three js mirror not reflecting all meshes - reflection

Question

Objective:
To simulate a reflective floor(like this) in three js.
Idea:
Make the floor translucent by setting opacity to 0.5.
Place a Mirror below it to reflect the meshes above it.
Expected Output:
To be able to see reflections of the house via the floor mirror.
Obtained Output:
Doesn't reflect the meshes which is part of the house.
Instead, reflects only the skybox and that too only in certain angles.
Screenshots:
Mirror reflecting skybox fully - http://prntscr.com/6yn52y
Mirror reflecting skybox partially - http://prntscr.com/6yn5f7
Mirror not reflecting anything - http://prntscr.com/6yn5qy
Questions:
Why aren't the other meshes of the house reflected through the mirror?
Why is the mirror not reflecting in certain orientations of the camera?
Code Attached:
.......
.......
function getReflectiveFloorMesh(floorMesh) {
var WIDTH = window.innerWidth;
var HEIGHT = window.innerHeight;
floorMirror = new THREE.Mirror( renderer, firstPerson.camera,
{ clipBias: 0.003,
textureWidth: WIDTH,
textureHeight: HEIGHT,
color: 0x889999 } );
var mirrorMesh = floorMesh.clone();
mirrorMesh.position.y -= 10; // Placing the mirror just below the actual translucent floor; Fixme: To be tuned
mirrorMesh.material = floorMirror.material;
mirrorMesh.material.side = THREE.BackSide; // Fixme: Normals were flipped. How to decide on normals?
mirrorMesh.material.needsUpdate = true;
mirrorMesh.add(floorMirror);
return mirrorMesh;
}
function getSkybox() {
var urlPrefix = "/img/skybox/sunset/";
var urls = [urlPrefix + "px.png", urlPrefix + "nx.png",
urlPrefix + "py.png", urlPrefix + "ny.png",
urlPrefix + "pz.png", urlPrefix + "nz.png"];
var textureCube = THREE.ImageUtils.loadTextureCube(urls);
// init the cube shadder
var shader = THREE.ShaderLib["cube"];
shader.uniforms["tCube"].value = textureCube;
var material = new THREE.ShaderMaterial({
fragmentShader: shader.fragmentShader,
vertexShader: shader.vertexShader,
uniforms: shader.uniforms,
side: THREE.BackSide
});
// build the skybox Mesh
var skyboxMesh = new THREE.Mesh(new THREE.CubeGeometry(10000, 10000, 10000, 1, 1, 1, null, true), material);
return skyboxMesh;
}
function setupScene(model, floor) {
scene.add(model); // Adding the house which contains translucent floor
scene.add(getSkybox()); // Adding Skybox
scene.add(getReflectiveFloorMesh(floor)); // Adds mirror just below floor
scope.animate();
}
....
....
this.animate = function () {
// Render the mirrors
if(floorMirror)
floorMirror.render();
renderer.render(scene, firstPerson.camera);
};

Answer 1

You have to attach the mirror to the mesh before doing any transformation.
So the code would be:
floorMirror = new THREE.Mirror( ... );
var mirrorMesh = floorMesh.clone();
mirrorMesh.add(floorMirror); // attach first!
mirrorMesh.position.y -= 10;
...
But another problem here is that you are cloning mirrorMesh from floorMesh, which has already been (probably) transformed.
At creation, a mirror object has the same default transform matrix as a regular Mesh with plane geometry (which is by default 'vertical').
When you attach the mirror to a floor (or any horizontal mesh), the matrix doesn't match with the mesh one and that's why you don't see the reflections, or only from a certain angle.
So, always attach a mirror to a non-transformed plane mesh, before you apply your transformations (translations or rotations).

Answer 2

Idea:
"Make the floor translucent by setting opacity to 0.5.
Place a Mirror below it to reflect the meshes above it".
I suggest another way, make floor as solid add mirror on top and change the alpha of the mirror instead, I think you have issues with the translucent floor restricting the mirror projection through the alpha..
If you move the mirror over from under the translucent floor or into an empty scene with just a cube or sphere geometry attached basic material does it reflect as expected?
You may need 2 mirrors, one for the room assuming you want polished floor boards and one for outside general reflection