Dither Node

Description

Dither is an intentional form of noise used to randomize quantization error. It is used to prevent large-scale patterns such as color banding in images. The Dither node applies dithering in screen-space to ensure a uniform distribution of the pattern. This can be adjusted by connecting another node to input Screen Position.

This Node is commonly used as an input to Alpha Clip Threshold on a Master Node to give the appearance of transparency to an opaque object. This is useful for creating objects that appear to be transparent but have the advantages of rendering as opaque, such as writing depth and/or being rendered in deferred.

Ports

Name	Direction	Type	Binding	Description
In	Input	Dynamic Vector	None	Input value
Screen Position	Input	Vector 4	Screen Position	Coordinates used to apply dither pattern
Out	Output	Dynamic Vector	None	Output value

Generated Code Example

The following example code represents one possible outcome of this node.

void Unity_Dither_float4(float4 In, float4 ScreenPosition, out float4 Out)
{
    float2 uv = ScreenPosition.xy * _ScreenParams.xy;
    float DITHER_THRESHOLDS[16] =
    {
        1.0 / 17.0,  9.0 / 17.0,  3.0 / 17.0, 11.0 / 17.0,
        13.0 / 17.0,  5.0 / 17.0, 15.0 / 17.0,  7.0 / 17.0,
        4.0 / 17.0, 12.0 / 17.0,  2.0 / 17.0, 10.0 / 17.0,
        16.0 / 17.0,  8.0 / 17.0, 14.0 / 17.0,  6.0 / 17.0
    };
    uint index = (uint(uv.x) % 4) * 4 + uint(uv.y) % 4;
    Out = In - DITHER_THRESHOLDS[index];
}