//
// This code was created by Jeff Molofee '99 (ported to Linux/GLUT by 
// Richard Campbell '99)
//
// If you've found this code useful, please let me know.
//
// Visit me at www.demonews.com/hosted/nehe 
// (email Richard Campbell at ulmont@bellsouth.net)
//

/* Linux
#include <GL/glut.h>    // Header File For The GLUT Library 
#include <GL/gl.h>	// Header File For The OpenGL32 Library
#include <GL/glu.h>	// Header File For The GLu32 Library
*/

// Mac OS X 
#include <OpenGL/OpenGL.h>
#include <GLUT/GLUT.h>
#include <unistd.h>     // Header file for sleeping.
#include <stdio.h>      // Header file for standard file i/o.
#include <stdlib.h>     // Header file for malloc/free.

/* number of stars to have */
#define STAR_NUM 50

/* ascii codes for various special keys */
#define ESCAPE 27
#define PAGE_UP 73
#define PAGE_DOWN 81
#define UP_ARROW 72
#define DOWN_ARROW 80
#define LEFT_ARROW 75
#define RIGHT_ARROW 77

/* The number of our GLUT window */
int window; 

/* twinkle on/off (1 = on, 0 = off) */
int twinkle = 0;

typedef struct {         // Star structure
    int r, g, b;         // stars' color
    GLfloat dist;        // stars' distance from center
    GLfloat angle;       // stars' current angle
} stars;                 // name is stars

stars star[STAR_NUM];    // make 'star' array of STAR_NUM size using info from the structure 'stars'

GLfloat zoom = -15.0f;   // viewing distance from stars.
GLfloat tilt = 90.0f;    // tilt the view
GLfloat spin;            // spin twinkling stars

GLuint loop;             // general loop variable
GLuint texture[1];       // storage for one texture;

/* Image type - contains height, width, and data */
struct Image {
    unsigned long sizeX;
    unsigned long sizeY;
    char *data;
};
typedef struct Image Image;

/*
 * getint and getshort are help functions to load the bitmap byte by byte on 
 * SPARC platform (actually, just makes the thing work on platforms of either
 * endianness, not just Intel's little endian)
 */

static unsigned int getint(fp)
     FILE *fp;
{
  int c, c1, c2, c3;

  // get 4 bytes
  c = getc(fp);  
  c1 = getc(fp);  
  c2 = getc(fp);  
  c3 = getc(fp);
  
  return ((unsigned int) c) +   
    (((unsigned int) c1) << 8) + 
    (((unsigned int) c2) << 16) +
    (((unsigned int) c3) << 24);
}

static unsigned int getshort(fp)
     FILE *fp;
{
  int c, c1;
  
  //get 2 bytes
  c = getc(fp);  
  c1 = getc(fp);

  return ((unsigned int) c) + (((unsigned int) c1) << 8);
}

// quick and dirty bitmap loader...for 24 bit bitmaps with 1 plane only.  
// See http://www.dcs.ed.ac.uk/~mxr/gfx/2d/BMP.txt for more info.

int ImageLoad(char *filename, Image *image) 
{
    FILE *file;
    unsigned long size;                 // size of the image in bytes.
    unsigned long i;                    // standard counter.
    unsigned short int planes;          // number of planes in image (must be 1) 
    unsigned short int bpp;             // number of bits per pixel (must be 24)
    char temp;                          // used to convert bgr to rgb color.

    // make sure the file is there.
    if ((file = fopen(filename, "rb"))==NULL) {
      printf("File Not Found : %s\n",filename);
      return 0;
    }
    
    // seek through the bmp header, up to the width/height:
    fseek(file, 18, SEEK_CUR);

    // No 100% errorchecking anymore!!!

    // read the width
    image->sizeX = getint (file);
    printf("Width of %s: %lu\n", filename, image->sizeX);
    
    // read the height 
    image->sizeY = getint (file);
    printf("Height of %s: %lu\n", filename, image->sizeY);
    
    // calculate the size (assuming 24 bits or 3 bytes per pixel).
    size = image->sizeX * image->sizeY * 3;

    // read the planes
    planes = getshort(file);
    if (planes != 1) {
	printf("Planes from %s is not 1: %u\n", filename, planes);
	return 0;
    }

    // read the bpp
    bpp = getshort(file);
    if (bpp != 24) {
      printf("Bpp from %s is not 24: %u\n", filename, bpp);
      return 0;
    }
	
    // seek past the rest of the bitmap header.
    fseek(file, 24, SEEK_CUR);

    // read the data. 
    image->data = http://www.mamicode.com/(char *) malloc(size);>

// $: 
clang -o lesson lesson9.c -Wno-deprecated -framework OpenGL -framework GLUT
NeHe OpenGL Lesson 9