[unity] `Spine/Sprite/Pixel Lit` shader: Fixed bug where parts were shining through - changed ZWrite to always On, otherwise ForwardAdd pass will incorrectly show lit hidden parts. Added recommendation warning box in SkeletonRenderer inspector for Z Spacing on enabled ZWrite shaders. Closes #1335.

spine-unity/Assets/Spine/Editor/spine-unity/Editor/Shaders/SpineSpriteShaderGUI.cs

@@ -200,7 +200,7 @@ public class SpineSpriteShaderGUI : ShaderGUI {
 
 		_pixelSnap = FindProperty("PixelSnap", props);
 
-		_writeToDepth = FindProperty("_ZWrite", props);
+		_writeToDepth = FindProperty("_ZWrite", props, false);
 		_depthAlphaCutoff = FindProperty("_Cutoff", props);
 		_shadowAlphaCutoff = FindProperty("_ShadowAlphaCutoff", props);
 		_renderQueue = FindProperty("_RenderQueue", props);
@@ -435,18 +435,23 @@ public class SpineSpriteShaderGUI : ShaderGUI {
 
 		EditorGUI.BeginChangeCheck();
 
-		bool mixedValue = _writeToDepth.hasMixedValue;
-		EditorGUI.showMixedValue = mixedValue;
-		bool writeTodepth = EditorGUILayout.Toggle(_depthText, _writeToDepth.floatValue != 0.0f);
+		bool showDepthAlphaCutoff = true;
+		// e.g. Pixel Lit shader always has ZWrite enabled
+		if (_writeToDepth != null) {
+			bool mixedValue = _writeToDepth.hasMixedValue;
+			EditorGUI.showMixedValue = mixedValue;
+			bool writeTodepth = EditorGUILayout.Toggle(_depthText, _writeToDepth.floatValue != 0.0f);
 
-		if (EditorGUI.EndChangeCheck()) {
-			SetInt("_ZWrite", writeTodepth ? 1 : 0);
-			_depthAlphaCutoff.floatValue = writeTodepth ? 0.5f : 0.0f;
-			mixedValue = false;
-			dataChanged = true;
-		}
+			if (EditorGUI.EndChangeCheck()) {
+				SetInt("_ZWrite", writeTodepth ? 1 : 0);
+				_depthAlphaCutoff.floatValue = writeTodepth ? 0.5f : 0.0f;
+				mixedValue = false;
+				dataChanged = true;
+			}
 
-		if (writeTodepth && !mixedValue && GetMaterialBlendMode((Material)_materialEditor.target) != eBlendMode.Opaque) {
+			showDepthAlphaCutoff = writeTodepth && !mixedValue && GetMaterialBlendMode((Material)_materialEditor.target) != eBlendMode.Opaque;
+		}
+		if (showDepthAlphaCutoff) {
 			EditorGUI.BeginChangeCheck();
 			_materialEditor.RangeProperty(_depthAlphaCutoff, _depthAlphaCutoffText.text);
 			dataChanged |= EditorGUI.EndChangeCheck();

spine-unity/Assets/Spine/Runtime/spine-unity/Shaders/Sprite/SpritesPixelLit.shader

@@ -4,9 +4,9 @@ Shader "Spine/Sprite/Pixel Lit"
 	{
 		_MainTex ("Main Texture", 2D) = "white" {}
 		_Color ("Color", Color) = (1,1,1,1)
-		
+		 
 		_BumpScale("Scale", Float) = 1.0
-		_BumpMap ("Normal Map", 2D) = "bump" {}
+		_BumpMap ("Normal Map", 2D) = "bump" {} 
 		
 		[MaterialToggle] PixelSnap ("Pixel snap", Float) = 0
 		[PerRendererData] _AlphaTex ("External Alpha", 2D) = "white" {}
@@ -24,7 +24,6 @@ Shader "Spine/Sprite/Pixel Lit"
 		_DiffuseRamp ("Diffuse Ramp Texture", 2D) = "gray" {}
 		
