Implement quaternion and matrix geometry

crates/libremetaverse-types/benches/geometry.rs

@@ -0,0 +1,65 @@
+use std::alloc::System;
+use std::hint::black_box;
+use std::time::Instant;
+
+use libremetaverse_types::{Matrix4, Quaternion, Vector3};
+use stats_alloc::{INSTRUMENTED_SYSTEM, Region, StatsAlloc};
+
+#[global_allocator]
+static ALLOCATOR: &StatsAlloc<System> = &INSTRUMENTED_SYSTEM;
+
+fn main() {
+    const ITERATIONS: usize = 250_000;
+
+    let rotation = Quaternion::create_from_eulers_with_single_single_single(0.25, 0.5, 0.75)
+        .expect("valid benchmark rotation");
+    let matrix = Matrix4::mul_with_matrix4_matrix4(
+        Matrix4::create_scale(Vector3 {
+            x: 2.0,
+            y: 3.0,
+            z: 4.0,
+        })
+        .expect("valid benchmark scale"),
+        Matrix4::create_translation(Vector3 {
+            x: 10.0,
+            y: 20.0,
+            z: 30.0,
+        })
+        .expect("valid benchmark translation"),
+    );
+
+    // Warm up runtime and formatting paths before entering the measured region.
+    black_box(Matrix4::transform(matrix, rotation).expect("matrix transform"));
+    black_box(
+        Quaternion::slerp(Quaternion::identity(), rotation, 0.5).expect("quaternion interpolation"),
+    );
+
+    let allocation_region = Region::new(ALLOCATOR);
+    let started = Instant::now();
+    let mut transformed = matrix;
+    let mut interpolated = Quaternion::identity();
+    for index in 0..ITERATIONS {
+        let amount = f32::from(u8::try_from(index & 255).expect("masked benchmark index")) / 255.0;
+        transformed = Matrix4::transform(black_box(transformed), black_box(rotation))
+            .expect("matrix transform");
+        interpolated = Quaternion::slerp(
+            black_box(interpolated),
+            black_box(rotation),
+            black_box(amount),
+        )
+        .expect("quaternion interpolation");
+    }
+    let elapsed = started.elapsed();
+    let allocation_stats = allocation_region.change();
+
+    black_box((transformed, interpolated));
+    println!(
+        "geometry hot paths: {ITERATIONS} iterations in {elapsed:?}, {} allocations, {} reallocations",
+        allocation_stats.allocations, allocation_stats.reallocations
+    );
+    assert_eq!(
+        (allocation_stats.allocations, allocation_stats.reallocations),
+        (0, 0),
+        "matrix transforms and quaternion interpolation must remain allocation-free"
+    );
+}