1. Computer Graphics Prof. Muhammad Saeed Dept. of Computer Science & IT
Federal Urdu University of Arts, Sciences and Technology

2. Computer Graphics Prof. Muhammad Saeed Dept. of Computer Science & IT
Federal Urdu University of Arts, Sciences and Technology

3. using Tao Framework in C#
Computer Graphics
3. OpenGL
using Tao Framework in C#
FUUAST
Dept. of Comp. Sc.& IT

4. 1. C# Wrapper (Tao Framework) i. Introduction to ‘Tao framework’
OpenGL Computer Graphics
Introduction
1. C# Wrapper (Tao Framework)
i. Introduction to ‘Tao framework’
ii. The installation and use in C#
2. Two Dimensional
i. Functions’ structure
a. end characters: i, f, d and v
b. next to end:2, 3,4
ii. 2D window and viewport
a. gluOrtho2D(left,right,bottom,right);
b. glViewport(x,y,width,height);
iii. Projection Matrix Mode
a. glMatrixMode(GL_PROJECTION)
b. glLoadIdentity()
FUUAST
Dept. of Comp. Sc.& IT

5. iv. Drawing primitives OpenGL Computer Graphics a. Points:
glBegin(GL_POINTS);
glVertex2d(x,y); …… ; glEnd();
b. Lines:
glBegin(GL_LINES);
glVertex2d(x,y); glVertex2d(x,y); ……. ;glEnd();
glBegin(GL_LINE_STRIP); …….. ; glEnd();
glBegin(GL_LINE_LOOP); ……. ;glEnd();
c. Triangles:
glBegin(GL_TRIANGLES); ……. ; glEnd();
glBegin(GL_TRIANGLE_STRIP); ……. ; glEnd();
glBegin(GL_TRIANGLE_FAN); ……. ; glEnd();
d. Quads:
glBegin(GL_QUADS); ……….. ; glEnd();
glBegin(GL_QUAD_STRIP); ……. glEnd();
e. Polygons:
glBegin(GL_POLYGON); …….. ; glEnd(); ,
FUUAST
Dept. of Comp. Sc.& IT

6. glClear(GL_COLOR_BUFFER_BIT);
OpenGL Computer Graphics
v. Colors:
a. Drawing color:
glColor3d(red, green, blue);
b. Background Color:
glClearColor(red, green, blue, alpha);
c. Clear Screen(Frame Buffer):
glClear(GL_COLOR_BUFFER_BIT);
d. Color Gradient:
Every vertex with different color.
2. Three Dimensional Initials
i. Viewing Systems :
a. 2D
b. Orthographic
c. Perspective.
FUUAST
Dept. of Comp. Sc.& IT

7. Orthographic Viewing System
Computer Graphics
Orthographic Viewing System y
top
Near Plane
Far Plane
left x
bottom
right N z F
FUUAST
Dept. of Comp. Sc.& IT

8. Projection Matrix and Orthographic Viewing
Computer Graphics
Projection Matrix and Orthographic Viewing
a. Orthographic:
glMatrixMode(GL_PROJECTION);
glLoadIdentity(); glOrtho(-x, x,-y, y, near far);
FUUAST
Dept. of Comp. Sc.& IT

9. Perspective Viewing System
Computer Graphics
Perspective Viewing System
top, left N d F
right, bottom
FUUAST
Dept. of Comp. Sc.& IT

10. Projection Matrix and Perspective viewing
Computer Graphics
Projection Matrix and Perspective viewing
b. Perspective:
glMatrixMode(GL_PROJECTION);
glLoadIdentity(); gluPerspective(view angle, aspect ratio, near, far);
FUUAST
Dept. of Comp. Sc.& IT

11. Camera Analogy Viewing Model OpenGL Computer Graphics Setting Model
Focus
Photograph
Viewing
Modeling
Projection
Viewport
Model
Modeling
Projection
Focus
Viewport
Photograph
FUUAST
Dept. of Comp. Sc.& IT

