Category Archives: OpenGL

Midpoint algo reference: http://www.eazynotes.com/notes/computer-graphics/algorithms/mid-point-circle-algorithm.pdf
http://suraj1693.blogspot.com/2013/11/c-program-for-drawing-circle-using.html
https://birunthag.blogspot.com/2014/05/openglc-draw-circle-with-midpoint.html
https://www.opengl.org/discussion_boards/showthread.php/169955-using-glutKeyboardFunc

Code:

#include <windows.h>
#include <GL\glut.h>
#include <stdlib.h>
#include<iostream>
#include<stdio.h>
using namespace std;

int r,p,flags=0;

void myInit (void)

{

    glClearColor(0.0,0.0,0.0,0.0); // sets background color to white

    // sets a point to be 4x4 pixels

    glMatrixMode(GL_PROJECTION);

    glLoadIdentity();

    gluOrtho2D(0.0, 500.0, 0.0, 400.0); // the display area in world coordinates.

}
void midpoint()
{
    r=20;
    p=1-r;
    int xk=0;
    int yk=r;
    int xc=200;
    int yc=200;
    while(xk<=yk)
    {
        if(p<0)
        {
            xk++;
            p=p+2*xk+3;
        }
        else if(p>0)
        {
            xk++;
            yk=yk-1;
            p=p+2*xk-2*yk+5;
        }
        glVertex2i(xc+xk,yc+yk);
        glVertex2i(xc-xk,yc+yk);
        glVertex2i(xc+xk,yc-yk);
        glVertex2i(xc-xk,yc-yk);
        glVertex2i(xc+yk,yc+xk);
        glVertex2i(xc-yk,yc+xk);
        glVertex2i(xc+yk,yc-xk);
        glVertex2i(xc-yk,yc-xk);
    }

}

void processKey(unsigned char key, int x, int y)
{
	switch(key){
		case '1':
			flags=1;
			printf("Hello world!");
			break;

		//default:
        // break;
	}
}

void myDisplay(void)
{
    //int nol = rand() % 100;

    glClear(GL_COLOR_BUFFER_BIT); // clears the screen
    // setsthe drawing colour

    glPointSize(4.0);

    glColor3f(1.0f,0.0f,1.0f) ;
    glBegin(GL_LINES);

    glVertex2i(0,200);
    glVertex2i(500,200);

    glVertex2i(255,0);
    glVertex2i(255,500);

    glEnd();


glBegin(GL_POINTS);
//midpoint();
if(flags==1){
    midpoint();
}

glEnd();


    glFlush(); // sends all output to display;

}


int main (int argc, char **argv)
{

//scanf("%d,%d,&d,&d",&x,&y,&a,&b);
    glutInit (&argc, argv); // to initialize the toolkit;

    glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB); // sets the display mode

    glutInitWindowSize (640, 480); // sets the window size

    glutInitWindowPosition (10, 10); // sets the starting position for the window

    glutCreateWindow ("My first OpenGL program!"); // creates the window and sets the title
    glutKeyboardFunc(processKey);
    glutDisplayFunc (myDisplay);
    myInit(); // additional initializations as necessary

    glutMainLoop(); // go into a loop until event occurs
    return 0;
}

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#include <windows.h>

#include <GL\glut.h>

#include <stdlib.h>

#include<iostream>

#include<stdio.h>

using namespace std;

int r,p,flags=0;

void myInit (void)

{

glClearColor(0.0,0.0,0.0,0.0); // sets background color to white

// sets a point to be 4x4 pixels

glMatrixMode(GL_PROJECTION);

glLoadIdentity();

gluOrtho2D(0.0, 500.0, 0.0, 400.0); // the display area in world coordinates.

}

void midpoint()

{

r=20;

p=1-r;

int xk=0;

int yk=r;

int xc=200;

int yc=200;

while(xk<=yk)

{

if(p<0)

{

xk++;

p=p+2*xk+3;

}

else if(p>0)

{

xk++;

yk=yk-1;

p=p+2*xk-2*yk+5;

}

glVertex2i(xc+xk,yc+yk);

glVertex2i(xc-xk,yc+yk);

glVertex2i(xc+xk,yc-yk);

glVertex2i(xc-xk,yc-yk);

glVertex2i(xc+yk,yc+xk);

glVertex2i(xc-yk,yc+xk);

glVertex2i(xc+yk,yc-xk);

glVertex2i(xc-yk,yc-xk);

}

void processKey(unsigned char key, int x, int y)

