diff --git a/hecl/extern/libBoo b/hecl/extern/libBoo
index b97ad76c4..62fae6004 160000
--- a/hecl/extern/libBoo
+++ b/hecl/extern/libBoo
@@ -1 +1 @@
-Subproject commit b97ad76c45b4965f3dd9f499e5975738714f5fa8
+Subproject commit 62fae6004226348bdf5e3b0f5401d091128ec86e
diff --git a/hecl/include/HECL/Backend/Metal.hpp b/hecl/include/HECL/Backend/Metal.hpp
new file mode 100644
index 000000000..6d33b6131
--- /dev/null
+++ b/hecl/include/HECL/Backend/Metal.hpp
@@ -0,0 +1,47 @@
+#ifndef HECLBACKEND_METAL_HPP
+#define HECLBACKEND_METAL_HPP
+#if __APPLE__
+
+#include "ProgrammableCommon.hpp"
+#include <Availability.h>
+
+#if __MAC_OS_X_VERSION_MAX_ALLOWED >= 101100
+#define HECL_HAS_METAL 1
+
+namespace HECL
+{
+namespace Backend
+{
+    
+struct Metal : ProgrammableCommon
+{
+    void reset(const IR& ir, Diagnostics& diag);
+    std::string makeVert(unsigned col, unsigned uv, unsigned w,
+                         unsigned skinSlots, unsigned texMtxs) const;
+    std::string makeFrag(const ShaderFunction& lighting=ShaderFunction()) const;
+    std::string makeFrag(const ShaderFunction& lighting,
+                         const ShaderFunction& post) const;
+    
+private:
+    std::string GenerateVertInStruct(unsigned col, unsigned uv, unsigned w) const;
+    std::string GenerateVertToFragStruct() const;
+    std::string GenerateVertUniformStruct(unsigned skinSlots, unsigned texMtxs) const;
+    
+    std::string EmitVec3(const atVec4f& vec) const
+    {
+        return HECL::Format("float3(%g,%g,%g)", vec.vec[0], vec.vec[1], vec.vec[2]);
+    }
+    
+    std::string EmitTexGenSource2(TexGenSrc src, int uvIdx) const;
+    std::string EmitTexGenSource4(TexGenSrc src, int uvIdx) const;
+};
+    
+}
+}
+
+#else
+#define HECL_HAS_METAL 0
+#endif
+
+#endif // __APPLE__
+#endif // HECLBACKEND_METAL_HPP
diff --git a/hecl/include/HECL/Runtime.hpp b/hecl/include/HECL/Runtime.hpp
index e0601da8a..84d335fec 100644
--- a/hecl/include/HECL/Runtime.hpp
+++ b/hecl/include/HECL/Runtime.hpp
@@ -149,6 +149,7 @@ class IShaderBackendFactory
 {
     friend class ShaderCacheManager;
 protected:
+    boo::ITextureR* m_rtHint = nullptr;
     using FReturnExtensionShader = std::function<void(boo::IShaderPipeline*)>;
     virtual ShaderCachedData buildShaderFromIR(const ShaderTag& tag,
                                                const HECL::Frontend::IR& ir,
@@ -205,6 +206,10 @@ public:
     : ShaderCacheManager(storeMgr, gfxFactory, ShaderCacheExtensions()) {}
     void reload();
 
+    /* Some platforms (like Metal) require information about the render target
+     * for encoding the pipeline state. This must be called before building shaders */
+    void setRenderTargetHint(boo::ITextureR* tex) {m_factory->m_rtHint = tex;}
+    
     boo::IShaderPipeline* buildShader(const ShaderTag& tag, const std::string& source,
                                       const std::string& diagName);
     boo::IShaderPipeline* buildShader(const ShaderTag& tag, const HECL::Frontend::IR& ir,
diff --git a/hecl/lib/Backend/CMakeLists.txt b/hecl/lib/Backend/CMakeLists.txt
index 3938d4ec8..cde5a79d7 100644
--- a/hecl/lib/Backend/CMakeLists.txt
+++ b/hecl/lib/Backend/CMakeLists.txt
@@ -1,5 +1,12 @@
+if(WIN32)
+  set(PLAT_SRCS HLSL.cpp)
+endif()
+if(APPLE)
+  set(PLAT_SRCS Metal.cpp)
+endif()
+
 add_library(HECLBackend
             GX.cpp
             ProgrammableCommon.cpp
             GLSL.cpp
-            HLSL.cpp)
+            ${PLAT_SRCS})
diff --git a/hecl/lib/Backend/GLSL.cpp b/hecl/lib/Backend/GLSL.cpp
