Laurens-Packages/Packages/com.unity.shadergraph/Editor/Data/Nodes/Utility/Logic/IsFrontFaceNode.cs

using UnityEngine;
using UnityEditor.Graphing;

namespace UnityEditor.ShaderGraph
{
    [Title("Utility", "Logic", "Is Front Face")]
    class IsFrontFaceNode : AbstractMaterialNode, IGeneratesBodyCode, IMayRequireFaceSign
    {
        public IsFrontFaceNode()
        {
            name = "Is Front Face";
            synonyms = new string[] { "face", "side" };
            UpdateNodeAfterDeserialization();
        }

        public override bool hasPreview { get { return false; } }

        public const int OutputSlotId = 0;
        private const string kOutputSlotName = "Out";

        public override void UpdateNodeAfterDeserialization()
        {
            AddSlot(new BooleanMaterialSlot(OutputSlotId, kOutputSlotName, kOutputSlotName, SlotType.Output, true, ShaderStageCapability.Fragment));
            RemoveSlotsNameNotMatching(new[] { OutputSlotId });
        }

        public void GenerateNodeCode(ShaderStringBuilder sb, GenerationMode generationMode)
        {
            sb.AppendLine(string.Format("$precision {0} = max(0, IN.{1}.x);", GetVariableNameForSlot(OutputSlotId), ShaderGeneratorNames.FaceSign));
        }

        public bool RequiresFaceSign(ShaderStageCapability stageCapability = ShaderStageCapability.Fragment)
        {
            return true;
        }
    }
}