12. OpenGL Computer Graphics
ii. Camera Setting:
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
gluLookAt( x1, y1, z1, x2, y2, z2, x, y, z);
iii. Lights:
Ambient, Diffuse and Specular. ( Defs. and Discussion )
a. Position
glLightfv(GL_LIGHT0, GL_POSITION, pos);
b. Ambient Light:
glLightfv(GL_LIGHT0, GL_AMBIENT, amb);
c. Diffuse:
glLightfv(GL_LIGHT0, GL_DIFFUSE, diff);
d. Specular:
glLightfv(GL_LIGHT0, GL_SPECULAR, spec);
Pos, amb, diff, spec are arrays of size 4. containing respective position and color values.
FUUAST
Dept. of Comp. Sc.& IT

13. OpenGL Computer Graphics
e. Enabling of light:
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0) ;
iv. Shading Model:
a. 1) Gouraud Shading
2) Phong Shading
b. 1) glShadeModel(GL_SMOOTH);
2) glShadeModel(GL_FLAT);
v. Buffers:
a) Double Buffer
b) Frame Buffer
c) Accummulation Buffer
vi. Hidden Surface Removal
Depth Buffer (Z-Buffer)
glEnable(GL_DEPTH_TEST);
glClear(GL_COLOR_BUFFER_BIT |
GL_DEPTH_BUFFER_BIT);
FUUAST
Dept. of Comp. Sc.& IT

14. i. 3D implicit and parametric curves (list given)
OpenGL Computer Graphics
3. 3D Mathematics
1. Vectors
i. component representation
ii. Addition, dot product and cross product
iii. Unit, parallel and normal vector on a plane
iv. Equation of a plane and normal vector
2. 3D Curves
i. 3D implicit and parametric curves (list given)
ii. Bezier Curves and B-Splines
4. Meshes and surfaces
1. Meshes
i. meshes by curve equations, Sine curve, and sphere etc.
ii. Meshes by rotation and translation
FUUAST
Dept. of Comp. Sc.& IT

15. 1. 3D Objects and Transformations
OpenGL Computer Graphics
5. Solid Modeling
1. 3D Objects and Transformations
i. Material colors, emission color and shininess
glMaterialfv(GL_FRONT, GL_AMBIENT, materialAmbient);
glMaterialfv(GL_FRONT, GL_DIFFUSE, materialAmbient);
glMaterialfv(GL_FRONT, GL_SPECULAR, materialSpecular);
glMaterialfv(GL_FRONT, GL_EMISSION, materialEmission);
glMaterialf(GL_FRONT, GL_SHININESS, materialShininess);
glColorMaterial(GL_FRONT, GL_DIFFUSE);
ii. Drawing sphere, cylinder, cone, disk, partial disk
GLUquadric quad = gluNewQuadric();
gluQuadricDrawStyle(quad, GLU_FILL); //GLU_POINT,GLU_LINE,GLU_SILHOUETTE
gluQuadricNormals(quad, GLU_SMOOTH);
//GLU_FLAT, GLU_NONE
gluQuadricOrientation(quad, GLU_INSIDE); //GLU_OUTSIDE
gluSphere(quad, radius, slices, stacks);
FUUAST
Dept. of Comp. Sc.& IT

16. i. vertices, edges and surfaces
OpenGL Computer Graphics
iii. Rotation, translation and scaling of 3D objects
glRotated(angle, x, y, z);
glTranslated(dx, dy, dz);
glScaled(s, s, s);
iv. User-defined matrices and OpenGL stacks, shearing matrix
glLoadMatrixf(array[16]);
glMultMatrixf( array[16]);
Surfaces and solids
i. vertices, edges and surfaces
ii. Platonic solids
ii. Constructing Cube, Sphere, Tetrahedron etc.
3. Surfaces of rotation
surfaces of sine curve, Bezier curve
FUUAST
Dept. of Comp. Sc.& IT

