Three.js: Apply SSAO (Screen Space Ambient Occlusion) to Displacement map

Question

have I've implemented the Screen Space Ambient Occlusion in my Three.js project correctly, and run perfect, like this:

//Setup SSAO pass   
depthMaterial = new THREE.MeshDepthMaterial();
depthMaterial.depthPacking = THREE.RGBADepthPacking;
depthMaterial.blending = THREE.NoBlending;

var pars = { minFilter: THREE.LinearFilter, magFilter: THREE.LinearFilter, format: THREE.RGBAFormat, stencilBuffer: true }; //Stancilbuffer true because not effect transparent object
depthRenderTarget = new THREE.WebGLRenderTarget(window.innerWidth, window.innerHeight, pars);
depthRenderTarget.texture.name = "SSAOShader.rt";
ssaoPass = new THREE.ShaderPass(THREE.SSAOShader);
///////ssaoPass.uniforms[ "tDiffuse" ].value will be set by ShaderPass
ssaoPass.uniforms["tDepth"].value = depthRenderTarget.texture;
ssaoPass.uniforms['size'].value.set(window.innerWidth, window.innerHeight);
ssaoPass.uniforms['cameraNear'].value = camera.near;
ssaoPass.uniforms['cameraFar'].value = camera.far;
ssaoPass.uniforms['radius'].value = radius;
ssaoPass.uniforms['aoClamp'].value = aoClamp;
ssaoPass.uniforms['lumInfluence'].value = lumInfluence;

But, when I set a material with displacementMap (that run correctly without SSAO enabled), this is the result. Notice that the SSAO is applied "correctly" to the original sphere (with a strange-trasparent-artificat), but I need to apply it to the "displaced vertex" of the sphere)

This is my composer passes:

   //Main render scene pass
    postprocessingComposer.addPass(renderScene);

    //Post processing pass
    if (ssaoPass) {
        postprocessingComposer.addPass(ssaoPass);
    }

And this is the rendering loop with composer

if (postprocessingComposer) {

    if (ssaoPass) {

        //Render depth into depthRenderTarget
        scene.overrideMaterial = depthMaterial;
        renderer.render(scene, camera, depthRenderTarget, true);

        //Render composer
        scene.overrideMaterial = null;
        postprocessingComposer.render();

        renderer.clearDepth();
        renderer.render(sceneOrtho, cameraOrtho);
    }
    else {
        //Render loop with post processing (no SSAO, becasue need more checks, see above)
        renderer.clear();
        postprocessingComposer.render();        
        renderer.clearDepth();
        renderer.render(sceneOrtho, cameraOrtho);
    }
}
else {
    //Simple render loop (no post-processing)
    renderer.clear();
    renderer.render(scene, camera);
    renderer.clearDepth();
    renderer.render(sceneOrtho, cameraOrtho);
}

How can i archive a correct Screen Space Ambient Occlusion applied to a mesh with Displacement Map? Thanks.

[UPDATE]: After some work i tried to this procedure for every child in the scene, with displacement map, to define a new a new overrideMaterial of the scene equal to a depthMaterial with displacement map parameters of the child material.

                    var myDepthMaterial = new THREE.MeshDepthMaterial({
                        depthPacking: THREE.RGBADepthPacking,
                        displacementMap: child.material.displacementMap,
                        displacementScale: child.material.displacementScale,
                        displacementBias: child.material.displacementBias
                    });
                    child.onBeforeRender = function (renderer, scene, camera, geometry, material, group) {
                        scene.overrideMaterial = myDepthMaterial;     
                    };

This solution sounds good, but doesnt work.

Answer 1

You are using SSAO with a displacement map. You need to specify the displacement map when you instantiate the depth material.

depthMaterial = new THREE.MeshDepthMaterial( {

    depthPacking: THREE.RGBADepthPacking,

    displacementMap: displacementMap,
    displacementScale: displacementScale,
    displacementBias: displacementBias

} );

three.js r.87