1 files changed, 57 insertions, 0 deletions
diff --git a/Assets/AmplifyShaderEditor/Plugins/Editor/Nodes/ImageEffects/DesaturateOpNode.cs b/Assets/AmplifyShaderEditor/Plugins/Editor/Nodes/ImageEffects/DesaturateOpNode.cs
new file mode 100644
index 00000000..507c678d
--- /dev/null
+++ b/Assets/AmplifyShaderEditor/Plugins/Editor/Nodes/ImageEffects/DesaturateOpNode.cs
@@ -0,0 +1,57 @@
+// Amplify Shader Editor - Visual Shader Editing Tool
+// Copyright (c) Amplify Creations, Lda <info@amplify.pt>
+
+// http://stackoverflow.com/questions/9320953/what-algorithm-does-photoshop-use-to-desaturate-an-image
+// https://www.shadertoy.com/view/lsdXDH
+
+namespace AmplifyShaderEditor
+{
+	[System.Serializable]
+	[NodeAttributes( "Desaturate", "Image Effects", "Generic desaturation operation" )]
+	public sealed class DesaturateOpNode : ParentNode
+	{
+		private const string GenericDesaturateOp0 = "dot( {0}, float3( 0.299, 0.587, 0.114 ))";
+		private const string GenericDesaturateOp1 = "lerp( {0}, {1}.xxx, {2} )";
+		//private const string GenericDesaturateOp = "lerp( {0},dot({0},float3(0.299,0.587,0.114)).xxx,{1})";
+
+		protected override void CommonInit( int uniqueId )
+		{
+			base.CommonInit( uniqueId );
+			AddInputPort( WirePortDataType.FLOAT3, false, "RGB" );
+			AddInputPort( WirePortDataType.FLOAT, false, "Fraction" );
+			AddOutputPort( WirePortDataType.FLOAT3, Constants.EmptyPortValue );
+			m_useInternalPortData = true;
+			m_previewShaderGUID = "faabe9efdf44b9648a523f1742abdfd3";
+		}
+
+		void UpdatePorts( int portId )
+		{
+			if ( portId == 0 )
+			{
+				m_inputPorts[ 0 ].MatchPortToConnection();
+				m_outputPorts[ 0 ].ChangeType( m_inputPorts[ 0 ].DataType, false );
+			}
+		}
+
+		public override string GenerateShaderForOutput( int outputId, ref MasterNodeDataCollector dataCollector, bool ignoreLocalvar )
+		{
+
+			if ( m_outputPorts[ 0 ].IsLocalValue( dataCollector.PortCategory ) )
+				return m_outputPorts[ 0 ].LocalValue( dataCollector.PortCategory );
+
+			string initalColorValue = m_inputPorts[ 0 ].GeneratePortInstructions( ref dataCollector );
+			string fraction = m_inputPorts[ 1 ].GeneratePortInstructions( ref dataCollector );
+
+			string initialColorVarName = "desaturateInitialColor" + OutputId;
+			dataCollector.AddLocalVariable( UniqueId, CurrentPrecisionType, WirePortDataType.FLOAT3, initialColorVarName, initalColorValue );
+
+			string dotVarName = "desaturateDot" + OutputId;
+			string dotVarValue = string.Format( GenericDesaturateOp0, initialColorVarName );
+
+			dataCollector.AddLocalVariable( UniqueId, CurrentPrecisionType, WirePortDataType.FLOAT, dotVarName, dotVarValue );
+			RegisterLocalVariable( 0, string.Format( GenericDesaturateOp1, initialColorVarName, dotVarName,fraction ), ref dataCollector, "desaturateVar" + OutputId );
+
+			return m_outputPorts[ 0 ].LocalValue( dataCollector.PortCategory );
+		}
+	}
+}