love.graphics.setStencilTest

Available since LÖVE 0.10.0

Together with love.graphics.stencil, it has replaced love.graphics.setStencil.

Configures or disables stencil testing.

When stencil testing is enabled, the geometry of everything that is drawn afterward will be clipped / stencilled out based on the arguments of this function compared with the stencil value of each pixel that the geometry touches. The stencil values of pixels are affected via love.graphics.stencil.

Each Canvas has its own per-pixel stencil values.

Function

Synopsis

love.graphics.setStencilTest( comparemode, comparevalue )

Arguments

CompareMode comparemode

The type of comparison to make for each pixel.

number comparevalue

The value to use when comparing with the stencil value of each pixel. Must be between 0 and 255.

Returns

Nothing.

Function

Disables stencil testing.

Synopsis

love.graphics.setStencilTest( )

Arguments

None.

Returns

Nothing.

Examples

Drawing circles masked by a rectangle

local function myStencilFunction()
   love.graphics.rectangle("fill", 225, 200, 350, 300)
end

function love.draw()
    -- draw a rectangle as a stencil. Each pixel touched by the rectangle will have its stencil value set to 1. The rest will be 0.
    love.graphics.stencil(myStencilFunction, "replace", 1)

    -- Only allow rendering on pixels whose stencil value is greater than 0.
    love.graphics.setStencilTest("greater", 0)

    love.graphics.setColor(255, 0, 0, 120)
    love.graphics.circle("fill", 300, 300, 150, 50)

    love.graphics.setColor(0, 255, 0, 120)
    love.graphics.circle("fill", 500, 300, 150, 50)

    love.graphics.setColor(0, 0, 255, 120)
    love.graphics.circle("fill", 400, 400, 150, 50)

    love.graphics.setStencilTest()
end

Drawing a circle with a hole

local function myStencilFunction()
   -- Draw a small circle as a stencil. This will be the hole.
   love.graphics.circle("fill", 400, 300, 50)
end

function love.draw()
   -- Each pixel touched by the circle will have its stencil value set to 1. The rest will be 0.
   love.graphics.stencil(myStencilFunction, "replace", 1)

   -- Configure the stencil test to only allow rendering on pixels whose stencil value is equal to 0.
   -- This will end up being every pixel *except* those that the circle drawn as a stencil touched.
   love.graphics.setStencilTest("equal", 0)
   love.graphics.circle("fill", 400, 300, 150)
   love.graphics.setStencilTest()
end

Drawing two masked triangles with different colors

local function myStencilFunction()
   love.graphics.circle("fill", 400, 300, 60, 25)
end

function love.draw()
   -- Each pixel touched by the circle will have its stencil value set to 1. The rest will be 0.
   love.graphics.stencil(myStencilFunction, "replace", 1)

   -- Only allow rendering on pixels whose stencil value is greater than 0.
   love.graphics.setStencilTest("greater", 0)
   love.graphics.setColor(155, 0, 128)
   love.graphics.polygon("fill", 400, 200, 486, 350, 314, 350)
 
   -- Now only allow rendering on pixels whose stencil value is equal to 0.
   love.graphics.setStencilTest("equal", 0)
   love.graphics.setColor(144, 214, 128)
   love.graphics.polygon("fill", 400, 200, 486, 350, 314, 350)

   love.graphics.setStencilTest()
end

The love.graphics.stencil wiki page includes more examples.

See Also

• love.graphics
• love.graphics.getStencilTest
• love.graphics.stencil

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