17. Structure-deforming Transformations
OpenGL Computer Graphics
2. Deformations
Structure-deforming Transformations
Tapering
Twisting
Bending
Dept. of Comp. Sc. & IT
FUUAST

18. i. Tapering: OpenGL Computer Graphics Tapered along Z-axis
Original Object
Transformation Equations:
X2 = r * X1
Y2 = r * Y1
Z2 = Z1
r = f(Z1)
Matrix Form: =
Dept. of Comp. Sc. & IT
FUUAST

19. ii. Twisting: OpenGL Computer Graphics Original Object
Twisted along Z-axis
Transformation Equations:
Matrix Form:
X2 = X1*cos() – Y1*sin()
Y2 = X1*sin() + Y1*cos()
Z2 = Z1
 = f(Z1) =
Dept. of Comp. Sc. & IT
FUUAST

20. iii. Bending (Composite Transformation):
OpenGL Computer Graphics
iii. Bending (Composite Transformation):
Original Object
Bent
Transformation Equations:
x = X
y =
Z =
Bend Region is along Y axis
Ymin≤ Y ≤ Ymax
Center of the Bend is at Y = Y0
Radius of Curvature = 1/k
Bending angle is:  = k( - Y0)
Where: =
Dept. of Comp. Sc. & IT
FUUAST

21. int num=glGenerateLists(1);
OpenGL Computer Graphics
Display Lists
int num=glGenerateLists(1);
glNewList(num, GL_COMPILE); //GL_COMPILE_AND_EXECUTE
……….
glEndList();
glCallList(num);
Fog
glEnable(GL_FOG);
float[] fogColor ={ 0.1f, 0.1f, 0.15f, 1.0f };
glFogi(GL_FOG_MODE, GL_EXP); //GL_EXP2;//GL_LINEAR;//GL_EXP;
glFogfv(GL_FOG_COLOR, fogColor);
glFogf(GL_FOG_DENSITY, 0.2f);
glHint(GL_FOG_HINT, GL_NICEST); //GL_FASTEST);//GL_DONT_CARE);//GL_NICEST
glFogf(GL_FOG_START, 3.5f);
glFogf(GL_FOG_END, 5.0f);
FUUAST
Dept. of Comp. Sc.& IT

22. 6. Spot Lights Blending glEnable(GL_BLEND); OpenGL Computer Graphics
glLighti(GL_LIGHT0, GL_SPOT_CUTOFF, 30);//20
glLightfv(GL_LIGHT0, GL_SPOT_DIRECTION, spotDirection);
glLightf(GL_LIGHT0, GL_SPOT_EXPONENT, 1.5f);
glLightf(GL_LIGHT0, GL_CONSTANT_ATTENUATION, 1.0f);
glLightf(GL_LIGHT0, GL_LINEAR_ATTENUATION, 0.2f);
glLightf(GL_LIGHT0, GL_QUADRATIC_ATTENUATION, 0.1f);
Blending
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
//glBlendEquation(GL_FUNC_ADD);
glEnable(GL_CULL_FACE);
glCullFace(GL_BACK);
FUUAST
Dept. of Comp. Sc.& IT

23. Quad trees, Octree and BSP trees Bitmap
OpenGL Computer Graphics
Ray Tracing
Quad trees, Octree and BSP trees
Bitmap
Color picColor;
Bitmap bitmap = (Bitmap)Bitmap.FromFile(file);
//bitmap = new Bitmap(file);
bitmapHeight = bitmap.Height;
bitmapWidth = bitmap.Width;
picColor = bitmap.GetPixel(i, j);
bitmap.SetPixel(i, j, picColor);
10. Zooming, Panning, Segmentation and Extruding
11. Texture Mapping
12. Animation
FUUAST
Dept. of Comp. Sc.& IT

24. END