Added ChannelMixer

Editor/AssetsHelpers/Implementation/Texture/ChannelMixer/ChannelMixer.shader

@@ -0,0 +1,61 @@
+Shader "Hidden/ChannelMixer"
+{
+    Properties
+    {
+        _MainTex ("Red Channel Texture", 2D) = "white"
+    }
+    SubShader
+    {
+        Cull Off 
+        ZWrite Off 
+        ZTest Always
+
+        Pass
+        {
+            CGPROGRAM
+
+            #pragma vertex vert
+            #pragma fragment frag
+
+            #pragma shader_feature_local _HAS_TEX_R
+            #pragma shader_feature_local _HAS_TEX_G
+            #pragma shader_feature_local _HAS_TEX_B
+            #pragma shader_feature_local _HAS_TEX_A
+
+            #include "UnityCG.cginc"
+
+            struct appdata {
+                float4 vertex : POSITION;
+                float2 uv : TEXCOORD0;
+            };
+
+            struct v2f {
+                float2 uv : TEXCOORD0;
+                float4 vertex : SV_POSITION;
+            };
+
+            v2f vert(appdata v) {
+                v2f o;
+                o.vertex = UnityObjectToClipPos(v.vertex);
+                o.uv = v.uv;
+                return o;
+            }
+
+            sampler2D _MainTex;
+            int4 _ChannelSource;
+
+            float4 frag (v2f i) : SV_Target
+            {
+                float4 color = tex2D(_MainTex, i.uv);
+
+                float r = color[_ChannelSource.x];
+                float g = color[_ChannelSource.y];
+                float b = color[_ChannelSource.z];
+                float a = color[_ChannelSource.w];
+
+                return float4(r, g, b, a);
+            }
+            ENDCG
+        }
+    }
+}

Editor/AssetsHelpers/Implementation/Texture/ChannelMixer/ChannelMixer.shader.meta

@@ -0,0 +1,9 @@
+fileFormatVersion: 2
+guid: 21d62fa27a1e5b1439a779be2e3ac586
+ShaderImporter:
+  externalObjects: {}
+  defaultTextures: []
+  nonModifiableTextures: []
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Editor/AssetsHelpers/Implementation/Texture/ChannelMixer/ChannelMixerMenu.cs

@@ -0,0 +1,33 @@
+using UnityEditor;
+using UnityEngine;
+
+namespace Misaki.ArtToolEditor
+{
+    internal class ChannelMixerMenu
+    {
+        [MenuItem("Assets/Art Tools/Texture Helpers/Channel Mixer", true)]
+        public static bool ChannelMixerValidator()
+        {
+            foreach (var selectedObject in Selection.objects)
+            {
+                if (selectedObject is not Texture2D)
+                {
+                    return false;
+                }
+            }
+
+            return true;
+        }
+
+        [MenuItem("Assets/Art Tools/Texture Helpers/Channel Mixer")]
+        public static void ChannelMixer()
+        {
+            var window = EditorWindow.GetWindow<OutputOptionsWindow>(true, "Channel Mixer Output Options");
+            window.WithItemSource(Selection.objects);
+            window.RegisterVisualProvider<ChannelMixerVisualProvider>();
+            window.RegisterProcessor<ChannelMixerProcessor>();
+
+            window.InitializeAndShow();
+        }
+    }
+}

Editor/AssetsHelpers/Implementation/Texture/ChannelMixer/ChannelMixerMenu.cs.meta

@@ -0,0 +1,2 @@
+fileFormatVersion: 2
+guid: fa98d95c359c67b44a90ea5568f872e2

Editor/AssetsHelpers/Implementation/Texture/ChannelMixer/ChannelMixerProcessor.cs

