diff --git a/src/Magnum/Shaders/DistanceFieldVector.frag b/src/Magnum/Shaders/DistanceFieldVector.frag
index 0421f17a1..16385febf 100644
--- a/src/Magnum/Shaders/DistanceFieldVector.frag
+++ b/src/Magnum/Shaders/DistanceFieldVector.frag
@@ -144,7 +144,11 @@ out lowp vec4 fragmentColor;
 
 void main() {
     #ifdef UNIFORM_BUFFERS
+    #if MATERIAL_COUNT > 1
     mediump const uint materialId = draws[drawId].draw_materialIdReserved & 0xffffu;
+    #else
+    #define materialId 0u
+    #endif
     lowp const float smoothness = materials[materialId].material_smoothness;
     lowp const vec4 color = materials[materialId].color;
     lowp const vec4 outlineColor = materials[materialId].outlineColor;
diff --git a/src/Magnum/Shaders/DistanceFieldVector.h b/src/Magnum/Shaders/DistanceFieldVector.h
index 8964793d7..5bd8510ac 100644
--- a/src/Magnum/Shaders/DistanceFieldVector.h
+++ b/src/Magnum/Shaders/DistanceFieldVector.h
@@ -101,8 +101,9 @@ struct DistanceFieldVectorDrawUniform {
      * more than one material is supplied or in a multi-draw scenario. Should
      * be less than the material count passed to the
      * @ref DistanceFieldVectorGL::DistanceFieldVectorGL(Flags, UnsignedInt, UnsignedInt)
-     * constructor. Default value is @cpp 0 @ce, meaning the first material
-     * gets used.
+     * constructor, if material count is @cpp 1 @ce, this field is assumed to
+     * be @cpp 0 @ce and isn't even read by the shader. Default value is
+     * @cpp 0 @ce, meaning the first material gets used.
      */
 
     /* This field is an UnsignedInt in the shader and materialId is extracted
diff --git a/src/Magnum/Shaders/Flat.frag b/src/Magnum/Shaders/Flat.frag
index 8f5e5a6d7..dff034e23 100644
--- a/src/Magnum/Shaders/Flat.frag
+++ b/src/Magnum/Shaders/Flat.frag
@@ -176,7 +176,11 @@ void main() {
     #ifdef OBJECT_ID
     highp const uint objectId = draws[drawId].draw_objectId;
     #endif
+    #if MATERIAL_COUNT > 1
     mediump const uint materialId = draws[drawId].draw_materialIdReserved & 0xffffu;
+    #else
+    #define materialId 0u
+    #endif
     lowp const vec4 color = materials[materialId].color;
     #ifdef ALPHA_MASK
     lowp const float alphaMask = materials[materialId].material_alphaMask;
diff --git a/src/Magnum/Shaders/Flat.h b/src/Magnum/Shaders/Flat.h
index 4a894c173..8e22d887d 100644
--- a/src/Magnum/Shaders/Flat.h
+++ b/src/Magnum/Shaders/Flat.h
@@ -108,8 +108,10 @@ struct FlatDrawUniform {
      * References a particular material from a @ref FlatMaterialUniform array.
      * Useful when an UBO with more than one material is supplied or in a
      * multi-draw scenario. Should be less than the material count passed to
-     * the @ref FlatGL::FlatGL(Flags, UnsignedInt, UnsignedInt) constructor.
-     * Default value is @cpp 0 @ce, meaning the first material gets used.
+     * the @ref FlatGL::FlatGL(Flags, UnsignedInt, UnsignedInt) constructor, if
+     * material count is @cpp 1 @ce, this field is assumed to be @cpp 0 @ce and
+     * isn't even read by the shader. Default value is @cpp 0 @ce, meaning the
+     * first material gets used.
      */
 
     /* This field is an UnsignedInt in the shader and materialId is extracted
diff --git a/src/Magnum/Shaders/MeshVisualizer.frag b/src/Magnum/Shaders/MeshVisualizer.frag
index 20bb89ec7..d1e467052 100644
--- a/src/Magnum/Shaders/MeshVisualizer.frag
+++ b/src/Magnum/Shaders/MeshVisualizer.frag
@@ -224,7 +224,11 @@ out lowp vec4 fragmentColor;
 