index faf2708eb..0d593e66f 100644
--- a/hecl/lib/Backend/GLSL.cpp
+++ b/hecl/lib/Backend/GLSL.cpp
@@ -94,7 +94,7 @@ std::string GLSL::GenerateVertUniformStruct(unsigned skinSlots, unsigned texMtxs
                                       skinSlots, skinSlots);
     if (texMtxs)
         retval += HECL::Format("    mat4 texMtxs[%u];\n", texMtxs);
-    return retval + "} vu;\n";
+    return retval + "};\n";
 }
 
 void GLSL::reset(const IR& ir, Diagnostics& diag)
@@ -119,20 +119,20 @@ std::string GLSL::makeVert(const char* glslVer, unsigned col, unsigned uv, unsig
         retval += "    vec4 posAccum = vec4(0.0,0.0,0.0,0.0);\n"
                   "    vec4 normAccum = vec4(0.0,0.0,0.0,0.0);\n";
         for (size_t i=0 ; i<s ; ++i)
-            retval += HECL::Format("    posAccum += (vu.mv[%" PRISize "] * vec4(posIn, 1.0)) * weightIn[%" PRISize "][%" PRISize "];\n"
-                                   "    normAccum += (vu.mvInv[%" PRISize "] * vec4(normIn, 1.0)) * weightIn[%" PRISize "][%" PRISize "];\n",
+            retval += HECL::Format("    posAccum += (mv[%" PRISize "] * vec4(posIn, 1.0)) * weightIn[%" PRISize "][%" PRISize "];\n"
+                                   "    normAccum += (mvInv[%" PRISize "] * vec4(normIn, 1.0)) * weightIn[%" PRISize "][%" PRISize "];\n",
                                    i, i/4, i%4, i, i/4, i%4);
         retval += "    posAccum[3] = 1.0;\n"
                   "    vtf.mvPos = posAccum;\n"
                   "    vtf.mvNorm = vec4(normalize(normAccum.xyz), 0.0);\n"
-                  "    gl_Position = vu.proj * posAccum;\n";
+                  "    gl_Position = proj * posAccum;\n";
     }
     else
     {
         /* non-skinned */
-        retval += "    vtf.mvPos = vu.mv[0] * vec4(posIn, 1.0);\n"
-                  "    vtf.mvNorm = vu.mvInv[0] * vec4(normIn, 0.0);\n"
-                  "    gl_Position = vu.proj * vtf.mvPos;\n";
+        retval += "    vtf.mvPos = mv[0] * vec4(posIn, 1.0);\n"
+                  "    vtf.mvNorm = mvInv[0] * vec4(normIn, 0.0);\n"
+                  "    gl_Position = proj * vtf.mvPos;\n";
     }
 
     int tcgIdx = 0;
@@ -142,7 +142,7 @@ std::string GLSL::makeVert(const char* glslVer, unsigned col, unsigned uv, unsig
             retval += HECL::Format("    vtf.tcgs[%u] = %s;\n", tcgIdx,
                                    EmitTexGenSource2(tcg.m_src, tcg.m_uvIdx).c_str());
         else
-            retval += HECL::Format("    vtf.tcgs[%u] = (vu.texMtxs[%u] * %s).xy;\n", tcgIdx, tcg.m_mtx,
+            retval += HECL::Format("    vtf.tcgs[%u] = (texMtxs[%u] * %s).xy;\n", tcgIdx, tcg.m_mtx,
                                    EmitTexGenSource4(tcg.m_src, tcg.m_uvIdx).c_str());
         ++tcgIdx;
     }
diff --git a/hecl/lib/Backend/Metal.cpp b/hecl/lib/Backend/Metal.cpp
new file mode 100644
index 000000000..313e0adba
--- /dev/null
+++ b/hecl/lib/Backend/Metal.cpp
@@ -0,0 +1,407 @@
+#include "HECL/Backend/Metal.hpp"
+#if HECL_HAS_METAL
+#include "HECL/Runtime.hpp"
+#include <Athena/MemoryReader.hpp>
+#include <Athena/MemoryWriter.hpp>
+#include <boo/graphicsdev/Metal.hpp>
+
+static LogVisor::LogModule Log("HECL::Backend::Metal");
+
+namespace HECL
+{
+namespace Backend
+{
+
+std::string Metal::EmitTexGenSource2(TexGenSrc src, int uvIdx) const
+{
+    switch (src)
+    {
+        case TG_POS:
+            return "v.posIn.xy\n";
+        case TG_NRM:
+            return "v.normIn.xy\n";
+        case TG_UV:
+            return HECL::Format("v.uvIn%u", uvIdx);
