A-frame中有没有一种方法来让屏幕空间反射正常工作？

首先需要在HTML中添加以下链接：

<script src="https://cdn.rawgit.com/mrdoob/three.js/r98/examples/js/postprocessing/EffectComposer.js"></script>
<script src="https://cdn.rawgit.com/mrdoob/three.js/r98/examples/js/postprocessing/RenderPass.js"></script>
<script src="https://cdn.rawgit.com/mrdoob/three.js/r98/examples/js/postprocessing/ShaderPass.js"></script>
<script src="https://cdn.rawgit.com/mrdoob/three.js/r98/examples/js/shaders/CopyShader.js"></script>
<script src="https://cdn.rawgit.com/mrdoob/three.js/r98/examples/js/shaders/SSAOShader.js"></script>
<script src="https://cdn.rawgit.com/mrdoob/three.js/r98/examples/js/shaders/SSAARenderPass.js"></script>

然后通过以下代码来创建反射纹理：

var reflector = new THREE.Reflector( geometry, {
   clipBias: 0.003,
   textureWidth: window.innerWidth * window.devicePixelRatio,
   textureHeight: window.innerHeight * window.devicePixelRatio,
   color: 0x888888
} );

scene.add( reflector );

最后需要将渲染器从THREE.WebGLRenderer更改为EffectComposer：

renderer = new THREE.WebGLRenderer({ antialias: true });
...
var composer = new THREE.EffectComposer( renderer );
var renderPass = new THREE.RenderPass( scene, camera );
composer.addPass( renderPass );

接下来将SSAO Shader应用于场景：

var ssaoPass = new THREE.ShaderPass( THREE.SSAOShader );
ssaoPass.renderToScreen = true;
composer.addPass( ssaoPass );

代码示例（包含完整版本）可在此处找到：https://codepen.io/dasifefe/pen/mdWvmqv