Initial metal support kickoff. Tweaked shader pragma targets from 5.0 to 4.5. Added metal to only_renderers lists. Added initial platform header API/Metal.hlsl. Couple of include paths changed to absolute until a bugfix lands on Unity side.

Assets/ScriptableRenderLoop/HDRenderPipeline/Debug/Resources/DebugViewMaterialGBuffer.shader

             Blend SrcAlpha OneMinusSrcAlpha // We will lerp only the values that are valid
 
             HLSLPROGRAM
-            #pragma target 5.0
-            #pragma only_renderers d3d11 ps4// TEMP: unitl we go futher in dev
+            #pragma target 4.5
+            #pragma only_renderers d3d11 ps4 metal // TEMP: unitl we go futher in dev
 
             #pragma vertex Vert
             #pragma fragment Frag

Assets/ScriptableRenderLoop/HDRenderPipeline/Debug/Resources/DebugViewTiles.shader

             Blend SrcAlpha OneMinusSrcAlpha
 
             HLSLPROGRAM
-            #pragma target 5.0
-            #pragma only_renderers d3d11 ps4// TEMP: unitl we go futher in dev
+            #pragma target 4.5
+            #pragma only_renderers d3d11 ps4 metal // TEMP: unitl we go futher in dev
 
             #pragma vertex Vert
             #pragma fragment Frag

Assets/ScriptableRenderLoop/HDRenderPipeline/Lighting/Resources/Deferred.shader

             Blend[_SrcBlend][_DstBlend]
 
             HLSLPROGRAM
-            #pragma target 5.0
-            #pragma only_renderers d3d11 ps4// TEMP: unitl we go futher in dev
+            #pragma target 4.5
+            #pragma only_renderers d3d11 ps4 metal // TEMP: unitl we go futher in dev
 
             #pragma vertex Vert
             #pragma fragment Frag

Assets/ScriptableRenderLoop/HDRenderPipeline/Material/Builtin/BuiltinData.hlsl

 // Note: These parameters can be store in GBuffer if the writer wants
 //-----------------------------------------------------------------------------
 
-#include "BuiltinData.cs.hlsl"
+//TODO: return this original relative path include after fixing a bug in Unity side
+//#include "BuiltinData.cs.hlsl"
+#include "Assets/ScriptableRenderLoop/HDRenderPipeline/Material/Builtin/BuiltinData.cs.hlsl"
 
 //-----------------------------------------------------------------------------
 // common Encode/Decode functions

Assets/ScriptableRenderLoop/HDRenderPipeline/Material/LayeredLit/LayeredLit.shader

 
     HLSLINCLUDE
 
-    #pragma target 5.0
-    #pragma only_renderers d3d11 ps4// TEMP: unitl we go futher in dev
+    #pragma target 4.5
+    #pragma only_renderers d3d11 ps4 metal // TEMP: unitl we go futher in dev
 
     #pragma shader_feature _ALPHATEST_ON
     #pragma shader_feature _DISTORTION_ON

Assets/ScriptableRenderLoop/HDRenderPipeline/Material/LayeredLit/LayeredLitTessellation.shader

 
     HLSLINCLUDE
 
-    #pragma target 5.0
-    #pragma only_renderers d3d11 ps4// TEMP: unitl we go futher in dev
+    #pragma target 4.5
+    #pragma only_renderers d3d11 ps4 metal // TEMP: unitl we go futher in dev
 
     #pragma shader_feature _ALPHATEST_ON
     #pragma shader_feature _DISTORTION_ON

Assets/ScriptableRenderLoop/HDRenderPipeline/Material/Lit/Lit.hlsl

 //-----------------------------------------------------------------------------
 
 // SurfaceData is define in Lit.cs which generate Lit.cs.hlsl
-#include "Lit.cs.hlsl"
+//TODO: return this original relative path include after fixing a bug in Unity side
+//#include "Lit.cs.hlsl"
+#include "Assets/ScriptableRenderLoop/HDRenderPipeline/Material/Lit/Lit.cs.hlsl"
 
 // In case we pack data uint16 buffer we need to change the output render target format to uint16
 // TODO: Is there a way to automate these output type based on the format declare in lit.cs ?

