//=================================================================
// showppm.cpp
//=================================================================

// #include "stdafx.h"
#include <stdio.h>
#include <stdlib.h>
#include <GL/glut.h>
#include "showPPM.h"

GLubyte *FBuffer;
int Width, Height;

void TexturePPM(char* PPMfileName) // Doesn't read ascii ppm files (P3) yet
{
  // LOAD FROM A BINARY .PPM FILE
  int Color;
  int NumComponents;
  char Buffer[100];
  if(PPMfileName == NULL)
	 { fprintf(stderr, "ERROR: No file name\n"); exit(1); }
  FILE* FilePtr = fopen(PPMfileName, "rb");
  if (FilePtr==NULL)
     { fprintf(stderr, "ERROR: unable to open %s!\n",PPMfileName); exit(1); }
  fgets(Buffer,99,FilePtr);
  if(Buffer[0] != 'P' || Buffer[1] != '6')
     { fprintf(stderr, "Not a binary ppm file: %s\n", PPMfileName); exit(1); }
  if(Buffer[2] == 'A')
     NumComponents = 4; // Special type of PPM file. No relevant to us.
  else
     NumComponents = 3; // This is our case

  Buffer[0] = getc(FilePtr);
  while(Buffer[0] == '#' || Buffer[0] == '\n')
  {
     ungetc(Buffer[0], FilePtr);
     fgets(Buffer,99,FilePtr);
     Buffer[0] = getc(FilePtr);
  }

  ungetc(Buffer[0], FilePtr);

  fscanf(FilePtr, "%d %d %d\n", &Width, &Height, &Color);
  if(Color != 255)
     { fprintf(stderr, "File does not have True color?\n"); exit(1); }
  printf("Reading %dx%d image (%d Component) from [%s]. . .\n",
          Width, Height, NumComponents, PPMfileName);

  int LineWidth = Width*NumComponents;
  int NumBytes = Width*Height*NumComponents;
  GLubyte* fBuffer = new GLubyte[NumBytes];

  fread(fBuffer, NumBytes, 1, FilePtr);
  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, Width, Height, 0, GL_RGB,
               GL_UNSIGNED_BYTE, fBuffer);
  fclose(FilePtr);

  return;
}