Open gl introduction
OpenGL is a software interface for graphics hardware that provides a portable low-level 3D graphics library. It consists of three main libraries - OpenGL (GL) for modeling objects with primitives, OpenGL Utility Library (GLU) for utilities like camera and projection as well as additional modeling functions, and OpenGL Utilities Toolkit (GLUT) for window creation and input handling along with more modeling functions. OpenGL originated from Silicon Graphics' efforts to improve the portability of their IRIS GL graphics API and has evolved through multiple generations to support both fixed and programmable graphics pipelines. It works procedurally by describing graphic rendering steps rather than describing a scene descriptively. Popular programs that use OpenGL include games, 3D modeling software, and virtual
![DESCRIPTIV
E
PROCEDURA
L
Orange cube
rotated at 90°
1. Rotate at 90°
2. Orange
3. Cube
4. Vertex 1 at [-1,1,1]
5. Vertex 2 at [1,1,1]
6. ….
7. ….](https://image.slidesharecdn.com/openglintroduction1-160529161022/85/Open-gl-introduction-10-320.jpg)
Open gl introduction
- 2. WHAT IS OPENGL? “a software interface to graphics hardware.” Low- level graphics API Fast and portable 3D graphics library NOTE: OpenGL is ONLY a graphics library
- 3. 3 OPENGL LIBRARIES OpenGL (GL) – used in modeling an object via a set of geometric primitives such as point, line and polygon. OpenGL Utility Library (GLU)- important utilities (such as setting camera view and projection) and more building models (such as quadric surfaces and polygon tessellation).
- 4. OpenGL Utilities Toolkit (GLUT) – used for creating a window, handling key and mouse inputs. It also provides more building models (such as sphere and torus).
- 5. HOW TO INCLUDE OPENGL LIBRARY #include <gl/gl.h> #include <gl/glu.h> #include <gl/glut.h>
- 7. Silicon Graphics Inc. (SGI) used “IRIS GL”, a 3D programming API in their high-end IRIS graphics workstations. When SGI tried porting IRIS GL to other hardware platforms problems occurred :( OpenGL is the result of SGI’s efforts to improve IRIS GL’s portability (came out in 1992). HISTORY
- 8. OpenGL 1.x - fixed function OpenGL 2.x - early programmable OpenGL 3.x/4.x - modern programmable, Core profile and deprecation OpenGL ES 1.x - mobile fixed function OpenGL ES 2.x - mobile programmable FIVE GENERATIONS OF OPENGL
- 9. HOW OPENGL WORKS OpenGL is a procedural rather than a descriptive graphics language. Instead of describing the scene and how it should appear, the programmer actually describes the steps necessary to achieve a certain appearance or effect.
- 10. DESCRIPTIV E PROCEDURA L Orange cube rotated at 90° 1. Rotate at 90° 2. Orange 3. Cube 4. Vertex 1 at [-1,1,1] 5. Vertex 2 at [1,1,1] 6. …. 7. ….
- 11. POPULAR OPENGL-BASED PROGRAMS Adobe After Effects Autodesk Maya Autodesk AutoCAD Google Earth Counter-Strike Minecraft Left 4 Dead 2 Portal2