+        default: break;
+    }
+    return std::string();
+}
+
+std::string Metal::EmitTexGenSource4(TexGenSrc src, int uvIdx) const
+{
+    switch (src)
+    {
+        case TG_POS:
+            return "float4(v.posIn, 1.0)\n";
+        case TG_NRM:
+            return "float4(v.normIn, 1.0)\n";
+        case TG_UV:
+            return HECL::Format("float4(v.uvIn%u, 0.0, 1.0)", uvIdx);
+        default: break;
+    }
+    return std::string();
+}
+
+std::string Metal::GenerateVertInStruct(unsigned col, unsigned uv, unsigned w) const
+{
+    std::string retval =
+    "struct VertData\n"
+    "{\n"
+    "    float3 posIn [[ attribute(0) ]];\n"
+    "    float3 normIn [[ attribute(1) ]];\n";
+    
+    unsigned idx = 2;
+    if (col)
+    {
+        for (unsigned i=0 ; i<col ; ++i, ++idx)
+            retval += HECL::Format("    float4 colIn%u [[ attribute(%u) ]];\n", i, idx);
+    }
+    
+    if (uv)
+    {
+        for (unsigned i=0 ; i<uv ; ++i, ++idx)
+            retval += HECL::Format("    float2 uvIn%u [[ attribute(%u) ]];\n", i, idx);
+    }
+    
+    if (w)
+    {
+        for (unsigned i=0 ; i<w ; ++i, ++idx)
+        retval += HECL::Format("    float4 weightIn%u [[ attribute(%u) ]];\n", i, idx);
+    }
+    
+    return retval + "};\n";
+}
+
+std::string Metal::GenerateVertToFragStruct() const
+{
+    std::string retval =
+    "struct VertToFrag\n"
+    "{\n"
+    "    float4 mvpPos [[ position ]];\n"
+    "    float4 mvPos;\n"
+    "    float4 mvNorm;\n";
+    
+    if (m_tcgs.size())
+    {
+        for (size_t i=0 ; i<m_tcgs.size() ; ++i)
+            retval += HECL::Format("    float2 tcgs%" PRISize ";\n", i);
+    }
+    
+    return retval + "};\n";
+}
+
+std::string Metal::GenerateVertUniformStruct(unsigned skinSlots, unsigned texMtxs) const
+{
+    if (skinSlots == 0)
+        skinSlots = 1;
+    std::string retval = HECL::Format("struct HECLVertUniform\n"
+                                      "{\n"
+                                      "    float4x4 mv[%u];\n"
+                                      "    float4x4 mvInv[%u];\n"
+                                      "    float4x4 proj;\n",
+                                      skinSlots, skinSlots);
+    if (texMtxs)
+        retval += HECL::Format("    float4x4 texMtxs[%u];\n", texMtxs);
+    return retval + "};\n";
+}
+
+void Metal::reset(const IR& ir, Diagnostics& diag)
+{
+    /* Common programmable interpretation */
+    ProgrammableCommon::reset(ir, diag, "Metal");
+}
+
+std::string Metal::makeVert(unsigned col, unsigned uv, unsigned w,
+                            unsigned s, unsigned tm) const
+{
+    std::string retval = "#include <metal_stdlib>\nusing namespace metal;\n" +
+    GenerateVertInStruct(col, uv, w) + "\n" +
+    GenerateVertToFragStruct() + "\n" +
+    GenerateVertUniformStruct(s, tm) +
+    "\nvertex VertToFrag vmain(VertData v [[ stage_in ]], constant HECLVertUniform& vu [[ buffer(1) ]])\n{\n"
+    "    VertToFrag vtf;\n";
+    
+    if (s)
+    {
+        /* skinned */
+        retval += "    float4 posAccum = float4(0.0,0.0,0.0,0.0);\n"
+        "    float4 normAccum = float4(0.0,0.0,0.0,0.0);\n";
+        for (size_t i=0 ; i<s ; ++i)
+            retval += HECL::Format("    posAccum += (vu.mv[%" PRISize "] * float4(v.posIn, 1.0)) * v.weightIn%" PRISize "[%" PRISize "];\n"
+                                   "    normAccum += (vu.mvInv[%" PRISize "] * float4(v.normIn, 1.0)) * v.weightIn%" PRISize "[%" PRISize "];\n",
