Fundamentals of Computer Graphics

Draw the polygons by using the mouse. Choose colors by clicking on the designed color pane. Use window port to draw. (Use DDA algorithm for line drawing) #include<string.h> #include<GL/glut.h> #define ROUND(x)((int)(x+0.5)) struct Point { GLint x; GLint y; }; struct Color { GLfloat r; GLfloat g; GLfloat b; }; Color getPixelColor(GLint x, GLint y)  //Fun for getting color of pixel {  Color color; glReadPixels(x,y,1,1,GL_RGB, GL_FLOAT, &color); return color; } void setPixelColor(GLint x, GLint y, Color color)   //set color of pixel {    glColor3f(color.r, color.g, color.b); glBegin(GL_POINTS); glVertex2i(x,y); glEnd(); glFlush(); } void floodFill(GLint x, GLint y, Color oldColor, Color newColor)//seed fill algorithm { Color color; color= getPixelColor(x,y); if(color.r == oldColor.r && color.g == oldColor.g && color.b == oldColor.b) { setPixelColor(x,y, newColor); floodFill(x+1,y, oldColor, newColor); floodFill(x,y+1, oldCol...

C program for Bresenham algorithm for Circle #include <stdio.h> //#include <math.h> #include <GL/gl.h> #include <GL/glu.h> #include <GL/glut.h> // Center of the cicle = (320, 240) int xc = 320, yc = 240; // Plot eight points using circle's symmetrical property void plot_point(int x, int y) {   glBegin(GL_POINTS);   glVertex2i(xc+x, yc+y);   glVertex2i(xc+x, yc-y);   glVertex2i(xc+y, yc+x);   glVertex2i(xc+y, yc-x);   glVertex2i(xc-x, yc-y);   glVertex2i(xc-y, yc-x);   glVertex2i(xc-x, yc+y);   glVertex2i(xc-y, yc+x);   glEnd(); } // Function to draw a circle using bresenham's // circle drawing algorithm void bresenham_circle(int r) {   int x=0,y=r;   float s=3-(2*r);   /* Plot the points */   /* Plot the first point */   plot_point(x,y);   int k;   /* Find all vertices till x=y */   while(x <= y)   {     //x = x + 1;     //s...

Bresenham line drawing program   #include<stdio.h> #include<GL/glut.h> #define sign(x) ((x>0)?1:(x<0)?-1:0); void setPixel(GLint x, GLint y) {  glBegin(GL_POINTS); //The basic shapes are referred to as primitives.and glbegin is used to delimit these primitives   // GL_POINTS is an argument of glBegin which consider each vertex as a single points  glVertex2i(x,y);    /* Plot the first point *///it is use to specify vertex  glEnd(); } void init() {  glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); //single buffer window  glutInitWindowPosition(0,0);  glutInitWindowSize(0,0);  glutCreateWindow("My Window");  glClearColor(0.0,0.0,0.0,0.0); /* Set clear color to black */  glColor3f(1.0,1.0,1.0);     /* Set fill color to white */ //used to specify color & 3f stand for float red , green, blue  gluOrtho2D(0,640,0,480);    //multiply the current matrix with an...

 

#include <stdio.h> #include <math.h> #include <GL/glut.h> //#include <GL/glu.h> //#include <GL/gl.h> double X1, Y1, X2, Y2; float round_value(float v) {   floor(v + 0.5);// This function is used to roundup the values   return v; } void LineDDA(void) {   double dx=(X2-X1);   double dy=(Y2-Y1);   double steps;   float xInc,yInc,x=X1,y=Y1;   /* Find out whether to increment x or y */   //steps=(abs(dx)>abs(dy))?(abs(dx)):(abs(dy));   if(abs(dx)>abs(dy))   steps=abs(dx);   else   steps=abs(dy);   xInc=dx/(float)steps;   yInc=dy/(float)steps;   /* Clears buffers to preset values */   glClear(GL_COLOR_BUFFER_BIT);//glClear is predefine function used to clear buffer and                   //GL_COLOR_BUFFER_BIT Indicates the buffers currently enabled for color writing.         ...

 GLUT it is open GL_U tility _T oolkit for openGL programming we need to install glut (pronounce as glat). Following are the steps to install GLUT on Ubuntu operating system. Step 1: sudo apt-get update               For updation of basic packages Step 2: sudo apt-get install build-essential               For installing essential packages. Step 3: sudo apt-get install freeglut3 freeglut3-dev               // its GL utility toolkit Step 4: sudo apt-get install binutils-gold             It is GNU gold linker utility.  Gold is a new linker, which is faster than the current linker included in binutils Step 5: sudo apt-get install g++ cmake         its a  Command-Line Reference.Users build a project b...

Dear friends on this platform we will discuss and help each other to learn computer graphics theory and programming. Now days all graphics programmer prefer openGL for the development, So lets understand basics of openGL openGL openGL stands for open_G raphics _L ybrary. It is standard API for developing graphical User interface, Computer aided designs, animations, simulations and art and commerce (ie attractive message with pictures). It has large number of built in capabilities for pixel operation and various graphical effects for developing the applications. GL (graphics Libraries) are used to include definitions of some predefine functions used for 2D or 3D drawings ......#include <GL/gl.h> GLU ( graphics Libraries Utilities) are used to include definitions of some predefine functions used for camera settings and shape descriptions........#include<GL/glu.h> GLUT (GL Utility Toolkit): This toolkit has numerous utility functions, mostly dea...