Trying to get outlines on every object added to a HighlightLayer

My scene has a ton of objects so I couldn’t take the approach of multiple HighlightLayers.

I’m also interested in other possible approaches. I tried using the SSAO post process to some success making outlines, but it didn’t quite capture the style I’m going for.

Playground link - I don’t want the outline of the two objects to merge together

I got some results I’m pretty happy with from modifying the sharpen post process. :smiley:

Here’s the glsl code:

#ifdef GL_ES
precision highp float;

// Samplers
varying vec2 vUV;
uniform sampler2D textureSampler;
uniform sampler2D depthSampler;
uniform vec2 screenSize;
uniform vec4 sharpnessAmounts; // x = amount, y = offset, z = color threshold, w = depth threshold

void main(void)
  vec2 onePixel = vec2(1.0, 1.0) / screenSize * sharpnessAmounts.w;
  vec4 color = texture2D(textureSampler, vUV);
  vec4 depth = texture2D(depthSampler, vUV);
  vec4 edgeDetection =
    texture2D(textureSampler, vUV + onePixel * vec2(0, -1)) +
    texture2D(textureSampler, vUV + onePixel * vec2(-1, 0)) +
    texture2D(textureSampler, vUV + onePixel * vec2(1, 0)) +
    texture2D(textureSampler, vUV + onePixel * vec2(0, 1)) -
        color * 4.0;
  vec4 depthEdgeDetection =
    texture2D(depthSampler, vUV + onePixel * vec2(0, -1)) +
    texture2D(depthSampler, vUV + onePixel * vec2(-1, 0)) +
    texture2D(depthSampler, vUV + onePixel * vec2(1, 0)) +
    texture2D(depthSampler, vUV + onePixel * vec2(0, 1)) -
        depth * 4.0;

  float amount = dot(edgeDetection.rgb, vec3(1.)) / 3.;
  float amountDepth = depthEdgeDetection.r;
  vec4 edge = (amount > sharpnessAmounts.y || amountDepth > sharpnessAmounts.z) ? vec4(vec3(clamp(1. - amount - amountDepth, 0., 1.)) / sharpnessAmounts.x, 1.) : vec4(1.);
  gl_FragColor = color * edge;

I believe your approach of choosing an alternative is good (although I do not know what result you wanted to achieve). Sadly, the highlight layer has multiple issues with the rendering order and is also heavily impacting performance. I hope some day we will be able to improve it but it doesn’t look like something easy.

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I haven’t looked into exactly how the HighlightLayer is working, however I recall seeing one method where each object is rendered with a different color before processing that achieved individually outlined objects.

Indeed, there are other methods such as i.e. the edge rendering

You can also achieve outline based on vertices, using shaders (such as the toons shader) and/or combined with a node material. It all depends on the type of design/fx you want to achieve.
But none really have the same ‘glowing’ fx as the highlight layer. So I believe an improved highlightLayer would certainly be welcomed.

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