fix falsey gravity zero bug

src/routes/showcase/cannon-fire/_routeLib/TargetGroup.svelte

@@ -1,14 +1,14 @@
 <script lang="ts">
-	import CubeTargets from './CubeTargets.svelte';
+	import TargetPlatform from './TargetPlatform.svelte';
 	export let targetCount: number = 10;
 
 	$: outerPlatforms = Array(targetCount - (targetCount % 3)).fill('x');
 	$: innerPlatforms = Array(targetCount % 3).fill('x');
 </script>
 
 {#each outerPlatforms as _, idx}
-	<CubeTargets />
+	<TargetPlatform />
 {/each}
 {#each innerPlatforms as _, idx}
-	<CubeTargets inner/>
+	<TargetPlatform inner/>
 {/each}

src/routes/showcase/cannon-fire/_routeLib/CubeTargets.svelte → src/routes/showcase/cannon-fire/_routeLib/TargetPlatform.svelte

@@ -7,7 +7,7 @@
 			if (Math.random() > 0.8) {
 				return new MeshPhysicalMaterial({ color: randomColor(), ...glazeProps });
 			} else {
-				return new MeshStandardMaterial({ color: randomColor() });
+				return new MeshBasicMaterial({ color: randomColor() });
 			}
 		});
 
@@ -31,7 +31,7 @@
 </script>
 
 <script lang="ts">
-	import { BoxBufferGeometry, Color, MeshStandardMaterial, MeshPhysicalMaterial } from 'three';
+	import { BoxBufferGeometry, Color, MeshBasicMaterial, MeshPhysicalMaterial } from 'three';
 	import { InstancedMesh, Instance, Group, Mesh } from '@threlte/core';
 	import { RigidBody, Collider } from '@threlte/rapier';
 	import { randomColor, randomVec3 } from '$lib';
@@ -58,7 +58,7 @@
 		<InstancedMesh {geometry} material={cubeMaterials[idx]}>
 			<RigidBody
 				type={'dynamic'}
-				gravityScale={$gravity || 1}
+				gravityScale={typeof $gravity === 'number' ? $gravity : 1}
 				position={{ y: idx * 1.05 * cube.dimension + (groundHeight / 2 + cube.dimension / 2) }}
 			>
 				<Collider