From b1d5c7c116c589c2712f00167fcffe48ae2423f1 Mon Sep 17 00:00:00 2001
From: Ilya Fedin <fedin-ilja2010@ya.ru>
Date: Sun, 19 Nov 2023 22:04:41 +0400
Subject: [PATCH] Allow Ui::GL::CheckCapapilities to work without QWidget

---
 ui/gl/gl_detection.cpp | 44 +++++++++++++++++++++++++++++++++---------
 ui/gl/gl_detection.h   |  4 +++-
 2 files changed, 38 insertions(+), 10 deletions(-)

diff --git a/ui/gl/gl_detection.cpp b/ui/gl/gl_detection.cpp
index 3d2a542..df38f90 100644
--- a/ui/gl/gl_detection.cpp
+++ b/ui/gl/gl_detection.cpp
@@ -14,9 +14,11 @@
 
 #include <QtCore/QSet>
 #include <QtCore/QFile>
+#include <QtGui/QtEvents>
 #include <QtGui/QWindow>
 #include <QtGui/QOpenGLContext>
 #include <QtGui/QOpenGLFunctions>
+#include <QOpenGLWindow>
 #include <QOpenGLWidget>
 
 #ifdef Q_OS_WIN
@@ -56,7 +58,7 @@ void CrashCheckStart() {
 
 const char kOptionAllowLinuxNvidiaOpenGL[] = "allow-linux-nvidia-opengl";
 
-Capabilities CheckCapabilities(QWidget *widget) {
+Capabilities CheckCapabilities(QWidget *widget, bool avoidWidgetCreation) {
 	if (ForceDisabled) {
 		LOG_ONCE(("OpenGL: Force-disabled."));
 		return {};
@@ -88,19 +90,43 @@ Capabilities CheckCapabilities(QWidget *widget) {
 	}
 
 	CrashCheckStart();
-	auto tester = QOpenGLWidget(widget);
-	tester.setFormat(format);
-	tester.grabFramebuffer(); // Force initialize().
-	if (!tester.window()->windowHandle()) {
-		tester.window()->createWinId();
-	}
+	const auto tester = [&] {
+		std::unique_ptr<QObject> result;
+		if (avoidWidgetCreation) {
+			const auto w = new QOpenGLWindow();
+			auto e = QResizeEvent(QSize(), QSize());
+			w->setFormat(format);
+			w->create();
+			static_cast<QObject*>(w)->event(&e); // Force initialize().
+			w->grabFramebuffer(); // Force makeCurrent().
+			result.reset(w);
+		} else {
+			const auto w = new QOpenGLWidget(widget);
+			w->setFormat(format);
+			w->grabFramebuffer(); // Force initialize().
+			if (!w->window()->windowHandle()) {
+				w->window()->createWinId();
+			}
+			result.reset(w);
+		}
+		return result;
+	}();
+	const auto testerWidget = avoidWidgetCreation
+		? nullptr
+		: static_cast<QOpenGLWidget*>(tester.get());
+	const auto testerWindow = avoidWidgetCreation
+		? static_cast<QOpenGLWindow*>(tester.get())
+		: nullptr;
+	/*const auto testerQWindow = avoidWidgetCreation
+		? static_cast<QWindow*>(tester.get())
+		: testerWidget->window()->windowHandle();*/
 	CrashCheckFinish();
 
-	const auto context = tester.context();
+	const auto context = avoidWidgetCreation ? testerWindow->context() : testerWidget->context();
 	if (!context
 		|| !context->isValid()/*
 		// This check doesn't work for a widget with WA_NativeWindow.
-		|| !context->makeCurrent(tester.window()->windowHandle())*/) {
+		|| !context->makeCurrent(testerQWindow)*/) {
 		LOG_ONCE(("OpenGL: Could not create widget in a window."));
 		return {};
 	}
diff --git a/ui/gl/gl_detection.h b/ui/gl/gl_detection.h
index 8ea77be..97e6606 100644
--- a/ui/gl/gl_detection.h
+++ b/ui/gl/gl_detection.h
@@ -24,7 +24,9 @@ struct Capabilities {
 	bool transparency = false;
 };
 
-[[nodiscard]] Capabilities CheckCapabilities(QWidget *widget = nullptr);
+[[nodiscard]] Capabilities CheckCapabilities(
+	QWidget *widget = nullptr,
+	bool avoidWidgetCreation = false);
 [[nodiscard]] Backend ChooseBackendDefault(Capabilities capabilities);
 
 void ForceDisable(bool disable);