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December 13, 2011

SSAO shader update v1.2

changes since 1.0:
• v1.2 - added fog calculation to mask AO. Some minor fixes.
• v1.1 - replaced rings sampling with new spiral sampling method. Taken from HERE

fragment shader HERE
blend HERE

4 comments:

  1. hey man looks awesome, keep up the good work!! the only problem I have is it also put ao on my skybox...

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  2. Hi, may I ask you some questions about your algorithm? What does it mean on

    1. #define DL 2.399963229728653", // PI * ( 3.0 - sqrt( 5.0 ) )
    I have no idea why you use parameter 3, 5.

    2. cameraCoef / ( cameraFarPlusNear - unpackDepth( texture2D( tDepth, coord ) ) * cameraFarMinusNear );
    I understand unpackDepth( texture2D( tDepth, coord ) ) * cameraFarMinusNear would compute the world-view depth value, because clip space depth value is from 0.0 to 1.0 by starting from near plane to far plane. but I have no idea you need to use cameraCoef and cameraFarPlusNear.

    Thanks

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    Replies
    1. Hey,
      1. that part nicely calculates spiral alignment of samples. Made by far wiser people than myself. Got it from here (look in Spirals section):
      http://web.archive.org/web/20120421191837/http://www.cgafaq.info/wiki/Evenly_distributed_points_on_sphere

      2. I am linearizing an exponential depth value there. I guess that is what unpackDepth thingy does.
      reference:
      http://www.ozone3d.net/blogs/lab/20090206/how-to-linearize-the-depth-value/

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    2. Thanks for your sharing, Martins.
      I understand it totally. You are so great, you really do a nice job.

      Delete