Don't use GLEW in Fireworks

The Frame Buffer Object (FBO) feature is part of OpenGL since version
3.0 from 2008. Nowadays, we can therefore assume that this feature
is always available. That means we don't have to use GLEW to check
whether this feature is present.

Like that, we can avoid using GLEW entirely, which is an implementation
detail of OpenGL loading in ROOT that will soon go away.

To make sure GLEW is not included anymore, this commit replaces includes
of `TGLIncludes.h` with the OpenGL headers only, because `TGLIncludes.h`
was including OpenGL plus GLEW.

See also:

  * root-project/root#18471
  * root-project/root#20294 (comment)

Author: guitargeek

Fireworks/Core/src/CmsAnnotation.cc

@@ -1,7 +1,9 @@
 #include <sstream>
 #include <cmath>
 
-#include "TGLIncludes.h"
+#include <GL/gl.h>
+#include <GL/glu.h>
+
 #include "TGLCamera.h"
 #include "TGLRnrCtx.h"
 #include "TGLSelectRecord.h"

Fireworks/Core/src/FWEveDigitSetScalableMarker.cc

@@ -1,4 +1,6 @@
-#include "TGLIncludes.h"
+#include <GL/gl.h>
+#include <GL/glu.h>
+
 #include "Fireworks/Core/src/FWEveDigitSetScalableMarker.h"
 
 void FWEveDigitSetScalableMarkerGL::DirectDraw(TGLRnrCtx& rnrCtx) const {

Fireworks/Core/src/FWGUIManager.cc

@@ -17,10 +17,12 @@
 #include <thread>
 #include <future>
 
+#include <GL/gl.h>
+#include <GL/glu.h>
+
 #include "TGButton.h"
 #include "TGLabel.h"
 #include "TSystem.h"
-#include "TGLIncludes.h"
 #include "TGLViewer.h"
 #include "TEveBrowser.h"
 #include "TEveManager.h"
@@ -849,16 +851,14 @@ void FWGUIManager::exportAllViews(const std::string& format, int height) {
       TString file;
       file.Form(format.c_str(), event->id().run(), event->id().event(), event->luminosityBlock(), view_name.Data());
 
-      if (GLEW_EXT_framebuffer_object) {
-        // Multi-threaded save
-        futures.push_back((*j)->CaptureAndSaveImage(file, height));
-      } else {
-        // Single-threaded save
-        if (height == -1)
-          (*j)->GetGLViewer()->SavePicture(file);
-        else
-          (*j)->GetGLViewer()->SavePictureHeight(file, height);
-      }
+      // Multi-threaded save
+      futures.push_back((*j)->CaptureAndSaveImage(file, height));
+
+      // Single-threaded save
+      // if (height == -1)
+      //   (*j)->GetGLViewer()->SavePicture(file);
+      // else
+      //   (*j)->GetGLViewer()->SavePictureHeight(file, height);
     }
   }
 

Fireworks/Core/src/FWGeoTopNodeGL.cc

@@ -1,7 +1,9 @@
 #include "Fireworks/Core/src/FWGeoTopNodeGL.h"
 #include "Fireworks/Core/interface/FWGeoTopNode.h"
 
-#include "TGLIncludes.h"
+#include <GL/gl.h>
+#include <GL/glu.h>
+
 #include "TGLRnrCtx.h"
 #include "TGLViewer.h"
 

Fireworks/Core/src/FWTEveViewer.cc

@@ -18,9 +18,11 @@
 // user include files
 
 #include "TMath.h"
-#include "TGLIncludes.h"
 #include "TGLFBO.h"
 
+#include <GL/gl.h>
+#include <GL/glu.h>
+
 #include "Fireworks/Core/interface/FWTEveViewer.h"
 #include "Fireworks/Core/interface/FWTGLViewer.h"
 

Fireworks/Core/src/FWTGLViewer.cc

@@ -18,7 +18,9 @@
 
 #include "TMath.h"
 
-#include "TGLIncludes.h"
+#include <GL/gl.h>
+#include <GL/glu.h>
+
 #include "TGLFBO.h"
 #include "TGLWidget.h"
 
@@ -142,10 +144,6 @@ TGLFBO* FWTGLViewer::GenerateFbo(Int_t w, Int_t h, Float_t pixel_object_scale) {
 
   static const TString eh("FWTGLViewer::SavePictureUsingFBO");
 
-  if (!GLEW_EXT_framebuffer_object) {
-    ::Warning(eh, "Missing FBO support.");
-  }
-
   if (!TakeLock(kDrawLock)) {
     ::Error(eh, "viewer locked - try later.");
     return nullptr;

Fireworks/Core/src/FWTextProjected.cc

@@ -20,7 +20,8 @@
 #include "TEveTrans.h"
 #include "TGLBoundingBox.h"
 
-#include "TGLIncludes.h"
+#include <GL/gl.h>
+#include <GL/glu.h>
 
 #include "TGLRnrCtx.h"
 #include "TGLUtil.h"

Fireworks/Vertices/src/TEveEllipsoidGL.cc

@@ -14,7 +14,9 @@
 #include "TMatrixDSym.h"
 
 #include "TDecompSVD.h"
-#include "TGLIncludes.h"
+
+#include <GL/gl.h>
+#include <GL/glu.h>
 
 //==============================================================================
 // TEveEllipsoidGL