Add some utility functions

3 files changed, 52 insertions, 6 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 58884c5..80d345a 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1068,6 +1068,12 @@ dependencies = [
 ]
 
 [[package]]
+name = "heck"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2304e00983f87ffb38b55b444b5e3b60a884b5d30c0fca7d82fe33449bbe55ea"
+
+[[package]]
 name = "hermit-abi"
 version = "0.3.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -2477,6 +2483,28 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6637bab7722d379c8b41ba849228d680cc12d0a45ba1fa2b48f2a30577a06731"
 
 [[package]]
+name = "strum"
+version = "0.27.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f64def088c51c9510a8579e3c5d67c65349dcf755e5479ad3d010aa6454e2c32"
+dependencies = [
+ "strum_macros",
+]
+
+[[package]]
+name = "strum_macros"
+version = "0.27.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c77a8c5abcaf0f9ce05d62342b7d298c346515365c36b673df4ebe3ced01fde8"
+dependencies = [
+ "heck",
+ "proc-macro2",
+ "quote",
+ "rustversion",
+ "syn",
+]
+
+[[package]]
 name = "subtle"
 version = "2.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -2649,6 +2677,7 @@ dependencies = [
  "reqwest",
  "serde",
  "serde_json",
+ "strum",
  "tobj",
  "tracing-wasm",
  "wasm-bindgen",
diff --git a/Cargo.toml b/Cargo.toml
index ea4902b..38c2063 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -15,6 +15,7 @@ codegen-units = 1
 opt-level = 2
 
 [dependencies]
+strum = {version = "*", features = ["derive"]} # utility macros for enums
 glow = {version = "=0.13.1", features = []} # rendering
 tobj = "*" # loader for .obj meshes loader
 gltf = {path = "deps/gltf", features = ["extras", "import", "names", "utils"]} # loader for .gltf scenes
diff --git a/src/utils.rs b/src/utils.rs
index 5d89310..05e9251 100644
--- a/src/utils.rs
+++ b/src/utils.rs
@@ -1,4 +1,7 @@
+use std::f32::consts::PI;
+
 use serde::{Serialize, Deserialize};
+use strum::EnumIter;
 
 pub type Erm<T> = color_eyre::Result<T>;
 
@@ -35,7 +38,7 @@ pub fn install_error_handler() {
     color_eyre::eyre::set_hook(Box::new(move |_| Box::new(ErrorHandler))).expect("failed to install error handler");
 }
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
+#[derive(Clone, Copy, Debug, EnumIter, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
 pub enum Cardinal {
     North,
     South,
@@ -43,8 +46,6 @@ pub enum Cardinal {
     East,
 }
 
-pub const CARDINALS: [Cardinal; 4] = [Cardinal::North, Cardinal::South, Cardinal::West, Cardinal::East];
-
 impl Cardinal {
     pub fn to_string(&self) -> &'static str {
         match self {
@@ -94,9 +95,9 @@ impl Cardinal {
     pub fn angle(&self) -> f32 {
         match self {
             Self::North => 0.0,
-            Self::South => std::f32::consts::PI,
-            Self::West => std::f32::consts::PI / 2.0,
-            Self::East => 3.0 * std::f32::consts::PI / 2.0,
+            Self::South => PI,
+            Self::West => PI / 2.0,
+            Self::East => 3.0 * PI / 2.0,
         }
     }
 
@@ -108,8 +109,23 @@ impl Cardinal {
             Self::East => self.turn_ccw(),
         }
     }
+
+    pub fn angle_between(&self, o: &Self) -> f32 {
+        if o == &self.turn_cw() { -PI / 2.0 }
+        else if o == &self.turn_ccw() { PI / 2.0 }
+        else if o == &self.turn_cw().turn_cw() { PI }
+        else { 0.0 }
+    }
 }
 
 pub fn lerp(a: f32, b: f32, t: f32) -> f32 {
     a + t.clamp(0.0, 1.0) * (b - a)
 }
+
+pub fn dir_lerp(a: &glam::Vec3, b: glam::Vec3, t: f32) -> glam::Vec3 {
+    let dirrotaxis = a.cross(b).normalize();
+    let dirrotangle = a.angle_between(b);
+    let dirrotfull = glam::Quat::from_axis_angle(dirrotaxis, dirrotangle);
+    let dirrot = glam::Quat::IDENTITY.slerp(dirrotfull, t);
+    dirrot.mul_vec3(a.clone())
+}