diff --git a/src/libslic3r/SLA/RasterBase.cpp b/src/libslic3r/SLA/RasterBase.cpp
index 0b6c45eff..7240b198d 100644
--- a/src/libslic3r/SLA/RasterBase.cpp
+++ b/src/libslic3r/SLA/RasterBase.cpp
@@ -11,11 +11,6 @@
 
 namespace Slic3r { namespace sla {
 
-const RasterBase::TMirroring RasterBase::NoMirror = {false, false};
-const RasterBase::TMirroring RasterBase::MirrorX  = {true, false};
-const RasterBase::TMirroring RasterBase::MirrorY  = {false, true};
-const RasterBase::TMirroring RasterBase::MirrorXY = {true, true};
-
 EncodedRaster PNGRasterEncoder::operator()(const void *ptr, size_t w, size_t h,
                                            size_t      num_components)
 {
diff --git a/src/libslic3r/SLA/RasterBase.hpp b/src/libslic3r/SLA/RasterBase.hpp
index ae8c0aefa..33d39eafb 100644
--- a/src/libslic3r/SLA/RasterBase.hpp
+++ b/src/libslic3r/SLA/RasterBase.hpp
@@ -60,10 +60,10 @@ public:
     enum Orientation { roLandscape, roPortrait };
     
     using TMirroring = std::array<bool, 2>;
-    static const TMirroring NoMirror;
-    static const TMirroring MirrorX;
-    static const TMirroring MirrorY;
-    static const TMirroring MirrorXY;
+    static const constexpr TMirroring NoMirror = {false, false};
+    static const constexpr TMirroring MirrorX  = {true, false};
+    static const constexpr TMirroring MirrorY  = {false, true};
+    static const constexpr TMirroring MirrorXY = {true, true};
     
     struct Trafo {
         bool mirror_x = false, mirror_y = false, flipXY = false;