replace the FullyGenericMaterial in spirv with an analog type from coremem_types

this represents the last spirv-specific material.
next steps are to start removing the materials from `coremem` itself
(i.e. re-exporting more from `coremem_types::mat`).

crates/spirv_backend/src/mat.rs

@@ -1,29 +1,4 @@
-use crate::support::Optional;
-use coremem_types::mat::{Material, MBPgram, MHPgram};
-use coremem_types::vec::Vec3;
-
-
-#[derive(Copy, Clone, Default, PartialEq)]
-pub struct FullyGenericMaterial {
-    pub conductivity: Vec3<f32>,
-    pub m_b_curve: Optional<MBPgram<f32>>,
-    pub m_h_curve: Optional<MHPgram<f32>>,
-}
-
-impl Material<f32> for FullyGenericMaterial {
-    fn conductivity(&self) -> Vec3<f32> {
-        self.conductivity
-    }
-    fn move_b_vec(&self, m: Vec3<f32>, target_b: Vec3<f32>) -> Vec3<f32> {
-        if self.m_b_curve.is_some() {
-            self.m_b_curve.unwrap().move_b_vec(m, target_b)
-        } else if self.m_h_curve.is_some() {
-            self.m_h_curve.unwrap().move_b_vec(m, target_b)
-        } else {
-            Default::default()
-        }
-    }
-}
-
+// TODO: plumb the R parameter through and remove this.
+pub type FullyGenericMaterial = coremem_types::mat::FullyGenericMaterial<f32>;
 pub type IsoConductorOr<M> = coremem_types::mat::IsoConductorOr<f32, M>;