{

switch(key){

case '1':

flags=1;

printf("Hello world!");

break;

//default:

// break;

}

void myDisplay(void)

{

//int nol = rand() % 100;

glClear(GL_COLOR_BUFFER_BIT); // clears the screen

// setsthe drawing colour

glPointSize(4.0);

glColor3f(1.0f,0.0f,1.0f) ;

glBegin(GL_LINES);

glVertex2i(0,200);

glVertex2i(500,200);

glVertex2i(255,0);

glVertex2i(255,500);

glEnd();

glBegin(GL_POINTS);

//midpoint();

if(flags==1){

midpoint();

}

glEnd();

glFlush(); // sends all output to display;

}

int main (int argc, char **argv)

{

//scanf("%d,%d,&d,&d",&x,&y,&a,&b);

glutInit (&argc, argv); // to initialize the toolkit;

glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB); // sets the display mode

glutInitWindowSize (640, 480); // sets the window size

glutInitWindowPosition (10, 10); // sets the starting position for the window

glutCreateWindow ("My first OpenGL program!"); // creates the window and sets the title

glutKeyboardFunc(processKey);

glutDisplayFunc (myDisplay);

myInit(); // additional initializations as necessary

glutMainLoop(); // go into a loop until event occurs

return 0;

}

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Posted in A ll Codes, Geometry, Graphics, Midpoint Circle, OpenGL

Tagged KeyboardFunc, Midpoint Circle Algorithm, OpenGL

Draw Brasenham Line Drawing Algorithms with Random Lines and Colors

Posted on July 17, 2016 | Leave a comment

Code:

#include <windows.h>
#include <GL\glut.h>
#include <stdlib.h>
#include<iostream>
using namespace std;

int x, y, a, b, nol, R, G, B;

void myInit (void)

{

    glClearColor(0.0,0.0,0.0,0.0); // sets background color to white

    // sets a point to be 4x4 pixels

    glMatrixMode(GL_PROJECTION);

    glLoadIdentity();

    gluOrtho2D(0.0, 500.0, 0.0, 400.0); // the display area in world coordinates.

}
void brasenham(int x1, int y1, int x2, int y2)
{

    int dx = x2-x1;
    int dy = y2-y1;
    int p = (2*dy)-dx;
    for(int i =0; i < dx; i++)
    {
        if(p < 0)
        {
            x1++;
            glVertex2i(x1, y1);
            p = p+(2*dy);

        }
        else if(p>0)
        {
            x1++;
            y1++;
            glVertex2i(x1, y1);
            p = p+(2*dy)-(2*dx);

        }


    }

}

void myDisplay(void)

{
    int nol = rand() % 100;

     glClear(GL_COLOR_BUFFER_BIT); // clears the screen
    // setsthe drawing colour

     glPointSize(4.0);

    for(int i = 0; i<nol; i++){
        int x = rand() % 750;
        int y = rand() % 850;
        int a = rand() % 950;
        int b = rand() % 680;
        int R = rand() % 255;
        int G = rand() % 255;
        int B = rand() % 255;
        glColor3ub(R, G, B) ;
     glBegin(GL_POINTS);
        brasenham(x, y, a, b);
     glEnd();
    }


     glFlush(); // sends all output to display;

}


int main (int argc, char **argv)
{

//scanf("%d,%d,&d,&d",&x,&y,&a,&b);



    glutInit (&argc, argv); // to initialize the toolkit;

    glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB); // sets the display mode

    glutInitWindowSize (640, 480); // sets the window size

    glutInitWindowPosition (10, 10); // sets the starting position for the window

    glutCreateWindow ("My first OpenGL program!"); // creates the window and sets the title

    glutDisplayFunc (myDisplay);
    myInit(); // additional initializations as necessary

    glutMainLoop(); // go into a loop until event occurs
    return 0;
}

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#include <windows.h>

#include <GL\glut.h>

#include <stdlib.h>

#include<iostream>

using namespace std;

int x, y, a, b, nol, R, G, B;

void myInit (void)

{

glClearColor(0.0,0.0,0.0,0.0); // sets background color to white

// sets a point to be 4x4 pixels

glMatrixMode(GL_PROJECTION);

glLoadIdentity();

gluOrtho2D(0.0, 500.0, 0.0, 400.0); // the display area in world coordinates.