@@ -0,0 +1,54 @@
+using System.IO;
+using UnityEditor;
+using UnityEngine;
+using UnityEngine.Experimental.Rendering;
+
+namespace Misaki.ArtToolEditor
+{
+    internal class ChannelMixerProcessor : IAssetsProcessor
+    {
+        private static class ShaderConstants
+        {
+            internal const string Channel_Mixer_Shader_Path = "Hidden/ChannelMixer";
+
+            internal const string Main_Texture_Property = "_MainTex";
+            internal const string Channel_Source_Property = "_ChannelSource";
+        }
+
+        public TextureChannel RChannelSource = TextureChannel.R;
+        public TextureChannel GChannelSource = TextureChannel.G;
+        public TextureChannel BChannelSource = TextureChannel.B;
+        public TextureChannel AChannelSource = TextureChannel.A;
+
+        public string outputNameSuffix = "_ChannelMixer";
+
+        public void OnPreProcess(AssetsProcessContext context)
+        {
+        }
+
+        public void OnProcess(Object source, string outputDirectory, AssetsProcessContext context)
+        {
+            if (source is not Texture2D texture)
+            {
+                return;
+            }
+
+            var tempRT = RenderTexture.GetTemporary(texture.width, texture.height, 0, GraphicsFormat.R8G8B8A8_UNorm);
+            var material = new Material(Shader.Find(ShaderConstants.Channel_Mixer_Shader_Path));
+
+            material.SetVector(ShaderConstants.Channel_Source_Property, new Vector4((int)RChannelSource, (int)GChannelSource, (int)BChannelSource, (int)AChannelSource));
+            Graphics.Blit(texture, tempRT, material);
+
+            var texturePath = Path.Combine(outputDirectory, texture.name + outputNameSuffix + Constants.Extensions.PNG);
+            TextureHelpers.ExportRenderTextureToPNG(tempRT, texturePath);
+            AssetDatabase.ImportAsset(texturePath);
+
+            Object.DestroyImmediate(material);
+            RenderTexture.ReleaseTemporary(tempRT);
+        }
+
+        public void OnPostProcess(AssetsProcessContext context)
+        {
+        }
+    }
+}

Editor/AssetsHelpers/Implementation/Texture/ChannelMixer/ChannelMixerProcessor.cs.meta

@@ -0,0 +1,2 @@
+fileFormatVersion: 2
+guid: b764f778d76e1f04f8b3e8edcd9d838d

Editor/AssetsHelpers/Implementation/Texture/ChannelMixer/ChannelMixerVisualProvider.cs

@@ -0,0 +1,35 @@
+using Unity.Properties;
+using UnityEngine.UIElements;
+
+namespace Misaki.ArtToolEditor
+{
+    internal class ChannelMixerVisualProvider : OptionsVisualProvider
+    {
+        public override VisualElement ContentAfterList()
+        {
+            var root = new VisualElement();
+
+            root.Add(CreateChannelSelector("Set Channel R From", nameof(ChannelMixerProcessor.RChannelSource)));
+            root.Add(CreateChannelSelector("Set Channel G From", nameof(ChannelMixerProcessor.GChannelSource)));
+            root.Add(CreateChannelSelector("Set Channel B From", nameof(ChannelMixerProcessor.BChannelSource)));
+            root.Add(CreateChannelSelector("Set Channel A From", nameof(ChannelMixerProcessor.AChannelSource)));
+
+            var nameSuffixField = new TextField("Output Name Suffix")
+            {
+                tooltip = "The suffix to append to the output texture name. Will overwrite original texture if set it to empty and use CurrentDirectory as output directory.",
+            };
+            nameSuffixField.SetBinding(nameof(TextField.value), new DataBinding() { dataSourcePath = PropertyPath.FromName(nameof(ChannelMixerProcessor.outputNameSuffix)) });
+            root.Add(nameSuffixField);
+
+            return root;
+        }
+
+        private static VisualElement CreateChannelSelector(string label, string binding)
+        {
+            var enumField = new EnumField(label, TextureChannel.R);
+            enumField.SetBinding(nameof(EnumField.value), new DataBinding() { dataSourcePath = PropertyPath.FromName(binding) });
+
+            return enumField;
+        }
+    }
+}

Editor/AssetsHelpers/Implementation/Texture/ChannelMixer/ChannelMixerVisualProvider.cs.meta

@@ -0,0 +1,2 @@
+fileFormatVersion: 2
+guid: 21d7828e4486449479a4adaeae5970ff