Revision Difference
render.SetStencilTestMask#513017
<function name="SetStencilTestMask" parent="render" type="libraryfunc">⤶
<description>Sets the unsigned 8-bit test bitflag mask to be used for any stencil testing.</description>⤶
<realm>Client</realm>⤶
<args>⤶
<arg name="mask" type="number">The mask bitflag.</arg>⤶
</args>⤶
</function>⤶
⤶
<example>⤶
<description>A brief demonstration of masks</description>⤶
<code>⤶
hook.Add( "PostDrawOpaqueRenderables", "Stencil Tutorial Example", function()⤶
--<page>⤶
To understand this tutorial you need to already understand the basics⤶
of binary and bitwise operations.⤶
⤶
It would also help to understand hexadecimal notation, since Lua⤶
doesn't have a bitmask input, but I will include binary notation in⤶
comments to help.⤶
--</page>⤶
⤶
-- 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 )⤶
-- Force everything to fail⤶
render.SetStencilCompareFunction( STENCIL_NEVER )⤶
-- Save all the things we don't draw⤶
render.SetStencilFailOperation( STENCIL_REPLACE )⤶
⤶
-- Set the reference value to 00011100⤶
render.SetStencilReferenceValue( 0x1C )⤶
-- Set the write mask to 01010101⤶
-- Any writes to the stencil buffer will be bitwise ANDed with this mask.⤶
-- With our current reference value, the result will be 00010100.⤶
render.SetStencilWriteMask( 0x55 )⤶
⤶
-- Fail to draw our entities.⤶
for _, ent in pairs( ents.FindByClass( "sent_stencil_test" ) ) do⤶
ent:DrawModel()⤶
end⤶
⤶
-- Set the test mask to 11110011.⤶
-- Any time a pixel is read out of the stencil buffer it will be bitwise ANDed with this mask.⤶
render.SetStencilTestMask( 0xF3 )⤶
-- Set the reference value to 00011100 & 01010101 & 11110011⤶
render.SetStencilReferenceValue( 0x10 )⤶
-- Pass if the masked buffer value matches the unmasked reference value⤶
render.SetStencilCompareFunction( STENCIL_EQUAL )⤶
⤶
-- Draw our entities⤶
render.ClearBuffersObeyStencil( 0, 148, 133, 255, false );⤶
⤶
-- Let everything render normally again⤶
render.SetStencilEnable( false )⤶
end )⤶
</code>⤶
⤶
</example>⤶
⤶
⤶
<example>⤶
<description>A somewhat more complicated mask example</description>⤶
<code>⤶
hook.Add( "PostDrawOpaqueRenderables", "Stencil Tutorial Example", function()⤶
--<page>⤶
To understand this tutorial you need to already understand the basics⤶
of binary and bitwise operations.⤶
⤶
It would also help to understand hexadecimal notation, since Lua⤶
doesn't have a bitmask input, but I will include binary notation in⤶
comments to help.⤶
--</page>⤶
⤶
-- 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 )⤶
⤶
-- Only write to the upper 4 bits of the stencil buffer⤶
render.SetStencilWriteMask( 0xF0 )⤶
-- Wipe the stencil buffer to be 0001111. This is not affected by the write mask.⤶
render.ClearStencilBufferRectangle( 0, 0, ScrW(), ScrH(), 0x0F )⤶
⤶
-- Always fail⤶
render.SetStencilCompareFunction( STENCIL_NEVER )⤶
-- Don't read any bits from the stencil buffer⤶
render.SetStencilTestMask( 0x00 )⤶
-- When an operation fails, read the current value from the stencil buffer, add⤶
-- one to it and then write it back to the buffer⤶
-- This is not affected by the test mask, but it is affected by the write mask⤶
-- This means we will read 00001111, then write 00010000.⤶
-- However, due to the write mask, this won't affect the last four bits already⤶
-- in the buffer, resulting in 00011111.⤶
render.SetStencilFailOperation( STENCIL_INCR )⤶
⤶
-- Add something interesting to the stencil buffer⤶
for _, ent in pairs( ents.FindByClass( "sent_stencil_test" ) ) do⤶
ent:DrawModel()⤶
end⤶
⤶
⤶
-- Go back to reading the full value from the stencil buffer⤶
render.SetStencilTestMask( 0xFF )⤶
-- Set the reference value to 00011111⤶
render.SetStencilReferenceValue( 0x1F )⤶
-- Render the result⤶
render.SetStencilCompareFunction( STENCIL_EQUAL )⤶
render.ClearBuffersObeyStencil( 0, 148, 133, 255, false );⤶
⤶
-- Let everything render normally again⤶
render.SetStencilEnable( false )⤶
end )⤶
</code>⤶
⤶
</example>