Fix compat profile intel linux

fixes #20

KSchuster modified the logic, seems to be working with intel on Linux now. Thanks for the quick response.

OpenFlipper.cc

@@ -516,12 +516,33 @@ bool verifySpecificContextFormat(QSurfaceFormat format, QSurfaceFormat* resultin
     // Human-readable name of current profile
     auto curProfileString = profileToString(resultFormat.profile());
 
-    // Check whether the actually applied OpenGL context profile matches the requested one
-    // and the current GL version is at least the requested one (but may be higher)
+    
+    // Example: OpenGL Version 4.6 -> 46
+    auto reqVersionInt = format.version().first * 10 + format.version().second;
+    auto curVersionInt = curVersion.first * 10 + curVersion.second;
+    
+    
+    // Qt Docs say: Whenever "NoProfile" is returned, either the GL version is < 3.2 or (GL >= 3.2) it is actually a core profile
+    // Thus we set the following guidelines:
+    // 1. Whenever the actually received GL version is < than the requested one, the context is not the one requested
+    // 2. If the requested version is >= 3.2 and Compat, only Compat is allowed (as NoProfile is considered core)
+    // 3. If the requested version is >= 3.2 and Core or NoProfile is requested, Compat is not allowed
+    
+    
+    // For >= 3.2, treat Core and NoProfile equally
+    bool reqCoreOrNoProfile = format.profile() == QSurfaceFormat::NoProfile || format.profile() == QSurfaceFormat::CoreProfile;
+    bool curCoreOrNoProfile = resultFormat.profile() == QSurfaceFormat::NoProfile || resultFormat.profile() == QSurfaceFormat::CoreProfile;
+        
+    if(curVersionInt < 32 && resultFormat.profile() == QSurfaceFormat::CoreProfile)
+    {
+        std::cerr << "Warning: Got an OpenGL core context with OpengGL version < 3.2 (" << curVersion.first << "." << curVersion.second << ")! This should not be possible." << std::endl;
+        return false;
+    }
+    
+    // Check whether the conditions above are met.
     // If not, print some error to the console
-    if(curVersion.first < format.version().first ||
-       ((curVersion.first == format.version().first) && (curVersion.second < format.version().second)) ||
-       format.profile() != resultFormat.profile())
+    if(curVersionInt < reqVersionInt ||
+       (reqVersionInt >= 32 && reqCoreOrNoProfile != curCoreOrNoProfile))
     {
         std::cout << "[OpenGL context] Requested: "
                   << format.version().first << "." << format.version().second << " (" << reqProfileString << ")"
@@ -533,6 +554,10 @@ bool verifySpecificContextFormat(QSurfaceFormat format, QSurfaceFormat* resultin
 
     std::cout << "[OpenGL context] Successfully created OpenGL context with version " << curVersion.first << "."
               << curVersion.second << " (" << curProfileString << ")." << std::endl;
+    if(resultFormat.profile() == QSurfaceFormat::NoProfile || curVersionInt < 32)
+    {
+        std::cout << "[OpenGL context] Note that 'NoProfile' is fine for OpenGL version < 3.2 as core profile was introduced in 3.2" << std::endl;
+    }
 
     return true;
 }
@@ -596,6 +621,7 @@ QSurfaceFormat getContextFormat()
     {
         std::cout << "[OpenGL context] Trying to create a 4.4 compat context..." << std::endl;
         success = verifySpecificContextFormat(createFormat(QSurfaceFormat::CompatibilityProfile, 4, 4, reqSamples, reqStereo, debugContext), &resultFormat);
+        
         if(!success)
         {
             std::cout << "[OpenGL context] Trying to create a 3.2 core context..." << std::endl;