From 95295bd41bc711bbc450ac6f5ccc68e64fefffa3 Mon Sep 17 00:00:00 2001
From: "Steinar H. Gunderson" <sgunderson@bigfoot.com>
Date: Sun, 4 Oct 2015 18:06:15 +0200
Subject: [PATCH] Use QGLWidget instead of QOpenGLWidget, as the latter is too
 slow.

---
 Makefile         |  4 ++--
 context.cpp      |  5 ++++-
 context.h        |  2 ++
 glwidget.cpp     | 16 +++++++++++-----
 glwidget.h       |  9 +++++++--
 main.cpp         |  6 ++++++
 ui_mainwindow.ui | 12 ++++++------
 7 files changed, 38 insertions(+), 16 deletions(-)

diff --git a/Makefile b/Makefile
index 16bd2b5..aa320d4 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,6 @@
 CXX=g++
-CXXFLAGS := -O2 -march=native -g -std=gnu++11 -Wall -Wno-deprecated-declarations -fPIC $(shell pkg-config --cflags Qt5Core Qt5Gui Qt5Widgets Qt5OpenGLExtensions libusb-1.0 movit) -pthread -DMOVIT_SHADER_DIR=\"$(shell pkg-config --variable=shaderdir movit)\"
-LDFLAGS=$(shell pkg-config --libs Qt5Core Qt5Gui Qt5Widgets Qt5OpenGLExtensions libusb-1.0 movit) -lEGL -lGL -pthread -lva -lva-drm -lva-x11 -lX11 -lavformat -lavcodec -lavutil
+CXXFLAGS := -O2 -march=native -g -std=gnu++11 -Wall -Wno-deprecated-declarations -fPIC $(shell pkg-config --cflags Qt5Core Qt5Gui Qt5Widgets Qt5OpenGLExtensions Qt5OpenGL libusb-1.0 movit) -pthread -DMOVIT_SHADER_DIR=\"$(shell pkg-config --variable=shaderdir movit)\"
+LDFLAGS=$(shell pkg-config --libs Qt5Core Qt5Gui Qt5Widgets Qt5OpenGLExtensions Qt5OpenGL libusb-1.0 movit) -lEGL -lGL -pthread -lva -lva-drm -lva-x11 -lX11 -lavformat -lavcodec -lavutil
 
 # Qt objects
 OBJS=glwidget.o main.o mainwindow.o window.o
diff --git a/context.cpp b/context.cpp
index 72275e9..946d40d 100644
--- a/context.cpp
+++ b/context.cpp
@@ -4,6 +4,9 @@
 #include <QOpenGLContext>
 #include <QOffscreenSurface>
 #include <QWindow>
+#include <QGLWidget>
+
+QGLWidget *global_share_widget = nullptr;
 
 QSurface *create_surface(const QSurfaceFormat &format)
 {
@@ -21,7 +24,7 @@ QSurface *create_surface(const QSurfaceFormat &format)
 QOpenGLContext *create_context()
 {
 	QOpenGLContext *context = new QOpenGLContext;
-	context->setShareContext(QOpenGLContext::globalShareContext());
+	context->setShareContext(global_share_widget->context()->contextHandle());
 	context->create();
 	return context;
 }
diff --git a/context.h b/context.h
index 5a75766..c670473 100644
--- a/context.h
+++ b/context.h
@@ -5,7 +5,9 @@
 class QSurface;
 class QOpenGLContext;
 class QSurfaceFormat;
+class QGLWidget;
 
+extern QGLWidget *global_share_widget;
 QSurface *create_surface(const QSurfaceFormat &format);
 QOpenGLContext *create_context();
 bool make_current(QOpenGLContext *context, QSurface *surface);
diff --git a/glwidget.cpp b/glwidget.cpp
index 17f7832..6e216a6 100644
--- a/glwidget.cpp
+++ b/glwidget.cpp
@@ -18,7 +18,7 @@
 #include <movit/util.h>
 
 GLWidget::GLWidget(QWidget *parent)
-    : QOpenGLWidget(parent),
+    : QGLWidget(parent, global_share_widget),
       resource_pool(new movit::ResourcePool)
 {
 }
@@ -37,10 +37,11 @@ void GLWidget::initializeGL()
 		QMetaObject::invokeMethod(t, "update", Qt::AutoConnection);
 	});
 
-	QSurface *surface = create_surface(format());
-	QSurface *surface2 = create_surface(format());
-	QSurface *surface3 = create_surface(format());
-	QSurface *surface4 = create_surface(format());
+	QSurfaceFormat fmt = QGLFormat::toSurfaceFormat(format());
+	QSurface *surface = create_surface(fmt);
+	QSurface *surface2 = create_surface(fmt);
+	QSurface *surface3 = create_surface(fmt);
+	QSurface *surface4 = create_surface(fmt);
 	start_mixer(surface, surface2, surface3, surface4);
 
