4. Add the Basic Structure

Start by including the ReShade.fxh header and defining a basic technique. At this stage, our pixel shader will simply return the original color of the game, serving as a starting point before we introduce any modifications.

#include "ReShade.fxh"

// Our pixel shader function will go here
float3 PS_Grayscale(float4 vpos : SV_Position, float2 texcoord : TexCoord) : SV_Target
{
    // For now, let's just return the original color
    float3 originalColor = tex2D(ReShade::BackBuffer, texcoord).rgb;
    return originalColor;
}

// Our technique
technique MyGrayscaleEffect
{
    pass
    {
        VertexShader = PostProcessVS; // Use the standard vertex shader
        PixelShader = PS_Grayscale;   // Use our pixel shader
    }
}