Assets/ScriptableRenderLoop/HDRenderPipeline/Material/Lit/Lit.shader

 
     HLSLINCLUDE
 
-    #pragma target 5.0
-    #pragma only_renderers d3d11 ps4// TEMP: until we go futher in dev
+    #pragma target 4.5
+    #pragma only_renderers d3d11 ps4 metal // TEMP: until we go futher in dev
 
     //-------------------------------------------------------------------------------------
     // Variant

Assets/ScriptableRenderLoop/HDRenderPipeline/Material/Lit/Resources/PreIntegratedFGD.shader

             HLSLPROGRAM
             #pragma vertex Vert
             #pragma fragment Frag
-            #pragma target 5.0
-            #pragma only_renderers d3d11 ps4// TEMP: unitl we go futher in dev
+            #pragma target 4.5
+            #pragma only_renderers d3d11 ps4 metal // TEMP: unitl we go futher in dev
 
             #include "Common.hlsl"
             #include "ImageBasedLighting.hlsl"

Assets/ScriptableRenderLoop/HDRenderPipeline/Material/Unlit/Unlit.shader

 
     HLSLINCLUDE
 
-    #pragma target 5.0
-    #pragma only_renderers d3d11 ps4 // TEMP: unitl we go futher in dev
+    #pragma target 4.5
+    #pragma only_renderers d3d11 ps4 metal  // TEMP: unitl we go futher in dev
 
     //-------------------------------------------------------------------------------------
     // Variant

Assets/ScriptableRenderLoop/HDRenderPipeline/PostProcess/Resources/EyeAdaptation.shader

 
     HLSLINCLUDE
 
-        #pragma target 5.0
+        #pragma target 4.5
         #include "Common.hlsl"
         #include "Assets/ScriptableRenderLoop/HDRenderPipeline/ShaderVariables.hlsl"
         #include "EyeAdaptation.hlsl"

Assets/ScriptableRenderLoop/HDRenderPipeline/PostProcess/Resources/FinalPass.shader

 
     HLSLINCLUDE
 
-        #pragma target 5.0
+        #pragma target 4.5
         #include "Common.hlsl"
         #include "Assets/ScriptableRenderLoop/HDRenderPipeline/ShaderVariables.hlsl"
         #include "ColorGrading.hlsl"

Assets/ScriptableRenderLoop/HDRenderPipeline/PostProcess/Resources/LutGen.shader

 {
     HLSLINCLUDE
 
-        #pragma target 5.0
+        #pragma target 4.5
         #include "Common.hlsl"
         #include "Assets/ScriptableRenderLoop/HDRenderPipeline/ShaderVariables.hlsl"
         #include "ColorGrading.hlsl"

Assets/ScriptableRenderLoop/HDRenderPipeline/Sky/HDRISky/Resources/SkyHDRI.shader

     #pragma vertex Vert
     #pragma fragment Frag
 
-    #pragma target 5.0
-    #pragma only_renderers d3d11 ps4// TEMP: unitl we go futher in dev
+    #pragma target 4.5
+    #pragma only_renderers d3d11 ps4 metal // TEMP: unitl we go futher in dev
 
     #include "Color.hlsl"
     #include "Common.hlsl"

Assets/ScriptableRenderLoop/HDRenderPipeline/Sky/ProceduralSky/Resources/SkyProcedural.shader

             Blend One OneMinusSrcAlpha, Zero One
 
             HLSLPROGRAM
-            #pragma target 5.0
-            #pragma only_renderers d3d11 ps4 // TEMP: unitl we go futher in dev
+            #pragma target 4.5
+            #pragma only_renderers d3d11 ps4 metal  // TEMP: unitl we go futher in dev
 
             #pragma vertex Vert
             #pragma fragment Frag

Assets/ScriptableRenderLoop/HDRenderPipeline/Sky/Resources/GGXConvolve.shader

             Blend One Zero
 
             HLSLPROGRAM
-            #pragma target 5.0
-            #pragma only_renderers d3d11 ps4 // TEMP: unitl we go futher in dev
+            #pragma target 4.5
+            #pragma only_renderers d3d11 ps4 metal  // TEMP: unitl we go futher in dev
 
             #pragma multi_compile _ USE_MIS
 

Assets/ScriptableRenderLoop/ShaderLibrary/Common.hlsl

 #include "API/PSSL.hlsl"
 #elif defined(SHADER_API_XBOXONE)
 #include "API/D3D11_1.hlsl"
+#elif defined(SHADER_API_METAL)
+#include "API/Metal.hlsl"
 #else
 #error unsupported shader api
 #endif