}

void brasenham(int x1, int y1, int x2, int y2)

{

int dx = x2-x1;

int dy = y2-y1;

int p = (2*dy)-dx;

for(int i =0; i < dx; i++)

{

if(p < 0)

{

x1++;

glVertex2i(x1, y1);

p = p+(2*dy);

}

else if(p>0)

{

x1++;

y1++;

glVertex2i(x1, y1);

p = p+(2*dy)-(2*dx);

}

void myDisplay(void)

{

int nol = rand() % 100;

glClear(GL_COLOR_BUFFER_BIT); // clears the screen

// setsthe drawing colour

glPointSize(4.0);

for(int i = 0; i<nol; i++){

int x = rand() % 750;

int y = rand() % 850;

int a = rand() % 950;

int b = rand() % 680;

int R = rand() % 255;

int G = rand() % 255;

int B = rand() % 255;

glColor3ub(R, G, B) ;

glBegin(GL_POINTS);

brasenham(x, y, a, b);

glEnd();

}

glFlush(); // sends all output to display;

}

int main (int argc, char **argv)

{

//scanf("%d,%d,&d,&d",&x,&y,&a,&b);

glutInit (&argc, argv); // to initialize the toolkit;

glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB); // sets the display mode

glutInitWindowSize (640, 480); // sets the window size

glutInitWindowPosition (10, 10); // sets the starting position for the window

glutCreateWindow ("My first OpenGL program!"); // creates the window and sets the title

glutDisplayFunc (myDisplay);

myInit(); // additional initializations as necessary

glutMainLoop(); // go into a loop until event occurs

return 0;

}

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Posted in A ll Codes, Brasenham Line Drawing, Graphics, OpenGL

Tagged Brasenham line drawing algorithm

Star Drawing with OpenGL

Posted on July 17, 2016 | Leave a comment

Draw 4 stars in screen with OpenGL
Screenshot:

Code:

#include <windows.h>
#include <GL\glut.h>

void myInit (void)

{

    glClearColor(0.0,0.0,0.0,0.0); // sets background color to white

    // sets a point to be 4x4 pixels

    glMatrixMode(GL_PROJECTION);

    glLoadIdentity();

    gluOrtho2D(0.0, 500.0, 0.0, 400.0); // the display area in world coordinates.

}


void myDisplay(void)

{

    glClear(GL_COLOR_BUFFER_BIT); // clears the screen
    ;// setsthe drawing colour

    glPointSize(4.0);

//Axis
    glColor3f(1.0f,0.0f,1.0f) ;
    glBegin(GL_LINES);
    glVertex2i(255,0);
    glVertex2i(255,500);

    glVertex2i(0,200);
    glVertex2i(500,200);

    glEnd();

    glColor3f(1.0f,0.0f,0.0f);
//
    glColor3f(1.0f,1.0f,0.0f) ;
    glBegin(GL_POLYGON);
//bottom

    glVertex2i (40,50);
    glVertex2i (60,50);
//left
    glVertex2i (40,50);
    glVertex2i (40,80);
//top
    glVertex2i (40,80);
    glVertex2i (60,80);
//right
    glVertex2i (60,50);
    glVertex2i (60,80);

    glEnd();
//BOTTOM TRIANGLE
    glColor3f(1.0f,0.0f,0.0f) ;
    glBegin(GL_POLYGON);
//bottom

    glVertex2i (40,50);
    glVertex2i (60,50);
//left
    glVertex2i (40,50);
    glVertex2i (50,30);

//RIGHT
    glVertex2i (60,50);
    glVertex2i (50,30);

    glEnd();

//RIGHT TRIANGLE
    glColor3f(1.0f,0.0f,0.0f) ;
    glBegin(GL_POLYGON);
//bottom

    glVertex2i (60,50);
    glVertex2i (60,80);

    glVertex2i (60,50);
    glVertex2i (70,60);

    glVertex2i (60,80);
    glVertex2i (70,60);

    glEnd();

//left triangle
    glColor3f(1.0f,0.0f,0.0f) ;
    glBegin(GL_POLYGON);

    glVertex2i (40,50);
    glVertex2i (40,80);

    glVertex2i (40,50);
    glVertex2i (30,64);

    glVertex2i (40,80);
    glVertex2i (30,62);

    glEnd();