+                                   i, i/4, i%4, i, i/4, i%4);
+        retval += "    posAccum[3] = 1.0;\n"
+        "    vtf.mvPos = posAccum;\n"
+        "    vtf.mvNorm = float4(normalize(normAccum.xyz), 0.0);\n"
+        "    vtf.mvpPos = vu.proj * posAccum;\n";
+    }
+    else
+    {
+        /* non-skinned */
+        retval += "    vtf.mvPos = vu.mv[0] * float4(v.posIn, 1.0);\n"
+        "    vtf.mvNorm = vu.mvInv[0] * float4(v.normIn, 0.0);\n"
+        "    vtf.mvpPos = vu.proj * vtf.mvPos;\n";
+    }
+    
+    int tcgIdx = 0;
+    for (const TexCoordGen& tcg : m_tcgs)
+    {
+        if (tcg.m_mtx < 0)
+            retval += HECL::Format("    vtf.tcgs%u = %s;\n", tcgIdx,
+                                   EmitTexGenSource2(tcg.m_src, tcg.m_uvIdx).c_str());
+        else
+            retval += HECL::Format("    vtf.tcgs%u = (vu.texMtxs[%u] * %s).xy;\n", tcgIdx, tcg.m_mtx,
+                                   EmitTexGenSource4(tcg.m_src, tcg.m_uvIdx).c_str());
+        ++tcgIdx;
+    }
+    
+    return retval + "    return vtf;\n}\n";
+}
+
+std::string Metal::makeFrag(const ShaderFunction& lighting) const
+{
+    std::string lightingSrc;
+    if (lighting.m_source)
+        lightingSrc = lighting.m_source;
+    
+    std::string texMapDecl;
+    if (m_texMapEnd)
+    {
+        for (int i=0 ; i<m_texMapEnd ; ++i)
+            texMapDecl += HECL::Format("\n, texture2d<float> tex%u [[ texture(%u) ]]", i, i);
+    }
+    
+    std::string retval = "#include <metal_stdlib>\nusing namespace metal;\n"
+    "constexpr sampler samp(address::repeat);\n" +
+    GenerateVertToFragStruct() + "\n" +
+    lightingSrc + "\n" +
+    "fragment float4 fmain(VertToFrag vtf [[ stage_in ]]" + texMapDecl + ")\n{\n";
+    
+    
+    if (m_lighting)
+    {
+        if (lighting.m_entry)
+            retval += HECL::Format("    float4 lighting = %s();\n", lighting.m_entry);
+        else
+            retval += "    float4 lighting = float4(1.0,1.0,1.0,1.0);\n";
+    }
+    
+    unsigned sampIdx = 0;
+    for (const TexSampling& sampling : m_texSamplings)
+        retval += HECL::Format("    float4 sampling%u = tex%u.sample(samp, vtf.tcgs%u);\n",
+                               sampIdx++, sampling.mapIdx, sampling.tcgIdx);
+    
+    if (m_alphaExpr.size())
+        retval += "    return float4(" + m_colorExpr + ", " + m_alphaExpr + ");\n";
+    else
+        retval += "    return float4(" + m_colorExpr + ", 1.0);\n";
+    
+    return retval + "}\n";
+}
+
+std::string Metal::makeFrag(const ShaderFunction& lighting,
+                            const ShaderFunction& post) const
+{
+    std::string lightingSrc;
+    if (lighting.m_source)
+        lightingSrc = lighting.m_source;
+    
+    std::string postSrc;
+    if (post.m_source)
+        postSrc = post.m_source;
+    
+    std::string postEntry;
+    if (post.m_entry)
+        postEntry = post.m_entry;
+    
+    std::string texMapDecl;
+    if (m_texMapEnd)
+    {
+        for (int i=0 ; i<m_texMapEnd ; ++i)
+            texMapDecl += HECL::Format("texture2d<float> tex%u [[ texture(%u) ]],\n", i, i);
+    }
+    
+    std::string retval = "#include <metal_stdlib>\nusing namespace metal;\n"
+    "constexpr sampler samp(address::repeat);\n" +
+    GenerateVertToFragStruct() + "\n" +
+    lightingSrc + "\n" +
+    "fragment float4 fmain(VertToFrag vtf [[ stage_in ]],\n" + texMapDecl + ")\n{\n";
+    
+    if (m_lighting)
+    {
+        if (lighting.m_entry)
