1 Dr. Scott Schaefer Computer Graphics CSCE 441. 2/46 Staff Instructor Dr. Scott Schaefer HRBB 527B Office Hours: MW 10:00am – 11:00am (or by appointment)

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Dr. Scott Schaefer

Computer Graphics CSCE 441

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Staff

Instructor Dr. Scott Schaefer HRBB 527B Office Hours: MW 10:00am – 11:00am

(or by appointment) TA

Lei He ETB 2016 (knock on door) Office Hours: R 10:00am – noon

F 1pm-3pm

Websites

Course Pagehttp://courses.cs.tamu.edu/schaefer/441_Spring2014

Piazza Discussion Board

http://piazza.com/tamu/spring2014/csce441/home

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Why did you take this class?

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Games

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Movies

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Visualization

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Industrial Design

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What will you learn in this class?

2D Graphics Drawing lines, polygons Fractals

3D Graphics Transformations Lighting Ray Tracing Solid Modeling Splines/Subdivision

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What you’re expected to know

Programming ExperienceAssignments in C/C++

Simple Mathematics

Graphics is mathematics made visible

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How much math?

General geometry/linear algebra Matrices

Multiplication, inversion, determinant Vectors

Dot product, cross product, linear independence

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First Homework Assignment!

Linear Algebra Test

http://projects.cs.tamu.edu/keyser/LAtest/

Complete before January 27, 2014 Take as many times as you like Must get at least 90% correct

Grade = ActualGrade * (exam 90% ? 1 : 0 )

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Other Assignments

Simple Painting Program Polygon Drawing Fractals and Iterated Affine Transformations 3D Rasterization and Hidden Surfaces Ray Tracing

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More on Assignments

Turn in code via CSNET

(get an account if you don’t already have one) Due by 11:59pm on day specified Code, solution file, proj file and Win32

executable Make your code readable (comment) You may discuss concepts, but coding is

individual (no “team coding” or web)

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Grading

60% Assignments 15% Midterm 25% Final

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Late Policy

Penalty = m: number of minutes late

1 2 3 4

20

40

60

80

100

days late

perc

enta

ge p

enal

ty%6.57

m

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Textbooks

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Suggested Reading

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Introduction to OpenGL

What is OpenGL? Computer-graphics API (application

programming interface) Developed by SGI in 1992 Efficient, streaming interface 250+ function calls for drawing 2D and 3D graphics Hardware independent Operating system independent Direct3D alternative API from Microsoft

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Introduction to OpenGL

What OpenGL is NOTNo commands for windowingNo commands for obtaining user inputNo commands for anything except

drawing on the screen

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A Smidgen of OpenGL Code# include <whateverYouNeed.h>

Main() {IntializeAWindowPlease();

glClearColor (0.0, 0.0, 0.0, 0.0);glClear (GL_COLOR_BUFFER_BIT);glColor3f ( 1.0, 1.0, 1.0);glOrtho (0.0, 1.0, 0.0, 1.0, -1.0, 1.0);glBegin (GL_POLYGON);

glVertex3f (0.25, 0.25, 0.0); glVertex3f (0.75, 0.25, 0.0); glVertex3f (0.75, 0.75, 0.0); glVertex3f (0.25, 0.75, 0.0);

glEnd();glFlush();

UpdateTheWindowAndCheckForEvents();}

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glEnd();glFlush();


Sets the color for clearing the screen

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glEnd();glFlush();


Clears the screen

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glEnd();glFlush();


Sets the current drawing color to white

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glEnd();glFlush();


Sets the window coordinates to (0,0,-1) – (1,1,1)

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glEnd();glFlush();


Starts drawing a polygon

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glEnd();glFlush();


Specifies the vertices of the polygon

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glEnd();glFlush();


Ends the polygon

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glEnd();glFlush();


Flushes all commands to ensure polygon is drawn

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OpenGL Command Formats

glVertex3fv( v )

Number ofcomponents

2 - (x,y) 3 - (x,y,z)4 - (x,y,z,w)

Data Typeb - byteub - unsigned bytes - shortus - unsigned shorti - intui - unsigned intf - floatd - double

Vector

omit “v” forscalar form

glVertex2f( x, y )

