//pixmap.h
typedef char byte;
typedef unsigned char ubyte;

struct pixmap
{
	unsigned width, 
					 height;
	ubyte *data;

	enum {RED = 0, GREEN, BLUE};

	pixmap(const char *fname);
	pixmap();
	~pixmap();

	void read(const char *fname);
	ubyte pixel_elem(int x, int y, int elem);
	ubyte *pixel_pos(int x, int y);
};


//pixmap.cpp

#include "pixmap.h"

#include <fstream>
#include <iostream>
#include <cstdlib>


pixmap::pixmap(const char *fname)
	: width(0), height(0), data(0)
{
	this->read(fname);
}

pixmap::pixmap()
	: width(0), height(0), data(0) {}

pixmap::~pixmap()
{
	if( data )
		delete[] data;
}

void pixmap::read(const char *fname)
{
	using namespace std;

	unsigned short planes;	// number of planes in image (must be 1) 
	unsigned short bpp;			// number of bits per pixel (must be 24)

	ifstream fin(fname, ios::in | ios::binary);
	if( !fin )
	{
		cerr << "File not found " << fname << '\n';
		exit(1);
	}
  
	fin.seekg(18, ios::cur);

	fin.read((byte *)&width, sizeof(unsigned));
	fin.read((byte *)&height, sizeof(unsigned));
	cout << "width: " << width << " height: " << height << '\n';

	fin.read((byte *)&planes, sizeof(unsigned short));
	if( planes != 1 )
	{
		cout << "Planes from " << fname << " is not 1: " << planes << "\n";
		exit(1);
	}

	fin.read((byte *)&bpp, sizeof(unsigned short));
	if( bpp != 24 )
	{
		cout << "Bpp from " << fname << " is not 24: " << bpp << "\n";
		exit(1);
	}
	
	fin.seekg(24, ios::cur);

	unsigned size(width * height * 3);				// size of the image in bytes (3 is to RGB component).
	data = new ubyte[size];
	fin.read((byte *)data, size);

	ubyte tmp;					// temporary color storage for bgr-rgb conversion.
	for( int i(0); i < size; i += 3 )
	{
		tmp = data;
		data = data[i+2];
		data[i+2] = tmp;
	}
}

ubyte pixmap::pixel_elem(int x, int y, int elem)
{
	int pos = (y*width+x) * 3 + elem;
	return data[pos];
}

ubyte *pixmap::pixel_pos(int x, int y)
{
	int pos = (y * width + x) * 3;
	return &data[pos];
}

//test program

#include <GL/glut.h>
#include <iostream>
#include <cstdlib>

#include "pixmap.h"

#define MAX_WIDTH 300
#define MAX_HEIGHT 200


pixmap *img(0);
GLfloat transx(0.0), transy(0.0);

void init_gl()
{
	glClearColor(0.0, 0.0, 0.0, 0.0);

	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	gluOrtho2D(0.0, (GLfloat)MAX_WIDTH, 0.0, (GLfloat)MAX_HEIGHT);
}

void reshape(int w, int h)
{
	glViewport (0, 0, (GLint)w, (GLint)h);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	gluOrtho2D(0.0, (GLfloat)w, 0.0, (GLfloat)h);
//	gluOrtho2D(-(GLfloat)MAX_WIDTH, (GLfloat)MAX_WIDTH, -(GLfloat)MAX_HEIGHT, (GLfloat)MAX_HEIGHT);
}

void render_scene()
{
	glClear(GL_COLOR_BUFFER_BIT);

// drawing it manually
/*	glBegin(GL_POINTS);
	for( int i(0); i < img->width; i++ )
		for( int j(0); j < img->height; j++ )
		{
//			glColor3ub(img->pixel_elem(i, j, pixmap::RED),
//								 img->pixel_elem(i, j, pixmap::GREEN),
//								 img->pixel_elem(i, j, pixmap::BLUE));
			glColor3ubv(img->pixel_pos(i, j));
			glVertex2i(i+(int)transx, j+(int)transy); 
		}
	glEnd();*/

// draw using OpenGL functions
	glTranslatef(transx, transy, 0.0);
	glRasterPos2i(0, 0);
	glDrawPixels(img->width, img->height, GL_RGB, GL_UNSIGNED_BYTE, img->data);

	glutSwapBuffers();
	glFlush();
}

void keyb_handler(unsigned char key, int x, int y)
{
	if( key == 27 )
		std::exit(0);
}

void special_key(int key, int x, int y)
{
	switch( key )
	{
		case GLUT_KEY_UP:
		{
			transy = -5.0;
			transx = 0.0;
			break;
		}

		case GLUT_KEY_DOWN:
		{
			transy = +5.0;
			transx = 0.0;
			break;
		}

		case GLUT_KEY_LEFT:
		{
			transx = +5.0;
			transy = 0.0;
			break;
		}

		case GLUT_KEY_RIGHT:
		{
			transx = -5.0;
			transy = 0.0;
			break;
		}
	}
	glutPostRedisplay();
}

void special_key2(int key, int x, int y)
{
	switch( key )
	{
		case GLUT_KEY_UP:
		{
			if( transy < MAX_HEIGHT ) transy += 5.0;
			break;
		}

		case GLUT_KEY_DOWN:
		{
			if( transy > 0 ) transy -= 5.0;
			break;
		}

		case GLUT_KEY_LEFT:
		{
			if( transx > 0 ) transx -= 5.0;
			break;
		}

		case GLUT_KEY_RIGHT:
		{
			if( transx < MAX_WIDTH ) transx += 5.0;
			break;
		}
	}
	glutPostRedisplay();
}

int main(int argc, char **argv)
{
	if( argc != 2 )
	{
		std::cerr << "INVALID ARGUMENTS\n";
		std::cerr << "You should specify the pixmap to load!\n";
		return 1;
	}

	img = new pixmap(argv[1]);

