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6.cpp
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6.cpp
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#include<glut.h>
#include<math.h>
void sphere()
{
double c = 3.142 / 180, phi, phir, phir20, theta, thetar, x, y, z, c80, xc, yc, r; // converting to radians
// to get longitudes
for (phi = -80.0; phi <= 80.0; phi += 10.0) // the increment size should be changed everywhere
{
//phi=-50.0;
phir = c * phi; // in radians – for the 1st point
phir20 = c * (phi + 10); // for the 2nd point
glBegin(GL_QUAD_STRIP);
// to get latitudes
for (theta = -180.0; theta <= 180.0; theta += 10.0)
{
thetar = c * theta; // =-180*c = -3.132 – 1st time
x = sin(thetar) * cos(phir);
y = cos(thetar) * cos(phir);
z = sin(phir);
glVertex3d(x, y, z); // 1st point
phir20 = c * (phi + 10);
x = sin(thetar) * cos(phir20);
y = cos(thetar) * cos(phir20);
z = sin(phir20);
glVertex3d(x, y, z); // 2nd point
}
glEnd();
}
//1st pole – use triangle fans
glBegin(GL_TRIANGLE_FAN);
glColor3f(1.0, 0.0, 0.0); // both triangle colors are affected by this
glVertex3d(0.0, 0.0, 1.0); // top pole
c80 = c * 80.0;
z = sin(c80);
for (theta = -180.0; theta <= 180.0; theta += 10.0)
{
thetar = c * theta;
x = sin(thetar) * cos(c80);
y = cos(thetar) * cos(c80);
glVertex3d(x, y, z);
}
glEnd();
//2nd pole – use triangle fans
glBegin(GL_TRIANGLE_FAN);
glVertex3d(0.0, 0.0, -1.0); // bottom pole
z = -sin(c80);
for (theta = -180.0; theta <= 180.0; theta += 10.0)
{
thetar = c * theta;
x = sin(thetar) * cos(c80);
y = cos(thetar) * cos(c80);
glVertex3d(x, y, z);
}
glEnd();
}
void display()
{
int j;
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glPolygonMode(GL_FRONT_AND_BACK, GL_LINE); // the quad doesn't get filled up and only boundary appears
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslatef(0.0, 0.0, -1);
// change the below parameter to control the viewing angle
glRotatef(60.0, 1.0, 1.0, 0.0); // rotate by how much angle and about which axis (angle,x,y,z)
sphere();
glFlush();
}
void myinit()
{
glClearColor(1.0, 1.0, 1.0, 0);
glColor3f(0, 0, 1.0);
glPointSize(1.0);
gluOrtho2D(-1, 1, -1, 1);
}
void main(int argc, char* argv[])
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
glutInitWindowSize(500, 500);
glutInitWindowPosition(100, 100);
glutCreateWindow("Sphere Display");
glutDisplayFunc(display);
myinit();
glutMainLoop();
}