private static Matrix4x4 ConvertMatrix(Matrix4x4 m)
{
    if (SystemInfo.usesReversedZBuffer)
    {
        m.m20 = -m.m20;
        m.m21 = -m.m21;
        m.m22 = -m.m22;
        m.m23 = -m.m23;
    }
    m.m00 = 0.5f * (m.m00 + m.m30);
    m.m01 = 0.5f * (m.m01 + m.m31);
    m.m02 = 0.5f * (m.m02 + m.m32);
    m.m03 = 0.5f * (m.m03 + m.m33);
    m.m10 = 0.5f * (m.m10 + m.m30);
    m.m11 = 0.5f * (m.m11 + m.m31);
    m.m12 = 0.5f * (m.m12 + m.m32);
    m.m13 = 0.5f * (m.m13 + m.m33);
    m.m20 = 0.5f * (m.m20 + m.m30);
    m.m21 = 0.5f * (m.m21 + m.m31);
    m.m22 = 0.5f * (m.m22 + m.m32);
    m.m23 = 0.5f * (m.m23 + m.m33);
    return m;
}

private static Matrix4x4 ApplyBiasMatrix(Matrix4x4 proj, Matrix4x4 view)
{
    if (SystemInfo.usesReversedZBuffer)
    {
        proj.m20 = -proj.m20;
        proj.m21 = -proj.m21;
        proj.m22 = -proj.m22;
        proj.m23 = -proj.m23;
    }

    Matrix4x4 worldToShadow = proj * view;

    var textureScaleAndBias = Matrix4x4.identity;
    textureScaleAndBias.m00 = 0.5f;
    textureScaleAndBias.m11 = 0.5f;
    textureScaleAndBias.m22 = 0.5f;
    textureScaleAndBias.m03 = 0.5f;
    textureScaleAndBias.m23 = 0.5f;
    textureScaleAndBias.m13 = 0.5f;

    return textureScaleAndBias * worldToShadow;
}

half4 MainLightShadowsData; //light strength, shadowBias, normalBias

half4 _MainLightShadowDistanceFade; //max distance, fadeWidth, 0, 0,

half fade =  1.0 - saturate ((distance (IN.positionWS, _WorldSpaceCameraPos.xyz) - _MainLightShadowDistanceFade.x) / _MainLightShadowDistanceFade.y );
shadow = LerpWhiteTo(shadow, MainLightShadowsData.x * fade);