Screen Space Ambient Occlusion 1.0.0 for Shake (shake plugin)

This plugin calculates a screen space based 2D ambient occlusion. I been thinking now and again over a couple of years that it should be possible to calculate some kind of faked ambient occlusion from just a depth pass and a normals pass. Then I got this paper from SIGGRAPH 2008 that does nearly that in graphics hardware. Their method is a bit more complex and yields a more accurate result because they still have access to the 3D scene. My method is a rewritten and altered 2D version of the one in the paper, but does have the same basic calculation structure. If you are interested in the maths involved, look at pages 13 to 20 in the PDF above.

This plugin calculates a kind of ambient occlusion using only a depth pass. It does this inside a macro including three plugins. The first one calculates a normals pass from the depth pass, so if you have a correct normals pass render you get better results by feeding that into the node as well. It then does a local neighboring occlusion sampling by comparing the depth of the surrounding samples. The samples are only used if they are on a surface that doesn't differ in normal angle from the pixel currently being calculated. This is to prevent self occlusion on flat surfaces. The result naturally becomes quite noisy, and is therefore post blurred using a special normals aware gaussian blur that doesn't blur over object edges or sharp features.
To sum up this plugin package is a macro that includes three plugins;
depth -> normals
depth&normals -> noisy SSAO
noisy SSAO -> smooth SSAO

NOTE: You can download the Linux version on my website https://www.pixelmania.se/shake