OpenGL in Qt

In the early days, Qt had a module named OpenGL, but in Qt 5.x, that module is deprecated. A new version of facilities for OpenGL supports is put into the gui module; if you search classes whose names start with QOpenGL in the Qt docs, you will find them. Besides the facilities that reside in the gui module, there's another important class named QOpenGLWidget in the widgets module. In this section, we will use some of these facilities to draw a triangle with OpenGL in Qt.

First, let's create the required Qt projects:

$ pwd
/home/kdr2/Work/Books/Qt5-And-OpenCV4-Computer-Vision-Projects/Chapter-08
$ mkdir QtGL
$ cd QtGL/
$ touch main.cpp
$ qmake -project
$ ls
QtGL.pro main.cpp
$

Then, we change the content of the QtGL.pro project file to the following:

TEMPLATE = app
TARGET = QtGL

QT += core gui widgets

INCLUDEPATH += .

DEFINES += QT_DEPRECATED_WARNINGS

# Input
HEADERS...