diff --git a/source/graphics/Material.cpp b/source/graphics/Material.cpp
index fa8d4444d6..40f6f025d8 100644
--- a/source/graphics/Material.cpp
+++ b/source/graphics/Material.cpp
@@ -35,11 +35,13 @@ void CMaterial::SetShaderEffect(const CStr& effect)
 void CMaterial::AddShaderDefine(const char* key, const char* value)
 {
 	m_ShaderDefines.Add(key, value);
+	m_CombinedShaderDefines.clear();
 }
 
 void CMaterial::AddConditionalDefine(const char* defname, const char* defvalue, int type, std::vector<float> &args)
 {
 	m_ConditionalDefines.Add(defname, defvalue, type, args);
+	m_CombinedShaderDefines.clear();
 }
 
 void CMaterial::AddStaticUniform(const char* key, const CVector4D& value)
@@ -57,4 +59,31 @@ void CMaterial::AddSampler(const TextureSampler& texture)
 void CMaterial::AddRenderQuery(const char* key)
 {
 	m_RenderQueries.Add(key);
-}
\ No newline at end of file
+}
+
+// Set up m_CombinedShaderDefines so that index i contains m_ShaderDefines, plus
+// the extra defines from m_ConditionalDefines[j] for all j where bit j is set in i.
+// This lets GetShaderDefines() cheaply return the defines for any combination of conditions.
+//
+// (This might scale badly if we had a large number of conditional defines per material,
+// but currently we don't expect to have many.)
+void CMaterial::RecomputeCombinedShaderDefines()
+{
+	m_CombinedShaderDefines.clear();
+	int size = m_ConditionalDefines.GetSize();
+
+	// Loop over all 2^n combinations of flags
+	for (int i = 0; i < (1 << size); i++)
+	{
+		CShaderDefines defs = m_ShaderDefines;
+		for (int j = 0; j < size; j++)
+		{
+			if (i & (1 << j))
+			{
+				CShaderConditionalDefines::CondDefine& def = m_ConditionalDefines.GetItem(j);
+				defs.Add(def.m_DefName.c_str(), def.m_DefValue.c_str());
+			}
+		}
+		m_CombinedShaderDefines.push_back(defs);
+	}
+}
diff --git a/source/graphics/Material.h b/source/graphics/Material.h
index eebe5d2dd2..a144a24c5d 100644
--- a/source/graphics/Material.h
+++ b/source/graphics/Material.h
@@ -53,7 +53,11 @@ public:
 	CStrIntern GetShaderEffect() const { return m_ShaderEffect; }
 
 	void AddShaderDefine(const char* key, const char* value);
-	const CShaderDefines& GetShaderDefines() const { return m_ShaderDefines; }
+
+	// conditionFlags is a bitmask representing which indexes of the
+	// GetConditionalDefines() list are currently matching.
+	// Use 0 if you don't care about conditional defines.
+	const CShaderDefines& GetShaderDefines(uint32_t conditionFlags) const { return m_CombinedShaderDefines.at(conditionFlags); }
 	
 	void AddConditionalDefine(const char* defname, const char* defvalue, int type, std::vector<float> &args);
 	const CShaderConditionalDefines& GetConditionalDefines() const { return m_ConditionalDefines; }
@@ -67,6 +71,9 @@ public:
 	void AddRenderQuery(const char* key);
 	const CShaderRenderQueries& GetRenderQueries() const { return m_RenderQueries; }
 
+	// Must be called after all AddShaderDefine and AddConditionalDefine
+	void RecomputeCombinedShaderDefines();
+
 private:
 	
 	// This pointer is kept to make it easier for the fixed pipeline to 
@@ -78,6 +85,7 @@ private:
 	CStrIntern m_ShaderEffect;
 	CShaderDefines m_ShaderDefines;
 	CShaderConditionalDefines m_ConditionalDefines;
+	std::vector<CShaderDefines> m_CombinedShaderDefines;
 	CShaderUniforms m_StaticUniforms;
 	CShaderRenderQueries m_RenderQueries;
 
diff --git a/source/graphics/MaterialManager.cpp b/source/graphics/MaterialManager.cpp
index 5cebd6ce5c..68b6923388 100644
--- a/source/graphics/MaterialManager.cpp
+++ b/source/graphics/MaterialManager.cpp
@@ -182,6 +182,8 @@ CMaterial CMaterialManager::LoadMaterial(const VfsPath& pathname)
 		}
 	}
 
