#include "GL/freeglut.h"
#include <stdio.h>
#include <stdlib.h>

typedef struct{ GLubyte r, g, b; } PIXEL;

PIXEL *imagineBMP;
GLint width, height;

PIXEL *ReadBMP(char *nume, int *ncol, int *nlin)
{
	int i, j, w, h, data_offset, r, lglin, tcompr;
	long dofs;
	short nbpp;
	char buf[20];
	PIXEL *img;
	GLubyte t;
	FILE *f;
	if ((f = fopen(nume, "rb")) == NULL)
	{
		fprintf(stderr, "ReadBMP --eroare deschidere fisier\n");
		exit(1);
	}
	else
	{
		fprintf(stderr, "Fisierul a fost deschis cu succes!");
	}
	fread(buf, 1, 2, f);
	buf[2] = '\0';
	fseek(f, 28L, SEEK_SET);
	fread(&nbpp, sizeof(short), 1, f);
	fseek(f, 30L, SEEK_SET);
	fread(&tcompr, sizeof(int), 1, f);
	if (strcmp(buf, "BM") != 0 || nbpp != 24 || tcompr != 0)
	{
		//se citeste un fisier BMP necomprimat
		fprintf(stderr, "ReadBMP -- format BMP incorect\n");
		exit(1);
	}

	fseek(f, 18L, SEEK_SET);
	fread(&w, sizeof(int), 1, f); //citesc numarul de coloane
	fread(&h, sizeof(int), 1, f); //citesc numarul de linii
	img = (PIXEL *)malloc(h*w*sizeof(PIXEL));
	fseek(f, 10L, SEEK_SET); //cauta deplasamentul zonei de date
	fread(&data_offset, sizeof(int), 1, f); //citesc deplas. zonei de
	// date fata de inceputul fisierului
	lglin = w * 3;
	if (r = lglin % 4) lglin += 4 - r;
	for (dofs = data_offset, i = 0; i < h; dofs += lglin, i++)
	{
		fseek(f, dofs, SEEK_SET);
		fread(&img[i*w], sizeof(PIXEL), w, f);
		for (j = 0; j < w; j++) //schimba red/blue
		{
			t = img[i*w + j].r;
			img[i*w + j].r = img[i*w + j].b;
			img[i*w + j].b = t;
		}
	}
	*nlin = h;
	*ncol = w;
	fclose(f);
	return img;
}



PIXEL *image;
static GLuint texName[1];


void Plane()
{
	glBegin(GL_QUADS);
	glVertex3d(0, 0, 1);
	glTexCoord2f(0.0, 0.0);
	glVertex3d(3, 0, 1);
	glTexCoord2f(1.0, 0.0);
	glVertex3d(3, 3,-1);
	glTexCoord2f(1.0, 1.0);
	glVertex3d(0, 3, -1);
	glTexCoord2f(0.0, 1.0);
	glEnd();
}



void init(void)
{
	glClearColor(1, 1, 1, 0);
	//texturare
	image = ReadBMP("bricks.bmp", &width, &height);

	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, image);
	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);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
	glEnable(GL_TEXTURE_2D);
}

void display(void)
{
	glClear(GL_COLOR_BUFFER_BIT);
	glPushMatrix();
	glTranslatef(-1.5, -1.5, -5);
	Plane();
	glPopMatrix();
	glutSwapBuffers();
}

void reshape(int w, int h)
{
	glViewport(0, 0, (GLsizei)w, (GLsizei)h);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	gluPerspective(60.0, (GLfloat)w / (GLfloat)h, 0.1, 100);
	glMatrixMode(GL_TEXTURE);
	glLoadIdentity();
	glScaled(2, 2, 2);
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
}

int main(int argc, char **argv)
{
	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
	glutInitWindowPosition(200, 200);
	glutInitWindowSize(600, 600);
	glutCreateWindow("SPG OpenGL");

	init();
	glutDisplayFunc(display);
	glutReshapeFunc(reshape);

	glutMainLoop();
	return 0;
}