//Top triangle
    glColor3f(1.0f,0.0f,0.0f) ;
    glBegin(GL_POLYGON);

    glVertex2i (40,80);
    glVertex2i (60,80);

    glVertex2i (40,80);
    glVertex2i (50,90);

    glVertex2i (60,80);
    glVertex2i (50,90);


    glEnd();

    glColor3f(1.0f, 0.0f, 0.0f);
    glRectf(120,120, 100, 100);


    glColor3f(1.0f,1.0f,0.0f) ;
    glBegin(GL_POLYGON);
//RIGHT

    glVertex2i (120,120);
    glVertex2i (120,100);

    glVertex2i (120,120);
    glVertex2i (150,110);

    glVertex2i (120,100);
    glVertex2i (150,110);
    glEnd();

    glBegin(GL_LINES);
    //RIGHT
    glVertex2i (120,120);
    glVertex2i (120,100);

    glVertex2i (120,120);
    glVertex2i (150,110);

    glVertex2i (120,100);
    glVertex2i (150,110);
    glEnd();

    //left
    glBegin(GL_POLYGON);
    glVertex2i (100,120);
    glVertex2i (62,107);

    glVertex2i (100,100);
    glVertex2i (62,107);
    glEnd();


    glColor3f(0.0f,0.0f,1.0f) ;
    glBegin(GL_POLYGON);
    glVertex2i (100,120);
    glVertex2i (110,130);

    glVertex2i(110,130);
    glVertex2i (120,120);
    glEnd();


    glColor3f(0.0f,0.0f,1.0f) ;
    glBegin(GL_POLYGON);
    glVertex2i (100,98);
    glVertex2i(110,70);

    glVertex2i (120,98);
    glVertex2i(110,70);


    glEnd();

glColor3f(1.0f,1.0f,1.0f);
glBegin(GL_POLYGON);
    glVertex2i (350,290);
    glVertex2i (350,315);

     glVertex2i (350,290);
     glVertex2i(370,290);

    glVertex2i (370,290);
    glVertex2i (370,315);

glVertex2i (350,315);
glVertex2i (370,315);


glEnd();

glColor3f(0.0f,0.0f,1.0f) ;
glBegin(GL_POLYGON);
glVertex2i (350,315);
glVertex2i (362,325);

glVertex2i (370,315);
glVertex2i (362,325);

glEnd();

//
glColor3f(0.0f,0.0f,1.0f) ;
glBegin(GL_POLYGON);
glVertex2i (370,290);
glVertex2i (385,305);

glVertex2i (370,315);
glVertex2i (385,305);

glEnd();


glColor3f(0.0f,0.0f,1.0f) ;
glBegin(GL_POLYGON);
 glVertex2i (350,290);
  glVertex2i (320,305);

  glVertex2i (350,315);
  glVertex2i (320,305);

glEnd();


glColor3f(0.0f,0.0f,1.0f) ;
glBegin(GL_POLYGON);
glVertex2i (350,290);
glVertex2i (362,270);

glVertex2i (370,290);
glVertex2i (362,270);

glEnd();

glColor3f(0.0f,0.0f,1.0f) ;
glBegin(GL_POLYGON);

glVertex2i (70,275);
glVertex2i (70,290);

glVertex2i(70,290);
glVertex2i(85,290);

glVertex2i(85,290);
glVertex2i(85,275);

glVertex2i(85,275);
glVertex2i(70,275);

glEnd();

glColor3f(1.0f,1.0f,1.0f);
glBegin(GL_POLYGON);
glVertex2i(70,275);
glVertex2i(76,220);

glVertex2i(85,275);
glVertex2i(76,220);

glEnd();


glColor3f(1.0f,1.0f,1.0f);
glBegin(GL_POLYGON);

glVertex2i(85,275);
glVertex2i(120,280);

glVertex2i(85,290);
glVertex2i(120,280);
glEnd();


glColor3f(1.0f,1.0f,1.0f);
glBegin(GL_POLYGON);

glVertex2i(70,275);
glVertex2i(38,280);

glVertex2i(70,290);
glVertex2i(38,280);
glEnd();


glColor3f(1.0f,1.0f,1.0f);
glBegin(GL_POLYGON);
glVertex2i(70,290);
glVertex2i(76,335);


glVertex2i(85,290);
glVertex2i(76,335);
glEnd();

    glFlush(); // sends all output to display;

}
int main (int argc, char **argv)
{

    glutInit (&argc, argv); // to initialize the toolkit;

    glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB); // sets the display mode

    glutInitWindowSize (640, 480); // sets the window size

    glutInitWindowPosition (10, 10); // sets the starting position for the window

    glutCreateWindow ("My first OpenGL program!"); // creates the window and sets the title

    glutDisplayFunc (myDisplay);
    myInit(); // additional initializations as necessary
    glutMainLoop(); // go into a loop until event occurs
    return 0;
}

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#include <windows.h>

#include <GL\glut.h>

void myInit (void)

{

glClearColor(0.0,0.0,0.0,0.0); // sets background color to white

// sets a point to be 4x4 pixels

glMatrixMode(GL_PROJECTION);

glLoadIdentity();

gluOrtho2D(0.0, 500.0, 0.0, 400.0); // the display area in world coordinates.

