/*
 * Logo.c
 *
 * draws a letter 'L'
 */

/*
#include <Windows.h>
*/

#include <GL/gl.h>
#include <GL/glu.h>
#include <GL/glut.h>

#include <stdio.h>
#include <string.h>
#include <stdlib.h>


int windType;
GLint windW, windH;

/* camera parameters */

#define EYEX_INIT 2.0
#define EYEY_INIT 3.0
#define EYEZ_INIT 10.0

GLdouble eyeX = EYEX_INIT;
GLdouble eyeY = EYEY_INIT;
GLdouble eyeZ = EYEZ_INIT;
GLdouble centerX = 1.0;
GLdouble centerY = 1.5;
GLdouble centerZ = 0.5;

GLuint letterL; // display list speeds up rendering

/* draw the letter L in a display list called L */

void drawL (void) 
{

	#define NPOINTS   12
	#define NPOLYGONS 10

	/* define all the points on the letter */

	GLdouble point[NPOINTS][3] = {
		{0.0, 0.0, 1.0},
		{2.0, 0.0, 1.0},
		{2.0, 1.0, 1.0},
		{1.0, 1.0, 1.0},
		{1.0, 3.0, 1.0},
		{0.0, 3.0, 1.0},
		{0.0, 0.0, 0.0},
		{2.0, 0.0, 0.0},
		{2.0, 1.0, 0.0},
		{1.0, 1.0, 0.0},
		{1.0, 3.0, 0.0},
		{0.0, 3.0, 0.0}};

	/* each polygonal face references 4 points */

	int polygon[NPOLYGONS][4] = {
		{0, 1, 2, 3}, /* front faces */
		{0, 3, 4, 5},
		{9, 8, 7, 6}, /* back faces */
		{11, 10, 9, 6},
		{0, 5, 11, 6}, /* side faces */
		{1, 0, 6, 7},
		{2, 1, 7, 8},
		{3, 2, 8, 9},
		{4, 3, 9, 10},
		{5, 4, 10, 11}};

	/* color array defines a different color for each face */

	GLdouble color[NPOLYGONS][3] = {
		{1.0, 1.0, 1.0}, /* front faces */
		{1.0, 1.0, 1.0},
		{0.2, 0.2, 0.2}, /* back faces */
		{0.2, 0.2, 0.2},
		{0.4, 0.4, 0.4}, /* side faces */
		{0.5, 0.5, 0.5},
		{0.6, 0.6, 0.6},
		{0.7, 0.7, 0.7},
		{0.8, 0.8, 0.8},
		{0.9, 0.9, 0.9}};

	int face, pt;

	/* Setup display list */
	letterL = glGenLists(1);
	glNewList (letterL, GL_COMPILE);

	/* Draw the letter */
	for (face = 0; face < NPOLYGONS; face++) {
		glColor3dv(color[face]);    /* set the color of the face */
		glBegin(GL_POLYGON);
		for (pt = 0; pt < 4; pt++)  /* draw all points on the face */
			glVertex3dv (point[polygon[face][pt]]);
		glEnd();
	}

	/* Finish the display list */
	glEndList();
}

/* Setup OpenGL state machine */

static void Init(void)
{
	/* Set background color */

    glClearColor(0.0, 0.0, 0.0, 0.0);

	/* Enable depth buffer */

	glEnable(GL_DEPTH_TEST);

	/* Enable back-face culling */
	glCullFace(GL_BACK);
	glEnable(GL_CULL_FACE);
}


/* Window size has changed:
   adjust viewport and perspective transformations */

static void Reshape(int width, int height)
{
	float aspect;

    windW = (GLint)width;
    windH = (GLint)height;

	aspect = (float)windW / (float)windH;
	aspect *= 2.0; /* widen the lense */

	/* Viewport fills the entire window */

    glViewport(0, 0, width, height);

	/* Use orthographic projection to set visibility boundaries relative to viewing coordinates */
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho (-aspect, aspect, -2.0, 2.0, 0.0, 1000.0); /* left, right, bottom, top, near, far */

	/* Return to modelview mode */
    glMatrixMode(GL_MODELVIEW);
}


/* Handle key presses */

static void Key(unsigned char key, int x, int y)
{

    switch (key) {
      case 27:			/* ESC to quit */
		exit(1);
		break;
      default:
		return;
    }

    glutPostRedisplay();	/* force update of the display */
}

/* Set modeling and viewing transformations,
   then draw the letter polygons */

static void Draw(void)
{
	// int face, pt;

	/* clear the screen AND the depth buffer */

	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

	/* Set the viewing transformation(s) */

	glLoadIdentity();
	gluLookAt(eyeX, eyeY, eyeZ, centerX, centerY, centerZ, 0.0, 1.0, 0.0);

	/* Draw the 1st letter */

	glCallList(letterL);

    glFlush();		/* force all changes to be applied to buffer */
	glutSwapBuffers();	/* display what you just drew */
}


void main(int argc, char **argv)
{
	/* Setup the window that logo will appear in */

    windW = 300;
    windH = 300;
    glutInitWindowPosition(0, 0); 
	glutInitWindowSize( windW, windH);

	/* Window uses depth buffer, full color, and double buffering */
    windType  = GLUT_DEPTH | GLUT_RGB | GLUT_DOUBLE;
    glutInitDisplayMode((GLenum)windType);

    if (glutCreateWindow("Logo") == GL_FALSE) {
		exit(1);
    }

    Init();
	drawL(); /* Create display list letterL */

    glutReshapeFunc(Reshape);
    glutKeyboardFunc(Key);
    glutDisplayFunc(Draw);
    glutMainLoop();
}