+	material.RecomputeCombinedShaderDefines();
+
 	m_Materials[pathname] = material;
 	return material;
 }
diff --git a/source/renderer/DecalRData.cpp b/source/renderer/DecalRData.cpp
index 87202b3573..ead1f5e61f 100644
--- a/source/renderer/DecalRData.cpp
+++ b/source/renderer/DecalRData.cpp
@@ -94,7 +94,7 @@ void CDecalRData::RenderDecals(std::vector<CDecalRData*>& decals, const CShaderD
 		if (!isDummyShader)
 		{
 			techBase = g_Renderer.GetShaderManager().LoadEffect(
-				material.GetShaderEffect(), contextDecal, material.GetShaderDefines());
+				material.GetShaderEffect(), contextDecal, material.GetShaderDefines(0));
 			
 			if (!techBase)
 			{
diff --git a/source/renderer/ModelRenderer.cpp b/source/renderer/ModelRenderer.cpp
index 8741e1eb44..e705a7503f 100644
--- a/source/renderer/ModelRenderer.cpp
+++ b/source/renderer/ModelRenderer.cpp
@@ -426,10 +426,10 @@ void ShaderModelRenderer::Render(const RenderModifierPtr& modifier, const CShade
 		for (size_t i = 0; i < m->submissions.size(); ++i)
 		{
 			CModel* model = m->submissions[i];
-			
-			CShaderDefines defs = model->GetMaterial().GetShaderDefines();
+
+			uint32_t condFlags = 0;
+
 			CShaderConditionalDefines condefs = model->GetMaterial().GetConditionalDefines();
-			
 			for (size_t j = 0; j < condefs.GetSize(); ++j)
 			{
 				CShaderConditionalDefines::CondDefine &item = condefs.GetItem(j);
@@ -445,13 +445,14 @@ void ShaderModelRenderer::Render(const RenderModifierPtr& modifier, const CShade
 						float dmax = item.m_CondArgs[1];
 						
 						if ((dmin < 0 || dist >= dmin) && (dmax < 0 || dist < dmax))
-							defs.Add(item.m_DefName.c_str(), item.m_DefValue.c_str());
+							condFlags |= (1 << j);
 						
 						break;
 					}
 				}
 			}
 
+			CShaderDefines defs = model->GetMaterial().GetShaderDefines(condFlags);
 			SMRMaterialBucketKey key(model->GetMaterial().GetShaderEffect(), defs);
 			std::vector<CModel*>& bucketItems = materialBuckets[key];
 			bucketItems.push_back(model);
diff --git a/source/renderer/PatchRData.cpp b/source/renderer/PatchRData.cpp
index 6ddd0bfd9c..af376dab15 100644
--- a/source/renderer/PatchRData.cpp
+++ b/source/renderer/PatchRData.cpp
@@ -770,7 +770,7 @@ void CPatchRData::RenderBases(const std::vector<CPatchRData*>& patches, const CS
 			}
 						
 			techBase = g_Renderer.GetShaderManager().LoadEffect(itt->first->GetMaterial().GetShaderEffect(),
-						context, itt->first->GetMaterial().GetShaderDefines());
+						context, itt->first->GetMaterial().GetShaderDefines(0));
 			
 			numPasses = techBase->GetNumPasses();
 		}
@@ -996,7 +996,7 @@ void CPatchRData::RenderBlends(const std::vector<CPatchRData*>& patches, const C
 		
 		if (!isDummyShader)
 		{
-			techBase = g_Renderer.GetShaderManager().LoadEffect(itt->m_Texture->GetMaterial().GetShaderEffect(), contextBlend, itt->m_Texture->GetMaterial().GetShaderDefines());
+			techBase = g_Renderer.GetShaderManager().LoadEffect(itt->m_Texture->GetMaterial().GetShaderEffect(), contextBlend, itt->m_Texture->GetMaterial().GetShaderDefines(0));
 			
 			numPasses = techBase->GetNumPasses();
 		}