 		_FixedNormal ("Fixed Normal", Vector) = (0,0,1,1)
-		_ZWrite ("Depth Write", Float) = 1.0
 		_Cutoff ("Depth alpha cutoff", Range(0,1)) = 0.5
 		_ShadowAlphaCutoff ("Shadow alpha cutoff", Range(0,1)) = 0.1
 		_CustomRenderQueue ("Custom Render Queue", Float) = 0.0
@@ -64,7 +63,8 @@ Shader "Spine/Sprite/Pixel Lit"
 			Name "FORWARD" 
 			Tags { "LightMode" = "ForwardBase" }
 			Blend [_SrcBlend] [_DstBlend]
-			ZWrite [_ZWrite]
+			// Note: ZWrite needs to be enabled for following ForwardAdd pass, otherwise parts will look as if shining through by getting lit.
+			ZWrite On
 			ZTest LEqual
 			Cull [_Cull]
 			

spine-unity/Assets/Spine/Runtime/spine-unity/Utility/MaterialChecks.cs

@@ -43,12 +43,24 @@ namespace Spine.Unity {
 			"Warning: Premultiply-alpha atlas textures not supported in Linear color space!\n\nPlease\n"
 			+ "a) re-export atlas as straight alpha texture with 'premultiply alpha' unchecked or\n"
 			+ "b) switch to Gamma color space via\nProject Settings - Player - Other Settings - Color Space.\n";
+		public static readonly string kZSpacingRequiredMessage = 
+			"Warning: Z Spacing required on selected shader! Otherwise you will receive incorrect results.\n\nPlease\n"
+			+ "1) make sure at least minimal 'Z Spacing' is set at the SkeletonRenderer/SkeletonAnimation component under 'Advanced' and\n"
+			+ "2) ensure that the skeleton has overlapping parts on different Z depth. You can adjust this in Spine via draw order.\n";
+		public static readonly string kZSpacingRecommendedMessage =
+			"Warning: Z Spacing recommended on selected shader configuration!\n\nPlease\n"
+			+ "1) make sure at least minimal 'Z Spacing' is set at the SkeletonRenderer/SkeletonAnimation component under 'Advanced' and\n"
+			+ "2) ensure that the skeleton has overlapping parts on different Z depth. You can adjust this in Spine via draw order.\n";
 
 		public static bool IsMaterialSetupProblematic (SkeletonRenderer renderer, ref string errorMessage) {
 			var materials = renderer.GetComponent<Renderer>().sharedMaterials;
 			bool isProblematic = false;
 			foreach (var mat in materials) {
-				isProblematic |= MaterialChecks.IsMaterialSetupProblematic(mat, ref errorMessage);
+				if (mat == null) continue;
+				isProblematic |= IsMaterialSetupProblematic(mat, ref errorMessage);
+				if (renderer.zSpacing == 0) {
+					isProblematic |= IsZSpacingRequired(mat, ref errorMessage);
+				}
 			}
 			return isProblematic;
 		}
@@ -57,6 +69,20 @@ namespace Spine.Unity {
 			return !IsColorSpaceSupported(material, ref errorMessage);
 		}
 
+		public static bool IsZSpacingRequired(Material material, ref string errorMessage) {
+			bool hasForwardAddPass = material.FindPass("FORWARD_DELTA") >= 0;
+			if (hasForwardAddPass) {
+				errorMessage += kZSpacingRequiredMessage;
+				return true;
+			}
+			bool zWrite = material.HasProperty("_ZWrite") && material.GetFloat("_ZWrite") > 0.0f;
+			if (zWrite) {
+				errorMessage += kZSpacingRecommendedMessage;
+				return true;
+			}
+			return false;
+		}
+
 		public static bool IsColorSpaceSupported (Material material, ref string errorMessage) {
 			if (QualitySettings.activeColorSpace == ColorSpace.Linear) {
 				if (IsPMAMaterial(material)) {