	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA);
	glutInitWindowSize(MAX_WIDTH, MAX_HEIGHT);
	glutInitWindowPosition(0, 0);
	glutCreateWindow("A pixmap loader - by Beloni");

	init_gl();

	glutDisplayFunc(&render_scene);
	glutReshapeFunc(&reshape);
	glutKeyboardFunc(&keyb_handler);
	glutSpecialFunc(&special_key);
//	glutFullScreen();

	glutMainLoop();
	delete img;
	return 0;
}

#include <GL/glut.h>#include <iostream>#include <exception>#include <cstdlib>#include "pixmap.h"#define MAX_WIDTH 600#define MAX_HEIGHT 400pixmap *img(0);GLfloat trans[] = {0.0, 0.0};unsigned pos[] = {0ul, MAX_WIDTH, MAX_HEIGHT, 0ul};GLuint texid(0);void init_gl(){	glClearColor(0.0, 0.0, 0.0, 0.0);// loading texture	glGenTextures(1, &texid);	glBindTexture(GL_TEXTURE_2D, texid);	glPixelStorei(GL_UNPACK_ALIGNMENT, 1);	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);	glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR); // scale linearly when image bigger than texture	glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR); // scale linearly when image smalled than texture	glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, img->width, img->height, 0, GL_RGB, GL_UNSIGNED_BYTE, img->data);	glMatrixMode(GL_PROJECTION);	glLoadIdentity();	gluOrtho2D(0.0, (GLfloat)MAX_WIDTH, 0.0, (GLfloat)MAX_HEIGHT);}void reshape(int w, int h){	glViewport (0, 0, (GLint)w, (GLint)h);	glMatrixMode(GL_PROJECTION);	glLoadIdentity();	gluOrtho2D(0.0, (GLfloat)w, 0.0, (GLfloat)h);}void render_scene(){	glClear(GL_COLOR_BUFFER_BIT);	glEnable (GL_TEXTURE_2D); /* enable texture mapping */	glBindTexture (GL_TEXTURE_2D, texid); /* bind to our texture, has id of 13 */	glBegin(GL_QUADS);		glTexCoord2f(0.0f, 0.0f); /* lower left corner of image */		glVertex2i(0, 0);		glTexCoord2f(1.0f, 0.0f); /* lower right corner of image */		glVertex2i(img->width, 0);		glTexCoord2f(1.0f, 1.0f); /* upper right corner of image */		glVertex2i(img->width, img->height);		glTexCoord2f(0.0f, 1.0f); /* upper left corner of image */		glVertex2i(0, img->height);	glEnd ();	glDisable(GL_TEXTURE_2D); /* disable texture mapping */	glutSwapBuffers();}void keyb_handler(unsigned char key, int x, int y){	if( key == 27 )		std::exit(0);}void special_key(int key, int x, int y){	bool flag(false);	switch( key )	{		case GLUT_KEY_UP:			if( pos[2] < (img->height-1) )			{				trans[1] = -5.0;				trans[0] = 0.0;				flag = true;				pos[2] += 5;				pos[0] += 5;			}			break;		case GLUT_KEY_DOWN:			if( pos[0] > 0 )			{				trans[1] = +5.0;				trans[0] = 0.0;				flag = true;				pos[0] -= 5;				pos[2] -= 5;			}			break;		case GLUT_KEY_LEFT:			if( pos[3] > 0 )			{				trans[0] = +5.0;				trans[1] = 0.0;				flag = true;				pos[3] -= 5;				pos[1] -= 5;			}			break;		case GLUT_KEY_RIGHT:			if( pos[1] < (img->width-1) )			{				trans[0] = -5.0;				trans[1] = 0.0;				flag = true;				pos[1] += 5;				pos[3] += 5;			}			break;	}	if( flag )	{		glTranslatef(trans[0], trans[1], 0.0);				glutPostRedisplay();	}}int main(int argc, char **argv){	if( argc != 2 )	{		std::cerr << "INVALID ARGUMENTS\n";		std::cerr << "You should specify the pixmap to load!\n";		return 1;	}	try	{		img = new pixmap(argv[1]);	}	catch( std::bad_alloc &ex )	{		std::cerr << ex.what() << '\n';		return 2;	}	glutInit(&argc, argv);	glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA);	glutInitWindowSize(MAX_WIDTH, MAX_HEIGHT);	glutInitWindowPosition(0, 0);	glutCreateWindow("A pixmap loader - by Beloni");	init_gl();	glutDisplayFunc(&render_scene);	glutReshapeFunc(&reshape);	glutKeyboardFunc(&keyb_handler);	glutSpecialFunc(&special_key);//	glutFullScreen();	glutMainLoop();	delete img;	return 0;}