Assets/ScriptableRenderLoop/fptl/LightBoundsDebug.shader

             CGPROGRAM
             #pragma vertex vert
             #pragma fragment frag
-            #pragma target 5.0
+            #pragma target 4.5
         
             #include "UnityCG.cginc"
             #include "LightDefinitions.cs.hlsl"

Assets/ScriptableRenderLoop/fptl/StandardTest.shader

             ZWrite [_ZWrite]
 
             CGPROGRAM
-            #pragma target 5.0
+            #pragma target 4.5
 
             // -------------------------------------
 
 			ZWrite On ZTest LEqual
 
             CGPROGRAM
-            #pragma target 5.0
+            #pragma target 4.5
 
             // TODO: figure out what's needed here wrt. alpha test etc.
 
             ZWrite On ZTest LEqual
 
             CGPROGRAM
-            #pragma target 5.0
+            #pragma target 4.5
 
             // -------------------------------------
 

Assets/ScriptableRenderLoop/ShaderLibrary/API/Metal.hlsl

+// This file assumes SHADER_API_METAL is defined
+// TODO: This is a straight copy from D3D11.hlsl. Go through all this stuff and adjust where needed.
+
+#define UNITY_UV_STARTS_AT_TOP 1
+#define UNITY_REVERSED_Z 1
+#define UNITY_NEAR_CLIP_VALUE (1.0)
+// This value will not go through any matrix projection convertion
+#define UNITY_RAW_FAR_CLIP_VALUE (0.0)
+#define FRONT_FACE_SEMATIC SV_IsFrontFace
+#define FRONT_FACE_TYPE bool
+#define IS_FRONT_VFACE(VAL, FRONT, BACK) ((VAL) ? (FRONT) : (BACK))
+
+#define CBUFFER_START(name) cbuffer name {
+#define CBUFFER_END };
+
+// Initialize arbitrary structure with zero values.
+// Do not exist on some platform, in this case we need to have a standard name that call a function that will initialize all parameters to 0
+#define ZERO_INITIALIZE(type, name) name = (type)0;
+
+// Texture util abstraction
+
+#define CALCULATE_TEXTURE2D_LOD(textureName, samplerName, coord2) textureName.CalculateLevelOfDetail(samplerName, coord2)
+
+// Texture abstraction
+
+#define TEXTURE2D(textureName) Texture2D textureName
+#define TEXTURE2D_ARRAY(textureName) Texture2DArray textureName
+#define TEXTURECUBE(textureName) TextureCube textureName
+#define TEXTURECUBE_ARRAY(textureName) TextureCubeArray textureName
+#define TEXTURE3D(textureName) Texture3D textureName
+
+#define SAMPLER2D(samplerName) SamplerState samplerName
+#define SAMPLERCUBE(samplerName) SamplerState samplerName
+#define SAMPLER3D(samplerName) SamplerState samplerName
+#define SAMPLER2D_SHADOW(samplerName) SamplerComparisonState samplerName
+#define SAMPLERCUBE_SHADOW(samplerName) SamplerComparisonState samplerName
+
+#define TEXTURE2D_ARGS(textureName, samplerName) Texture2D textureName, SamplerState samplerName
+#define TEXTURE2D_ARRAY_ARGS(textureName, samplerName) Texture2DArray textureName, SamplerState samplerName
+#define TEXTURECUBE_ARGS(textureName, samplerName) TextureCube textureName, SamplerState samplerName
+#define TEXTURECUBE_ARRAY_ARGS(textureName, samplerName) TextureCubeArray textureName, SamplerState samplerName
+#define TEXTURE3D_ARGS(textureName, samplerName) Texture3D textureName, SamplerState samplerName
+#define TEXTURE2D_SHADOW_ARGS(textureName, samplerName) Texture2D textureName, SamplerComparisonState samplerName
+#define TEXTURE2D_ARRAY_SHADOW_ARGS(textureName, samplerName) Texture2DArray textureName, SamplerComparisonState samplerName
+#define TEXTURECUBE_SHADOW_ARGS(textureName, samplerName) TextureCube textureName, SamplerComparisonState samplerName
+
+#define TEXTURE2D_PARAM(textureName, samplerName) textureName, samplerName
