<function name="SetStencilZFailOperation" parent="render" type="libraryfunc"> <description>Sets the operation to be performed on the stencil buffer values if the stencil test is passed but the depth buffer test fails.</description> <realm>Client</realm>⤶ <realm>Client and Menu</realm>⤶ <args> <arg name="zFailOperation" type="number">Z fail operation function, see <page>Enums/STENCILOPERATION</page></arg> </args> </function> <example> <description>This shows how to reveal hidden sections of entities, wallhack style (from [Lex's Stencil Tutorial](https://github.com/Lexicality/stencil-tutorial)).</description> <code> hook.Add( "PostDrawOpaqueRenderables", "Stencil Tutorial Example", function() -- Reset everything to known good render.SetStencilWriteMask( 0xFF ) render.SetStencilTestMask( 0xFF ) render.SetStencilReferenceValue( 0 ) render.SetStencilCompareFunction( STENCIL_ALWAYS ) render.SetStencilPassOperation( STENCIL_KEEP ) render.SetStencilFailOperation( STENCIL_KEEP ) render.SetStencilZFailOperation( STENCIL_KEEP ) render.ClearStencil() -- Enable stencils render.SetStencilEnable( true ) -- Set the reference value to 1. This is what the compare function tests against render.SetStencilReferenceValue( 1 ) -- Always draw everything render.SetStencilCompareFunction( STENCIL_ALWAYS ) -- If something would draw to the screen but is behind something, set the pixels it draws to 1 render.SetStencilZFailOperation( STENCIL_REPLACE ) -- Draw our entities. They will draw as normal for _, ent in ipairs( ents.FindByClass( "prop_physics" ) ) do ent:DrawModel() end -- Now, only draw things that have their pixels set to 1. This is the hidden parts of the stencil tests. render.SetStencilCompareFunction( STENCIL_EQUAL ) -- Flush the screen. This will draw teal over all hidden sections of the stencil tests render.ClearBuffersObeyStencil( 0, 148, 133, 255, false ) -- Let everything render normally again render.SetStencilEnable( false ) end ) </code> <output><image src="basic_zfail_operation.jpg" alt="800px"/></output> </example>