Draw a 3D cylinder using openGL.

Applications Programming
1

Hi,

please give me, how to code to draw 3D cylinder in openGL, that should be rotated in x-direction.
waiting for your reply ..

2

Is this a homework question? Please post it in the appropriate forums
Please show us what have you tried so far.

3

Hi Sir,

Sorry for asking code..
I made a code to draw cylinder is given below :

code :

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <GL/glut.h>

#ifndef M_PI
#define M_PI 3.14159265
#endif

int win, win2;
int needsLightUpdate = GL_TRUE;
int useLighting = GL_TRUE;
int useSpecularTexture = GL_FALSE;
int useTexture = GL_FALSE;
int useHighRes = GL_FALSE;
int usePattern = GL_FALSE;
int moveLight = GL_FALSE;
int moveObject = GL_FALSE;

int drawObj = 0, maxObj = 2;
GLfloat lightRotX, lightRotY;
GLfloat objectRotX, objectRotY;
int curx, cury, width, height;

void
drawCylinder(int numMajor, int numMinor, float height, float radius)
{
double majorStep = height / numMajor;
double minorStep = 2.0 * M_PI / numMinor;
int i, j;

for (i = 0; i < numMajor; ++i) {
GLfloat z0 = 0.5 * height - i * majorStep;
GLfloat z1 = z0 - majorStep;

glBegin(GL_TRIANGLE_STRIP);
for (j = 0; j <= numMinor; ++j) {
double a = j * minorStep;
GLfloat x = radius * cos(a);
GLfloat y = radius * sin(a);
glNormal3f(x / radius, y / radius, 0.0);
glTexCoord2f(j / (GLfloat) numMinor, i / (GLfloat) numMajor);
glVertex3f(x, y, z0);

glNormal3f(x / radius, y / radius, 0.0);
glTexCoord2f(j / (GLfloat) numMinor, (i + 1) / (GLfloat) numMajor);
glVertex3f(x, y, z1);
}
glEnd();
}
}
void
initialize(void)
{
glMatrixMode(GL_PROJECTION);
glFrustum(-0.50, 0.50, -0.50, 0.50, 1.0, 3.0);
glMatrixMode(GL_MODELVIEW);
glTranslatef(0.0, 0.0, -2.0);

glDepthFunc(GL_LEQUAL);

glLightModeli(GL_LIGHT_MODEL_LOCAL_VIEWER, GL_TRUE);
}

void
redraw(void)
{
glClearColor(0.1, 0.1, 0.1, 1.0);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);


 glBegin(GL_QUADS);
glColor3f(0.0, 0.3, 7.0);
glVertex3f(-2.0, -2.0, -1.0);
glColor3f(0.0, 0.3, 7.0);
glVertex3f(2.0, -2.0, -1.0);
glColor3f(0.0, 0.3, 0.7);
glVertex3f(2.0, 2.0, -1.0);
glColor3f(0.0, 0.3, 0.7);
glVertex3f(-2.0, 2.0, -1.0);
glEnd();
glEnable(GL_DEPTH_TEST);


  if (useLighting) {
glEnable(GL_LIGHTING);
glPushMatrix();
glRotatef(lightRotY, 0, 1, 0);
glRotatef(lightRotX, 1, 0, 0);
glPopMatrix();
} else {
glColor3f(0.2, 0.2, 0.2);
}
if (useTexture || useSpecularTexture) {
glEnable(GL_TEXTURE_2D);
}

if (useSpecularTexture) {
/* pass one */
glEnable(GL_BLEND);
glBlendFunc(GL_ONE, GL_ZERO);


}

glPushMatrix();
glRotatef(objectRotY, 0, 1, 0);
glRotatef(objectRotX, 1, 0, 0);
drawCylinder(6, 16, 1.0, 0.4);

glPopMatrix();

if (useSpecularTexture) {
/* pass two */
if (!useLighting) {
glColor3f(1.0, 1.0, 1.0);
}
glBlendFunc(GL_ONE, GL_ONE);
glEnable(GL_TEXTURE_GEN_S);
glEnable(GL_TEXTURE_GEN_T);
glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_SPHERE_MAP);
glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_SPHERE_MAP);
glPushMatrix();
glRotatef(objectRotY, 0, 1, 0);
glRotatef(objectRotX, 1, 0, 0);
drawCylinder(6, 16, 1.0, 0.4);
glPopMatrix();
}
glDisable(GL_DEPTH_TEST);
glDisable(GL_LIGHTING);
glDisable(GL_TEXTURE_2D);
glDisable(GL_BLEND);
glDisable(GL_TEXTURE_GEN_S);
glDisable(GL_TEXTURE_GEN_T);
}

void
motion(int x, int y)
{
if (moveLight || moveObject) {
GLfloat dx = (y - cury) * 360.0 / height;
GLfloat dy = (x - curx) * 360.0 / width;
if (moveLight) {
lightRotX += dx;
if (lightRotX > 360)
lightRotX -= 360;
if (lightRotX < 0)
lightRotX += 360;
lightRotY += dy;
if (lightRotY > 360)
lightRotY -= 360;
if (lightRotY < 0)
lightRotY += 360;
needsLightUpdate = GL_TRUE;
} else if (moveObject) {
objectRotX += dx;
if (objectRotX > 360)
objectRotX -= 360;
if (objectRotX < 0)
objectRotX += 360;
objectRotY += dy;
if (objectRotY > 360)
objectRotY -= 360;
if (objectRotY < 0)
objectRotY += 360;
}
curx = x;
cury = y;
}
glutPostRedisplay();
}

void
mouse(int button, int state, int x, int y)
{
if (state == GLUT_DOWN) {
switch (button) {
case GLUT_LEFT_BUTTON:
moveObject = GL_TRUE;
motion(curx = x, cury = y);
break;
case GLUT_MIDDLE_BUTTON:
moveLight = GL_TRUE;
motion(curx = x, cury = y);
break;
}
} else if (state == GLUT_UP) {
switch (button) {
case GLUT_LEFT_BUTTON:
moveObject = GL_FALSE;
break;
case GLUT_MIDDLE_BUTTON:
moveLight = GL_FALSE;
break;
}
}
}

void
display(void)
{
redraw();
glFlush();
glutSwapBuffers();

}


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

glutInit(&argc, argv);
glutInitWindowSize(width = 500, height = 500);
                              
glutInitDisplayMode(GLUT_RGBA | GLUT_DEPTH | GLUT_DOUBLE);

for (i = 1; i < argc; ++i) {

exit(1);
}
win = glutCreateWindow("envphong");
glutDisplayFunc(display);

glutMouseFunc(mouse);
glutMotionFunc(motion);
initialize();
glutMainLoop();
return 0;
}

This is working good, please guide me how to place multiple images on the surface of the cylinder ..

Please guide me Sir.. waiting for reply..