RFC: SSAO Effect

• Authors: Jian Huang

• Date: July. 2019

• Status: For Review

Abstract

SSAO is an efficient approximation of ambient occlusion, which tunes the ambient lighting based on depths of the current pixel and the surrounding area.

Proposal

API

SSAOEffect class is the public interface to create the SSAO effect.

Example

const ssaoEffect = new SSAOEffect();
const deckgl = new Deck({
  canvas: 'my-deck-canvas',
  effects: [ssaoEffect],
  layers: [
	  // building layer
	  new SolidPolygonLayer({
      ...})]
});

Workflow

• SSAO effect is constructed by the user
• SSAO shader module is set to default in the constructor and a depth pass is also created
• In the depth pass, all the layers are rendered to a depth map
• After all the effects are processed, 3D layers with SSAO module injected tunes the ambient lighting factor based on depths.

Limitations

We only apply SSAO to 3D layers. Pixels in 2D layers close to 3D objects should also have this effect.