#include "GL/glut.h"
#include <string.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>

#define WIN_WIDTH 128
#define WIN_HEIGHT 128
#define SQUARE_SIDE 64
#define MY_MIN_LOD 100

GLfloat mipmapImage64[64][64][3];
GLfloat mipmapImage32[32][32][3];
GLfloat mipmapImage16[16][16][3];
GLfloat mipmapImage8[8][8][3];
GLfloat mipmapImage4[4][4][3];
GLfloat mipmapImage2[2][2][3];
GLfloat mipmapImage1[1][1][3];
GLfloat buf[64*64*3];


void makeImages(void)
{
	int i, j;

	for (i = 0; i < 64; i++) {
		for (j = 0; j < 64; j++) {
			mipmapImage64[i][j][0] = 0.64;
			mipmapImage64[i][j][1] = 0.0;
			mipmapImage64[i][j][2] = 0.0;
		}
	}

	for (i = 0; i < 32; i++) {
		for (j = 0; j < 32; j++) {
			mipmapImage32[i][j][0] = 0.32;
			mipmapImage32[i][j][1] = 0.0;
			mipmapImage32[i][j][2] = 0.0;
		}
	}
	for (i = 0; i < 16; i++) {
		for (j = 0; j < 16; j++) {
			mipmapImage16[i][j][0] = 0.16;
			mipmapImage16[i][j][1] = 0.0;
			mipmapImage16[i][j][2] = 0.0;
		}
	}
	for (i = 0; i < 8; i++) {
		for (j = 0; j < 8; j++) {
			mipmapImage8[i][j][0] = 0.8;
			mipmapImage8[i][j][1] = 0.0;
			mipmapImage8[i][j][2] = 0.0;
		}
	}

	for (i = 0; i < 4; i++) {
		for (j = 0; j < 4; j++) {
			mipmapImage4[i][j][0] = 0.4;
			mipmapImage4[i][j][1] = 0.0;
			mipmapImage4[i][j][2] = 0.0;
		}
	}

	for (i = 0; i < 2; i++) {
		for (j = 0; j < 2; j++) {
			mipmapImage2[i][j][0] = 0.2;
			mipmapImage2[i][j][1] = 0.0;
			mipmapImage2[i][j][2] = 0.0;
		}
	}

	mipmapImage1[0][0][0] = 0.1;
	mipmapImage1[0][0][1] = 0.0;
	mipmapImage1[0][0][2] = 0.0;
}


static GLuint texName;

void init()
{
	int i;
	
	for (i = 0; i < 64*64*3; i ++)
		buf[i]=2.2;	//init w/ invalid value
	
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	glTranslatef(-1.0, -1.0, 0.0);
	glScalef(2.0/WIN_WIDTH, 2.0/WIN_HEIGHT, 1.0);

	glClearColor(0, 0, 0, 0);
	glDisable(GL_DITHER);
	glEnable(GL_TEXTURE_2D);
	makeImages();

	glGenTextures(1, &texName);
	glBindTexture(GL_TEXTURE_2D, texName);

	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, 
		GL_NEAREST);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, 
		GL_NEAREST_MIPMAP_NEAREST);

	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, 64, 64, 0,
		GL_RGB, GL_FLOAT, mipmapImage64);
	glTexImage2D(GL_TEXTURE_2D, 1, GL_RGB, 32, 32, 0,
		GL_RGB, GL_FLOAT, mipmapImage32);
	glTexImage2D(GL_TEXTURE_2D, 2, GL_RGB, 16, 16, 0,
		GL_RGB, GL_FLOAT, mipmapImage16);
	glTexImage2D(GL_TEXTURE_2D, 3, GL_RGB, 8, 8, 0,
		GL_RGB, GL_FLOAT, mipmapImage4);
	glTexImage2D(GL_TEXTURE_2D, 4, GL_RGB, 4, 4, 0,
		GL_RGB, GL_FLOAT, mipmapImage4);
	glTexImage2D(GL_TEXTURE_2D, 5, GL_RGB, 2, 2, 0,
		GL_RGB, GL_FLOAT, mipmapImage2);
	glTexImage2D(GL_TEXTURE_2D, 6, GL_RGB, 1, 1, 0,
		GL_RGB, GL_FLOAT, mipmapImage1);

	glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);
}

void display()
{
	GLint ret_size;
	int i;

	glClear(GL_COLOR_BUFFER_BIT);

	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, 1);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 1000);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_LOD, MY_MIN_LOD);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LOD, 1000);
	glBegin(GL_POLYGON);
		glTexCoord2f(0.0, 0.0);
		glVertex2i(0, 0);
		glTexCoord2f(0.0, 1.0);
		glVertex2i(0, SQUARE_SIDE);
		glTexCoord2f(1.0, 1.0);
		glVertex2i(SQUARE_SIDE, SQUARE_SIDE);
		glTexCoord2f(1.0, 0.0);
		glVertex2i(SQUARE_SIDE, 0);
	glEnd();

	glReadPixels(0, 0, SQUARE_SIDE, SQUARE_SIDE, GL_RGB, GL_FLOAT, buf);
	for (i = 0; i < SQUARE_SIDE *SQUARE_SIDE*3; i+=3) {
		printf("R[%1.1f], G[%1.1f], B[%1.1f] \n", 
			buf[i], buf[i+1], buf[i+2]);
	}
}


int main(int argc, char** argv)
{
	glutInit(&argc, argv);
	glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
	glutInitWindowSize (WIN_WIDTH, WIN_HEIGHT);
	glutInitWindowPosition (100, 100);
	glutCreateWindow ("hello");
	init();
	glutDisplayFunc(display);
	glutMainLoop();
}