 void main() {
     #ifdef UNIFORM_BUFFERS
+    #if MATERIAL_COUNT > 1
     mediump const uint materialId = draws[drawId].draw_materialIdReserved & 0xffffu;
+    #else
+    #define materialId 0u
+    #endif
     #if (defined(WIREFRAME_RENDERING) || defined(INSTANCED_OBJECT_ID) || defined(VERTEX_ID) || defined(PRIMITIVE_ID) || defined(PRIMITIVE_ID_FROM_VERTEX_ID)) && !defined(TBN_DIRECTION)
     lowp const vec4 color = materials[materialId].color;
     lowp const vec4 wireframeColor = materials[materialId].wireframeColor;
diff --git a/src/Magnum/Shaders/MeshVisualizer.h b/src/Magnum/Shaders/MeshVisualizer.h
index 2e4038412..9b0a540c4 100644
--- a/src/Magnum/Shaders/MeshVisualizer.h
+++ b/src/Magnum/Shaders/MeshVisualizer.h
@@ -100,8 +100,9 @@ struct MeshVisualizerDrawUniform2D {
      * more than one material is supplied or in a multi-draw scenario. Should
      * be less than the material count passed to the @ref MeshVisualizerGL2D::MeshVisualizerGL2D(Flags, UnsignedInt, UnsignedInt)
      * / @ref MeshVisualizerGL3D::MeshVisualizerGL3D(Flags, UnsignedInt, UnsignedInt)
-     * constructor. Default value is @cpp 0 @ce, meaning the first material
-     * gets used.
+     * constructor, if material count is @cpp 1 @ce, this field is assumed to
+     * be @cpp 0 @ce and isn't even read by the shader. Default value is
+     * @cpp 0 @ce, meaning the first material gets used.
      */
 
     /* This field is an UnsignedInt in the shader and materialId is extracted
diff --git a/src/Magnum/Shaders/Phong.frag b/src/Magnum/Shaders/Phong.frag
index 57ab5b2d5..ccfb8371a 100644
--- a/src/Magnum/Shaders/Phong.frag
+++ b/src/Magnum/Shaders/Phong.frag
@@ -339,7 +339,11 @@ void main() {
     #ifdef OBJECT_ID
     highp const uint objectId = draws[drawId].draw_objectId;
     #endif
+    #if MATERIAL_COUNT > 1
     mediump const uint materialId = draws[drawId].draw_materialIdReserved & 0xffffu;
+    #else
+    #define materialId 0u
+    #endif
     lowp const vec4 ambientColor = materials[materialId].ambientColor;
     #if LIGHT_COUNT
     lowp const vec4 diffuseColor = materials[materialId].diffuseColor;
diff --git a/src/Magnum/Shaders/Phong.h b/src/Magnum/Shaders/Phong.h
index c315e171d..8ac861067 100644
--- a/src/Magnum/Shaders/Phong.h
+++ b/src/Magnum/Shaders/Phong.h
@@ -141,8 +141,9 @@ struct PhongDrawUniform {
      * Useful when a UBO with more than one material is supplied or in a
      * multi-draw scenario. Should be less than the material count passed to
      * the @ref PhongGL::PhongGL(Flags, UnsignedInt, UnsignedInt, UnsignedInt)
-     * constructor. Default value is @cpp 0 @ce, meaning the first material
-     * gets used.
+     * constructor, if material count is @cpp 1 @ce, this field is assumed to
+     * be @cpp 0 @ce and isn't even read by the shader. Default value is
+     * @cpp 0 @ce, meaning the first material gets used.
      */
 
     /* This field is an UnsignedInt in the shader and materialId is extracted
diff --git a/src/Magnum/Shaders/Vector.frag b/src/Magnum/Shaders/Vector.frag
index 1b78de18f..50477a9b2 100644
--- a/src/Magnum/Shaders/Vector.frag
+++ b/src/Magnum/Shaders/Vector.frag
@@ -123,7 +123,11 @@ out lowp vec4 fragmentColor;
 
 void main() {
     #ifdef UNIFORM_BUFFERS
+    #if MATERIAL_COUNT > 1
     mediump const uint materialId = draws[drawId].draw_materialIdReserved & 0xffffu;
+    #else
+    #define materialId 0u
+    #endif
     lowp const vec4 color = materials[materialId].color;
     lowp const vec4 backgroundColor = materials[materialId].backgroundColor;
     #endif
diff --git a/src/Magnum/Shaders/Vector.h b/src/Magnum/Shaders/Vector.h
index 4d6b44675..daaf3d70a 100644
--- a/src/Magnum/Shaders/Vector.h
+++ b/src/Magnum/Shaders/Vector.h
@@ -96,8 +96,9 @@ struct VectorDrawUniform {
      * array. Useful when an UBO with more than one material is supplied or in
      * a multi-draw scenario. Should be less than the material count passed to
      * the @ref VectorGL::VectorGL(Flags, UnsignedInt, UnsignedInt)
-     * constructor. Default value is @cpp 0 @ce, meaning the first material
-     * gets used.
+     * constructor, if material count is @cpp 1 @ce, this field is assumed to
+     * be @cpp 0 @ce and isn't even read by the shader. Default value is
+     * @cpp 0 @ce, meaning the first material gets used.
      */
 
     /* This field is an UnsignedInt in the shader and materialId is extracted