From fa30bd55789dea740cde15b32ffc3e723cf50d91 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E2=80=9CIsaac?= <isaac@isaacmason.com>
Date: Sun, 25 Aug 2024 22:55:54 +1000
Subject: [PATCH] fix: add bounding sphere to grass shader demo

---
 demos/grass-shader/src/Grass.jsx | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/demos/grass-shader/src/Grass.jsx b/demos/grass-shader/src/Grass.jsx
index 7a07aa42..83c5aa4f 100755
--- a/demos/grass-shader/src/Grass.jsx
+++ b/demos/grass-shader/src/Grass.jsx
@@ -27,11 +27,20 @@ export default function Grass({ options = { bW: 0.12, bH: 1, joints: 5 }, width
     geo.computeVertexNormals()
     return geo
   }, [width])
-  useFrame(state => (materialRef.current.uniforms.time.value = state.clock.elapsedTime / 4))
+  const boundingSphere = useMemo(() => {
+    return new THREE.Sphere(new THREE.Vector3(), (Math.sqrt(2) * width) / 2)
+  }, [width])
+
+  useFrame((state) => (materialRef.current.uniforms.time.value = state.clock.elapsedTime / 4))
+
   return (
     <group {...props}>
       <mesh>
-        <instancedBufferGeometry index={baseGeom.index} attributes-position={baseGeom.attributes.position} attributes-uv={baseGeom.attributes.uv}>
+        <instancedBufferGeometry
+          index={baseGeom.index}
+          attributes-position={baseGeom.attributes.position}
+          attributes-uv={baseGeom.attributes.uv}
+          boundingSphere={boundingSphere}>
           <instancedBufferAttribute attach="attributes-offset" args={[new Float32Array(attributeData.offsets), 3]} />
           <instancedBufferAttribute attach="attributes-orientation" args={[new Float32Array(attributeData.orientations), 4]} />
           <instancedBufferAttribute attach="attributes-stretch" args={[new Float32Array(attributeData.stretches), 1]} />