From c67e1ca728e0c43e9ca67a09cf37f2698a314762 Mon Sep 17 00:00:00 2001
From: crosstyan <crosstyan@outlook.com>
Date: Mon, 24 Mar 2025 16:36:02 +0800
Subject: [PATCH] Refactor Scene component to improve camera positioning and
 rendering. Adjust default near clipping plane value, update floor position,
 and streamline camera view creation with extrinsic matrix handling.

---
 src/App.tsx | 43 ++++++++++++++++++++++++++-----------------
 1 file changed, 26 insertions(+), 17 deletions(-)

diff --git a/src/App.tsx b/src/App.tsx
index a798b1e..992a971 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -12,7 +12,7 @@ const THREE_ADDONS = {
 } as const
 
 
-const DEFAULT_NEAR = 0.1
+const DEFAULT_NEAR = 0.05
 const DEFAULT_FAR = 1
 const CAMERA_EXTRINSIC_MATRIX_MAP: Record<string, number[]> = {
   "AE_01": [
@@ -70,7 +70,7 @@ const intrinsicToFov = (intrinsic: number[], image_size: { width: number, height
 const Scene = () => {
   function Floor() {
     return (
-      <mesh rotation-x={-Math.PI / 2} position-y={-0.05} receiveShadow>
+      <mesh rotation-x={-Math.PI / 2} position-y={-0.5} receiveShadow>
         <planeGeometry args={[15, 15]} />
         <meshStandardMaterial color="#ccc" />
       </mesh>
@@ -92,11 +92,17 @@ const Scene = () => {
   // https://www.ilyameerovich.com/simple-3d-text-meshes-in-three-js/
 
   const CameraViewFromExtrinsic = ({ extrinsic, name, near, far, fov, textSize, aspect }: CameraViewFromExtrinsicProps) => {
+    console.assert(extrinsic.length === 16, "extrinsic must be a 4x4 matrix")
     const font = new FontLoader().parse(HelvetikerRegular)
     const camera = new THREE.PerspectiveCamera(fov ?? 60, aspect ?? 4 / 3, near ?? DEFAULT_NEAR, far ?? DEFAULT_FAR)
+    // the camera by default is looking up to the y-axis
+    // we want it to look at the origin
+    camera.rotation.x = -Math.PI / 2
     const helper = <cameraHelper args={[camera]} />
+    const Rt = new THREE.Matrix4()
     // @ts-expect-error 16 elements
-    camera.applyMatrix4(new THREE.Matrix4(...extrinsic))
+    Rt.set(...extrinsic)
+    camera.applyMatrix4(Rt)
 
     const textRef = useRef<THREE.Mesh>(null)
     const { camera: viewCamera } = useThree()
@@ -110,11 +116,8 @@ const Scene = () => {
     let text: JSX.Element | null = null
     if (name) {
       const geo = new THREE_ADDONS.TextGeometry(name ?? "", { font, size: textSize ?? 0.1, depth: 0.001 })
-      const matrix = new THREE.Matrix4()
-      // @ts-expect-error 16 elements
-      matrix.set(...extrinsic)
       const position = new THREE.Vector3()
-      position.setFromMatrixPosition(matrix)
+      position.setFromMatrixPosition(Rt)
 
       text = (
         <mesh ref={textRef} position={position}>
@@ -132,24 +135,30 @@ const Scene = () => {
     )
   }
 
+  const scene = (<group>
+    {/* <OrbitControls /> */}
+    <ambientLight intensity={0.05} />
+    <directionalLight castShadow position={[3.3, 6, 4.4]} intensity={5} />
+    <Floor />
+    {Object.entries(CAMERA_EXTRINSIC_MATRIX_MAP).map(([key, value]) => {
+      const intrinsic = CAMERA_INTRINSIC_MATRIX_MAP[key]
+      const { fov_x, fov_y } = intrinsicToFov(intrinsic, { width: IMAGE_WIDTH, height: IMAGE_HEIGHT })
+      // make the far reverse proportional to the fov
+      const far = (1 / fov_x) * 20
+      return <CameraViewFromExtrinsic key={key} name={`${key}(${fov_x.toFixed(1)})`} extrinsic={value} fov={fov_x} aspect={IMAGE_WIDTH / IMAGE_HEIGHT} far={far} />
+    })}
+    <Axes />
+  </group>)
   return (
     // Note that we don't need to import anything, All three.js objects will be treated
     // as native JSX elements, just like you can just write <div /> or <span /> in
     // regular ReactDOM. The general rule is that Fiber components are available under
     // the camel-case version of their name in three.js.
+
     <>
       <CameraControls />
-      {/* <OrbitControls /> */}
-      <ambientLight intensity={0.05} />
-      <directionalLight castShadow position={[3.3, 6, 4.4]} intensity={5} />
-      <Floor />
-      {Object.entries(CAMERA_EXTRINSIC_MATRIX_MAP).map(([key, value]) => {
-        const intrinsic = CAMERA_INTRINSIC_MATRIX_MAP[key]
-        const fov = intrinsicToFov(intrinsic, { width: IMAGE_WIDTH, height: IMAGE_HEIGHT })
-        return <CameraViewFromExtrinsic key={key} name={key} extrinsic={value} fov={fov.fov_x} aspect={IMAGE_WIDTH / IMAGE_HEIGHT} />
-      })}
-      <Axes />
       <Stats />
+      {scene}
     </>
   )
 }