}

void myDisplay(void)

{

glClear(GL_COLOR_BUFFER_BIT); // clears the screen

;// setsthe drawing colour

glPointSize(4.0);

//Axis

glColor3f(1.0f,0.0f,1.0f) ;

glBegin(GL_LINES);

glVertex2i(255,0);

glVertex2i(255,500);

glVertex2i(0,200);

glVertex2i(500,200);

glEnd();

glColor3f(1.0f,0.0f,0.0f);

glColor3f(1.0f,1.0f,0.0f) ;

glBegin(GL_POLYGON);

//bottom

glVertex2i (40,50);

glVertex2i (60,50);

//left

glVertex2i (40,50);

glVertex2i (40,80);

//top

glVertex2i (40,80);

glVertex2i (60,80);

//right

glVertex2i (60,50);

glVertex2i (60,80);

glEnd();

//BOTTOM TRIANGLE

glColor3f(1.0f,0.0f,0.0f) ;

glBegin(GL_POLYGON);

//bottom

glVertex2i (40,50);

glVertex2i (60,50);

//left

glVertex2i (40,50);

glVertex2i (50,30);

//RIGHT

glVertex2i (60,50);

glVertex2i (50,30);

glEnd();

//RIGHT TRIANGLE

glColor3f(1.0f,0.0f,0.0f) ;

glBegin(GL_POLYGON);

//bottom

glVertex2i (60,50);

glVertex2i (60,80);

glVertex2i (60,50);

glVertex2i (70,60);

glVertex2i (60,80);

glVertex2i (70,60);

glEnd();

//left triangle

glColor3f(1.0f,0.0f,0.0f) ;

glBegin(GL_POLYGON);

glVertex2i (40,50);

glVertex2i (40,80);

glVertex2i (40,50);

glVertex2i (30,64);

glVertex2i (40,80);

glVertex2i (30,62);

glEnd();

//Top triangle

glColor3f(1.0f,0.0f,0.0f) ;

glBegin(GL_POLYGON);

glVertex2i (40,80);

glVertex2i (60,80);

glVertex2i (40,80);

glVertex2i (50,90);

glVertex2i (60,80);

glVertex2i (50,90);

glEnd();

glColor3f(1.0f, 0.0f, 0.0f);

glRectf(120,120, 100, 100);

glColor3f(1.0f,1.0f,0.0f) ;

glBegin(GL_POLYGON);

//RIGHT

glVertex2i (120,120);

glVertex2i (120,100);

glVertex2i (120,120);

glVertex2i (150,110);

glVertex2i (120,100);

glVertex2i (150,110);

glEnd();

glBegin(GL_LINES);

//RIGHT

glVertex2i (120,120);

glVertex2i (120,100);

glVertex2i (120,120);

glVertex2i (150,110);

glVertex2i (120,100);

glVertex2i (150,110);

glEnd();

//left

glBegin(GL_POLYGON);

glVertex2i (100,120);

glVertex2i (62,107);

glVertex2i (100,100);

glVertex2i (62,107);

glEnd();

glColor3f(0.0f,0.0f,1.0f) ;

glBegin(GL_POLYGON);

glVertex2i (100,120);

glVertex2i (110,130);

glVertex2i(110,130);

glVertex2i (120,120);

glEnd();

glColor3f(0.0f,0.0f,1.0f) ;

glBegin(GL_POLYGON);

glVertex2i (100,98);

glVertex2i(110,70);

glVertex2i (120,98);

glVertex2i(110,70);

glEnd();

glColor3f(1.0f,1.0f,1.0f);

glBegin(GL_POLYGON);

glVertex2i (350,290);

glVertex2i (350,315);

glVertex2i (350,290);

glVertex2i(370,290);

glVertex2i (370,290);

glVertex2i (370,315);

glVertex2i (350,315);

glVertex2i (370,315);

glEnd();

glColor3f(0.0f,0.0f,1.0f) ;

glBegin(GL_POLYGON);

glVertex2i (350,315);

glVertex2i (362,325);

glVertex2i (370,315);

glVertex2i (362,325);

glEnd();

glColor3f(0.0f,0.0f,1.0f) ;

