Introduction to Computer Graphics
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This document provides an overview of computer graphics programming and OpenGL. It discusses common uses of computer graphics such as games, simulations, and medical imaging. It then explains core graphics concepts like the graphics pipeline, 2D and 3D coordinates, projections, and RGB color space. The document also covers OpenGL specifications, functions, data types, and related APIs.
Introduction to Computer Graphics
- 1. CSC 307 1.0 Graphics Programming Budditha Hettige Department of Statistics and Computer Science
- 3. Common Uses for Computer Graphics • Applications for real-time 3D graphics range from interactive games and simulations to data visualization for scientific, medical, or business uses – Military flight simulators – Computer-aided design (CAD) – Architectural or civil planning – Scientific visualization – Entertainment 3Budditha Hettige
- 7. CAD-CAM & Design Budditha Hettige 7
- 12. Graphics System 12 User ProgramUser Program IO DevicesIO Devices Graphics API Graphics System Graphics System Budditha Hettige
- 14. Graphics: Conceptual Model Real Object Real Object Human Eye Human Eye Display Device Graphics System Synthetic Model Synthetic Camera Real Light Synthetic Light Source Budditha Hettige 14
- 15. OpenGL • Standard specification defining a cross-language, cross- platform API • Is not a programming language • Writing applications that produce 2D and 3D computer graphics • A software interface to graphics hardware • Designed and optimized for the display and manipulation of 3D graphics • Developed by Silicon Graphics Inc. (SGI) in 1992 15Budditha Hettige
- 16. OpenGL-Graphics rendering API • Rendering API – High-quality color images composed of geometric and image primitives – Window system independent – Operating system independent • OpenGL Pipeline 16Budditha Hettige
- 17. OpenGL Architecture 17 Display List Polynomial Evaluator Per Vertex Operations & Primitive Assembly Rasterization Per Fragment Operations Frame Buffer Texture Memory CPU Pixel Operations Budditha Hettige
- 18. Software & Hardware Interfaces 18 Software Interface Hardware Interface Budditha Hettige
- 19. OpenGL and Related APIs 19 GLUT GLU GL GLX, AGL or WGL X, Win32, Mac O/S software and/or hardware application program OpenGL Motif widget or similar Budditha Hettige
- 20. Related APIs • AGL, GLX, WGL – glue between OpenGL and windowing systems • GLU (OpenGL Utility Library) – part of OpenGL – NURBS, tessellators, quadric shapes, etc. • GLUT (OpenGL Utility Toolkit) – portable windowing API – not officially part of OpenGL • Initial header inclusions (for Windows) – #include<windows.h> – #include<gl/gl.h> – #include<gl/glu.h> – #include <GL/glut.h> 20Budditha Hettige
- 21. Function-Naming Conventions • All OpenGL functions take the following format <Library prefix><Root command><Optional argument count><Optional argument type> 21Budditha Hettige
- 22. OpenGL data types 22Budditha Hettige
- 25. Viewports • Mapping Drawing Coordinates to Window Coordinates 25 viewport defined as twice the size of the clipping area Budditha Hettige
- 26. Viewports 26 viewport that matches the clipping area Budditha Hettige
- 27. OpenGL 3-D coordinates • Right-handed system • From point of view of camera looking out into scene: +X right, -X left +Y up, -Y down +Z behind camera, -Z in front • Positive rotations are counterclockwise around axis of rotation 27Budditha Hettige
- 28. 28 OpenGL Geometric Primitives GL_QUAD_STRIP GL_POLYGON GL_TRIANGLE_STRIP GL_TRIANGLE_FAN GL_POINTS GL_LINES GL_LINE_LOOPGL_LINE_STRIP GL_TRIANGLES GL_QUADS Primitives are one- or two-dimensional entities or surfaces such as points, lines, and polygons Budditha Hettige
- 29. The Vertex—A Position in Space • Each corner of the any primitive is called a vertex. Ex: three-dimensional cube consists of six two dimensional squares, each placed on a separate face 29Budditha Hettige
- 30. Projections: Getting 3D to 2D • Orthographic Projections • Perspective Projections 30Budditha Hettige
- 31. RGB Color Space Green (1,0,0) Blue (0,0,1) Red (1,0,0) Yellow (1,1,0) Magenta (1,0,1) Blk Cyan (0,1,1) White (1,1,1) G B R Image: Pixel maps to color Budditha Hettige 31
- 32. Common Composite Colors 32Budditha Hettige