#include "EF.h"
#include <string.h>
#include <math.h>
#include <stdio.h>

void computeChecks(EF_Image *image, EF_Image *outimage, float param)
{
    int x,y;

    /* remap param so that it can be used to describe the number of pixels
       across each check is: its range is 0->1 when this is called, this maps
       a param of 0 to 1, and a param of 1 to 101. */
    float extent = (100. * (param + .01));
  
    /* Loop over every pixel (x,y)  */
    for (x = 0; x < image->xSize; x++)
	for (y = 0; y < image->ySize; y++)
	    {
		/* Use the pixel number (x,y) to decide if there is a
		   check at this pixel or not.  Val is either 0 or 1. */
		int val = ((int)(x / extent)+ (int)(y  / extent)) % 2;
	
		/* Set the RGBA components of the pixel depending on val.
		   Note that pixels without a check have alpha of zero. */
		RED(EF_ImageXY(outimage, x, y)) = val*50;
		GREEN(EF_ImageXY(outimage, x, y)) = val*50;
		BLUE(EF_ImageXY(outimage, x, y)) = val*200;
		ALPHA(EF_ImageXY(outimage, x, y)) = val*255;
	    } 
}

void pluginInit(EF_PluginOptions *options)
{
    if (options->structSize!=sizeof(EF_PluginOptions))
	{ puts("Plugin is wrong version"); return; }

    options->pluginApply = computeChecks;
    strcpy(options->name,"Checks");
}