Show some OpenGL information in Dhewm3SettingsMenu's Video tab

hopefully helps detecting when you're using the wrong GPU in a system
with iGPU and dGPU, like in #559

Changelog.md

@@ -28,6 +28,10 @@ Note: Numbers starting with a "#" like #330 refer to the bugreport with that num
   Note that this required changing the format of demos. dhewm3 can still play old demos, but ones
   recorded with current dhewm3 are not compatible with older dhewm3 versions, original Doom3 or
   other source ports (unless they do the same change).
+* Make sure macOS doesn't show popups for key-alternatives when pressing a key for longer while ingame
+* Windows: Show error MessageBox if dhewm3log.txt can't be created on startup (#544)
+* Running a timedemo with sound disabled (`s_noSound 1`) doesn't crash anymore (#163)
+* Show some OpenGL/GPU information in the *Video Options* tab of the *dhewm3 Settings Menu*
 
 1.5.4 (2024-08-03)
 ------------------------------------------------------------------------

neo/framework/Dhewm3SettingsMenu.cpp

@@ -1969,6 +1969,25 @@ static void DrawVideoOptionsMenu()
 	// options that take effect immediately, just by modifying their CVar:
 
 	DrawOptions( videoOptionsImmediately, IM_ARRAYSIZE(videoOptionsImmediately) );
+
+	ImGui::Separator();
+
+	if ( ImGui::TreeNode("OpenGL Info") ) {
+		ImGui::BeginDisabled();
+
+		ImGui::Text( "OpenGL vendor: %s", glConfig.vendor_string );
+		ImGui::Text( "OpenGL renderer: %s", glConfig.renderer_string );
+		ImGui::Text( "OpenGL version: %s", glConfig.version_string );
+
+		if ( glConfig.glDebugOutputAvailable && glConfig.haveDebugContext ) {
+			ImGui::Text( "    using an OpenGL debug context to show warnings from the OpenGL driver" );
+		}
+
+		ImGui::EndDisabled();
+		ImGui::TreePop();
+	} else {
+		AddTooltip( "Click to show information about the currently used Graphics Card (GPU)" );
+	}
 }
 
 static idStrList alDevices;