Add support for unshaded displacements

Content.Client/DisplacementMap/DisplacementMapSystem.cs

@@ -12,7 +12,14 @@ public sealed class DisplacementMapSystem : EntitySystem
     public bool TryAddDisplacement(DisplacementData data, SpriteComponent sprite, int index, string key, HashSet<string> revealedLayers)
     {
         if (data.ShaderOverride != null)
-            sprite.LayerSetShader(index, data.ShaderOverride);
+        {
+            //imp edit start - replaced the simple shader replacement w/ a ternary that checks if the layer is unshaded before setting the shader
+            sprite.LayerSetShader(index,
+                sprite[index] is SpriteComponent.Layer { ShaderPrototype: "unshaded" }
+                    ? data.ShaderOverrideUnshaded
+                    : data.ShaderOverride);
+            //imp edit end
+        }
 
         var displacementKey = $"{key}-displacement";
         if (!revealedLayers.Add(displacementKey))

Content.Shared/DisplacementMap/DisplacementData.cs

@@ -11,4 +11,7 @@ public sealed partial class DisplacementData
 
     [DataField]
     public string? ShaderOverride = "DisplacedStencilDraw";
+
+    [DataField]
+    public string ShaderOverrideUnshaded = "DisplacedStencilDrawUnshaded";
 }

Resources/Prototypes/_Impstation/Shaders/shaders.yml

@@ -2,3 +2,14 @@
   id: AccessibleFullStealth
   kind: source
   path: "/Textures/_Impstation/Shaders/accessible_full_stealth.swsl"
+
+- type: shader
+  id: DisplacedStencilDrawUnshaded
+  kind: source
+  path: "/Textures/_Impstation/Shaders/displacement_unshaded.swsl"
+  stencil:
+    ref: 1
+    op: Keep
+    func: NotEqual
+  params:
+    displacementSize: 127

Resources/Textures/_Impstation/Shaders/displacement_unshaded.swsl

@@ -0,0 +1,20 @@
+light_mode unshaded;
+
+uniform sampler2D displacementMap;
+uniform highp float displacementSize;
+uniform highp vec4 displacementUV;
+
+varying highp vec2 displacementUVOut;
+
+void vertex() {
+    displacementUVOut = mix(displacementUV.xy, displacementUV.zw, tCoord2);
+}
+
+void fragment() {
+    highp vec4 displacementSample = texture2D(displacementMap, displacementUVOut);
+    highp vec2 displacementValue = (displacementSample.xy - vec2(128.0 / 255.0)) / (1.0 - 128.0 / 255.0);
+    COLOR = zTexture(UV + displacementValue * TEXTURE_PIXEL_SIZE * displacementSize * vec2(1.0, -1.0));
+    COLOR.a *= displacementSample.a;
+}
+
+