glBegin(GL_POLYGON);

glVertex2i (370,290);

glVertex2i (385,305);

glVertex2i (370,315);

glVertex2i (385,305);

glEnd();

glColor3f(0.0f,0.0f,1.0f) ;

glBegin(GL_POLYGON);

glVertex2i (350,290);

glVertex2i (320,305);

glVertex2i (350,315);

glVertex2i (320,305);

glEnd();

glColor3f(0.0f,0.0f,1.0f) ;

glBegin(GL_POLYGON);

glVertex2i (350,290);

glVertex2i (362,270);

glVertex2i (370,290);

glVertex2i (362,270);

glEnd();

glColor3f(0.0f,0.0f,1.0f) ;

glBegin(GL_POLYGON);

glVertex2i (70,275);

glVertex2i (70,290);

glVertex2i(70,290);

glVertex2i(85,290);

glVertex2i(85,275);

glVertex2i(70,275);

glEnd();

glColor3f(1.0f,1.0f,1.0f);

glBegin(GL_POLYGON);

glVertex2i(70,275);

glVertex2i(76,220);

glVertex2i(85,275);

glVertex2i(76,220);

glEnd();

glColor3f(1.0f,1.0f,1.0f);

glBegin(GL_POLYGON);

glVertex2i(85,275);

glVertex2i(120,280);

glVertex2i(85,290);

glVertex2i(120,280);

glEnd();

glColor3f(1.0f,1.0f,1.0f);

glBegin(GL_POLYGON);

glVertex2i(70,275);

glVertex2i(38,280);

glVertex2i(70,290);

glVertex2i(38,280);

glEnd();

glColor3f(1.0f,1.0f,1.0f);

glBegin(GL_POLYGON);

glVertex2i(70,290);

glVertex2i(76,335);

glVertex2i(85,290);

glVertex2i(76,335);

glEnd();

glFlush(); // sends all output to display;

}

int main (int argc, char **argv)

{

glutInit (&argc, argv); // to initialize the toolkit;

glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB); // sets the display mode

glutInitWindowSize (640, 480); // sets the window size

glutInitWindowPosition (10, 10); // sets the starting position for the window

glutCreateWindow ("My first OpenGL program!"); // creates the window and sets the title

glutDisplayFunc (myDisplay);

myInit(); // additional initializations as necessary

glutMainLoop(); // go into a loop until event occurs

return 0;

}

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Posted in A ll Codes, Graphics, OpenGL

Tagged Star Drawing

OpenGL Graphics Code: Build a house with GLUT

Posted on May 30, 2016 | Leave a comment

#include <windows.h>
#include <GL\glut.h>

void myInit (void)

{

     glClearColor(0.0,0.0,0.0,0.0); // sets background color to white

     // sets a point to be 4x4 pixels

     glMatrixMode(GL_PROJECTION);

     glLoadIdentity();

     gluOrtho2D(0.0, 500.0, 0.0, 400.0); // the display area in world coordinates.

}


void myDisplay(void)

{

     glClear(GL_COLOR_BUFFER_BIT); // clears the screen
    glColor3f(0.5f,0.5f,0.5f) ;// setsthe drawing colour

     glPointSize(4.0);

     glBegin(GL_POLYGON);
//bottom

          glVertex2i (20, 20);
          glVertex2i (320, 20);

          //top
          glVertex2i (20, 200);
          glVertex2i (320, 200);
        //left
          glVertex2i (20, 200);
          glVertex2i (20, 20);
        //right
          glVertex2i (320, 200);
          glVertex2i (320, 20);

          //glVertex2i (10, -50);

    glEnd();


//Left Window

 glColor3f(1.0f,0.0f,0.0f) ;
glPointSize(4.0);
 glRectf(30,30,100,100);

 //Right Window
 glColor3f(1.0f,0.0f,0.0f) ;
glBegin(GL_POLYGON);
//bottom

        glVertex2i (200,30);
          glVertex2i (200, 100);

//top
          glVertex2i (200, 100);
          glVertex2i (300, 100);

//left
          glVertex2i (300, 100);
          glVertex2i (300, 30);
 //right
         glVertex2i (300, 30);
          glVertex2i (200, 30);

          //glVertex2i (10, -50);

    glEnd();


//door
glColor3f(0.0f,0.0f,1.0f) ;
glBegin(GL_POLYGON);
//left

        glVertex2i (120,30);
          glVertex2i (120, 100);

//top
          glVertex2i (120, 100);
          glVertex2i (170, 100);

