/*******************************************************************
	      Support Routines for a Simple Hand Model
********************************************************************
    Author: Stan Sclaroff
      Date: October 2, 2006
  Comments: This is just meant for demonstration.  You can
            extend/rewrite this code for the assignment.
********************************************************************/

#include <math.h>
#include <GL/glut.h>
#include <GL/gl.h>
#include <GL/glu.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "const.h"
#include "types.h"

static GLint hand_object;

/* You will need to modify this routine! */
void updateHandObject(GLint hand_object, handType *hand)
{

  glNewList(hand_object,GL_COMPILE);

  glColor3f(0.8,0.5,0.2);
  /* create an ellipsoid by scaling a sphere */
  glScalef(0.5,1.0,2.0);
  glutSolidSphere(hand->scale,36,18);

  glEndList();
}


/* create the hand geometry */
GLint createHandObject(handType *hand)
{
  GLint hand_object;

  hand_object = glGenLists(1);
  updateHandObject(hand_object,hand);

  return(hand_object);
}

/* draw the OpenGL object for the hand */
void drawHandObject(handType *hand)
{
  static GLint hand_object;
  /* if the hand object does not exist, create it */
  /* then create/recreate the hand object with updated info */
  if(!hand_object)
    hand_object = createHandObject(hand);
  else
    updateHandObject(hand_object,hand);
  
  /* call the hand's OpenGL object */
  glCallList(hand_object);
}


/* Hand structure maint. functions*/
/* create a hand */
handType *createHand(float scale)
{
  handType *h;
  int i;

  h = calloc(sizeof(handType),1);
  h->scale = scale;
  h->active_rotation_axis = AXIS_X;
  h->active_joint = JOINT_DISTAL;
  h->angles[0] = h->angles[1] = 0.0;

  for(i=0;i<5;++i)
    h->active_fingers[i] = FALSE;

  return(h);
}

/* Toggle which fingers are active */
void toggleFinger(handType *hand, int finger)
{
  if(hand && finger >= 0 && finger < 5)
    {
      if(hand->active_fingers[finger] == FALSE)
	hand->active_fingers[finger] = TRUE;
      else
	hand->active_fingers[finger] = FALSE;
    }
}

/* select axis (x,y,z) is used for rotation */
void selectRotationAxis(handType *hand, int axis_num)
{
  if(hand)
    hand->active_rotation_axis = axis_num;
}

/* select which of three finger joints is active */
void selectJoint(handType *hand, int joint_id)
{
  if(hand)
    hand->active_joint = joint_id;
}

/* increment/decrement the rotation angle */
void incrementAngle(handType *hand, float delta)
{
  /* you will need to completely rewrite this function */
  if(hand)
    hand->angles[hand->active_rotation_axis]+=delta;
}