From 685db2ab5e830b88dba32b47c636dee701d49b1b Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Mon, 21 Jun 2021 10:27:11 +0400
Subject: [PATCH] Simplify native child OpenGL window creation.

---
 CMakeLists.txt      |   2 +
 ui/gl/gl_window.cpp | 106 ++++++++++++++++++++++++++++++++++++++++++++
 ui/gl/gl_window.h   |  39 ++++++++++++++++
 3 files changed, 147 insertions(+)
 create mode 100644 ui/gl/gl_window.cpp
 create mode 100644 ui/gl/gl_window.h

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 28b5e9f..3a22f9e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -69,6 +69,8 @@ PRIVATE
     ui/gl/gl_shader.h
     ui/gl/gl_surface.cpp
     ui/gl/gl_surface.h
+    ui/gl/gl_window.cpp
+    ui/gl/gl_window.h
     ui/image/image_prepare.cpp
     ui/image/image_prepare.h
     ui/layers/box_content.cpp
diff --git a/ui/gl/gl_window.cpp b/ui/gl/gl_window.cpp
new file mode 100644
index 0000000..497aba1
--- /dev/null
+++ b/ui/gl/gl_window.cpp
@@ -0,0 +1,106 @@
+// This file is part of Desktop App Toolkit,
+// a set of libraries for developing nice desktop applications.
+//
+// For license and copyright information please follow this link:
+// https://github.com/desktop-app/legal/blob/master/LEGAL
+//
+#include "ui/gl/gl_window.h"
+
+#include "ui/gl/gl_detection.h"
+#include "ui/widgets/window.h"
+#include "base/platform/base_platform_info.h"
+#include "base/debug_log.h"
+
+namespace Ui::GL {
+namespace {
+
+constexpr auto kUseNativeChild = ::Platform::IsWindows();
+
+} // namespace
+
+Window::Window()
+: _window(std::make_unique<Ui::Window>())
+, _bodyNativeWrap(createNativeBodyWrap())
+, _body(_bodyNativeWrap ? _bodyNativeWrap.get() : _window->body().get()) {
+}
+
+Window::~Window() = default;
+
+Backend Window::backend() const {
+	return _backend;
+}
+
+not_null<Ui::Window*> Window::window() const {
+	return _window.get();
+}
+
+not_null<Ui::RpWidget*> Window::widget() const {
+	return _body.get();
+}
+
+std::unique_ptr<Ui::Window> Window::createWindow() {
+	auto result = std::make_unique<Ui::Window>();
+	if constexpr (!kUseNativeChild) {
+		const auto capabilities = Ui::GL::CheckCapabilities(result.get());
+		const auto use = ::Platform::IsMac()
+			? true
+			: ::Platform::IsWindows()
+			? capabilities.supported
+			: capabilities.transparency;
+		LOG(("OpenGL: %1 (Ui::GL::Window)").arg(use ? "[TRUE]" : "[FALSE]"));
+		_backend = use ? Ui::GL::Backend::OpenGL : Ui::GL::Backend::Raster;
+
+		if (!use) {
+			// We have to create a new window, if OpenGL initialization failed.
+			result = std::make_unique<Ui::Window>();
+		}
+	}
+	return result;
+}
+
+std::unique_ptr<Ui::RpWidget> Window::createNativeBodyWrap() {
+	if constexpr (!kUseNativeChild) {
+		return nullptr;
+	}
+	const auto create = [] {
+		auto result = std::make_unique<Ui::RpWidget>();
+		result->setWindowFlags(Qt::FramelessWindowHint | Qt::Window);
+		result->setAttribute(Qt::WA_NativeWindow);
+		result->setAttribute(Qt::WA_DontCreateNativeAncestors);
+		result->setAttribute(Qt::WA_OpaquePaintEvent);
+		result->setAttribute(Qt::WA_NoSystemBackground);
+		return result;
+	};
+
+	auto result = create();
+	const auto capabilities = Ui::GL::CheckCapabilities(result.get());
+	const auto use = ::Platform::IsMac()
+		? true
+		: ::Platform::IsWindows()
+		? capabilities.supported
+		: capabilities.transparency;
+	LOG(("OpenGL: %1 (Ui::GL::WindowBody)").arg(use ? "[TRUE]" : "[FALSE]"));
+	_backend = use ? Ui::GL::Backend::OpenGL : Ui::GL::Backend::Raster;
+
+	if (!use) {
+		// We have to create a new window, if OpenGL initialization failed.
+		result = create();
+	}
+
+	const auto nativeParent = _window->body();
+	nativeParent->setAttribute(Qt::WA_OpaquePaintEvent);
+	nativeParent->setAttribute(Qt::WA_NoSystemBackground);
+
+	const auto raw = result.get();
+	raw->setParent(nativeParent);
+	raw->show();
+	raw->update();
+	_window->sizeValue(
+	) | rpl::start_with_next([=](QSize size) {
+		raw->setGeometry(QRect(QPoint(), size));
+	}, raw->lifetime());
+
+	return result;
+}
+
+} // namespace Ui::GL
diff --git a/ui/gl/gl_window.h b/ui/gl/gl_window.h
new file mode 100644
index 0000000..bfa4199
--- /dev/null
+++ b/ui/gl/gl_window.h
@@ -0,0 +1,39 @@
+// This file is part of Desktop App Toolkit,
+// a set of libraries for developing nice desktop applications.
+//
+// For license and copyright information please follow this link:
+// https://github.com/desktop-app/legal/blob/master/LEGAL
+//
+#pragma once
+
+
+namespace Ui {
+class Window;
+class RpWidget;
+} // namespace Ui
+
+namespace Ui::GL {
+
+enum class Backend;
+
+class Window final {
+public:
+	Window();
+	~Window();
+
+	[[nodiscard]] Backend backend() const;
+	[[nodiscard]] not_null<Ui::Window*> window() const;
+	[[nodiscard]] not_null<Ui::RpWidget*> widget() const;
+
+private:
+	[[nodiscard]] std::unique_ptr<Ui::Window> createWindow();
+	[[nodiscard]] std::unique_ptr<Ui::RpWidget> createNativeBodyWrap();
+
+	Ui::GL::Backend _backend = Ui::GL::Backend();
+	const std::unique_ptr<Ui::Window> _window;
+	const std::unique_ptr<Ui::RpWidget> _bodyNativeWrap;
+	const not_null<Ui::RpWidget*> _body;
+
+};
+
+} // namespace Ui::GL