Trying to understand what OpenGL really is...

1. I am Mrinmoy Dalal
I am here because I love to give presentations.
You can find me at mrinmoydalal@live.com
Hello!

2. GRAPHICS and
COMPUTERS
Let’s start with the first set of slides

3. “
Because of the nature of Moore's
law, anything that an extremely
clever graphics programmer can
do at one point can be replicated
by a merely competent
programmer some number of
years later.
-John Carmack

4. What is COMPUTER GRAPHICS
Computer graphics are pictures and movies
created using computers - usually referring
to image data created by a computer
specifically with help from specialized graphical
hardware and software.

6. Open Graphics Library
The Cross – Platform, Cross – Application
Graphics API

7. ◉ OpenGL (Open Graphics Library) was developed originally
by SGI (Silicon Graphics Incorporated)
◉ Utilities in OpenGL library can be called from C, C++
◉ Bindings available also for other programming languages
such as Java, Tcl, Python, Ada, and Fortran
◉ Built on graphics hardware and works fast
◉ Portable to most other systems and able to use other
architectures’ graphics capabilities
What is OpenGL?

8. Why learn OpenGL
Good support of hardware
◉ Microsoft DX 10 and DX11 can only run on the platform upon
Windows Vista.
◉ The same function can be implemented by OpenGL on Windows XP.
◉ OpenGL provides extensions for the latest function of GPU vendors.
Cross-platform
◉ OpenGL works on Windows/ Linux/ Mac
◉ OpenGL ES
◉ WebGL

9. OpenGL Libraries
OpenGL core library
◉ OpenGL32 on Windows
◉ GL on most unix/linux system
OpenGL Utility Library (GLU)
◉ Provides functionality in OpenGL core but avoids having to
rewrite code
Links with window system
◉ GLX for X window systems
◉ WGL for Windows

10. GLUT
◉ OpenGL Utility Toolkit library
◉ A tool which allows the creation of windows and handling of
input on multiple systems
◉ Making OpenGL cross-platform and extremely simple to set
up
◉ Original GLUT is no longer being developed
◉ There is a remake of GLUT called FreeGLUT

11. GLEW
◉ OpenGL Extension Wrangler
◉ A cross-platform open-source C/C++ extension loading library
◉ Provides efficient run-time mechanisms for determining which
OpenGL extensions are supported on the target platform

12. API HIERARCHY

13. OpenGL Pipeline

14. OpenGL Pipeline

15. OpenGL API
void glutInit(int*argcp, char **argv);
Initialized GLUT
void glutInitDisplayMode(unsigned intmode);
Sets the display mode
void glutInitWindowSize(intwidth, intheight);
void glutInitWindowPosition(intx, inty);
Set the size and the position on the screen for GLUT window
int glutCreateWindow(char *name);
Create window and give it a title/caption

16. OpenGL API
void glutDisplayFunc(void (*func) (void));
Sets the display callback for the current window
void glutMainLoop(void);
Enters the GLUT event processing loop
void glClearColor(GLfloatred, GLfloatgreen, GLfloatblue, GLfloatalpha);
Specify clear values for the color buffers
void glClear(GLbitfieldmask);
Clear buffers to preset values

17. Place your screenshot here
Desktop project
First OpenGL test run
with a Torus…

18. What’s Happening
◉ OpenGL pipeline is the process, from vertex buffers to
framebuffer, that your data goes through when you
make a single "draw" call in OpenGL.
◉ Rendering a scene usually involves multiple draw jobs,
switching out textures, other uniform state, or shaders
between passes and using the framebuffer's depth and
stencil buffers to combine the results of each pass.

19. CONCLUSION
OpenGL is that technology which has literally
unlimited scope. All one needs is to channel their
creativity in the right direction and one could use
this technology to earn millions, even probably,
from the comfort of one’s home.

20. Any questions ?
You can find me at
◉ @mrinmoydalal
◉ mrinmoydalal@live.com
Thanks!

21. Credits
Special thanks to all the people who made and
released these awesome resources for free:
◉Presentation template by SlidesCarnival
◉Photographs by Unsplash
Also please refer to the video attached for an
insight as to how I made the Rotating Torus.