diff --git a/src/OpenGl/OpenGl_ShaderManager.cxx b/src/OpenGl/OpenGl_ShaderManager.cxx
index 5bea2eff4a..fcc1c1d8c3 100644
--- a/src/OpenGl/OpenGl_ShaderManager.cxx
+++ b/src/OpenGl/OpenGl_ShaderManager.cxx
@@ -1626,7 +1626,7 @@ Standard_Boolean OpenGl_ShaderManager::prepareStdProgramUnlit (Handle(OpenGl_Sha
       EOL"        k = -1.0;"
       EOL"                 "
       EOL"      vec3 pn = normalize(vec3(proj_normal.xy, 0.0));"
-      EOL"      pdelta = k * pn * aShift / 2;"
+      EOL"      pdelta = k * pn * aShift / 2.0;"
       EOL"    }"
       EOL"  }"
       EOL"  else"
@@ -1634,7 +1634,7 @@ Standard_Boolean OpenGl_ShaderManager::prepareStdProgramUnlit (Handle(OpenGl_Sha
       EOL"    if (occIsSilhouettePass > 0.1)"
       EOL"    {"
       EOL"      vec4 proj_vertex = occProjectionMatrix * occWorldViewMatrix * occModelWorldMatrix * vertex;"
-      EOL"      delta = occNormal.xyz * aShift/2 * proj_vertex.w;"
+      EOL"      delta = occNormal.xyz * aShift / 2.0 * proj_vertex.w;"
       EOL"    }"
       EOL"  }"
       EOL"  "