 	// Prepare the shaders to actually get the texture shown (ick).
@@ -89,6 +90,11 @@ void GLWidget::initializeGL()
 #endif
 }
 
+void GLWidget::resizeGL(int width, int height)
+{
+	glViewport(0, 0, width, height);
+}
+
 void GLWidget::paintGL()
 {
 	DisplayFrame frame;
diff --git a/glwidget.h b/glwidget.h
index d2ff50c..bb62940 100644
--- a/glwidget.h
+++ b/glwidget.h
@@ -1,13 +1,17 @@
 #ifndef GLWIDGET_H
 #define GLWIDGET_H
 
-#include <QOpenGLWidget>
+#include <QGLWidget>
 
 namespace movit {
 class ResourcePool;
 }
 
-class GLWidget : public QOpenGLWidget
+// Note: We use the older QGLWidget instead of QOpenGLWidget as it is
+// much faster (does not go through a separate offscreen rendering step).
+//
+// TODO: Consider if QOpenGLWindow could do what we want.
+class GLWidget : public QGLWidget
 {
 	Q_OBJECT
 
@@ -17,6 +21,7 @@ public:
 
 protected:
 	void initializeGL() override;
+	void resizeGL(int width, int height) override;
 	void paintGL() override;
 
 private:
diff --git a/main.cpp b/main.cpp
index b39fafe..8ebe6d2 100644
--- a/main.cpp
+++ b/main.cpp
@@ -3,9 +3,11 @@
 #include <QDesktopWidget>
 #include <QSurfaceFormat>
 #include <QtGui/QOpenGLContext>
+#include <QGLFormat>
 
 #include "mainwindow.h"
 #include "mixer.h"
+#include "context.h"
 
 int main(int argc, char *argv[])
 {
@@ -22,6 +24,10 @@ int main(int argc, char *argv[])
 	fmt.setMinorVersion(1);
 	QSurfaceFormat::setDefaultFormat(fmt);
 
+	QGLFormat::setDefaultFormat(QGLFormat::fromSurfaceFormat(fmt));
+
+	global_share_widget = new QGLWidget();
+
 	MainWindow mainWindow;
 	mainWindow.resize(QSize(1280, 720));
 	mainWindow.show();
diff --git a/ui_mainwindow.ui b/ui_mainwindow.ui
index 8240ecf..b7091f9 100644
--- a/ui_mainwindow.ui
+++ b/ui_mainwindow.ui
@@ -34,7 +34,7 @@
            <number>0</number>
           </property>
           <item>
-           <widget class="QOpenGLWidget" name="me_preview">
+           <widget class="QGLWidget" name="me_preview">
             <property name="sizePolicy">
              <sizepolicy hsizetype="Expanding" vsizetype="Expanding">
               <horstretch>1</horstretch>
@@ -140,7 +140,7 @@
          <number>0</number>
         </property>
         <item>
-         <widget class="QOpenGLWidget" name="preview2">
+         <widget class="QGLWidget" name="preview2">
           <property name="sizePolicy">
            <sizepolicy hsizetype="Expanding" vsizetype="Expanding">
             <horstretch>1</horstretch>
@@ -150,7 +150,7 @@
          </widget>
         </item>
         <item>
-         <widget class="QOpenGLWidget" name="preview1">
+         <widget class="QGLWidget" name="preview1">
           <property name="sizePolicy">
            <sizepolicy hsizetype="Expanding" vsizetype="Expanding">
             <horstretch>1</horstretch>
@@ -160,7 +160,7 @@
          </widget>
         </item>
         <item>
-         <widget class="QOpenGLWidget" name="preview3">
+         <widget class="QGLWidget" name="preview3">
           <property name="sizePolicy">
            <sizepolicy hsizetype="Expanding" vsizetype="Expanding">
             <horstretch>1</horstretch>
@@ -170,7 +170,7 @@
          </widget>
         </item>
         <item>
-         <widget class="QOpenGLWidget" name="preview4">
+         <widget class="QGLWidget" name="preview4">
           <property name="sizePolicy">
            <sizepolicy hsizetype="Expanding" vsizetype="Expanding">
             <horstretch>1</horstretch>
@@ -232,7 +232,7 @@
  <customwidgets>
   <customwidget>
    <class>GLWidget</class>
-   <extends>QOpenGLWidget</extends>
+   <extends>QGLWidget</extends>
    <header>glwidget.h</header>
   </customwidget>
  </customwidgets>
-- 
2.39.2