Graphics Lab 1
1 Graphics Models and Libraries
A graphics display is a drawing area composed of an array of fine points called pixels. At the heart of a
graphics system there is a magic pen, which can move at lightning speed to a specific pixel and draw the
pixel with a specific color — a red, green, and blue (RGB) vector value. This pen can be controlled
directly by hand through an input device (mouse or keyboard) like a simple paintbrush. In this case, we
can draw whatever we imagine, but it takes a real artist to come up with a good painting.
Computer graphics, however, is about using this pen automatically through programming.
A real or imaginary object is represented in a computer as a model and is displayed as an image. A model
is an abstract description of the object’s shape (vertices) and attributes (colors), which can be used to find
all the points and their colors on the object corresponding to the pixels in the drawing area. Given a
model, the application program will control the pen through a graphics library to generate the
corresponding image. An image is simply a 2D array of pixels.
A graphics library provides a set of graphics commands or functions. These commands can be bound in
C, C++, Java, or other programming languages on different platforms. Graphics commands can specify
primitive 2D and 3D geometric models to be digitized and displayed. Here primitive means that only
certain simple shapes (such as points, lines, and polygons) can be accepted by a graphics library. To
draw a complex shape, we need an application program to assemble or construct it by displaying pieces of
simple shapes (primitives). We have the magic pen that draws a pixel. If we can draw a pixel, we can
draw a line, a polygon, a curve, a block, a building, an airplane, and so forth. A general application
program can be included into a graphics library as a command to draw a complex shape. Because our pen
is magically fast, we can draw a complex object, clear the drawing area, draw the object
at a slightly different location or shape, and repeat the above processes — the object is now animated.
OpenGL is a graphics library that we will integrate with the Java programming language to introduce
graphics theory, programming, and applications. When we introduce program examples, we will
succinctly discuss Java-specific concepts and programming as well for C/C++ programmers.
2 OpenGL Programming in Java: JOGL
OpenGL is the most widely used graphics library (GL) or application programming interface (API), and is
supported across all popular desktop and workstation platforms, ensuring wide application deployment.
JOGL implements Java bindings for OpenGL. It provides hardware-supported 3D graphics to applications
written in Java. It is part of a suite of open-source technologies initiated by the Game Technology Group
at Sun Microsystems. JOGL provides full access to OpenGL functions and integrates with the AWT and
Swing widget sets.
3. Instructions for today
Execute the sample Netbeans code provided.
Implement the code for drawing a line through the DDA algorithm
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