PPMLoader.cpp

#include "PPMLoader.h"
#include <stdio.h>
#include <stdlib.h>


GLubyte *image;

PPMLoader::PPMLoader()
{
	
}
GLubyte* PPMLoader::loadPPM(char* file, int* width, int* height, int* max)
{
	GLubyte* img;
	FILE *fd;
	int n, m;
	int  k, nm;
	char c;
	int i;
	char b[100];
	float s;
	int red, green, blue;
	
	/* first open file and check if it's an ASCII PPM (indicated by P3 at the start) */
	fd = fopen(file, "r");
	fscanf(fd,"%[^\n] ",b);
	if(b[0]!='P'|| b[1] != '3')
	{
		printf("%s is not a PPM file!\n",file); 
		exit(0);
	}
	printf("%s is a PPM file\n", file);
	fscanf(fd, "%c",&c);

	/* next, skip past the comments - any line starting with #*/
	while(c == '#') 
	{
		fscanf(fd, "%[^\n] ", b);
		printf("%s\n",b);
		fscanf(fd, "%c",&c);
	}
	ungetc(c,fd); 

	/* now get the dimensions and max colour value from the image */
	fscanf(fd, "%d %d %d", &n, &m, &k);

	printf("%d rows  %d columns  max value= %d\n",n,m,k);

	/* calculate number of pixels and allocate storage for this */
	nm = n*m;
	img = (GLubyte*)malloc(3*sizeof(GLuint)*nm);
	s=255.0/k;

	/* for every pixel, grab the read green and blue values, storing them in the image data array */
	for(i=0;i<nm;i++) 
	{
		fscanf(fd,"%d %d %d",&red, &green, &blue );
		img[3*nm-3*i-3]=red*s;
		img[3*nm-3*i-2]=green*s;
		img[3*nm-3*i-1]=blue*s;
	}

	/* finally, set the "return parameters" (width, height, max) and return the image array */
	*width = n;
	*height = m;
	*max = k;

	return img;
}