Add AttrStore

src/mesh/attr.rs

@@ -4,19 +4,92 @@
 //! fit more data.
 
 use super::*;
+use std::any::TypeId;
+use std::collections::HashMap;
 
 /// An externally-defined identifier for a mesh attribute.
 #[repr(transparent)]
 #[derive(Copy, Clone, Debug, Hash, PartialEq, Eq)]
 pub struct AttrId(pub usize);
 
-/// A description of a mesh attribute.
-#[derive(Clone, Debug, Hash, PartialEq, Eq)]
+/// A description of a attribute's layout in memory.
+#[derive(Copy, Clone, Debug, Hash, PartialEq, Eq)]
 pub struct AttrLayout {
     /// The size (in bytes) of this attribute.
     pub size: usize,
 }
 
+/// Information about an [Attribute] registered in [AttrStore].
+#[derive(Copy, Clone, Debug, Hash, PartialEq, Eq)]
+pub struct AttrInfo {
+    pub layout: AttrLayout,
+    pub default_pool_size: usize,
+}
+
+/// A compile-time attribute data type.
+pub trait Attribute: Sized {
+    /// The memory layout of this data.
+    fn get_layout() -> AttrLayout {
+        AttrLayout {
+            size: std::mem::size_of::<Self>(),
+        }
+    }
+
+    /// The default size for new pools of this attribute.
+    ///
+    /// Defaults to 1024 * 1024. (Around one million.)
+    fn get_default_pool_size() -> usize {
+        1024 * 1024
+    }
+}
+
+/// A store of [AttrIds][AttrId].
+pub struct AttrStore {
+    attributes: Slab<AttrInfo>,
+    types: HashMap<TypeId, AttrId>,
+}
+
+impl AttrStore {
+    pub fn new() -> Self {
+        Self {
+            attributes: Default::default(),
+            types: Default::default(),
+        }
+    }
+
+    /// Dynamically creates a new [AttrId].
+    pub fn add(&mut self, info: AttrInfo) -> AttrId {
+        let index = self.attributes.insert(info);
+        AttrId(index)
+    }
+
+    /// Gets the [AttrId] for a type implementing [Attribute].
+    ///
+    /// Creates a new [AttrId] for unrecognized types, otherwise reuses an
+    /// existing [AttrId].
+    pub fn get_type<T: 'static + Attribute>(&mut self) -> AttrId {
+        let type_id = TypeId::of::<T>();
+        if let Some(id) = self.types.get(&type_id) {
+            *id
+        } else {
+            let layout = T::get_layout();
+            let default_pool_size = T::get_default_pool_size();
+            let info = AttrInfo {
+                layout,
+                default_pool_size,
+            };
+            let id = self.add(info);
+            self.types.insert(type_id, id);
+            id
+        }
+    }
+
+    /// Gets the [AttrInfo] for an [AttrId].
+    pub fn get_info(&self, id: &AttrId) -> Option<&AttrInfo> {
+        self.attributes.get(id.0)
+    }
+}
+
 /// An attribute buffer that has been allocated in an [AttrPool].
 #[derive(Copy, Clone, Debug, Hash, PartialEq, Eq)]
 pub struct AttrAlloc {
@@ -41,12 +114,10 @@ pub struct AttrPool {
 }
 
 impl AttrPool {
-    pub fn new(
-        group: usize,
-        id: AttrId,
-        layout: AttrLayout,
-        size: usize,
-    ) -> Result<Self, PoolError> {
+    pub fn new(group: usize, id: AttrId, info: AttrInfo) -> Result<Self, PoolError> {
+        let layout = info.layout;
+        let size = info.default_pool_size;
+
         Ok(Self {
             group,
             id,

src/mesh/group.rs

@@ -1,6 +1,7 @@
 //! Fixed-room pooling of mesh data.
 
 use super::*;
+use std::sync::Arc;
 
 /// A mesh that has been allocated in a [MeshGroup].
 pub struct MeshAlloc {
@@ -10,49 +11,35 @@ pub struct MeshAlloc {
 /// A set of GPU-side vertex attribute pools and index pools.
 pub struct MeshGroup {
     id: usize,
+    attr_store: Arc<AttrStore>,
     pools: HashMap<AttrId, AttrPool>,
     meshes: Slab<MeshAlloc>,
 }
 
 impl MeshGroup {
-    pub fn new(id: usize) -> Self {
+    pub fn new(id: usize, attr_store: Arc<AttrStore>) -> Self {
         Self {
             id,
+            attr_store,
             pools: Default::default(),
             meshes: Default::default(),
         }
     }
 