+            retval += HECL::Format("    float4 lighting = %s();\n", lighting.m_entry);
+        else
+            retval += "    float4 lighting = float4(1.0,1.0,1.0,1.0);\n";
+    }
+    
+    unsigned sampIdx = 0;
+    for (const TexSampling& sampling : m_texSamplings)
+        retval += HECL::Format("    float4 sampling%u = tex%u.sample(samp, vtf.tcgs%u);\n",
+                               sampIdx++, sampling.mapIdx, sampling.tcgIdx);
+    
+    if (m_alphaExpr.size())
+        retval += "    return " + postEntry + "(float4(" + m_colorExpr + ", " + m_alphaExpr + "));\n";
+    else
+        retval += "    return " + postEntry + "(float4(" + m_colorExpr + ", 1.0));\n";
+    
+    return retval + "}\n";
+}
+
+}
+namespace Runtime
+{
+
+struct MetalBackendFactory : IShaderBackendFactory
+{
+    Backend::Metal m_backend;
+    boo::MetalDataFactory* m_gfxFactory;
+    
+    MetalBackendFactory(boo::IGraphicsDataFactory* gfxFactory)
+    : m_gfxFactory(dynamic_cast<boo::MetalDataFactory*>(gfxFactory)) {}
+    
+    ShaderCachedData buildShaderFromIR(const ShaderTag& tag,
+                                       const HECL::Frontend::IR& ir,
+                                       HECL::Frontend::Diagnostics& diag,
+                                       boo::IShaderPipeline** objOut)
+    {
+        if (!m_rtHint)
+            Log.report(LogVisor::FatalError,
+                       "ShaderCacheManager::setRenderTargetHint must be called before making metal shaders");
+        
+        m_backend.reset(ir, diag);
+        size_t cachedSz = 2;
+        
+        std::string vertSource =
+        m_backend.makeVert(tag.getColorCount(), tag.getUvCount(), tag.getWeightCount(),
+                           tag.getSkinSlotCount(), tag.getTexMtxCount());
+        cachedSz += vertSource.size() + 1;
+        
+        std::string fragSource = m_backend.makeFrag();
+        cachedSz += fragSource.size() + 1;
+        *objOut =
+        m_gfxFactory->newShaderPipeline(vertSource.c_str(), fragSource.c_str(),
+                                        tag.newVertexFormat(m_gfxFactory), m_rtHint,
+                                        m_backend.m_blendSrc, m_backend.m_blendDst,
+                                        tag.getDepthTest(), tag.getDepthWrite(),
+                                        tag.getBackfaceCulling());
+        if (!*objOut)
+            Log.report(LogVisor::FatalError, "unable to build shader");
+        
+        ShaderCachedData dataOut(tag, cachedSz);
+        Athena::io::MemoryWriter w(dataOut.m_data.get(), dataOut.m_sz);
+        w.writeUByte(m_backend.m_blendSrc);
+        w.writeUByte(m_backend.m_blendDst);
+        w.writeString(vertSource);
+        w.writeString(fragSource);
+        
+        return dataOut;
+    }
+    
+    boo::IShaderPipeline* buildShaderFromCache(const ShaderCachedData& data)
+    {
+        if (!m_rtHint)
+            Log.report(LogVisor::FatalError,
+                       "ShaderCacheManager::setRenderTargetHint must be called before making metal shaders");
+        
+        const ShaderTag& tag = data.m_tag;
+        Athena::io::MemoryReader r(data.m_data.get(), data.m_sz);
+        boo::BlendFactor blendSrc = boo::BlendFactor(r.readUByte());
+        boo::BlendFactor blendDst = boo::BlendFactor(r.readUByte());
+        std::string vertSource = r.readString();
+        std::string fragSource = r.readString();
+        boo::IShaderPipeline* ret =
+        m_gfxFactory->newShaderPipeline(vertSource.c_str(), fragSource.c_str(),