//right
          glVertex2i (170, 100);
          glVertex2i (170, 30);

 //bottom
         glVertex2i (120, 30);
          glVertex2i (170, 30);

          //glVertex2i (10, -50);

    glEnd();

    //Triangle

    glColor3f(0.0f,1.0f,0.0f) ;
    glBegin(GL_POLYGON);
//bottom

          glVertex2i (20, 200);
          glVertex2i (320, 200);

          //top
          glVertex2i (200, 310);
          glVertex2i (320, 200);

        //left
          glVertex2i (20, 200);
          glVertex2i (200, 310);


          //glVertex2i (10, -50);

    glEnd();




     glFlush(); // sends all output to display;

}
int main (int argc, char **argv)
{

     glutInit (&argc, argv); // to initialize the toolkit;

     glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB); // sets the display mode

     glutInitWindowSize (640, 480); // sets the window size

     glutInitWindowPosition (10, 10); // sets the starting position for the window

     glutCreateWindow ("My first OpenGL program!"); // creates the window and sets the title

     glutDisplayFunc (myDisplay);
     myInit(); // additional initializations as necessary
     glutMainLoop(); // go into a loop until event occurs
     return 0;
}

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#include <windows.h>

#include <GL\glut.h>

void myInit (void)

{

glClearColor(0.0,0.0,0.0,0.0); // sets background color to white

// sets a point to be 4x4 pixels

glMatrixMode(GL_PROJECTION);

glLoadIdentity();

gluOrtho2D(0.0, 500.0, 0.0, 400.0); // the display area in world coordinates.

}

void myDisplay(void)

{

glClear(GL_COLOR_BUFFER_BIT); // clears the screen

glColor3f(0.5f,0.5f,0.5f) ;// setsthe drawing colour

glPointSize(4.0);

glBegin(GL_POLYGON);

//bottom

glVertex2i (20, 20);

glVertex2i (320, 20);

//top

glVertex2i (20, 200);

glVertex2i (320, 200);

//left

glVertex2i (20, 200);

glVertex2i (20, 20);

//right

glVertex2i (320, 200);

glVertex2i (320, 20);

//glVertex2i (10, -50);

glEnd();

//Left Window

glColor3f(1.0f,0.0f,0.0f) ;

glPointSize(4.0);

glRectf(30,30,100,100);

//Right Window

glColor3f(1.0f,0.0f,0.0f) ;

glBegin(GL_POLYGON);

//bottom

glVertex2i (200,30);

glVertex2i (200, 100);

//top

glVertex2i (200, 100);

glVertex2i (300, 100);

//left

glVertex2i (300, 100);

glVertex2i (300, 30);

//right

glVertex2i (300, 30);

glVertex2i (200, 30);

//glVertex2i (10, -50);

glEnd();

//door

glColor3f(0.0f,0.0f,1.0f) ;

glBegin(GL_POLYGON);

//left

glVertex2i (120,30);

glVertex2i (120, 100);

//top

glVertex2i (120, 100);

glVertex2i (170, 100);

//right

glVertex2i (170, 100);

glVertex2i (170, 30);

//bottom

glVertex2i (120, 30);

glVertex2i (170, 30);

//glVertex2i (10, -50);

glEnd();

//Triangle

glColor3f(0.0f,1.0f,0.0f) ;

glBegin(GL_POLYGON);

//bottom

glVertex2i (20, 200);

glVertex2i (320, 200);

//top

glVertex2i (200, 310);

glVertex2i (320, 200);

//left

glVertex2i (20, 200);

glVertex2i (200, 310);

//glVertex2i (10, -50);

glEnd();

glFlush(); // sends all output to display;

}

int main (int argc, char **argv)

{

glutInit (&argc, argv); // to initialize the toolkit;

glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB); // sets the display mode

glutInitWindowSize (640, 480); // sets the window size

glutInitWindowPosition (10, 10); // sets the starting position for the window

glutCreateWindow ("My first OpenGL program!"); // creates the window and sets the title

glutDisplayFunc (myDisplay);

myInit(); // additional initializations as necessary

glutMainLoop(); // go into a loop until event occurs

return 0;

}

Screenshot:

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Posted in A ll Codes, Graphics, OpenGL, Programming

Tagged House, OpenGL

OpenGL GLUT Tutorials – C Graphics

Posted on May 15, 2016 | Leave a comment

Lectures:
About OpenGL colors:
http://www.cs.brandeis.edu/~cs155/OpenGL%20Lecture_02.pdf
https://en.wikibooks.org/wiki/OpenGL_Programming/Basics/Color

