From 89fb2f7ef3e6a24a0048f33ea45eb9944119fcaf Mon Sep 17 00:00:00 2001
From: Muaz Ahmad <m.ahmed_2000@hotmail.com>
Date: Tue, 2 May 2023 14:16:05 +0500
Subject: [PATCH] Added basic opengl rendering

---
 3dobj-renderer.pro |  8 +++++---
 opglwidget.cpp     | 22 ++++++++++++++++++----
 opglwidget.h       |  4 ++++
 3 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/3dobj-renderer.pro b/3dobj-renderer.pro
index 317b9a9..10ca2df 100644
--- a/3dobj-renderer.pro
+++ b/3dobj-renderer.pro
@@ -4,7 +4,10 @@
 
 TEMPLATE = app
 TARGET = 3dobj-renderer
-INCLUDEPATH += .
+INCLUDEPATH += . \
+	/usr/include/GL
+DEPENDPATH += . \
+	/usr/include/GL
 
 # You can make your code fail to compile if you use deprecated APIs.
 # In order to do so, uncomment the following line.
@@ -14,7 +17,6 @@ INCLUDEPATH += .
 #DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0
 
 # Input
-SOURCES += main.cpp
+SOURCES += main.cpp opglwidget.cpp
 FORMS += mainwindow.ui
-
 QT += core gui widgets
diff --git a/opglwidget.cpp b/opglwidget.cpp
index c75dfa7..0907b3d 100644
--- a/opglwidget.cpp
+++ b/opglwidget.cpp
@@ -1,8 +1,22 @@
 #include "opglwidget.h"
-#include <QtGui/QOpenGLFunctions>
+#include <GL/gl.h>
+#include <math.h>
 
-//virtual void OPGLWidget::initializeGL() override {}
+void OPGLWidget::initializeGL() {
+	glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
+}
 
-//virtual void OPGLWidget::paintGL() override {}
+void OPGLWidget::paintGL() {
+	glClear(GL_COLOR_BUFFER_BIT);
+}
 
-//virtual void OPGLWidget::resizeGL(int w, int h) override {}
+void OPGLWidget::resizeGL(int w, int h) {
+	glViewport(0, 0, w, h);
+	glMatrixMode(GL_PROJECTION);
+	glLoadIdentity();
+	float aspect = w / float(h);
+	float top = 0.2f * tan(M_PI / 8);
+	float right = 0.2f * tan(M_PI / 8) * aspect;
+	glFrustum(-right , right, -top, top, 0.1f, 100.0f);
+	glMatrixMode(GL_MODELVIEW);
+}
diff --git a/opglwidget.h b/opglwidget.h
index 022f020..3a32627 100644
--- a/opglwidget.h
+++ b/opglwidget.h
@@ -4,4 +4,8 @@ class OPGLWidget : public QOpenGLWidget
 {
 public:
 	OPGLWidget(QWidget *parent) : QOpenGLWidget(parent) {}
+protected:
+	void paintGL();
+	void initializeGL();
+	void resizeGL(int w, int h);
 };