[unstable-rust] mesh: Use ! type in place of NoTexture.

all-is-cubes-base/src/util/custom_format.rs

@@ -27,6 +27,12 @@ impl<T> Fmt<TypeName> for PhantomData<T> {
 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
 pub struct ConciseDebug;
 
+impl Fmt<ConciseDebug> for ! {
+    fn fmt(&self, _: &mut fmt::Formatter<'_>, _: &ConciseDebug) -> fmt::Result {
+        match *self {}
+    }
+}
+
 impl<T: Fmt<ConciseDebug>, const N: usize> Fmt<ConciseDebug> for [T; N] {
     fn fmt(&self, fmt: &mut fmt::Formatter<'_>, fopt: &ConciseDebug) -> fmt::Result {
         fmt.debug_list()

all-is-cubes-desktop/src/glue/rerun_mesh.rs

@@ -14,13 +14,12 @@ use all_is_cubes_mesh as mesh;
 use all_is_cubes_render::camera::Camera;
 
 use mesh::dynamic::ChunkedSpaceMesh;
-use mesh::texture::NoTexture;
 
 struct Mt;
 impl mesh::MeshTypes for Mt {
     type Vertex = Vertex;
     type Alloc = mesh::texture::NoTextures;
-    type Tile = NoTexture;
+    type Tile = !;
 }
 impl mesh::dynamic::DynamicMeshTypes for Mt {
     type RenderData = Option<DroppingMesh>;
@@ -43,8 +42,8 @@ struct Vertex {
     color: rg::components::Color,
 }
 
-impl From<mesh::BlockVertex<NoTexture>> for Vertex {
-    fn from(v: mesh::BlockVertex<NoTexture>) -> Self {
+impl From<mesh::BlockVertex<!>> for Vertex {
+    fn from(v: mesh::BlockVertex<!>) -> Self {
         Self {
             position: v.position.to_f32().to_array().into(),
             color: match v.coloring {
@@ -59,7 +58,7 @@ impl mesh::GfxVertex for Vertex {
 
     type Coordinate = f32;
 
-    type TexPoint = NoTexture;
+    type TexPoint = !;
 
     type BlockInst = Vector3D<f32, Cube>;
 

all-is-cubes-desktop/src/lib.rs

@@ -1,3 +1,5 @@
+#![feature(never_type)]
+
 //! Components for creating a desktop application that renders interactive [`all_is_cubes`]
 //! content.
 //!

all-is-cubes-mesh/src/lib.rs

@@ -1,3 +1,5 @@
+#![feature(never_type)]
+
 //! Data structures and algorithms for converting [`all_is_cubes`] voxel data to triangle
 //! meshes for rendering or export.
 //!

all-is-cubes-mesh/src/texture.rs

@@ -8,7 +8,6 @@ use all_is_cubes::block::{Evoxel, Evoxels};
 use all_is_cubes::content::palette;
 use all_is_cubes::euclid::Point3D;
 use all_is_cubes::math::{Axis, Cube, GridAab, GridSizeCoord, Rgb, Vol};
-use all_is_cubes::util::{ConciseDebug, Fmt};
 
 /// Numeric type used to calculate texture coordinates and store them in [`BlockVertex`].
 ///
@@ -289,26 +288,18 @@ pub fn copy_voxels_into_xmaj_texture(
 pub struct NoTextures;
 
 impl Allocator for NoTextures {
-    type Tile = NoTexture;
-    type Point = NoTexture;
+    type Tile = !;
+    type Point = !;
 
     fn allocate(&self, _: GridAab, _: Channels) -> Option<Self::Tile> {
         None
     }
 }
 
-/// Uninhabited [`Tile`] type; no instance of this ever exists.
-///
-/// TODO: this can and should be just ! (never) when that's available in stable Rust
-#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
-#[allow(clippy::exhaustive_enums)]
-pub enum NoTexture {}
-
-impl Tile for NoTexture {
+impl Tile for ! {
     type Point = Self;
     type Plane = Self;
     const REUSABLE: bool = true;
-
     fn bounds(&self) -> GridAab {
         match *self {}
     }
@@ -325,17 +316,10 @@ impl Tile for NoTexture {
         match *self {}
     }
 }
-
-impl Plane for NoTexture {
+impl Plane for ! {
     type Point = Self;
 
     fn grid_to_texcoord(&self, _: Point3D<TextureCoordinate, TexelUnit>) -> Self::Point {
         match *self {}
     }
 }
-
-impl Fmt<ConciseDebug> for NoTexture {
-    fn fmt(&self, _: &mut fmt::Formatter<'_>, _: &ConciseDebug) -> fmt::Result {
-        match *self {}
-    }
-}

all-is-cubes-port/src/lib.rs

@@ -1,3 +1,5 @@
+#![feature(never_type)]
+
 //! Data import and export between [`all_is_cubes`] types and other data formats.
 //!
 //! Currently supported formats:

all-is-cubes-port/src/stl.rs

@@ -11,11 +11,7 @@ use all_is_cubes::math::{notnan, Cube, FreeCoordinate};
 use all_is_cubes::space::Space;
 use all_is_cubes::universe::PartialUniverse;
 use all_is_cubes::util::YieldProgress;
-use all_is_cubes_mesh::{
-    self as mesh,
-    texture::{NoTexture, NoTextures},
-    BlockVertex,
-};
+use all_is_cubes_mesh::{self as mesh, texture::NoTextures, BlockVertex};
 use all_is_cubes_render::camera::GraphicsOptions;
 
 pub(crate) async fn export_stl(
@@ -115,9 +111,9 @@ enum StlMt {}
 
 impl mesh::MeshTypes for StlMt {
     // TODO: It'd be more efficient to use a custom vertex type but we're not bothering for now.
-    type Vertex = BlockVertex<NoTexture>;
+    type Vertex = BlockVertex<!>;
     type Alloc = NoTextures;
-    type Tile = NoTexture;
+    type Tile = !;
 }
 
 #[cfg(test)]

all-is-cubes-render/src/lib.rs

@@ -16,6 +16,7 @@
 //!   * [`raytracer::RtRenderer`] does not implement [`headless::HeadlessRenderer`].
 
 #![no_std]
+#![feature(never_type)]
 // Crate-specific lint settings. (General settings can be found in the workspace manifest.)
 #![forbid(unsafe_code)]