diff --git a/include/ShaderLayer.h b/include/ShaderLayer.h
index 0adad905e3..72e435f062 100644
--- a/include/ShaderLayer.h
+++ b/include/ShaderLayer.h
@@ -153,6 +153,9 @@ class ShaderLayer
 	 */
 	virtual float getTexGenParam(std::size_t index) const = 0;
 
+    // The expressions used to calcualte the tex gen params. Index in [0..2]
+    virtual shaders::IShaderExpressionPtr getTexGenExpression(std::size_t index) const = 0;
+
     /**
      * \brief
      * Return the GL blend function for this layer.
diff --git a/radiant/ui/materials/MaterialEditor.cpp b/radiant/ui/materials/MaterialEditor.cpp
index efe48d8dfb..73d29e27f4 100644
--- a/radiant/ui/materials/MaterialEditor.cpp
+++ b/radiant/ui/materials/MaterialEditor.cpp
@@ -871,6 +871,14 @@ void MaterialEditor::updateStageControls()
             {
                 getControl<wxPanel>("MaterialStageWobblySkyPanel")->Show();
 
+                auto wobbleSkyX = selectedStage->getTexGenExpression(0);
+                getControl<wxTextCtrl>("MaterialStageWobbleSkyX")->SetValue(wobbleSkyX ? wobbleSkyX->getExpressionString() : "");
+
+                auto wobbleSkyY = selectedStage->getTexGenExpression(1);
+                getControl<wxTextCtrl>("MaterialStageWobbleSkyY")->SetValue(wobbleSkyY ? wobbleSkyY->getExpressionString() : "");
+
+                auto wobbleSkyZ = selectedStage->getTexGenExpression(2);
+                getControl<wxTextCtrl>("MaterialStageWobbleSkyZ")->SetValue(wobbleSkyZ ? wobbleSkyZ->getExpressionString() : "");
             }
             else
             {
diff --git a/radiantcore/shaders/Doom3ShaderLayer.cpp b/radiantcore/shaders/Doom3ShaderLayer.cpp
index 51db807bd4..c28a2ec988 100644
--- a/radiantcore/shaders/Doom3ShaderLayer.cpp
+++ b/radiantcore/shaders/Doom3ShaderLayer.cpp
@@ -119,7 +119,7 @@ Doom3ShaderLayer::Doom3ShaderLayer(ShaderTemplate& material, ShaderLayer::Type t
 	_shear[0] = REG_ZERO;
 	_shear[1] = REG_ZERO;
 
-	_texGenParams[0] = _texGenParams[1] = _texGenParams[2] = 0;
+	_texGenParams[0] = _texGenParams[1] = _texGenParams[2] = REG_ZERO;
 }
 
 TexturePtr Doom3ShaderLayer::getTexture() const
diff --git a/radiantcore/shaders/Doom3ShaderLayer.h b/radiantcore/shaders/Doom3ShaderLayer.h
index 7097f0c514..eec04a752c 100644
--- a/radiantcore/shaders/Doom3ShaderLayer.h
+++ b/radiantcore/shaders/Doom3ShaderLayer.h
@@ -85,7 +85,8 @@ class Doom3ShaderLayer
 
     // texgen normal, reflect, skybox, wobblesky
     TexGenType _texGenType;
-    float _texGenParams[3]; // 3 parameters for wobblesky texgen
+    std::size_t _texGenParams[3]; // 3 registers for wobblesky texgen
+    IShaderExpressionPtr _texGenExpressions[3]; // the 3 expressions
 
     // The register indices of this stage's scale expressions
     std::size_t _scale[2];
@@ -158,17 +159,17 @@ class Doom3ShaderLayer
 
     void evaluateExpressions(std::size_t time) 
     {
-        for (Expressions::iterator i = _expressions.begin(); i != _expressions.end(); ++i)
+        for (const auto& i : _expressions)
         {
-            (*i)->evaluate(time);
+            i->evaluate(time);
         }
     }
 
     void evaluateExpressions(std::size_t time, const IRenderEntity& entity)
     {
-        for (Expressions::iterator i = _expressions.begin(); i != _expressions.end(); ++i)
+        for (const auto& i : _expressions)
         {
-            (*i)->evaluate(time, entity);
+            i->evaluate(time, entity);
         }
     }
 
@@ -248,16 +249,26 @@ class Doom3ShaderLayer
         _texGenType = type;
     }
 
-    float getTexGenParam(std::size_t index) const 
+    float getTexGenParam(std::size_t index) const override
     {
         assert(index < 3);
-        return _texGenParams[index];
+        return _registers[_texGenParams[index]];
     }
 
-    void setTexGenParam(std::size_t index, float value)
+    IShaderExpressionPtr getTexGenExpression(std::size_t index) const override
     {
         assert(index < 3);
-        _texGenParams[index] = value;
+        return _texGenExpressions[index];
+    }
+
+    void setTexGenExpression(std::size_t index, const IShaderExpressionPtr& expression)
+    {
+        assert(index < 3);
+
+        // Store the expression in our list
+        _expressions.push_back(expression);
+        _texGenExpressions[index] = expression;
+        _texGenParams[index] = expression->linkToRegister(_registers);
     }
 
     /**
diff --git a/radiantcore/shaders/ShaderTemplate.cpp b/radiantcore/shaders/ShaderTemplate.cpp
index 01df2b40a8..54ecaeae76 100644
--- a/radiantcore/shaders/ShaderTemplate.cpp
+++ b/radiantcore/shaders/ShaderTemplate.cpp
@@ -580,13 +580,10 @@ bool ShaderTemplate::parseBlendMaps(parser::DefTokeniser& tokeniser, const std::
 		{
 			_currentLayer->setTexGenType(ShaderLayer::TEXGEN_WOBBLESKY);
 
-			// Parse the 3 wobblesky parameters
-			// greebo: The D3 SDK says that registers could be used here (to support expressions), 
-			// but no D3 material uses an expression for the texgen parameters
-			for (std::size_t i = 0; i < 3; ++i)
-			{
-				_currentLayer->setTexGenParam(i, string::convert<float>(tokeniser.nextToken()));
-			}
+			// Parse the 3 wobblesky expressions
+            _currentLayer->setTexGenExpression(0, parseSingleExpressionTerm(tokeniser));
+            _currentLayer->setTexGenExpression(1, parseSingleExpressionTerm(tokeniser));
+            _currentLayer->setTexGenExpression(2, parseSingleExpressionTerm(tokeniser));
 		}
 	}
 	else if (token == "cubemap")