0029290: Visualization, TKOpenGl - allow defining Light source per ZLayer

Graphic3d_CLight is now defined as a class inheriting Standard_Transient,
so that it's fields now should be accessed through methods.
Graphic3d_CLight::IsEnabled() - new property allowing to disable light source everywhere.
Confusing alias OpenGl_Light has been removed.

Graphic3d_CLight::SetAttenuation() - the upper limit 1.0 of attenuation factors has been removed
since it contradicts to OpenGL specs and does not make sense.

Graphic3d_ZLayerSettings::Lights() - light sources list is now property of ZLayer.
When defined, it overrides light sources defined for View/Viewer.
New class Graphic3d_LightSet has been defined to define a set of light sources.

V3d_Light - removed obsolete interface for debug drawing lights sources.
V3d_Light is now an alias to Graphic3d_CLight.
V3d_TypeOfLight is now defined as a typedef to Graphic3d_TypeOfLightSource.

src/Graphic3d/Graphic3d_LightSet.cxx

@@ -0,0 +1,146 @@
+// Copyright (c) 2017 OPEN CASCADE SAS
+//
+// This file is part of Open CASCADE Technology software library.
+//
+// This library is free software; you can redistribute it and/or modify it under
+// the terms of the GNU Lesser General Public License version 2.1 as published
+// by the Free Software Foundation, with special exception defined in the file
+// OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
+// distribution for complete text of the license and disclaimer of any warranty.
+//
+// Alternatively, this file may be used under the terms of Open CASCADE
+// commercial license or contractual agreement.
+
+#include <Graphic3d_LightSet.hxx>
+
+#include <NCollection_LocalArray.hxx>
+
+IMPLEMENT_STANDARD_RTTIEXT(Graphic3d_LightSet, Standard_Transient)
+
+namespace
+{
+  //! Suffixes identifying light source type.
+  static const char THE_LIGHT_KEY_LETTERS[Graphic3d_TypeOfLightSource_NB] =
+  {
+    'a', // Graphic3d_TOLS_AMBIENT
+    'd', // Graphic3d_TOLS_DIRECTIONAL
+    'p', // Graphic3d_TOLS_POSITIONAL
+    's'  // Graphic3d_TOLS_SPOT
+  };
+}
+
+// =======================================================================
+// function : Graphic3d_LightSet
+// purpose  :
+// =======================================================================
+Graphic3d_LightSet::Graphic3d_LightSet()
+: myAmbient (0.0f, 0.0f, 0.0f, 0.0f),
+  myNbEnabled (0),
+  myRevision (1),
+  myCacheRevision (0)
+{
+  memset (myLightTypes,        0, sizeof(myLightTypes));
+  memset (myLightTypesEnabled, 0, sizeof(myLightTypesEnabled));
+}
+
+// =======================================================================
+// function : Add
+// purpose  :
+// =======================================================================
+Standard_Boolean Graphic3d_LightSet::Add (const Handle(Graphic3d_CLight)& theLight)
+{
+  if (theLight.IsNull())
+  {
+    throw Standard_ProgramError ("Graphic3d_LightSet::Add(), NULL argument");
+  }
+
+  const Standard_Integer anOldExtent = myLights.Extent();
+  const Standard_Integer anIndex     = myLights.Add (theLight, 0);
+  if (anIndex <= anOldExtent)
+  {
+    return Standard_False;
+  }
+
+  myLightTypes[theLight->Type()] += 1;
+  myLights.ChangeFromIndex (anIndex) = theLight->Revision();
+  ++myRevision;
+  return Standard_True;
+}
+
+// =======================================================================
+// function : Remove
+// purpose  :
+// =======================================================================
+Standard_Boolean Graphic3d_LightSet::Remove (const Handle(Graphic3d_CLight)& theLight)
+{
+  const Standard_Integer anIndToRemove = myLights.FindIndex (theLight);
+  if (anIndToRemove <= 0)
+  {
+    return Standard_False;
+  }
+
+  ++myRevision;
+  myLights.RemoveFromIndex (anIndToRemove);
+  myLightTypes[theLight->Type()] -= 1;
+  return Standard_True;
+}
+
+// =======================================================================
+// function : UpdateRevision
+// purpose  :
+// =======================================================================
+Standard_Size Graphic3d_LightSet::UpdateRevision()
+{
+  if (myCacheRevision == myRevision)
+  {
+    // check implicit updates of light sources
+    for (NCollection_IndexedDataMap<Handle(Graphic3d_CLight), Standard_Size>::Iterator aLightIter (myLights); aLightIter.More(); aLightIter.Next())
+    {
+      const Handle(Graphic3d_CLight)& aLight = aLightIter.Key();
+      if (aLightIter.Value() != aLight->Revision())
+      {
+        ++myRevision;
+        break;
+      }
+    }
+  }
+  if (myCacheRevision == myRevision)
+  {
+    return myRevision;
+  }
+
+  myCacheRevision = myRevision;
+  myAmbient.SetValues (0.0f, 0.0f, 0.0f, 0.0f);
+  memset (myLightTypesEnabled, 0, sizeof(myLightTypesEnabled));
+  NCollection_LocalArray<char, 32> aKeyLong (myLights.Extent() + 1);
+  Standard_Integer aLightLast = 0;
+  for (NCollection_IndexedDataMap<Handle(Graphic3d_CLight), Standard_Size>::Iterator aLightIter (myLights); aLightIter.More(); aLightIter.Next())
+  {
+    const Handle(Graphic3d_CLight)& aLight = aLightIter.Key();
+    aLightIter.ChangeValue() = aLight->Revision();
+    if (!aLight->IsEnabled())
+    {
+      continue;
+    }
+
+    myLightTypesEnabled[aLight->Type()] += 1;
+    if (aLight->Type() == Graphic3d_TOLS_AMBIENT)
+    {
+      myAmbient += aLight->PackedColor() * aLight->Intensity();
+    }
+    else
+    {
+      aKeyLong[aLightLast++] = THE_LIGHT_KEY_LETTERS[aLight->Type()];
+    }
+  }
+  aKeyLong[aLightLast] = '\0';
+  myAmbient.a() = 1.0f;
+  myNbEnabled = myLightTypesEnabled[Graphic3d_TOLS_DIRECTIONAL]
+              + myLightTypesEnabled[Graphic3d_TOLS_POSITIONAL]
+              + myLightTypesEnabled[Graphic3d_TOLS_SPOT];
+  myKeyEnabledLong  = aKeyLong;
+  myKeyEnabledShort = TCollection_AsciiString (myLightTypesEnabled[Graphic3d_TOLS_DIRECTIONAL] > 0 ? THE_LIGHT_KEY_LETTERS[Graphic3d_TOLS_DIRECTIONAL] : '\0')
+                    + TCollection_AsciiString (myLightTypesEnabled[Graphic3d_TOLS_POSITIONAL]  > 0 ? THE_LIGHT_KEY_LETTERS[Graphic3d_TOLS_POSITIONAL]  : '\0')
+                    + TCollection_AsciiString (myLightTypesEnabled[Graphic3d_TOLS_SPOT]        > 0 ? THE_LIGHT_KEY_LETTERS[Graphic3d_TOLS_SPOT]        : '\0');
+  return myRevision;
+}