/*
 * File:
 *   cliographics.c
 * Summary:
 *   Graphics utilities for clio.  See cliographics.h for details.
 * Author:
 *   Samuel A. Rebelsky
 * Version:
 *   0.1 of July 2003.
 */

/*********************************************************************
 * Headers *
 ***********/

#include "cliographics.h"
#include "clio.h"


float fNormalX, fNormalY, fNormalZ;


/*********************************************************************
 * Local Function Predeclarations *
 **********************************/

static void drawBox(float xmin, float ymin, float zmin,
                    float xmax, float ymax, float zmax);
static void frameBox(float xmin, float ymin, float zmin,
                     float xmax, float ymax, float zmax);


/*********************************************************************
 * Exported Functions *
 **********************/

void clioBox(int color, float shade,
             float x, float y, float z,
             float w, float h, float d) 
{
  int xmin,ymin,zmin,xmax,ymax,zmax; 
  float component;


  /* Compute various components. */
  xmin = x - w/2.0;
  ymin = y - h/2.0;
  zmin = z - d/2.0;
  xmax = xmin + w;
  ymax = ymin + h;
  zmax = zmin + d;

  /* Set the color to something fun. */
  component = shade/MAXC;
  switch (color) {
    case 0: glColor3f(component, 0.0, 0.0); break;
    case 1: glColor3f(0.0, component, 0.0); break;
    case 2: glColor3f(0.0, 0.0, component); break;
    case 3: glColor3f(component, component, 0.0); break;
    case 4: glColor3f(component, 0.0, component); break;
  } /* switch */
 
  /* Draw the faces of the box. */
  drawBox(xmin,ymin,zmin,xmax,ymax,zmax);
  /* Frame the box afterwards. */
  glColor3f(1.0,1.0,1.0);
  //frameBox(xmin,ymin,zmin,xmax,ymax,zmax);
} /* clioBox() */
  
                                    
/*********************************************************************
 * Local Functions *
 *******************/

void 
drawBox(float xmin, float ymin, float zmin,
                    float xmax, float ymax, float zmax)
{
  float v1[]= {xmax, ymax, zmax};
  float v2[]= {xmin, ymax, zmax};
  float v3[]= {xmin, ymin, zmax};
  float v4[]= {xmax, ymin, zmax};

  float v5[]= {xmax, ymax, zmin};
  float v6[]= {xmax, ymin, zmin};
  
  float v7[]= {xmin, ymax, zmin};
  float v8[]= {xmin, ymin, zmin};

  glBegin(GL_QUADS);
 
      CalculateVectorNormal(v1, v2, v3, &fNormalX,
                            &fNormalY, &fNormalZ);
      // Set the normal vector for the polygon
      glNormal3f(fNormalX, fNormalY, fNormalZ);
      
      /* "Front" Face */
      glVertex3fv(v1);
      glVertex3fv(v2);
      glVertex3fv(v3);
      glVertex3fv(v4);
  glEnd();
 

  glBegin(GL_QUADS);
      CalculateVectorNormal(v7, v5, v6, &fNormalX,
                            &fNormalY, &fNormalZ);
      // Set the normal vector for the polygon
      glNormal3f(fNormalX, fNormalY, fNormalZ);
      /* "Rear" Face */
      glVertex3fv(v7);
      glVertex3fv(v5);
      glVertex3fv(v6);
      glVertex3fv(v8);
  glEnd();

  glBegin(GL_QUADS);
      CalculateVectorNormal(v5, v1, v4, &fNormalX,
                            &fNormalY, &fNormalZ);
      // Set the normal vector for the polygon
      glNormal3f(fNormalX, fNormalY, fNormalZ);
      /* "Right" Face */
      glVertex3fv(v5);
      glVertex3fv(v1);
      glVertex3fv(v4);
      glVertex3fv(v6);
   glEnd();
  
   glBegin(GL_QUADS);
        CalculateVectorNormal(v2, v7, v8, &fNormalX,
                              &fNormalY, &fNormalZ);
        // Set the normal vector for the polygon
        glNormal3f(fNormalX, fNormalY, fNormalZ);
        /* "Left" Face */
        glVertex3fv(v2);
        glVertex3fv(v7);
        glVertex3fv(v8);
        glVertex3fv(v3);
   glEnd();

   glBegin(GL_QUADS);
        CalculateVectorNormal(v5, v7, v2, &fNormalX,
                              &fNormalY, &fNormalZ);
        // Set the normal vector for the polygon
        glNormal3f(fNormalX, fNormalY, fNormalZ);
        /* "Top" Face */
        glVertex3fv(v5);
        glVertex3fv(v7);
        glVertex3fv(v2);
        glVertex3fv(v1);
   glEnd();
  
   
   glBegin(GL_QUADS);
       CalculateVectorNormal(v4, v3, v8, &fNormalX,
                            &fNormalY, &fNormalZ);
      // Set the normal vector for the polygon
      glNormal3f(fNormalX, fNormalY, fNormalZ);
      /* "Bottom" Face */
      glVertex3fv(v4);
      glVertex3fv(v3);
      glVertex3fv(v8);
      glVertex3fv(v6);
  glEnd();
} /* drawBox() */

void 
frameBox(float xmin, float ymin, float zmin,
         float xmax, float ymax, float zmax)
{

  glBegin(GL_LINES);

  /* "Front" face */
  glVertex3f(xmin,ymin,zmin);
  glVertex3f(xmin,ymin,zmax);
  glVertex3f(xmin,ymin,zmax);
  glVertex3f(xmin,ymax,zmax);
  glVertex3f(xmin,ymax,zmax);
  glVertex3f(xmin,ymax,zmin);
  glVertex3f(xmin,ymax,zmin);
  glVertex3f(xmin,ymin,zmin);
                                                                                
  /* "Rear" Face */
  glVertex3f(xmax,ymin,zmin);
  glVertex3f(xmax,ymin,zmax);
  glVertex3f(xmax,ymin,zmax);
  glVertex3f(xmax,ymax,zmax);
  glVertex3f(xmax,ymax,zmax);
  glVertex3f(xmax,ymax,zmin);
  glVertex3f(xmax,ymax,zmin);
  glVertex3f(xmax,ymin,zmin);
                                                                                
  /* The Rest */
  glVertex3f(xmin,ymin,zmin);
  glVertex3f(xmax,ymin,zmin);
  glVertex3f(xmin,ymin,zmax);
  glVertex3f(xmax,ymin,zmax);
  glVertex3f(xmin,ymax,zmax);
  glVertex3f(xmax,ymax,zmax);
  glVertex3f(xmin,ymax,zmin);
  glVertex3f(xmax,ymax,zmin);

  /* That's it. */
  glEnd();
} /* frameBox() */

void CalculateVectorNormal( float fVert1[], float fVert2[],
                            float fVert3[], float *fNormalX,
                            float *fNormalY, float *fNormalZ)
{
  
  float Qx, Qy, Qz, Px, Py, Pz;
  
  Qx = fVert2[0]-fVert1[0];
  Qy = fVert2[1]-fVert1[1];
  Qz = fVert2[2]-fVert1[2];
  Px = fVert3[0]-fVert1[0];
  Py = fVert3[1]-fVert1[1];
  Pz = fVert3[2]-fVert1[2];
  
  *fNormalX = -1*(Py*Qz - Pz*Qy);
  *fNormalY = -1*(Pz*Qx - Px*Qz);
  *fNormalZ = -1*(Px*Qy - Py*Qx);
  
}