+                                        tag.newVertexFormat(m_gfxFactory), m_rtHint,
+                                        blendSrc, blendDst,
+                                        tag.getDepthTest(), tag.getDepthWrite(),
+                                        tag.getBackfaceCulling());
+        if (!ret)
+            Log.report(LogVisor::FatalError, "unable to build shader");
+        return ret;
+    }
+    
+    ShaderCachedData buildExtendedShaderFromIR(const ShaderTag& tag,
+                                               const HECL::Frontend::IR& ir,
+                                               HECL::Frontend::Diagnostics& diag,
+                                               const std::vector<ShaderCacheExtensions::ExtensionSlot>& extensionSlots,
+                                               FReturnExtensionShader returnFunc)
+    {
+        if (!m_rtHint)
+            Log.report(LogVisor::FatalError,
+                       "ShaderCacheManager::setRenderTargetHint must be called before making metal shaders");
+        
+        m_backend.reset(ir, diag);
+        size_t cachedSz = 2;
+        
+        std::string vertSource =
+        m_backend.makeVert(tag.getColorCount(), tag.getUvCount(), tag.getWeightCount(),
+                           tag.getSkinSlotCount(), tag.getTexMtxCount());
+        cachedSz += vertSource.size() + 1;
+        
+        std::vector<std::string> fragSources;
+        fragSources.reserve(extensionSlots.size());
+        for (const ShaderCacheExtensions::ExtensionSlot& slot : extensionSlots)
+        {
+            fragSources.push_back(m_backend.makeFrag(slot.lighting, slot.post));
+            cachedSz += fragSources.back().size() + 1;
+            boo::IShaderPipeline* ret =
+            m_gfxFactory->newShaderPipeline(vertSource.c_str(), fragSources.back().c_str(),
+                                            tag.newVertexFormat(m_gfxFactory), m_rtHint,
+                                            m_backend.m_blendSrc, m_backend.m_blendDst,
+                                            tag.getDepthTest(), tag.getDepthWrite(),
+                                            tag.getBackfaceCulling());
+            if (!ret)
+                Log.report(LogVisor::FatalError, "unable to build shader");
+            returnFunc(ret);
+        }
+        
+        ShaderCachedData dataOut(tag, cachedSz);
+        Athena::io::MemoryWriter w(dataOut.m_data.get(), dataOut.m_sz);
+        w.writeUByte(m_backend.m_blendSrc);
+        w.writeUByte(m_backend.m_blendDst);
+        w.writeString(vertSource);
+        for (const std::string src : fragSources)
+            w.writeString(src);
+        
+        return dataOut;
+    }
+    
+    void buildExtendedShaderFromCache(const ShaderCachedData& data,
+                                      const std::vector<ShaderCacheExtensions::ExtensionSlot>& extensionSlots,
+                                      FReturnExtensionShader returnFunc)
+    {
+        if (!m_rtHint)
+            Log.report(LogVisor::FatalError,
+                       "ShaderCacheManager::setRenderTargetHint must be called before making metal shaders");
+        
+        const ShaderTag& tag = data.m_tag;
+        Athena::io::MemoryReader r(data.m_data.get(), data.m_sz);
+        boo::BlendFactor blendSrc = boo::BlendFactor(r.readUByte());
+        boo::BlendFactor blendDst = boo::BlendFactor(r.readUByte());
+        std::string vertSource = r.readString();
+        for (const ShaderCacheExtensions::ExtensionSlot& slot : extensionSlots)
+        {
+            std::string fragSource = r.readString();
+            boo::IShaderPipeline* ret =
+            m_gfxFactory->newShaderPipeline(vertSource.c_str(), fragSource.c_str(),
+                                            tag.newVertexFormat(m_gfxFactory), m_rtHint,
+                                            blendSrc, blendDst,
+                                            tag.getDepthTest(), tag.getDepthWrite(),
+                                            tag.getBackfaceCulling());
+            if (!ret)
+                Log.report(LogVisor::FatalError, "unable to build shader");
+            returnFunc(ret);
+        }
+    }
+};
+
+IShaderBackendFactory* _NewMetalBackendFactory(boo::IGraphicsDataFactory* gfxFactory)
+{
+    return new struct MetalBackendFactory(gfxFactory);
+}
+    
+}
+}
+
+#endif
diff --git a/hecl/lib/CMakeLists.txt b/hecl/lib/CMakeLists.txt
index 6b80f9802..14076944c 100644
--- a/hecl/lib/CMakeLists.txt
+++ b/hecl/lib/CMakeLists.txt
@@ -22,6 +22,7 @@ add_library(HECLCommon
             ../include/HECL/Backend/ProgrammableCommon.hpp
             ../include/HECL/Backend/GLSL.hpp
             ../include/HECL/Backend/HLSL.hpp
+            ../include/HECL/Backend/Metal.hpp
             ../include/HECL/Frontend.hpp
             ../include/HECL/Database.hpp
             ../include/HECL/Runtime.hpp
diff --git a/hecl/lib/Runtime/ShaderCacheManager.cpp b/hecl/lib/Runtime/ShaderCacheManager.cpp
index 386a1db72..395dd2d7e 100644
--- a/hecl/lib/Runtime/ShaderCacheManager.cpp
+++ b/hecl/lib/Runtime/ShaderCacheManager.cpp
@@ -6,13 +6,20 @@
 #include <ctime>
 
 #include "HECL/Backend/GLSL.hpp"
+#if __APPLE__
+#include "HECL/Backend/Metal.hpp"
+#endif
 
 namespace HECL
 {
 namespace Runtime
 {
 IShaderBackendFactory* _NewGLSLBackendFactory(boo::IGraphicsDataFactory* gfxFactory);
+#if _WIN32
 IShaderBackendFactory* _NewHLSLBackendFactory(boo::IGraphicsDataFactory* gfxFactory);
+#elif __APPLE__
+IShaderBackendFactory* _NewMetalBackendFactory(boo::IGraphicsDataFactory* gfxFactory);
+#endif
 
 static LogVisor::LogModule Log("ShaderCacheManager");
 static uint64_t IDX_MAGIC = SBig(uint64_t(0xDEADFEEDC001D00D));
@@ -110,10 +117,16 @@ ShaderCacheManager::ShaderCacheManager(const FileStoreManager& storeMgr,
     case boo::IGraphicsDataFactory::PlatformOGL:
         m_factory.reset(_NewGLSLBackendFactory(gfxFactory));
         break;
+#if _WIN32
     case boo::IGraphicsDataFactory::PlatformD3D11:
     case boo::IGraphicsDataFactory::PlatformD3D12:
         m_factory.reset(_NewHLSLBackendFactory(gfxFactory));
         break;
+#elif __APPLE__ && HECL_HAS_METAL
+    case boo::IGraphicsDataFactory::PlatformMetal:
+        m_factory.reset(_NewMetalBackendFactory(gfxFactory));
+        break;
+#endif
     default:
         Log.report(LogVisor::FatalError, _S("unsupported backend %s"), gfxFactory->platformName());
     }
diff --git a/hecl/test/main.cpp b/hecl/test/main.cpp
index c9881bf8e..93b7ded36 100644
--- a/hecl/test/main.cpp
+++ b/hecl/test/main.cpp
@@ -80,6 +80,7 @@ struct HECLApplicationCallback : boo::IApplicationCallback
             /* HECL managers */
             HECL::Runtime::FileStoreManager fileMgr(app->getUniqueName());
             HECL::Runtime::ShaderCacheManager shaderMgr(fileMgr, gfxF);
+            shaderMgr.setRenderTargetHint(renderTex);
 
             /* Compile HECL shader */
             static std::string testShader = "HECLOpaque(Texture(0, UV(0)))";