/*
======================================================================
sombrero.c

Ernie Wright  02 Jun 05

This version has been modified to fit your TV.
====================================================================== */

/* sombrero.c - example of the use of heightfield output
   From: Alexander Enzmann <70323.2461@compuserve.com>
   Updated: 4/22/95 Eduard Schwan - Added code to match other
   example styles, and made width/height variable based on size parameter
 * size_factor  width/height  patches
 *      1          32x32
 *      2          64x64
 *      3         128x128
 *      4         256x256

*/

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include "lwmod.h"
#include "def.h"
#include "lib.h"


static int size_factor;
static char *spdName = "Sombrero";

/* Define constants for the sombrero function */
static double a_const, b_const, c_const, two_pi_a;

static float **
create_sombrero(width, height, x0, x1, y0, y1)
unsigned width, height;
double x0, x1, y0, y1;
{
   float **data;
   double x, deltax, y, deltay;
   unsigned i, j;

   a_const = 1.0;
   b_const = 1.0;
   c_const = 3.0;
   two_pi_a = 2.0 * 3.14159265358 * a_const;

   deltax = (x1 - x0) / (double)width;
   deltay = (y1 - y0) / (double)height;

   if ((data = malloc(height * sizeof(float *))) == NULL) {
      fprintf(stderr, "HF allocation failed\n");
      exit(1);
   }
   for (i=0,y=y0;i<height;i++,y+=deltay) {
      if ((data[i] = malloc(width * sizeof(float ))) == NULL) {
         fprintf(stderr, "HF allocation failed\n");
         exit(1);
      }
      for (j=0,x=x0;j<width;j++,x+=deltax) {
         if ( lwMonitorStep( 1 ))
            return data;

         /* your function here...
          * For the conversion to work for POV-Ray, Polyray, or any other
          * format which converts fixed range heightfield data to an image,
          * make sure the function produces values between -1 and 1. */
         data[i][j] = (float)(c_const * cos(two_pi_a * sqrt(x * x + y * y)) *
            exp(-b_const * sqrt(x * x + y * y))/3.0);

         /* here's a simple sine wave function:
         data[i][j] = (float)(((cos(two_pi_a * x / 2.0) + sin(two_pi_a * y / 2.0)/2.0))/1.5) ;
          */
      }
   }
   return data;
}


void spdSombrero( int sf )
{
   COORD4 back_color, obj_color;
   COORD4 from, at, up, light;
   double lscale;
   unsigned width = 64, height = 64;
   float **data;


   size_factor = sf;

   /* output background color - UNC sky blue */
   SET_COORD3(back_color, 0.078, 0.361, 0.753);
   lib_output_background_color(back_color);

   /* output viewpoint */
   SET_COORD3(from, 0, 5, -8);
   SET_COORD3(at, 0, 0, 0);
   SET_COORD3(up, 0, 0, 1);
   lib_output_viewpoint(from, at, up, 40.0, 1.0, 0.01, 512, 512);

    /*
    * For raytracers that don't scale the light intensity,
    * we will do it for them
    */
   #define NUM_LIGHTS    1
    lscale = 1.0 / sqrt(NUM_LIGHTS);

   /* output light sources */
   SET_COORD4(light, 10, 10, -10, lscale);
   lib_output_light(light);

   /* Height field color - shiny_red */
   SET_COORD3(obj_color, 1, 0.1, 0.1);
   lib_output_color(spdName, 1, obj_color, 0.1, 0.8, 0.0, 0.5, 40.0, 0.0, 1.0);

   /* Create the height field */
   width = 32*(1 << (size_factor-1) ); /* 32, 64, 128, 256... */
   height = width;
   data = create_sombrero(width, height, -4.0, 4.0, -4.0, 4.0);
   lwMonitorBegin( spdName, "Creating sombrero", width * height );
   lib_output_height(NULL, data, width, height, -4.0, 4.0, -3.0, 3.0, -4.0, 4.0);
   lwMonitorDone();
   free( data );
}