spirv: remove the Optionality around entry points: compute them statically with traits

crates/spirv_backend/src/lib.rs

@@ -15,7 +15,6 @@ use spirv_std::macros::spirv;
 mod adapt;
 mod support;
 
-use coremem_types::compound::Optional;
 use coremem_types::mat::{Ferroxcube3R1MH, FullyGenericMaterial, IsoConductorOr};
 use coremem_types::step::SimMeta;
 use coremem_types::vec::{Vec3, Vec3u};
@@ -26,28 +25,26 @@ fn glam_vec_to_internal(v: glam::UVec3) -> Vec3u {
     Vec3u::new(v.x, v.y, v.z)
 }
 
-/// Return the step_h/step_e entry point names for the provided material
-pub fn entry_points<M: 'static>() -> Optional<(&'static str, &'static str)> {
-    use core::any::TypeId;
-    let mappings = [
-        (TypeId::of::<FullyGenericMaterial<f32>>(),
-            ("step_h_generic_material", "step_e_generic_material")
-        ),
-        (TypeId::of::<Iso3R1<f32>>(),
-            ("step_h_iso_3r1", "step_e_iso_3r1")
-        ),
-    ];
+mod private {
+    pub trait Sealed {}
+}
 
-    for (id, names) in mappings {
-        if id == TypeId::of::<M>() {
-            return Optional::some(names);
-        }
-    }
-    Optional::none()
+pub trait HasEntryPoints<R>: private::Sealed {
+    fn step_h() -> &'static str;
+    fn step_e() -> &'static str;
 }
 
 macro_rules! steps {
     ($flt:ty, $mat:ty, $step_h:ident, $step_e:ident) => {
+        impl private::Sealed for $mat { }
+        impl HasEntryPoints<$flt> for $mat {
+            fn step_h() -> &'static str {
+                stringify!($step_h)
+            }
+            fn step_e() -> &'static str {
+                stringify!($step_e)
+            }
+        }
         // LocalSize/numthreads
         #[spirv(compute(threads(4, 4, 4)))]
         pub fn $step_h(