URP UniversalFragmentBlinnPhong function returns nothing

Unity Engine
, , ,
1

I am having a major problem with the URP Blinn-Phong function not returning the actual diffuse lighting values. All it returns is completely pitch black.

(The default shader on the left and my shader on the right)
(The default shader on the left and my shader on the right)761×306 46.8 KB

#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl"

struct Attributes {
	float3 positionOS : POSITION;
	float3 normalOS : NORMAL;
	float2 uv : TEXCOORD0;
};

struct Interpolator {
	float4 positionCS : SV_POSITION;

	float2 uv : TEXCOORD0;
	float3 normalWS : TEXCOORD1;
};

TEXTURE2D(_ColorMap); SAMPLER(sampler_ColorMap);
float4 _ColorMap_ST;
float4 _ColorTint;

Interpolator Vertex(Attributes input)
{
	Interpolator output;

	VertexPositionInputs posnInputs = GetVertexPositionInputs(input.positionOS);
	VertexNormalInputs normInputs = GetVertexNormalInputs(input.normalOS);

	output.positionCS = posnInputs.positionCS;
	output.uv = TRANSFORM_TEX(input.uv, _ColorMap);
	output.normalWS = normInputs.normalWS;

	return output;
}

float4 Fragment(Interpolator input) : SV_TARGET
{
    
    float4 colorSample = SAMPLE_TEXTURE2D(_ColorMap, sampler_ColorMap, input.uv);

	InputData lightingInput = (InputData)0;
	lightingInput.normalWS = input.normalWS;

	SurfaceData surfaceInput = (SurfaceData)0;
	surfaceInput.albedo = colorSample.rgb * _ColorTint.rgb;
	surfaceInput.alpha = colorSample.a * _ColorTint.a;

    return UniversalFragmentBlinnPhong(lightingInput, surfaceInput);
}