blend`: the blend
+        // processor has already converted it to a hybrid GLB by this point.
         let model_bytes = load_context
             .read_asset_bytes(&manifest.model_path)
             .await

src/lib.rs

@@ -38,6 +38,7 @@ use crate::{
 };
 
 mod args;
+pub mod blend_asset;
 pub mod camera;
 pub mod debug_tools;
 pub mod fighter;
@@ -179,6 +180,7 @@ impl Plugin for AssetProcessingPlugin {
     fn build(&self, app: &mut App) {
         app.add_plugins((
             GameAssetPlugin,
+            blend_asset::BlendAssetProcessingPlugin,
             scripting::importer::FighterScriptImportPlugin,
             fighter::baked_animation::BakedAnimationAssetProcessingPlugin,
         ));