/*
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <mpi.h>
#include "mpe_graphics.h"
#include "mpe.h"
*/

int XDIM = 800;
int YDIM = 600;
int ZDIM = 400;
#define PI 3.1415927

// zoom ratio - right now, not tied to ZDIM, but probably should!
double ZR = 0.25;
double tiltR = PI/2;  // tilt angle in radians
// shortening ratio (scales z axis): usually should set to one:
double SR = 1.0;


int xshift, yshift;  // these are static shift values for entire window
//MPE_XGraph graph;

double toDegrees (double radians)
{ return radians * 180/PI; }

double toRadians (double degrees)
{ return degrees * PI/180; }

// critical function to convert 3d coordinate to 2d coordinate
// returns 0 on success
int point(int x, int y, int z, int *x2, int *y2)
{
  double s;
  s = (1-((1-ZR)*z/((double)ZDIM)));
  *x2 = (int) ((s*x) + (z * cos(tiltR) * SR));
  *y2 = (int) ((s*y) + (z * sin(tiltR) * SR));
  *y2 += (int)abs(yshift);
  if(xshift<0) *x2 -= (int)xshift;
  return 0;
}

void drawbox(MPE_XGraph graph, int x0, int y0, int z0, int xd, int yd, int zd, MPE_Color mc)
{
  int a, b, u, v, x, y, p, q;
  point(x0,y0,z0,&a,&b);
  point(x0+xd,y0,z0,&x,&y);
  point(x0,y0+yd,z0,&u,&v);
  point(x0+xd,y0+yd,z0,&p,&q);
  // front
  MPE_Draw_line(graph,a,b,x,y,mc);
  MPE_Draw_line(graph,a,b,u,v,mc);
  MPE_Draw_line(graph,u,v,p,q,mc);
  MPE_Draw_line(graph,p,q,x,y,mc);
  // sides
  point(x0,y0,z0+zd,&x,&y);
  point(x0,y0+yd,z0+zd,&p,&q);
  MPE_Draw_line(graph,a,b,x,y,mc);  
  MPE_Draw_line(graph,u,v,p,q,mc);
  MPE_Draw_line(graph,x,y,p,q,mc);
  point(x0+xd,y0,z0+zd,&a,&b);
  point(x0+xd,y0+yd,z0+zd,&u,&v);
  MPE_Draw_line(graph,x,y,a,b,mc);
  MPE_Draw_line(graph,p,q,u,v,mc);
  MPE_Draw_line(graph,a,b,u,v,mc);
  point(x0+xd,y0,z0,&x,&y);
  point(x0+xd,y0+yd,z0,&p,&q);
  MPE_Draw_line(graph,a,b,x,y,mc);
  MPE_Draw_line(graph,u,v,p,q,mc);
}

void drawline(MPE_XGraph graph, int x0, int y0, int z0, int x1, int y1, int z1, MPE_Color mc)
{  int a, b, x, y;
   point(x0,y0,z0,&a,&b);
   point(x1,y1,z1,&x,&y);
   MPE_Draw_line(graph,a,b,x,y,mc);
}

// fill circle with scaled radius
void fillcircle(MPE_XGraph graph, int x0, int y0, int z0, double r, MPE_Color mc)
{
  int x, y;  double rs;
  point(x0,y0,z0,&x,&y);
  rs = (1-((1-ZR)*((double)z0)/ZDIM)) * r;
  //  printf("%d, %f and %f\n",z0,rs,r);
  if (rs<1) rs = 1;
  MPE_Fill_circle(graph,x,y,(int)rs,mc);
  //  MPE_Draw_circle(graph,x,y,(int)rs-2,MPE_BLACK);  // 3d effect?
}

// drawcircle with scaled radius
void drawcircle(MPE_XGraph graph, int x0, int y0, int z0, double r, MPE_Color mc)
{
  int x, y;  double rs;
  point(x0,y0,z0,&x,&y);
  rs = (1-((1-ZR)*((double)z0)/ZDIM)) * r;
  //  printf("%d, %f and %f\n",z0,rs,r);
  if (rs<1) rs = 1;
  MPE_Draw_circle(graph,x,y,(int)rs,mc);
}

double dscale(double x, double z0)
{
  return (1-((1-ZR)*((double)z0)/ZDIM)) * x;
}