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Stencil Op/Comparison Values

Discussion in 'Documentation' started by Giometric, Oct 20, 2015.

  1. Giometric

    Giometric

    Joined:
    Dec 20, 2011
    Posts:
    157
    The ShaderLab stencil documentation lists what the available stencil operations and comparison functions are, but does not mention that these correspond to various integer values (the UI shaders use Float variables that appear to get set by the masks/etc at runtime to take advantage of this). It would be nice if these were listed in the docs along with the values. The Stencil Operations list seems to match up, but the Comparison Functions does not. I couldn't find a list of the latter anywhere online, so I messed about for a bit and came up with one (hopefully it doesn't turn out this is device-specific or something, though I don't imagine the UI shaders working too well if that were the case):

    Comparison Functions
    • 0 - Always (?)
    • 1 - Never
    • 2 - Less
    • 3 - Equal
    • 4 - LEqual
    • 5 - Greater
    • 6 - NotEqual
    • 7 - GEqual
    • 8 - Always (? This is the default for the UI shaders so I suspect this one is technically the 'correct' Always, but any value beyond it will also count as Always)
    Stencil Operations (these seem to line up with the order they're shown in the docs):
    • 0 - Keep (?)
    • 1 - Zero
    • 2 - Replace
    • 3 - IncrSat
    • 4 - DecrSat
    • 5 - Invert
    • 6 - IncrWrap
    • 7 - DecrWrap
     
    MaK28 and Thomas-Mountainborn like this.
  2. Gambit-MSplitz

    Gambit-MSplitz

    Joined:
    May 16, 2015
    Posts:
    1,010
    Thank you so much! This should really be somewhere easy to find in the docs... maybe even the shaderlab page.
     
  3. Alex_May

    Alex_May

    Joined:
    Dec 29, 2013
    Posts:
    135
    Good spot - thanks for reporting it and doing the research. I've added it to our list.
     
  4. Aras

    Aras

    Graphics Plumber Unity Technologies

    Joined:
    Nov 7, 2005
    Posts:
    4,527
  5. rainChu

    rainChu

    Joined:
    May 17, 2013
    Posts:
    1
    I'm sorry to bump such an old thread, but I wanted to point out 2 years later that, as of Unity 2018, the documented order of the comparison function enumeration still does not match up with these values in the ShaderLab manual... it gave me a headache for this past half hour. Would you please add it to the documentation to save others the trouble of relying on user support for reference that should be part of the product?