0025276: Visualization - Lighting is broken if some kinds of transformation applied to a shape

In order to solve the problem, triangle vertices order is inverted in
mirrored mesh (triangulation). Mesh considered to be mirrored if its
transformation matrix determinant is less than 0.

To handle AIS object mirror transformations "Mirrored" flag stored in
OpenGl_Structure. If this flag is enabled, glFrontFace (GL_CW) applied
before the draw call.

New DRAW commands for visualization level transformations added.

src/OpenGl/OpenGl_Context.cxx

@@ -120,6 +120,7 @@ OpenGl_Context::OpenGl_Context (const Handle(OpenGl_Caps)& theCaps)
   myGlVerMinor (0),
   myIsInitialized (Standard_False),
   myIsStereoBuffers (Standard_False),
+  myIsGlNormalizeEnabled (Standard_False),
 #if !defined(GL_ES_VERSION_2_0)
   myRenderMode (GL_RENDER),
 #else
@@ -2126,3 +2127,32 @@ void OpenGl_Context::SetPointSize (const Standard_ShortReal theSize)
   }
 #endif
 }
+
+// =======================================================================
+// function : SetGlNormalizeEnabled
+// purpose  :
+// =======================================================================
+Standard_Boolean OpenGl_Context::SetGlNormalizeEnabled (Standard_Boolean isEnabled)
+{
+  if (isEnabled == myIsGlNormalizeEnabled)
+  {
+    return myIsGlNormalizeEnabled;
+  }
+
+  Standard_Boolean anOldGlNormalize = myIsGlNormalizeEnabled;
+
+  myIsGlNormalizeEnabled = isEnabled;
+
+#if !defined(GL_ES_VERSION_2_0)
+  if (isEnabled)
+  {
+    glEnable (GL_NORMALIZE);
+  }
+  else
+  {
+    glDisable (GL_NORMALIZE);
+  }
+#endif
+
+  return anOldGlNormalize;
+}