Setup:
https://openglprojects.com/setting-up-opengl-in-windows-linux-mac/
Tut:
http://www.lighthouse3d.com/tutorials/glut-tutorial/
http://ogldev.atspace.co.uk/www/tutorial03/tutorial03.html
https://www3.ntu.edu.sg/home/ehchua/programming/opengl/CG_Introduction.html

Vid:

https://www.youtube.com/watch?v=xCRzpNd5k3Y

Projects:
http://www.openglprojects.in/2015/08/bubble-shooter-game-computer-graphics-programs-in-c.html#gsc.tab=0

https://openglprojects.com/opengl-project-ideas/
http://vtupro.blogspot.com/2014/10/opengl-mini-project-for-csisit-students.html

Leave a comment

Posted in Graphics, OpenGL, Programming

Tagged Glut, Graphics, OpenGL

Draw a rectangle with OpenGL

Posted on May 14, 2016 | Leave a comment

Code:

#include<windows.h>
#include <GL/gl.h>
#include <GL/glut.h>
void display(void)
{
/* clear all pixels */
glClear (GL_COLOR_BUFFER_BIT);
/* draw white polygon (rectangle) with corners at
* (0.25, 0.25, 0.0) and (0.75, 0.75, 0.0)
*/
glColor3f (1.0, 0.25, 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();
/* don't wait!
* start processing buffered OpenGL routines
*/
glFlush ();
}
void init (void)
{
/* select clearing (background) color */
glClearColor (0.0, 0.0, 0.0, 0.0);
/* initialize viewing values */
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0.0, 1.0, 0.0, 1.0, -1.0, 1.0);
}
/*
* Declare initial window size, position, and display mode
* (single buffer and RGBA). Open window with "hello"
* in its title bar. Call initialization routines.
* Register callback function to display graphics.
* Enter main loop and process events.
*/
int main(int argc, char** argv)
{
glutInit(&argc, argv);
glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
glutInitWindowSize (500, 500);
glutInitWindowPosition (100, 100);
glutCreateWindow ("hello");
init ();
glutDisplayFunc(display);
glutMainLoop();
return 0; /* ISO C requires main to return int. */
}

#include<windows.h>

#include <GL/gl.h>

#include <GL/glut.h>

void display(void)

{

/* clear all pixels */

glClear (GL_COLOR_BUFFER_BIT);

/* draw white polygon (rectangle) with corners at

* (0.25, 0.25, 0.0) and (0.75, 0.75, 0.0)

glColor3f (1.0, 0.25, 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();

/* don't wait!

* start processing buffered OpenGL routines

glFlush ();

}

void init (void)

{

/* select clearing (background) color */

glClearColor (0.0, 0.0, 0.0, 0.0);

/* initialize viewing values */

glMatrixMode(GL_PROJECTION);

glLoadIdentity();

glOrtho(0.0, 1.0, 0.0, 1.0, -1.0, 1.0);

}

* Declare initial window size, position, and display mode

* (single buffer and RGBA). Open window with "hello"

* in its title bar. Call initialization routines.

* Register callback function to display graphics.

* Enter main loop and process events.

int main(int argc, char** argv)

{

glutInit(&argc, argv);

glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);

glutInitWindowSize (500, 500);

glutInitWindowPosition (100, 100);

glutCreateWindow ("hello");

init ();

glutDisplayFunc(display);

glutMainLoop();

return 0; /* ISO C requires main to return int. */

}

Output:

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Posted in A ll Codes, Graphics, OpenGL

Tagged OpenGL, Rectangle

Category Archives: OpenGL

Use codeblocks with OpenGl

Draw Midpoint Circle Algorithm with Keyboard Function

Draw Brasenham Line Drawing Algorithms with Random Lines and Colors

Star Drawing with OpenGL

OpenGL Graphics Code: Build a house with GLUT

OpenGL GLUT Tutorials – C Graphics

Draw a rectangle with OpenGL

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Category Archives: OpenGL

Use codeblocks with OpenGl

Draw Midpoint Circle Algorithm with Keyboard Function

Draw Brasenham Line Drawing Algorithms with Random Lines and Colors

Star Drawing with OpenGL

OpenGL Graphics Code: Build a house with GLUT

OpenGL GLUT Tutorials – C Graphics

Draw a rectangle with OpenGL

Random Quote

Random Quotes

Categories

Recent Comments

About Me & MyBlog

Caution and Tips:

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