Bring QSurfaceFormat configurability to qmlscene's level in the qml tool

Restore the --transparent and --multisample options.  Also make the
default QSurfaceFormat setting universal (no need to tie it to the
option of forcing a core profile context), and prevent the warning
that is printed when the default surfaceformat is changed after the
application is already created with AA_ShareOpenGLContexts set. This
involves having to handle the relevant arguments manually early on,
not through QCommandLineParser.

All this matches the qmlscene behavior.

NB qmlscene requests 16 samples with --multisample which is completely
pointless in practice. Use the common 4 now.

Change-Id: I671e5f22846a715675ea936bb7cf2a31a849dc28
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>
Reviewed-by: Andy Nichols <andy.nichols@qt.io>

1 files changed, 39 insertions, 12 deletions

diff --git a/tools/qml/main.cpp b/tools/qml/main.cpp
index f09f3a5ff8..e9a084a059 100644
--- a/tools/qml/main.cpp
+++ b/tools/qml/main.cpp
@@ -80,6 +80,9 @@ static bool verboseMode = false;
 static bool quietMode = false;
 static bool glShareContexts = true;
 static bool disableShaderCache = true;
+static bool requestAlphaChannel = false;
+static bool requestMSAA = false;
+static bool requestCoreProfile = false;
 
 static void loadConf(const QString &override, bool quiet) // Terminates app on failure
 {
@@ -327,6 +330,12 @@ static void getAppFlags(int argc, char **argv)
             glShareContexts = false;
         } else if (!strcmp(argv[i], "-enable-shader-cache") || !strcmp(argv[i], "--enable-shader-cache")) {
             disableShaderCache = false;
+        } else if (!strcmp(argv[i], "-transparent") || !strcmp(argv[i], "--transparent")) {
+            requestAlphaChannel = true;
+        } else if (!strcmp(argv[i], "-multisample") || !strcmp(argv[i], "--multisample")) {
+            requestMSAA = true;
+        } else if (!strcmp(argv[i], "-core-profile") || !strcmp(argv[i], "--core-profile")) {
+            requestCoreProfile = true;
         }
     }
 #else
@@ -365,6 +374,27 @@ int main(int argc, char *argv[])
 {
     getAppFlags(argc, argv);
 
+    // Must set the default QSurfaceFormat before creating the app object if
+    // AA_ShareOpenGLContexts is going to be set.
+#if defined(QT_GUI_LIB)
+    QSurfaceFormat surfaceFormat;
+    surfaceFormat.setDepthBufferSize(24);
+    surfaceFormat.setStencilBufferSize(8);
+    if (requestMSAA)
+        surfaceFormat.setSamples(4);
+    if (requestMSAA)
+        surfaceFormat.setAlphaBufferSize(8);
+    if (qEnvironmentVariableIsSet("QSG_CORE_PROFILE")
+            || qEnvironmentVariableIsSet("QML_CORE_PROFILE")
+            || requestCoreProfile)
+    {
+        // intentionally requesting 4.1 core to play nice with macOS
+        surfaceFormat.setVersion(4, 1);
+        surfaceFormat.setProfile(QSurfaceFormat::CoreProfile);
+    }
+    QSurfaceFormat::setDefaultFormat(surfaceFormat);
+#endif
+
     if (glShareContexts)
         QCoreApplication::setAttribute(Qt::AA_ShareOpenGLContexts);
     if (disableShaderCache)
@@ -449,14 +479,22 @@ int main(int argc, char *argv[])
     parser.addOption(glSoftwareOption); // Just for the help text... we've already handled this argument above
     QCommandLineOption glCoreProfile(QStringLiteral("core-profile"),
         QCoreApplication::translate("main", "Force use of OpenGL Core Profile."));
-    parser.addOption(glCoreProfile);
+    parser.addOption(glCoreProfile); // Just for the help text... we've already handled this argument above
     QCommandLineOption glContextSharing(QStringLiteral("disable-context-sharing"),
         QCoreApplication::translate("main", "Disable the use of a shared GL context for QtQuick Windows"));
     parser.addOption(glContextSharing); // Just for the help text... we've already handled this argument above
+    // Options relevant for other 3D APIs as well
     QCommandLineOption shaderCaching(QStringLiteral("enable-shader-cache"),
         QCoreApplication::translate("main", "Enable persistent caching of generated shaders"));
     parser.addOption(shaderCaching); // Just for the help text... we've already handled this argument above
+    QCommandLineOption transparentOption(QStringLiteral("transparent"),
+        QCoreApplication::translate("main", "Requests an alpha channel in order to enable semi-transparent windows."));
+    parser.addOption(transparentOption); // Just for the help text... we've already handled this argument above
+    QCommandLineOption multisampleOption(QStringLiteral("multisample"),
+        QCoreApplication::translate("main", "Requests 4x multisample antialiasing."));
+    parser.addOption(multisampleOption); // Just for the help text... we've already handled this argument above
 #endif // QT_GUI_LIB
+
     // Debugging and verbosity options
     QCommandLineOption quietOption(QStringLiteral("quiet"),
         QCoreApplication::translate("main", "Suppress all output."));
@@ -525,17 +563,6 @@ int main(int argc, char *argv[])
     if (!customSelectors.isEmpty())
         e.setExtraFileSelectors(customSelectors);
 
-#if defined(QT_GUI_LIB)
-    if (qEnvironmentVariableIsSet("QSG_CORE_PROFILE") || qEnvironmentVariableIsSet("QML_CORE_PROFILE") || parser.isSet(glCoreProfile)) {
-        QSurfaceFormat surfaceFormat;
-        surfaceFormat.setStencilBufferSize(8);
-        surfaceFormat.setDepthBufferSize(24);
-        surfaceFormat.setVersion(4, 1);
-        surfaceFormat.setProfile(QSurfaceFormat::CoreProfile);
-        QSurfaceFormat::setDefaultFormat(surfaceFormat);
-    }
-#endif
-
     files << parser.values(qmlFileOption);
     if (parser.isSet(configOption))
         confFile = parser.value(configOption);