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Computer graphic
--OpenGL Tutorial
2
About me
• Who: Jie Chen
• What: Teaching assistant, Lab exercises
• How: TS329
• Email: jiechen@ee.oulu.fi
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• Website:http://www.ee.oulu.fi/~jiechen/Course.htm
• Prerequisiteprogramming skills using C/C++
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• Tools: OpenGL
• Task: what OpenGL is and how it enables us to program in 3D.
• GL: graphic library
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What is OpenGL?• It's a way to draw stuff in 3D.
– It can also be used for 2D drawing, but this course doesn't focus on that. There are better tools for straight 2D drawing, such asSDL and Allegro.
• The purpose of OpenGL is to communicate with the graphics card about our 3D scene. – The graphics card is where the 3D computation happens. – So why not talk to the graphics card directly?
• Each graphics card is a little different.• In a sense, they all speak different "languages". To talk to them all,
we can either learn all of their languages, or find a "translator" that knows all of their languages and talk to the translator, so that we only have to know one language.
• OpenGL serves as a "translator" for graphics cards.
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Some Terminologies• OpenGL
– GL: graphic library
– a software interface to graphics hardware.
– This interface consists of about 150 distinct commands.
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Some Terminologies• GLU (OpenGL Utility Library)
– GLU is a standard part of every OpenGL implementation.
– A sophisticated library that provides the features could be built on top of OpenGL.
– Provides many of the modeling features, such as • quadric surfaces and • NURBS (Non-Uniform Rational B-Spline) curves and
surfaces.
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Some Terminologies• GLUT (OpenGL Utility Toolkit)
– a window system independent toolkit for writing OpenGL programs.
– It implements a simple windowing application programming interface (API) for OpenGL.
– GLUT makes it much easier to learn about and explore OpenGL Programming.
– Controlling the IO layer • input: mouse and keyboard • output: visual windows
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Include Files
• For all OpenGL applications, we need to include the gl.h header file in every file.
• Almost all OpenGL applications use GLU, which requires inclusion of the glu.h header file. So almost every OpenGL source file begins with– #include <GL/gl.h>– #include <GL/glu.h>
• If we are using GLUT for managing our window manager tasks, we should include– #include <GL/glut.h>
• Note that glut.h includes gl.h and glu.hautomatically
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Getting OpenGL Set Up• In following part, we will show how to get
OpenGL and GLUT set up on Windows, so that we can get started making 3D programs.
• we can use OpenGL on other operating systems, but this part doesn't cover how to get it set up on those OSes.– Mac OS X
http://www.videotutorialsrock.com/opengl_tutorial/get_opengl_setup_mac_osx/home.php
– Linuxhttp://www.videotutorialsrock.com/opengl_tutorial/get_opengl_setup_linux/home.php
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Getting OpenGL Set Up on Windows
• Explain how to get OpenGL and GLUT set up on Windows (e.g., windows XP).
• Use the Visual C++ 6.0. • You can also use other version, such as Visual
C++ 2003, 2005, 2008. – CSE: Computer science and engineering laboratory
• You can find it in our server– Other department:
• you can downloade here:• http://msdn.microsoft.com/zh-cn/express/default.aspx• You have to register, which is free, within 30 days.
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OpenGL
• Download – OpenGL installer – GLUT binary
• http://www.ee.oulu.fi/~jiechen/Course.htm• Lecture notes ->Lecture 3
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OpenGL setup
• Run the OpenGL installer.
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GLUT setup• Extract GLUT to the directory of your choice. • We can do this by creating a new directory,
locating and opening the ZIP file using Windows Explorer, and copying the files to the new directory using copy-paste.
• Alternatively, We can use a free program like WinZip to extract GLUT.
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GLUT setup
• In the directory GLUT, make two folders – one called "include" and – one called "lib".
• File assignment:– In the "include" folder, create another folder
called "GL", and move glut.h to that folder (..\Include\GL).
– Move all of the other extracted files for GLUT into the "lib" folder.
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Setup for Visual C++• Run Visual C++ • Go to Tools -> Options-> Directories • Adding " GLUT \include", and " GLUT \lib"
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Setup for Visual C++
• glut32.dll (dll: Dynamic-link library)
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Compiling and Running the Test Program
• To make sure that everything was set up correctly, we're going to see if we can get a test program to work.
• Download test program and extract it somewhere on your computer.– http://www.ee.oulu.fi/~jiechen/Course.htm– Lecture notes ->Lecture 3
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Compiling and Running the Test Program
• Run Visual C++. • Go to File -> New ->
Project• Select Win32 Console
applications• Set the project file
location. • Enter in a name for
your project (such as “CG") and click ok.
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Compiling and Running the Test Program
• Select “a ‘hello world’ applications”• click “Finish” to finish creating the project.
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Compiling and Running the Test Program
• File copy– extracted the downloaded test program– Copy the following files to the current folder
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Compiling and Running the Test Program
• File content modification– Copy the code in main.cpp to replace those in
CG.cpp
– Add #include "stdafx.h” at the beginning of CG.cpp
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Compiling and Running the Test Program
• Change from "Debug" to "Release".
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Compiling and Running the Test Program
• File adding– Two files: imageloader.h and imageloader.cpp– Press ok
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Compiling and Running the Test Program
• File adding– Lib file: glut32.lib– Press ok
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Compiling and Running the Test Program
• Workspace view
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Compiling and Running the Test Program
• Go to Build -> Build project_name (e.g., Build CG.cpp) to build our project.
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Compiling and Running the Test Program
• Run it!
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Compiling and Running the Test Program
• Take a look at main.cpp. – Notice that the include directives
for OpenGL appear after the #include directives for the normal C++ include files.
– If we had them in the opposite order, you'd get a compiler error. So make sure that the include files for the standard C++ stuff appear before the include files for OpenGL. ERROR
Correct
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Compiling and Running the Test Program
• Whew! We've finished setting up OpenGL.
• Now we're ready to learn how to program in 3D.
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Demo
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• OpenGL Programming Guide or ‘The Red Book’– http://unreal.srk.fer.hr/theredbook/
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• The end of this lecture!
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