Implement experimental WebGPU support (#1238)

* Web gpu execution MVP

Ready infrastructure for wgpu experimentation

Start implementing simple gpu test case

Fix Extract Node not working with nested networks

Convert inputs for extracted node to network inputs

Fix missing cors headers

Feature gate gcore to make it once again no-std compatible

Add skeleton structure gpu shader

Work on gpu node graph output saving

Fix Get and Set nodes

Fix storage nodes

Fix shader construction errors -> spirv errors

Add unsafe version

Add once cell node

Web gpu execution MVP

node-graph/gcore/src/value.rs

@@ -1,6 +1,10 @@
 use crate::Node;
 
-use core::marker::PhantomData;
+use core::{
+	borrow::BorrowMut,
+	cell::{Cell, RefCell, RefMut},
+	marker::PhantomData,
+};
 
 #[derive(Default, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
 pub struct IntNode<const N: u32>;
@@ -13,7 +17,7 @@ impl<'i, const N: u32> Node<'i, ()> for IntNode<N> {
 	}
 }
 
-#[derive(Default, Debug)]
+#[derive(Default, Debug, Clone, Copy)]
 pub struct ValueNode<T>(pub T);
 
 impl<'i, T: 'i> Node<'i, ()> for ValueNode<T> {
@@ -35,12 +39,62 @@ impl<T> From<T> for ValueNode<T> {
 		ValueNode::new(value)
 	}
 }
-impl<T: Clone> Clone for ValueNode<T> {
-	fn clone(&self) -> Self {
-		Self(self.0.clone())
+
+#[derive(Default, Debug, Clone)]
+pub struct RefCellMutNode<T>(pub RefCell<T>);
+
+impl<'i, T: 'i> Node<'i, ()> for RefCellMutNode<T> {
+	type Output = RefMut<'i, T>;
+	#[inline(always)]
+	fn eval(&'i self, _input: ()) -> Self::Output {
+		#[cfg(not(target_arch = "spirv"))]
+		let a = self.0.borrow_mut();
+		#[cfg(target_arch = "spirv")]
+		let a = unsafe { self.0.try_borrow_mut().unwrap_unchecked() };
+		a
+	}
+}
+
+impl<T> RefCellMutNode<T> {
+	pub const fn new(value: T) -> RefCellMutNode<T> {
+		RefCellMutNode(RefCell::new(value))
+	}
+}
+/// #Safety: Never use this as it is unsound.
+#[derive(Default, Debug)]
+pub struct UnsafeMutValueNode<T>(pub T);
+
+/// #Safety: Never use this as it is unsound.
+impl<'i, T: 'i> Node<'i, ()> for UnsafeMutValueNode<T> {
+	type Output = &'i mut T;
+	#[inline(always)]
+	fn eval(&'i self, _input: ()) -> Self::Output {
+		unsafe { &mut *(&self.0 as &T as *const T as *mut T) }
+	}
+}
+
+impl<T> UnsafeMutValueNode<T> {
+	pub const fn new(value: T) -> UnsafeMutValueNode<T> {
+		UnsafeMutValueNode(value)
+	}
+}
+
+#[derive(Default)]
+pub struct OnceCellNode<T>(pub Cell<T>);
+
+impl<'i, T: Default + 'i> Node<'i, ()> for OnceCellNode<T> {
+	type Output = T;
+	#[inline(always)]
+	fn eval(&'i self, _input: ()) -> Self::Output {
+		self.0.replace(T::default())
+	}
+}
+
+impl<T> OnceCellNode<T> {
+	pub const fn new(value: T) -> OnceCellNode<T> {
+		OnceCellNode(Cell::new(value))
 	}
 }
-impl<T: Clone + Copy> Copy for ValueNode<T> {}
 
 #[derive(Clone, Copy)]
 pub struct ClonedNode<T: Clone>(pub T);
@@ -75,6 +129,7 @@ impl<'i, T: Clone + 'i> Node<'i, ()> for DebugClonedNode<T> {
 	#[inline(always)]
 	fn eval(&'i self, _input: ()) -> Self::Output {
 		// KEEP THIS `debug!()` - It acts as the output for the debug node itself
+		#[cfg(not(target_arch = "spirv"))]
 		log::debug!("DebugClonedNode::eval");
 
 		self.0.clone()