Some Additional GLUT Commands.

• Some more GLUT functions we need.
• void glutDisplayFunc( void (*func)(void))
  • This is the function which gets called when it is time to redraw the window.
  • Your code in this function accomplishes what ever is needed to accomplish the redraw.
  • This is where I did my animations for example.
• void glutIdleFunc(void (*func)(void))
  • Designed for background computations and animation
  • Passing a NULL disables the callback
• And as mentioned last time void glutPostRedisplay(void).
  • Causes the window to be marked for redisplay
  • or causes the redisplay function to be called.
• Take a quick look at my keyboard function

  • 
         switch ( key ) {
            case 'a':
                  DO_ANIMATION =true;
                  glutIdleFunc(idle);
                  ANIMATION_STEP = 0;
                  break;
            case 'h':
                  SHOW_LAST = !SHOW_LAST;
                  glutPostRedisplay();
                  break;
            case 'r':
                  Init();
                  glutPostRedisplay();
                  break;
            case 'd':
                  FlakeIt(data,1);
                  glutPostRedisplay();
                  break;
            case 'q':
                  exit(0);
    re>
        

• My general strategy
  • I have two idle functions
    • The first is responsible for a single curve iteration's animation
    • it is

      void SingleStepAnimateIdle() {
          glutPostRedisplay();
          ANIMATION_STEP++;
          if (ANIMATION_STEP ==  MAX_ANIMATION_STEPS) {
              DO_ANIMATION = false;
      	glutIdleFunc(NULL);
          }
          return;
      }
      	     

  • The second does the same thing
    • But it will reset ANIMATION_STEP to 0 when it reaches MAX_ANIMATION_STEPS
    • And it will call Flake_IT
    • And it will turn off animation when TOTAL_DEPTH = MAX_DEPTH
  • Finally, display does two things:
    • 
    • Flake it have computed points P₀, P₁ and P₂
    • If it is a normal step, just draw lines between each vertex pair in order.
      • Draw P₀ P₁ and P₁ P₂
    • If history is on, draw lines between every other vertex.
      • Draw P₀ P₂
    • If it is an animation step (animation is active)
      • Compute P_m.
      • Compute P_t = P_m + (step/max_steps) P₁.
      • Draw P₀ P_t and P_t P₂