PrefixInitial capital letters

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OpenGL Geometric Primitives

All geometric primitives are specified by vertices

GL_QUAD_STRIPGL_QUAD_STRIP

GL_POLYGONGL_POLYGON

GL_TRIANGLE_STRIPGL_TRIANGLE_STRIP

GL_TRIANGLE_FANGL_TRIANGLE_FAN

GL_POINTSGL_POINTSGL_LINESGL_LINES

GL_LINE_LOOPGL_LINE_LOOPGL_LINE_STRIPGL_LINE_STRIP

GL_TRIANGLESGL_TRIANGLES

GL_QUADSGL_QUADS

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OpenGL Drawing Functions

glBegin (GL_POINTS);glVertex2iv (p1);glVertex2iv (p2);glVertex2iv (p3);glVertex2iv (p4);glVertex2iv (p5);glVertex2iv (p6);

glEnd();

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P2 P3

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P5P6

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glBegin (GL_LINES);glVertex2iv (p1);glVertex2iv (p2);glVertex2iv (p3);glVertex2iv (p4);glVertex2iv (p5);glVertex2iv (p6);

glEnd();

P1

P2 P3

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P5P6

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glBegin (GL_LINE_STRIP);glVertex2iv (p1);glVertex2iv (p2);glVertex2iv (p3);glVertex2iv (p4);glVertex2iv (p5);glVertex2iv (p6);

glEnd();

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glBegin (GL_LINE_LOOP);glVertex2iv (p1);glVertex2iv (p2);glVertex2iv (p3);glVertex2iv (p4);glVertex2iv (p5);glVertex2iv (p6);

glEnd();

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P2 P3

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P5P6

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glBegin (GL_POLYGON);glVertex2iv (p1);glVertex2iv (p2);glVertex2iv (p3);glVertex2iv (p4);glVertex2iv (p5);glVertex2iv (p6);

glEnd();

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glBegin (GL_TRIANGLES);glVertex2iv (p1);glVertex2iv (p2);glVertex2iv (p6);glVertex2iv (p3);glVertex2iv (p4);glVertex2iv (p5);

glEnd();

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glBegin (GL_TRIANGLES_STRIP);glVertex2iv (p1);glVertex2iv (p2);glVertex2iv (p6);glVertex2iv (p3);glVertex2iv (p5);glVertex2iv (p4);

glEnd();

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glBegin (GL_TRIANGLES_FAN);glVertex2iv (p1);glVertex2iv (p2);glVertex2iv (p3);glVertex2iv (p4);glVertex2iv (p5);glVertex2iv (p6);

glEnd();

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glBegin (GL_QUADS);glVertex2iv (p1);glVertex2iv (p2);glVertex2iv (p3);glVertex2iv (p4);glVertex2iv (p5);glVertex2iv (p6);glVertex2iv (p7);glVertex2iv (p8);

glEnd();

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P4 P5

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P8

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glBegin (GL_QUADS_STRIP);glVertex2iv (p1);glVertex2iv (p2);glVertex2iv (p4);glVertex2iv (p3);glVertex2iv (p5);glVertex2iv (p6);glVertex2iv (p8);glVertex2iv (p7);

glEnd();

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OpenGL-Related Libraries

GLU (OpenGL Utility Library) - Part of OpenGL - Provides higher-level drawing routines such as Spheres, NURBS, tessellators, quadric shapes, etc…

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OpenGL-Related Libraries

GLU (OpenGL Utility Library) - Part of OpenGL - Provides higher-level drawing routines such as Spheres, NURBS, tessellators, quadric shapes, etc…

GLUT (OpenGL Utility Toolkit) - perform system-level I/O with the host operating system - cross platform

- portable windowing API - not officially part of OpenGL

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GLUT: OpenGL Utility Toolkit

Application StructureConfigure and open window Initialize OpenGL stateRegister input callback functions

renderresizeinput: keyboard, mouse, etc.

Enter event processing loop

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Sample Program

void main( int argc, char* argv[]){

glutInit (&argc, argv); glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB );

glutInitWindowSize (250, 250);glutInitWindowPosition (100, 100);

glutCreateWindow ( "HELLO");

init();

glutDisplayFunc ( display );

glutMainLoop();}

/* OpenGL Initialization */

/* callback function */

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GLUT Callback Functions

Routine to call when something happenswindow resized, user input, window needs

drawing, etc… “Register” callbacks with GLUT

glutDisplayFunc( display );glutIdleFunc( idle );glutKeyboardFunc( keyboard );glutMouseFunc( mouse );

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Assignment 1 – Simple OpenGL/GLUT Application

Build a simple OpenGL/GLUT application Designed to get you started using OpenGL

and callbacks for interaction

Full description available on course webpagehttp://courses.cs.tamu.edu/schaefer/441_Spring2014

Documents

1 Dr. Scott Schaefer Computer Graphics CSCE 441. 2/46 Staff Instructor Dr. Scott Schaefer HRBB 527B Office Hours: MW 10:00am – 11:00am (or by appointment)