+#define TEXTURE2D_ARRAY_PARAM(textureName, samplerName) textureName, samplerName
+#define TEXTURECUBE_PARAM(textureName, samplerName) textureName, samplerName
+#define TEXTURECUBE_ARRAY_PARAM(textureName, samplerName) textureName, samplerName
+#define TEXTURE3D_PARAM(textureName, samplerName) textureName, samplerName
+#define TEXTURE2D_SHADOW_PARAM(textureName, samplerName) textureName, samplerName
+#define TEXTURE2D_ARRAY_SHADOW_PARAM(textureName, samplerName) textureName, samplerName
+#define TEXTURECUBE_SHADOW_PARAM(textureName, samplerName) textureName, samplerName
+
+#define SAMPLE_TEXTURE2D(textureName, samplerName, coord2) textureName.Sample(samplerName, coord2)
+#define SAMPLE_TEXTURE2D_LOD(textureName, samplerName, coord2, lod) textureName.SampleLevel(samplerName, coord2, lod)
+#define SAMPLE_TEXTURE2D_GRAD(textureName, samplerName, coord2, ddx, ddy) textureName.SampleGrad(samplerName, coord2, ddx, ddy)
+#define SAMPLE_TEXTURE2D_ARRAY(textureName, samplerName, coord2, index) textureName.Sample(samplerName, float3(coord2, index))
+#define SAMPLE_TEXTURE2D_ARRAY_LOD(textureName, samplerName, coord2, index, lod) textureName.SampleLevel(samplerName, float3(coord2, index), lod)
+#define SAMPLE_TEXTURECUBE(textureName, samplerName, coord3) textureName.Sample(samplerName, coord3)
+#define SAMPLE_TEXTURECUBE_LOD(textureName, samplerName, coord3, lod) textureName.SampleLevel(samplerName, coord3, lod)
+#define SAMPLE_TEXTURECUBE_ARRAY(textureName, samplerName, coord3, index) textureName.Sample(samplerName, float4(coord3, index))
+#define SAMPLE_TEXTURECUBE_ARRAY_LOD(textureName, samplerName, coord3, index, lod) textureName.SampleLevel(samplerName, float4(coord3, index), lod)
+#define SAMPLE_TEXTURE3D(textureName, samplerName, coord3) textureName.Sample(samplerName, coord3)
+#define SAMPLE_TEXTURE2D_SHADOW(textureName, samplerName, coord3) textureName.SampleCmpLevelZero(samplerName, (coord3).xy, (coord3).z)
+#define SAMPLE_TEXTURE2D_ARRAY_SHADOW(textureName, samplerName, coord3, index) textureName.SampleCmpLevelZero(samplerName, float3((coord3).xy, index), (coord3).z)
+#define SAMPLE_TEXTURECUBE_SHADOW(textureName, samplerName, coord4) textureName.SampleCmpLevelZero(samplerName, (coord3).xyz, (coord3).w)
+
+#define TEXTURE2D_HALF TEXTURE2D
+#define TEXTURE2D_FLOAT TEXTURE2D
+#define SAMPLER2D_HALF SAMPLER2D
+#define SAMPLER2D_FLOAT SAMPLER2D
+
+#define LOAD_TEXTURE2D(textureName, unCoord2) textureName.Load(int3(unCoord2, 0))
+#define LOAD_TEXTURE2D_LOD(textureName, unCoord2, lod) textureName.Load(int3(unCoord2, lod))
+#define LOAD_TEXTURE2D_MSAA(textureName, unCoord2, sampleIndex) textureName.Load(unCoord2, sampleIndex)
+#define LOAD_TEXTURE2D_ARRAY(textureName, unCoord2, index) textureName.Load(int4(unCoord2, index, 0))
+#define LOAD_TEXTURE2D_ARRAY_LOD(textureName, unCoord2, index, lod) textureName.Load(int4(unCoord2, index, lod))
+
+#define GATHER_TEXTURE2D(textureName, samplerName, coord2) textureName.Gather(samplerName, coord2)
+#define GATHER_TEXTURE2D_ARRAY(textureName, samplerName, coord2, index) textureName.Gather(samplerName, float3(coord2, index))
+#define GATHER_TEXTURECUBE(textureName, samplerName, coord3) textureName.Gather(samplerName, coord3)
+#define GATHER_TEXTURECUBE_ARRAY(textureName, samplerName, coord3, index) textureName.Gather(samplerName, float4(coord3, index))

Assets/ScriptableRenderLoop/ShaderLibrary/API/Metal.hlsl.meta

+fileFormatVersion: 2
+guid: f4d51e77f119d4dc8899ff02b46bb621
+timeCreated: 1484817807
+licenseType: Pro
+ShaderImporter:
+  defaultTextures: []
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: