diff --git a/radiantcore/CMakeLists.txt b/radiantcore/CMakeLists.txt
index 56108cff58..62c97fde59 100644
--- a/radiantcore/CMakeLists.txt
+++ b/radiantcore/CMakeLists.txt
@@ -211,6 +211,7 @@ add_library(radiantcore MODULE
             rendersystem/backend/glprogram/GLSLDepthFillAlphaProgram.cpp
             rendersystem/backend/OpenGLShader.cpp
             rendersystem/backend/OpenGLShaderPass.cpp
+            rendersystem/backend/DepthFillPass.cpp
             rendersystem/debug/SpacePartitionRenderer.cpp
             rendersystem/GLFont.cpp
             rendersystem/OpenGLModule.cpp
diff --git a/radiantcore/rendersystem/backend/DepthFillPass.cpp b/radiantcore/rendersystem/backend/DepthFillPass.cpp
new file mode 100644
index 0000000000..209f899fc8
--- /dev/null
+++ b/radiantcore/rendersystem/backend/DepthFillPass.cpp
@@ -0,0 +1,35 @@
+#include "DepthFillPass.h"
+
+#include "../OpenGLRenderSystem.h"
+#include "GLProgramFactory.h"
+
+namespace render
+{
+
+DepthFillPass::DepthFillPass(OpenGLShader& owner, OpenGLRenderSystem& renderSystem) :
+    OpenGLShaderPass(owner)
+{
+    // Mask colour => we only write to the depth buffer
+    _glState.setRenderFlag(RENDER_MASKCOLOUR);
+
+    _glState.setRenderFlag(RENDER_FILL);
+    _glState.setRenderFlag(RENDER_CULLFACE);
+    _glState.setRenderFlag(RENDER_DEPTHTEST);
+    _glState.setRenderFlag(RENDER_DEPTHWRITE);
+    _glState.setRenderFlag(RENDER_PROGRAM);
+    
+    // Our shader will discard any fragments not passing the alphatest (if active)
+    _glState.setRenderFlag(RENDER_ALPHATEST);
+    
+    // We need texture coords and the full vertex attribute stack
+    _glState.setRenderFlag(RENDER_TEXTURE_2D);
+    _glState.setRenderFlag(RENDER_BUMP);
+
+    // ZFILL will make this pass pretty much top priority
+    _glState.setSortPosition(OpenGLState::SORT_ZFILL);
+
+    // Load the GLSL program tailored for this pass
+    _glState.glProgram = renderSystem.getGLProgramFactory().getBuiltInProgram("depthFillAlpha");
+}
+
+}
diff --git a/radiantcore/rendersystem/backend/DepthFillPass.h b/radiantcore/rendersystem/backend/DepthFillPass.h
new file mode 100644
index 0000000000..e5351fabd0
--- /dev/null
+++ b/radiantcore/rendersystem/backend/DepthFillPass.h
@@ -0,0 +1,21 @@
+#pragma once
+
+#include "OpenGLShaderPass.h"
+
+namespace render
+{
+
+class OpenGLRenderSystem;
+
+/**
+ * Special render pass filling the depth buffer. 
+ * This is the first pass before any interaction shaders are run.
+ */
+class DepthFillPass :
+    public OpenGLShaderPass
+{
+public:
+    DepthFillPass(OpenGLShader& owner, OpenGLRenderSystem& renderSystem);
+};
+
+}
diff --git a/radiantcore/rendersystem/backend/OpenGLShader.cpp b/radiantcore/rendersystem/backend/OpenGLShader.cpp
index fc5e94d069..c615c1216c 100644
--- a/radiantcore/rendersystem/backend/OpenGLShader.cpp
+++ b/radiantcore/rendersystem/backend/OpenGLShader.cpp
@@ -2,6 +2,7 @@
 
 #include "GLProgramFactory.h"
 #include "../OpenGLRenderSystem.h"
+#include "DepthFillPass.h"
 
 #include "icolourscheme.h"
 #include "ishaders.h"
@@ -256,6 +257,12 @@ OpenGLState& OpenGLShader::appendDefaultPass()
     return state;
 }
 
+OpenGLState& OpenGLShader::appendDepthFillPass()
+{
+    auto& pass = _shaderPasses.emplace_back(std::make_shared<DepthFillPass>(*this, _renderSystem));
+    return pass->state();
+}
+
 // Test if we can render in bump map mode
 bool OpenGLShader::canUseLightingMode() const
 {
@@ -316,23 +323,14 @@ void OpenGLShader::appendInteractionLayer(const DBSTriplet& triplet)
     if (triplet.needDepthFill && triplet.diffuse)
     {
         // Create depth-buffer fill pass with alpha test
-        OpenGLState& zPass = appendDefaultPass();
-        zPass.setRenderFlag(RENDER_MASKCOLOUR);
-        zPass.setRenderFlag(RENDER_FILL);
-        zPass.setRenderFlag(RENDER_CULLFACE);
-        zPass.setRenderFlag(RENDER_DEPTHTEST);
-        zPass.setRenderFlag(RENDER_DEPTHWRITE);
-        zPass.setRenderFlag(RENDER_PROGRAM);
-        zPass.setRenderFlag(RENDER_ALPHATEST);
-        zPass.setRenderFlag(RENDER_TEXTURE_2D);
-        zPass.setRenderFlag(RENDER_BUMP);
+        OpenGLState& zPass = appendDepthFillPass();
+
+        // Store the alpha test value
         zPass.alphaThreshold = static_cast<GLfloat>(alphaTest);
 
-        zPass.setSortPosition(OpenGLState::SORT_ZFILL);
+        // We need a diffuse stage to be able to performthe alpha test
         zPass.stage0 = triplet.diffuse;
         zPass.texture0 = getTextureOrInteractionDefault(triplet.diffuse)->getGLTexNum();
-
-        zPass.glProgram = _renderSystem.getGLProgramFactory().getBuiltInProgram("depthFillAlpha");
     }
 
     // Add the DBS pass
diff --git a/radiantcore/rendersystem/backend/OpenGLShader.h b/radiantcore/rendersystem/backend/OpenGLShader.h
index aa6caaa3d6..d99eae75bc 100644
--- a/radiantcore/rendersystem/backend/OpenGLShader.h
+++ b/radiantcore/rendersystem/backend/OpenGLShader.h
@@ -70,6 +70,7 @@ class OpenGLShader final :
 
     // Add a shader pass to the end of the list, and return its state object
 	OpenGLState& appendDefaultPass();
+	OpenGLState& appendDepthFillPass();
 
     // Test if we can render using lighting mode
     bool canUseLightingMode() const;
diff --git a/radiantcore/rendersystem/backend/OpenGLShaderPass.h b/radiantcore/rendersystem/backend/OpenGLShaderPass.h
index 910bfd25fd..73422704b6 100644
--- a/radiantcore/rendersystem/backend/OpenGLShaderPass.h
+++ b/radiantcore/rendersystem/backend/OpenGLShaderPass.h
@@ -25,6 +25,7 @@ class OpenGLShader;
  */
 class OpenGLShaderPass
 {
+protected:
 	OpenGLShader& _owner;
 
 	// The state applied to this bucket
diff --git a/tools/msvc/DarkRadiantCore.vcxproj b/tools/msvc/DarkRadiantCore.vcxproj
index d94f9e38e3..d34dc83165 100644
--- a/tools/msvc/DarkRadiantCore.vcxproj
+++ b/tools/msvc/DarkRadiantCore.vcxproj
@@ -598,6 +598,7 @@
     <ClCompile Include="..\..\radiantcore\log\StringLogDevice.cpp" />
     <ClCompile Include="..\..\radiantcore\modulesystem\ModuleLoader.cpp" />
     <ClCompile Include="..\..\radiantcore\modulesystem\ModuleRegistry.cpp" />
+    <ClCompile Include="..\..\radiantcore\rendersystem\backend\DepthFillPass.cpp" />
     <ClCompile Include="..\..\radiantcore\rendersystem\backend\GLProgramFactory.cpp" />
     <ClCompile Include="..\..\radiantcore\rendersystem\backend\glprogram\GenericVFPProgram.cpp" />
     <ClCompile Include="..\..\radiantcore\rendersystem\backend\glprogram\GLSLBumpProgram.cpp" />
@@ -928,6 +929,7 @@
     <ClInclude Include="..\..\radiantcore\messagebus\MessageBus.h" />
     <ClInclude Include="..\..\radiantcore\modulesystem\ModuleLoader.h" />
     <ClInclude Include="..\..\radiantcore\modulesystem\ModuleRegistry.h" />
+    <ClInclude Include="..\..\radiantcore\rendersystem\backend\DepthFillPass.h" />
     <ClInclude Include="..\..\radiantcore\rendersystem\backend\GLProgramFactory.h" />
     <ClInclude Include="..\..\radiantcore\rendersystem\backend\glprogram\GenericVFPProgram.h" />
     <ClInclude Include="..\..\radiantcore\rendersystem\backend\glprogram\GLSLBumpProgram.h" />
diff --git a/tools/msvc/DarkRadiantCore.vcxproj.filters b/tools/msvc/DarkRadiantCore.vcxproj.filters
index d7529927da..14c4e1a762 100644
--- a/tools/msvc/DarkRadiantCore.vcxproj.filters
+++ b/tools/msvc/DarkRadiantCore.vcxproj.filters
@@ -1042,6 +1042,9 @@
     <ClCompile Include="..\..\radiantcore\rendersystem\backend\glprogram\GLSLDepthFillAlphaProgram.cpp">
       <Filter>src\rendersystem\backend\glprogram</Filter>
     </ClCompile>
+    <ClCompile Include="..\..\radiantcore\rendersystem\backend\DepthFillPass.cpp">
+      <Filter>src\rendersystem\backend</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="..\..\radiantcore\modulesystem\ModuleLoader.h">
@@ -2127,5 +2130,8 @@
     <ClInclude Include="..\..\radiantcore\rendersystem\backend\glprogram\GLSLProgramBase.h">
       <Filter>src\rendersystem\backend\glprogram</Filter>
     </ClInclude>
+    <ClInclude Include="..\..\radiantcore\rendersystem\backend\DepthFillPass.h">
+      <Filter>src\rendersystem\backend</Filter>
+    </ClInclude>
   </ItemGroup>
 </Project>
\ No newline at end of file