#include <stdlib.h>

#include <math.h>

#ifdef __APPLE__

#include <GLUT/glut.h>

#else

#include <GL/glut.h>

#endif

// angle of rotation for the camera direction

float angle = 0.0f;

// actual vector representing the camera's direction

float lx=0.0f,lz=-1.0f;

// XZ position of the camera

float x=0.0f, z=5.0f;

// the key states. These variables will be zero

//when no key is being presses

float deltaAngle = 0.0f;

float deltaMove = ;

void changeSize(int w, int h) {

    // Prevent a divide by zero, when window is too short

    // (you cant make a window of zero width).

    if (h == )

        h = ;

    float ratio =  w * 1.0 / h;

    // Use the Projection Matrix

    glMatrixMode(GL_PROJECTION);

    // Reset Matrix

    glLoadIdentity();

    // Set the viewport to be the entire window

    glViewport(, , w, h);

    // Set the correct perspective.

    gluPerspective(45.0f, ratio, 0.1f, 100.0f);

    // Get Back to the Modelview

    glMatrixMode(GL_MODELVIEW);

}

void drawSnowMan() {

    glColor3f(1.0f, 1.0f, 1.0f);

// Draw Body

    glTranslatef(0.0f ,0.75f, 0.0f);

    glutSolidSphere(0.75f,,);

// Draw Head

    glTranslatef(0.0f, 1.0f, 0.0f);

    glutSolidSphere(0.25f,,);

// Draw Eyes

    glPushMatrix();

    glColor3f(0.0f,0.0f,0.0f);

    glTranslatef(0.05f, 0.10f, 0.18f);

    glutSolidSphere(0.05f,,);

    glTranslatef(-0.1f, 0.0f, 0.0f);

    glutSolidSphere(0.05f,,);

    glPopMatrix();

// Draw Nose

    glColor3f(1.0f, 0.5f , 0.5f);

    glRotatef(0.0f,1.0f, 0.0f, 0.0f);

    glutSolidCone(0.08f,0.5f,,);

}

void computePos(float deltaMove) {

    x += deltaMove * lx * 0.1f;

    z += deltaMove * lz * 0.1f;

}

void computeDir(float deltaAngle) {

    angle += deltaAngle;

    lx = sin(angle);

    lz = -cos(angle);

}

void renderScene(void) {

    if (deltaMove)

        computePos(deltaMove);

    if (deltaAngle)

        computeDir(deltaAngle);

    // Clear Color and Depth Buffers

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    // Reset transformations

    glLoadIdentity();

    // Set the camera

    gluLookAt(    x, 1.0f, z,

                x+lx, 1.0f,  z+lz,

                0.0f, 1.0f,  0.0f);

// Draw ground

    glColor3f(0.9f, 0.9f, 0.9f);

    glBegin(GL_QUADS);

        glVertex3f(-100.0f, 0.0f, -100.0f);

        glVertex3f(-100.0f, 0.0f,  100.0f);

        glVertex3f( 100.0f, 0.0f,  100.0f);

        glVertex3f( 100.0f, 0.0f, -100.0f);

    glEnd();

// Draw 36 SnowMen

    for(int i = -; i < ; i++)

        for(int j=-; j < ; j++) {

            glPushMatrix();

            glTranslatef(i*10.0,,j * 10.0);

            drawSnowMan();

            glPopMatrix();

        }

    glutSwapBuffers();

}

void pressKey(int key, int xx, int yy) {

    switch (key) {

        case GLUT_KEY_LEFT : deltaAngle = -0.01f; break;

        case GLUT_KEY_RIGHT : deltaAngle = 0.01f; break;

        case GLUT_KEY_UP : deltaMove = 0.5f; break;

        case GLUT_KEY_DOWN : deltaMove = -0.5f; break;

    }

}

void releaseKey(int key, int x, int y) {

    switch (key) {

        case GLUT_KEY_LEFT :

        case GLUT_KEY_RIGHT : deltaAngle = 0.0f;break;

        case GLUT_KEY_UP :

        case GLUT_KEY_DOWN : deltaMove = ;break;

    }

}

int main(int argc, char **argv) {

    // init GLUT and create window

    glutInit(&argc, argv);

    glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA);

    glutInitWindowPosition(,);

    glutInitWindowSize(,);

    glutCreateWindow("Lighthouse3D - GLUT Tutorial");

    // register callbacks

    glutDisplayFunc(renderScene);

    glutReshapeFunc(changeSize);

    glutIdleFunc(renderScene);

    glutSpecialFunc(pressKey);

    // here are the new entries

    glutIgnoreKeyRepeat();

    glutSpecialUpFunc(releaseKey);

    // OpenGL init

    glEnable(GL_DEPTH_TEST);

    // enter GLUT event processing cycle

    glutMainLoop();

    return ;

}