Fix distance biases and add option for atlas compression

- Fix distance biases because some colors of text could still turn into quads at a distance.
- Add option to compress font atlas with BC7 compression if people really care about the extra few MB of VRAM.
- Change _TextColor param on test mesh shader to _Color to match the normal shader.
- Add support for text color to the text mesh shader

Author: MerlinVR

Merlin/Scripts/MSDFAtlasGenerator.cs

@@ -36,6 +36,7 @@ public class MSDFAtlasGenerator : EditorWindow
     public Font FontToConvert = null;
 
     public Texture2D AtlasToSave = null;
+    public bool UseTextureCompression = false;
 
     private const string MSDFGenPath = "Assets/Merlin/MSDF/bin/msdfgen.exe";
     private const string MSDFTempPath = "Assets/Merlin/MSDF/gen/glyph{0}.png";
@@ -53,6 +54,13 @@ void OnGUI()
 
         FontToConvert = (Font)EditorGUILayout.ObjectField("Font Asset:", FontToConvert, typeof(Font), false);
 
+        UseTextureCompression = EditorGUILayout.Toggle("Compress Font Atlas", UseTextureCompression);
+
+        if (UseTextureCompression)
+        {
+            EditorGUILayout.HelpBox("Enabling compression can cause visible artifacts on text depending on the font. On most fonts the artifacts may make the text look wobbly along edges. Check to make sure artifacts do not appear when you enable this.", MessageType.Warning);
+        }
+
         EditorGUI.BeginDisabledGroup(FontToConvert == null);
         if (GUILayout.Button("Generate Atlas"))
         {
@@ -148,9 +156,15 @@ private void GenerateAtlas()
 
         }
 
-        EditorUtility.ClearProgressBar();
-
         newAtlas.Apply(false);
+        
+        if (UseTextureCompression)
+        {
+            EditorUtility.DisplayProgressBar("Generating MSDF Atlas...", "Compressing Atlas...", 1f);
+            EditorUtility.CompressTexture(newAtlas, TextureFormat.BC7, TextureCompressionQuality.Best);
+        }
+
+        EditorUtility.ClearProgressBar();
 
         string fontPath = AssetDatabase.GetAssetPath(FontToConvert);
         string savePath = Path.Combine(Path.GetDirectoryName(fontPath), Path.GetFileNameWithoutExtension(fontPath) + "_msdfAtlas.asset");

Merlin/Shaders/MSDFTMFont.shader

@@ -3,15 +3,14 @@
     Properties
     {
         [HideInInspector]_MainTex ("Texture", 2D) = "white" {}
-		[HDR]_TextColor("Text Color", Color) = (1, 1, 1, 1)
+		[HDR]_Color("Text Color", Color) = (1, 1, 1, 1)
 		[NoScaleOffset]_MSDFTex("MSDF Texture", 2D) = "black" {}
-		_PixelRange("Pixel Range", Float) = 4.0
+		[HideIninspector]_PixelRange("Pixel Range", Float) = 4.0
     }
     SubShader
     {
-        Tags { "RenderType"="Cutout" "Queue"="AlphaTest+1" 
+        Tags { "RenderType"="Cutout" "Queue"="AlphaTest" 
 			   "IgnoreProjector" = "True" }
-        LOD 100
 
         Pass
         {
@@ -27,16 +26,18 @@
             struct appdata
             {
                 float4 vertex : POSITION;
+                float4 color : COLOR;
                 float2 uv : TEXCOORD0;
             };
 
             struct v2f
             {
 				float4 vertex : SV_POSITION;
+                float4 color : COLOR;
                 float2 uv : TEXCOORD0;
             };
 
-			float4 _TextColor;
+			float4 _Color;
 			sampler2D _MSDFTex; float4 _MSDFTex_TexelSize;
 			float _PixelRange;
 
@@ -50,6 +51,7 @@
                 v2f o;
                 o.vertex = UnityObjectToClipPos(v.vertex);
                 o.uv = v.uv;
+                o.color = v.color * _Color;
 
                 return o;
             }
@@ -59,14 +61,13 @@
 				float2 msdfUnit = _PixelRange / _MSDFTex_TexelSize.zw;
 
 				float4 sampleCol = tex2D(_MSDFTex, i.uv);
-				float sigDist = median(sampleCol.r, sampleCol.g, sampleCol.b) - 0.46;
-				sigDist *= max(dot(msdfUnit, 0.5/fwidth(i.uv)), 0.9); // Max to handle fading out to quads in the distance
+				float sigDist = median(sampleCol.r, sampleCol.g, sampleCol.b) - 0.5;
+				sigDist *= max(dot(msdfUnit, 0.5/fwidth(i.uv)), 1); // Max to handle fading out to quads in the distance
 				float opacity = clamp(sigDist + 0.5, 0.0, 1.0);
-				float4 color = float4(_TextColor.rgb, _TextColor.a * opacity);
+				float4 color = float4(i.color.rgb, i.color.a * opacity);
 
 				clip(color.a - 0.005);
 
-				//return sampleCol;
 				return color;
             }
             ENDCG

Merlin/Shaders/MSDFUIFont.shader

@@ -115,8 +115,8 @@ Shader "Merlin/UI/MSDF UI Font"
 				float2 msdfUnit = _PixelRange / _MSDFTex_TexelSize.zw;
 
 				float4 sampleCol = tex2D(_MSDFTex, texcoord);
-				float sigDist = median(sampleCol.r, sampleCol.g, sampleCol.b) - 0.46;
-				sigDist *= max(dot(msdfUnit, 0.5 / fwidth(texcoord)), 0.9); // Max to handle fading out to quads in the distance
+				float sigDist = median(sampleCol.r, sampleCol.g, sampleCol.b) - 0.5;
+				sigDist *= max(dot(msdfUnit, 0.5 / fwidth(texcoord)), 1); // Max to handle fading out to quads in the distance
 				float opacity = clamp(sigDist + 0.5, 0.0, 1.0);
 				float4 color = float4(1, 1, 1, opacity);