Visualization

For OpenGL visualization of the two dimensional soft body I used $GL\_QUADS$ type which gave me simply way to draw filled body. Below a complete GLUT callback procedure which draw a body in a GLUT window is presented:

void Draw(void)
{
  int i;
  glClearColor(1,1,1,0);
  glClear(GL_COLOR_BUFFER_BIT);

  glBegin(GL_QUADS);
  for(i = 1 ; i <= NUMS-1 ; i++)
  {
    glColor3f(1,0.4,0.4);
    glVertex2f(myPoints[ mySprings[i].i ].x,
               myPoints[ mySprings[i].i ].y);
    glVertex2f(myPoints[ mySprings[i].j ].x,
               myPoints[ mySprings[i].j ].y);
 
    glVertex2f(myPoints[ NUMP - 
                         mySprings[i].i + 1].x,
               myPoints[ NUMP - 
                         mySprings[i].i + 1].y);
    glVertex2f(myPoints[ NUMP - 
                         mySprings[i].j + 1].x,
               myPoints[ NUMP - 
                         mySprings[i].j + 1].y);
  }
  glEnd();

  glutSwapBuffers(); 
}

As we see in above code we simply draw QUADS (i,j,NUMP-i+1,NUMP-i+1), it is done as simply as possible and of course some nice features can be added here easly (normal/velocity vectors drawing, color differences while pressure changes etc.).