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render.OverrideBlend

  render.OverrideBlend( boolean enabled, number sourceMultiplier, number destinationMultiplier, number blendingFunction )
  render.OverrideBlend( boolean enabled, number sourceColorMultiplier, number destinationColorMultiplier, number colorBlendingFunction, number sourceAlphaMultiplier = none, number destinationAlphaMultiplier = none, number alphaBlendingFunction = none )
  render.OverrideBlend( boolean enabled )
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Description

Overrides the way that the final color and alpha is calculated for each pixel affected by upcoming draw operations.

When a draw operation is performed, the rendering system examines each pixel that is affected by the draw operation and determines its new color by combining (or "Blending") the pixel's current color (Called the "Destination" or "Dst" color) with the new color produced by the draw operation (Called the "Source" or "Src" color.)

This function allows you to control the way that those two colors (The Source and Destination) are combined to produce the final pixel color.

It's important to know that while Colors use values in the range (0-255), the color and alpha values used here are normalized to the range (0-1) so that they can be multiplied together to produce a value that is still in the range (0-1).

Default Arguments

1 boolean enabled
Set to true to enable Blend Overrides.
2 number sourceMultiplier
This determines which value each affected pixel's Source color and alpha will be multiplied by before they are sent to the Blending Function.
One of the BLEND enum enums.
3 number destinationMultiplier
This determines which value each affected pixel's Destination color and alpha will be multiplied by before they are sent to the Blending Function.
One of the BLEND enum enums.
4 number blendingFunction
After the Source and Destination color and alpha have been multiplied against their corresponding multipliers, they are passed to the Blending Function which combines them into the final color and alpha for the pixel.
One of the BLENDFUNC enum enums.

Argument Overload: Separate Color and Alpha Blending

1 boolean enabled
Set to true to enable Blend Overrides.
2 number sourceColorMultiplier
This determines which value each affected pixel's Source color will be multiplied by before they are sent to the Color Blending Function.
One of the BLEND enum enums.
3 number destinationColorMultiplier
This determines which value each affected pixel's Destination color will be multiplied by before they are sent to the Color Blending Function.
One of the BLEND enum enums.
4 number colorBlendingFunction
After the Source and Destination colors have been multiplied against their corresponding multipliers, they are passed to the Color Blending Function which combines them into the final color and alpha for the pixel.
One of the BLENDFUNC enum enums.
5 number sourceAlphaMultiplier = none
This determines which value each affected pixel's Source alpha will be multiplied by before they are sent to the Alpha Blending Function.
One of the BLEND enum enums.
6 number destinationAlphaMultiplier = none
This determines which value each affected pixel's Destination alpha will be multiplied by before they are sent to the Alpha Blending Function.
One of the BLEND enum enums.
7 number alphaBlendingFunction = none
After the Source and Destination alphas have been multiplied against their corresponding multipliers, they are passed to the Alpha Blending Function which combines them into the final alpha for the pixel.

Argument Overload: Disabling Blend Overrides

1 boolean enabled
Set to false to disable blend overrides.

Example

In this example we draw a lightning bolt over our player's head.

We shouldn't really draw the lightning in the PreDrawTranslucentRenderables hook as this causes issues rendering transparent objects behind the lightning, but it's a quick example of how the function works. Normally it should be drawn in a custom lua effect's EFFECT:Render.

This override might not work properly on Linux

Issue Tracker: 5693
-- Our sprite texture to render. Rendering this texture without -- render.OverrideBlendFunc will result in black borders around the lightning beam. local lightningMaterial = Material("sprites/lgtning") hook.Add( "PreDrawTranslucentRenderables", "LightningExample", function(isDrawingDepth, isDrawingSkybox) if isDrawingDepth or isDrawSkybox then return end local ply = Entity(1) if !IsValid(ply) then return end -- Calculate a random UV to use for the lightning to give it some movement local uv = math.Rand(0, 1) -- Enable blend override to interpret the color and alpha from the texture. render.OverrideBlend( true, BLEND_SRC_COLOR, BLEND_SRC_ALPHA, BLENDFUNC_ADD, BLEND_ONE, BLEND_ZERO, BLENDFUNC_ADD ) render.SetMaterial(lightningMaterial) -- Render a lightning beam along points randomly offset from a line above the player. render.StartBeam(5) render.AddBeam(ply:GetPos() + Vector(0,0,035), 20, uv, Color(255,255,255,255)) render.AddBeam(ply:GetPos() + Vector(0,0,135) + Vector(math.Rand(-20,20),math.Rand(-20,20),0), 20, uv*2, Color(255,255,255,255)) render.AddBeam(ply:GetPos() + Vector(0,0,235) + Vector(math.Rand(-20,20),math.Rand(-20,20),0), 20, uv*3, Color(255,255,255,255)) render.AddBeam(ply:GetPos() + Vector(0,0,335) + Vector(math.Rand(-20,20),math.Rand(-20,20),0), 20, uv*4, Color(255,255,255,255)) render.AddBeam(ply:GetPos() + Vector(0,0,435) + Vector(math.Rand(-20,20),math.Rand(-20,20),0), 20, uv*5, Color(255,255,255,255)) render.EndBeam() -- Disable blend override render.OverrideBlend( false ) end )
Output:

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