using UnityEngine;

namespace UnityEditor.Graphs.Material
{
	[Title("Input/View Direction Node")]
	public class ViewDirectionNode : BaseMaterialNode, IGeneratesVertexToFragmentBlock
	{
		private const string kOutputSlotName = "ViewDirection";

		public override bool hasPreview { get { return true; } }
		public override PreviewMode previewMode
		{
			get { return PreviewMode.Preview3D; }
		}

		public override void Init()
		{
			base.Init ();
			name = "View Direction";
			AddSlot (new Slot (SlotType.OutputSlot, kOutputSlotName));
		}

		public override string GetOutputVariableNameForSlot(Slot slot, GenerationMode generationMode)
		{
			if (generationMode == GenerationMode.Preview2D)
				Debug.LogError("Trying to generate 2D preview on a node that does not support it!");

			return "float4 (IN.viewDir, 1)";
		}

		public void GenerateVertexToFragmentBlock(ShaderGenerator visitor, GenerationMode generationMode)
		{
			if (generationMode == GenerationMode.Preview2D)
				Debug.LogError("Trying to generate 2D preview on a node that does not support it!");

			visitor.AddShaderChunk("float3 viewDir;", true);
		}
	}
}