-    /// Registers an [AttrId], and creates the [AttrPool] for it.
-    ///
-    /// Fails if the [AttrId] has already been registered.
-    ///
-    /// `pool_size` defines the size of the new pool. Once an attribute pool
-    /// has been created, it cannot be resized, so if it runs out of room for
-    /// new attributes, a new [MeshGroup] must be created.
-    pub fn add_attribute(
-        &mut self,
-        id: AttrId,
-        layout: AttrLayout,
-        pool_size: usize,
-    ) -> Result<(), PoolError> {
-        if self.pools.contains_key(&id) {
-            return Err(PoolError::AttrTaken);
-        }
-
-        let pool = AttrPool::new(self.id, id, layout, pool_size)?;
-        self.pools.insert(id, pool);
-
-        Ok(())
-    }
-
     /// Checks to see if a mesh can be loaded within this group.
     pub fn can_load(&self, buf: &MeshBuffer) -> Result<(), PoolError> {
         for attr in buf.attributes.iter() {
             match self.pools.get(&attr.id) {
-                None => return Err(PoolError::AttrUnregistered),
-                Some(pool) => pool.can_load(attr)?,
-            };
+                None => {
+                    match self.attr_store.get_info(&attr.id) {
+                        Some(_) => {} // new pools of valid attrs can be made
+                        None => return Err(PoolError::AttrUnregistered),
+                    };
+                }
+                Some(pool) => {
+                    pool.can_load(attr)?;
+                }
+            }
         }
 
         Ok(())
@@ -66,14 +53,24 @@ impl MeshGroup {
         let mut copies = Vec::new();
 
         for attr in buf.attributes.iter() {
-            match self.pools.get_mut(&attr.id) {
-                None => unreachable!(),
-                Some(pool) => {
-                    let (alloc, copy) = pool.load(attr)?;
-                    allocs.push((alloc, attr.id));
-                    copies.push(copy);
+            let id = &attr.id;
+            let pool = match self.pools.get_mut(id) {
+                Some(pool) => pool,
+                None => {
+                    let info = match self.attr_store.get_info(id) {
+                        Some(info) => *info,
+                        None => return Err(PoolError::AttrUnregistered),
+                    };
+
+                    let new_pool = AttrPool::new(self.id, *id, info)?;
+                    self.pools.insert(*id, new_pool);
+                    self.pools.get_mut(id).unwrap()
                 }
-            }
+            };
+
+            let (alloc, copy) = pool.load(attr)?;
+            allocs.push((alloc, attr.id));
+            copies.push(copy);
         }
 
         let mesh = MeshAlloc { attributes: allocs };

src/mesh/mod.rs

@@ -45,6 +45,7 @@
 //! TODO: make spillover buffers GPU-transferrable on iGPUs
 
 use slab::Slab;
+use std::sync::Arc;
 use smallvec::SmallVec;
 use std::collections::HashMap;
 
@@ -94,14 +95,16 @@ pub struct MeshHandle {
 
 /// The top-level mesh data pool.
 pub struct MeshPool {
-    pub staging: StagingPool,
-    pub groups: Vec<MeshGroup>,
+    staging: StagingPool,
+    attr_store: Arc<AttrStore>,
+    groups: Vec<MeshGroup>,
 }
 
 impl MeshPool {
-    pub fn new() -> Self {
+    pub fn new(attr_store: Arc<AttrStore>) -> Self {
         Self {
             staging: StagingPool::new(1_000_000),
+            attr_store,
             groups: Default::default(),
         }
     }
@@ -119,7 +122,7 @@ impl MeshPool {
         }
 
         let group_index = self.groups.len();
-        self.groups.push(MeshGroup::new(group_index));
+        self.groups.push(MeshGroup::new(group_index, self.attr_store.clone()));
         let group = self.groups.get_mut(group_index).unwrap();
 
         let (handle, copies) = group.load(buf)?;