threejs-camera

When to use this skill

ALWAYS use this skill when the user mentions:

• Switching perspective vs orthographic, fov, aspect, zoom, near, far
• CubeCamera for real-time environment maps or reflections (update rate caveats)
• ArrayCamera/StereoCamera for multi-view or stereo off-axis projection (non-XR)

IMPORTANT: camera vs webxr vs post

Topic	Skill
Standard desktop projection	threejs-camera
XR reference spaces, IPD	threejs-webxr
Offscreen pass cameras inside composer	threejs-postprocessing

Trigger phrases include:

• "PerspectiveCamera", "OrthographicCamera", "CubeCamera", "aspect", "near", "far"
• "透视相机", "正交", "立方体相机"

How to use this skill

1. Perspective: set aspect = width/height; update on resize (threejs-renderers example workflow).
2. Orthographic: define left/right/top/bottom in world units for CAD/2.5D views.
3. Near/far: balance depth precision vs containing scene bounds; relate to fog (threejs-scenes).
4. CubeCamera: position at reflection probe; call update when scene static enough; use render target outputs per docs.
5. Stereo/Array: advanced; cite docs for eye parameters; defer XR to threejs-webxr.
6. Projection matrix: call updateProjectionMatrix() after parameter edits.
7. Helpers: CameraHelper lives in threejs-helpers.

Example: Resize handler with updateProjectionMatrix

window.addEventListener('resize', () => {
  camera.aspect = window.innerWidth / window.innerHeight;
  camera.updateProjectionMatrix();
  renderer.setSize(window.innerWidth, window.innerHeight);
});

See examples/workflow-perspective-resize.md.

Doc map (official)

Docs section	Representative links
Cameras (index)	https://threejs.org/docs/#Cameras
Cameras	https://threejs.org/docs/Camera.html
Perspective	https://threejs.org/docs/PerspectiveCamera.html
Orthographic	https://threejs.org/docs/OrthographicCamera.html
Cube	https://threejs.org/docs/CubeCamera.html
Multi-view	https://threejs.org/docs/ArrayCamera.html
Stereo (non-XR)	https://threejs.org/docs/StereoCamera.html

Scope

• In scope: Core camera classes and parameters; cube/array/stereo overview.
• Out of scope: WebXR reference spaces, eye matrices, session lifecycle (threejs-webxr); shadow map camera tuning (threejs-lights); pass-internal cameras in composer (threejs-postprocessing).

Common pitfalls and best practices

• Wrong aspect after resize stretches image—always sync with canvas.
• Too small near hurts depth precision in large worlds.
• CubeCamera every frame is expensive—throttle for performance.

Documentation and version

Camera parameters and CubeCamera update behavior follow the Cameras section of three.js docs. WebXR uses different projection paths—hand off to threejs-webxr when the user mentions headsets or reference spaces.

Agent response checklist

When answering under this skill, prefer responses that:

1. Link PerspectiveCamera, OrthographicCamera, or CubeCamera as relevant.
2. Pair resize with threejs-renderers setSize / DPR patterns when relevant.
3. Route XR/WebXRManager questions to threejs-webxr after one-line renderer mention.
4. Mention updateProjectionMatrix() after intrinsic changes.
5. Use threejs-helpers CameraHelper for shadow frustum debug when discussing lights.

References

• https://threejs.org/docs/#Cameras
• https://threejs.org/docs/PerspectiveCamera.html
• https://threejs.org/docs/CubeCamera.html

Keywords

English: perspectivecamera, orthographiccamera, cubecamera, projection, aspect, near, far, three.js

中文： 相机、透视、正交、投影、近裁剪、远裁剪、CubeCamera、three.js