auto-git:

[add] tests/unit/light-volume-utils.test.ts

tests/unit/light-volume-utils.test.ts

@@ -0,0 +1,92 @@
+import { describe, expect, it } from "vitest";
+
+import { deriveBoxLightVolumePointLights } from "../../src/runtime-three/light-volume-utils";
+
+describe("deriveBoxLightVolumePointLights", () => {
+  it("derives a bounded four-light cluster from the dominant box axes", () => {
+    const lights = deriveBoxLightVolumePointLights({
+      size: {
+        x: 8,
+        y: 4,
+        z: 2
+      },
+      intensity: 2,
+      padding: 0.25,
+      falloff: "linear"
+    });
+
+    expect(lights).toHaveLength(4);
+    expect(new Set(lights.map((light) => light.localPosition.z))).toEqual(
+      new Set([0])
+    );
+    expect(lights.every((light) => light.intensity === 1)).toBe(true);
+    expect(lights.every((light) => light.distance > 0.75)).toBe(true);
+    expect(lights.every((light) => light.decay === 1.4)).toBe(true);
+  });
+
+  it("shrinks the light cluster inward and reduces reach as padding increases", () => {
+    const withoutPadding = deriveBoxLightVolumePointLights({
+      size: {
+        x: 6,
+        y: 6,
+        z: 3
+      },
+      intensity: 1.5,
+      padding: 0,
+      falloff: "smoothstep"
+    });
+    const withPadding = deriveBoxLightVolumePointLights({
+      size: {
+        x: 6,
+        y: 6,
+        z: 3
+      },
+      intensity: 1.5,
+      padding: 1,
+      falloff: "smoothstep"
+    });
+
+    expect(withPadding).toHaveLength(withoutPadding.length);
+    expect(
+      Math.abs(withPadding[0]?.localPosition.x ?? 0)
+    ).toBeLessThan(Math.abs(withoutPadding[0]?.localPosition.x ?? 0));
+    expect(
+      Math.abs(withPadding[0]?.localPosition.y ?? 0)
+    ).toBeLessThan(Math.abs(withoutPadding[0]?.localPosition.y ?? 0));
+    expect((withPadding[0]?.distance ?? 0)).toBeLessThan(
+      withoutPadding[0]?.distance ?? 0
+    );
+  });
+
+  it("uses a softer smoothstep layout than linear falloff", () => {
+    const linear = deriveBoxLightVolumePointLights({
+      size: {
+        x: 5,
+        y: 5,
+        z: 2
+      },
+      intensity: 1.25,
+      padding: 0.4,
+      falloff: "linear"
+    });
+    const smoothstep = deriveBoxLightVolumePointLights({
+      size: {
+        x: 5,
+        y: 5,
+        z: 2
+      },
+      intensity: 1.25,
+      padding: 0.4,
+      falloff: "smoothstep"
+    });
+
+    expect(Math.abs(smoothstep[0]?.localPosition.x ?? 0)).toBeGreaterThan(
+      Math.abs(linear[0]?.localPosition.x ?? 0)
+    );
+    expect(Math.abs(smoothstep[0]?.localPosition.y ?? 0)).toBeGreaterThan(
+      Math.abs(linear[0]?.localPosition.y ?? 0)
+    );
+    expect(smoothstep[0]?.decay).toBe(2);
+    expect(linear[0]?.decay).toBe(1.4);
+  });
+});