#include <GL/glut.h>
#include <stdlib.h>

int shoulder = 0, elbow1 = 0, elbow2 = 0;
int roty= 0;

void init(void) 
{
   glClearColor (0.0, 0.0, 0.0, 0.0);
}

void display(void)
{
   glClear (GL_COLOR_BUFFER_BIT);

   glPushMatrix();
   glMatrixMode(GL_MODELVIEW);
   glLoadIdentity();
   glTranslatef (0.0, 0.0, -8.0);

   glBegin(GL_LINES);
   glColor3f(1.0,0.0,0.0);
   glVertex3f(0.0,0.0,0.0);
   glVertex3f(1.0,0.0,0.0);
   glColor3f(0.0,1.0,0.0);
   glVertex3f(0.0,0.0,0.0);
   glVertex3f(0.0,1.0,0.0);
   glColor3f(0.0,0.0,1.0);
   glVertex3f(0.0,0.0,0.0);
   glVertex3f(0.0,0.0,1.0);
   glEnd();
   
   glColor3f(1.0,1.0,1.0);

   glRotatef((GLfloat) roty, 0.0, 1.0, 0.0);
   glRotatef ((GLfloat) shoulder, 0.0, 0.0, 1.0);
   glTranslatef (1.0, 0.0, 0.0);
   
   glPushMatrix();
   // polso
   glPushMatrix();
    glScalef (2.0, 0.4, 4.0);
    glutWireCube (1.0);
   glPopMatrix();

// primo dito
   glPushMatrix();
	glTranslatef (1.0, 0.0, -1.0); // traslazione del dito al punto di attacco alla mano
    glRotatef ((GLfloat) elbow1, 0.0, 0.0, 1.0); // rotazione rispetto alla base del dito
    glTranslatef (1.0, 0.0, 0.0); // traslazione del dito nell'origine
    glScalef (2.0, 0.4, 1.0);
    glutWireCube (1.0);
   glPopMatrix();

   // secondo dito
   glPushMatrix();
    glTranslatef (1.0, 0.0, 1.0);
    glRotatef ((GLfloat) elbow2, 0.0, 0.0, 1.0);
    glTranslatef (1.0, 0.0, 0.0);
    glScalef (2.0, 0.4, 1.0);
    glutWireCube (1.0);
   glPopMatrix();


   glPopMatrix();
   glPopMatrix();

   glutSwapBuffers();
}

void reshape (int w, int h)
{
   glViewport (0, 0, (GLsizei) w, (GLsizei) h); 
   glMatrixMode (GL_PROJECTION);
   glLoadIdentity ();
   gluPerspective(65.0, (GLfloat) w/(GLfloat) h, 1.0, 20.0);
}

void keyboard (unsigned char key, int x, int y)
{
   switch (key) {
      case 's':
         shoulder = (shoulder + 5) % 360;
         glutPostRedisplay();
         break;
      case 'S':
         shoulder = (shoulder - 5) % 360;
         glutPostRedisplay();
         break;
      case 'e':
         elbow1 = (elbow1 + 5) % 360;
         glutPostRedisplay();
         break;
      case 'E':
         elbow1 = (elbow1 - 5) % 360;
         glutPostRedisplay();
         break;
      case 'd':
         elbow2 = (elbow2 + 5) % 360;
         glutPostRedisplay();
         break;
      case 'D':
         elbow2 = (elbow2 - 5) % 360;
         glutPostRedisplay();
         break;
     case 'w':
         roty = (roty + 5) % 360 ;
         glutPostRedisplay();
         break;
      case 'W':
         roty = (roty - 5) % 360;
         glutPostRedisplay();
         break;
      case 27:
         exit(0);
         break;
      default:
         break;
   }
}

int main(int argc, char** argv)
{
   glutInit(&argc, argv);
   glutInitDisplayMode (GLUT_DOUBLE | GLUT_RGB);
   glutInitWindowSize (500, 500); 
   glutInitWindowPosition (100, 100);
   glutCreateWindow (argv[0]);
   init ();
   glutDisplayFunc(display); 
   glutReshapeFunc(reshape);
   glutKeyboardFunc(keyboard);
   glutMainLoop();
   return 0;
}