This document discusses graphics programming and concepts such as viewing, transformations, projection, animation, and examples. It covers translation, rotation, and scaling transformations, as well as viewing transformations like gluLookAt. It also discusses projection transformations including perspective and orthographic projection. Finally, it provides examples of animating a spinning rectangle and building a solar system and robot arm.

1. CSC 307 1.0
Graphics Programming
Budditha Hettige
Department of Statistics and Computer Science

2. Graphics Programming
Viewing
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3. Translate
• void glTranslate{fd}(TYPE x, TYPE y, TYPE z);
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4. Rotate
void glRotate{fd}(TYPE angle, TYPE x, TYPE y, TYPE z);
glRotatef(45.0, 0.0, 0.0, 1.0) - rotation of 45 degrees
about the z-axis
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5. Scale
void glScale{fd}(TYPE x, TYPE y, TYPE z);
Example: glScalef(2.0, –0.5, 1.0)
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6. Viewing and Modeling
Transformations
• Rotating First or Translating First
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7. Viewpoint
• Object and Viewpoint at the Origin
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8. Viewpoint and the Object
• Separating the Viewpoint and the Object
• glTranslatef(0.0, 0.0, -5.0);
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9. Using the gluLookAt()
void gluLookAt
(
GLdouble eyex, GLdouble eyey, GLdouble eyez,
GLdouble centerx, GLdouble centery, GLdouble centerz,
GLdouble upx, GLdouble upy, GLdouble upz
);
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10. Default Camera Position
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gluLookAt(0.0, 0.0, 0.0, 0.0, 0.0, -100.0, 0.0, 1.0, 0.0);
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11. Using gluLookAt()
gluLookAt(4.0, 2.0, 1.0, 2.0, 4.0, -3.0, 2.0, 2.0, -1.0);
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12. Projection Transformations
• Perspective Projection
void glFrustum(GLdouble left, GLdouble right,
GLdouble bottom, GLdouble top,
GLdouble near, GLdouble far);
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13. Orthographic Projection
void glOrtho(GLdouble left, GLdouble right,
GLdouble bottom, GLdouble top,
GLdouble near, GLdouble far);
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14. Viewport Transformation
• Defining the Viewport
• void glViewport(GLint x, GLint y,
GLsizei width, GLsizei height);
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15. The Transformed Depth Coordinate
• void glDepthRange(GLclampd near,
GLclampd far);
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16. Animation
• Is an important part of computer graphics
• Taking a sequence of pictures and projecting
them at 24 frames per second on the screen
• void glutSwapBuffers(void);
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17. Example
# include <windows.h>
#include <GL/glut.h>
#include <stdlib.h>
static GLfloat spin = 0.0;
void spinDisplay(void)
{
spin = spin + 0.05;
if (spin > 360.0)
spin = spin - 360.0;
glutPostRedisplay();
}
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void display(void)
{
glClear(GL_COLOR_BUFFER_BIT);
glPushMatrix();
glRotatef(spin, 0.0, 0.0, 1.0);
glColor3f(1.0, 1.0, 1.0);
glRectf(-25.0, -25.0, 25.0, 25.0);
glPopMatrix();
glutSwapBuffers();
spinDisplay();
}
void reshape(int w, int h)
{
glViewport(0, 0, (GLsizei) w, (GLsizei) h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(-50.0, 50.0, -50.0, 50.0, -1.0, 1.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
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18. Example
int main(int argc, char** argv)
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
glutInitWindowSize(250, 250);
glutInitWindowPosition(100, 100);
glutCreateWindow(argv[0]);
glClearColor(0.0, 0.0, 0.0, 0.0);
glShadeModel(GL_FLAT);
glutDisplayFunc(display);
glutReshapeFunc(reshape);
glutMainLoop();
return 0;
}
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19. Building a Solar System
• planet example (planet.cpp)
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20. Building an Articulated Robot Arm
• robotArm.cpp
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