This code defines functions to draw a cylinder object that can be rotated and zoomed in/out on the 3D plane. Key presses control the zoom level, projection type, and rotation of the cylinder along the x and y axes. The main function initializes the OpenGL window and rendering context and sets callbacks for drawing, resizing, and keyboard/special key input handling.

1. PRACTICA case 27:
exit(0);
#include <GL/glut.h> case '+':
#include <GL/gl.h> zoom++;
#include <stdlib.h> break;
case '-':
GLUquadricObj *cilindro; zoom--;
GLfloatgirax=0,giray=0,zoom=0; break;
case 'p':
GLbooleanmalla=GL_FALSE, ejes=GL_TRUE; glMatrixMode(GL_PROJECTION);
glLoadIdentity();
void mover(void){ gluPerspective(45,1,10,100);
glTranslated(0,0,zoom); zoom=-40;
glRotated(girax,1.0,0.0,0.0); break;
glRotated(giray,0.0,1.0,0.0); case 'o':
} glMatrixMode(GL_PROJECTION);
glLoadIdentity();
voidcreaMalla(void){ glOrtho(-15,15,-15,15,-30,30);
int i, long_eje=10; zoom=0;
glColor3f(1.0,0.0,0.0); break;
glBegin(GL_LINES); case 'm':
for(i=-long_eje;i<=long_eje;i++){ malla= !malla;
glVertex3f(i,0,-long_eje); break;
glVertex3f(i,0,long_eje); case 'e':
glVertex3f(-long_eje,0,i); ejes= !ejes;
glVertex3f(long_eje,0,i); default: break;
} }
glEnd(); glutPostRedisplay();
} }
voidcreaEjes(void){ voidflechas(int key, int x, int y){
glColor3f(0.0,0.0,0.0); switch(key){
glBegin(GL_LINES); case GLUT_KEY_LEFT:
glVertex3f(0.0,0.0,0.0); giray-=15;
glVertex3f(11.0,0.0,0.0); break;
glVertex3f(0.0,0.0,0.0); case GLUT_KEY_RIGHT:
glVertex3f(0.0,11.0,0.0); giray+=15;
glVertex3f(0.0,0.0,0.0); break;
glVertex3f(0.0,0.0,11.0); case GLUT_KEY_UP:
glEnd(); girax-=15;
glBegin(GL_TRIANGLES); break;
glVertex3f(11.0,0.0,0.0); case GLUT_KEY_DOWN:
glVertex3f(10.5,0.0,-.50); girax+=15;
glVertex3f(10.5,0.0,.50); break;
glVertex3f(0.0,11.0,0.0); default: break;
glVertex3f(-.50,10.5,0.0); }
glVertex3f(.50,10.5,0.0); glutPostRedisplay();
glColor3f(1.0,0.0,1.0); }
glVertex3f(0.0,0.0,11.0); void ajusta(int ancho, int alto){
glVertex3f(-.50,0.0,10.5); glClearColor(1.0,1.0,1.0,0.0);
glVertex3f(.50,0.0,10.5); glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glEnd(); glOrtho(-15,15,-15,15,-30,30);
glMatrixMode(GL_MODELVIEW);
} glLoadIdentity();
glClear(GL_DEPTH_TEST);
void dibuja(void) }
{
cilindro=gluNewQuadric(); int main (intargc, char** argv)
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); {
glPushMatrix();
mover(); glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
if(malla) creaMalla(); glutInitWindowPosition(100,100);
if(ejes) creaEjes(); glutInitWindowSize(600,600);
glColor3f(.2,.2,1.); glutInit(&argc, argv);
gluQuadricDrawStyle(cilindro,GLU_LINE); glutCreateWindow("CILINDRO");
gluCylinder(cilindro,1,1,9,20,20); glutDisplayFunc(dibuja);
glPopMatrix(); glutReshapeFunc(ajusta);
glutSwapBuffers(); glutKeyboardFunc(teclado);
} glutSpecialFunc(flechas);
glutMainLoop();
voidteclado(unsigned char key, int x, int y){ return 0;
switch(key){ }