OpenGL (Animation & Keyboard)

//
//  main.cpp
//  OpenGL-05
//
//  Created by Alexander Kevin on 4/3/16.
//  Copyright © 2016 Alexander Kevin. All right reserved.
//

//CASE LINK : https://www.dropbox.com/s/2y8siyes8tfqmfr/T00740020220154042Tugas%20dan%20Latihan%20GSLC-2.doc?dl=0
//.exe LINK : https://www.dropbox.com/s/giwgt1llyr406p8/OpenGL-05?dl=0

#ifdef WIN32
#include <windows.h>
#endif

#include <stdlib.h>
#include <iostream>
#include <fstream>

#ifdef __APPLE__
#include <GLUT/glut.h>
#include <OpenGL/gl.h>
#include <OpenGL/glu.h>
#else
#include <GL/glut.h>
#include <GL/glu.h>
#include <GL/gl.h>
#endif

float r=0,g=1,b=1;
int flag=0;
bool isdownKeyPressed,isupKeyPressed;
static GLfloat spin = 0.0;
int sumbu_x=0,sumbu_y=0,sumbu_z=1;

void init()
{
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(-7.0,7.0,-7.0,7.0,-7.0,7.0);
    glMatrixMode(GL_MODELVIEW);
    glClearColor(0.0,0.0,0.0,1.0);
    glColor3f(0.0,0.0,0.0);
    glShadeModel(GL_FLAT);
    glEnable(GL_DEPTH_TEST);
}

void display(void)
{
    glClear(GL_COLOR_BUFFER_BIT);
    //bintang itu panah keatas sama panah ke kiri/kanan
    //panah keatas
    glFlush();
}

void display_soal_satu(void)
{
    glClear(GL_COLOR_BUFFER_BIT);
    //bintang itu panah keatas sama panah ke kiri/kanan
    //panah keatas
    glColor3f(r,g,b);
    glBegin(GL_POLYGON);
    glVertex3f(0, -2.7, 0);
    glVertex3f(-3.1, -5.0, 0);
    glVertex3f(0, 5.0, 0);
    glVertex3f(3.1, -5.0, 0);
    glEnd();

    //panah kekiri
    glBegin(GL_POLYGON);
    glVertex3f(1.9, -1.3, 0);
    glVertex3f(3.1, -5, 0);
    glVertex3f(-5, 1.2, 0);
    glVertex3f(5, 1.2, 0);
    glEnd();

    glFlush();
}

void spinDisplay(void)
{
    spin = spin + 1;
    if (spin > 360.0)
        spin = spin - 360.0;
    glutPostRedisplay();
}

void display_soal_dua(void)
{
    glClear(GL_COLOR_BUFFER_BIT);
    glPushMatrix();
    glRotatef(spin, sumbu_x,sumbu_y,sumbu_z);
    glColor3f(1.0, 0, 1.0);
    glRectf(-5, -5, 5, 5);
    glPopMatrix();

    glutSwapBuffers();
}

void handleSpecialKeypress(int key, int x, int y) {
    switch (key) {
        case GLUT_KEY_DOWN:
            isupKeyPressed = true;
            if (!isdownKeyPressed) {
                srand(time(NULL));
                r=(float)rand()/(float)(RAND_MAX/1.0);
                g=(float)rand()/(float)(RAND_MAX/0.8);
                b=(float)rand()/(float)(RAND_MAX/0.6);
            }
            glutPostRedisplay();
            break;
        case GLUT_KEY_UP:
            isdownKeyPressed = true;
            if (!isupKeyPressed) {
                srand(time(NULL));
                r=(float)rand()/(float)(RAND_MAX/1);
                g=(float)rand()/(float)(RAND_MAX/0.8);
                b=(float)rand()/(float)(RAND_MAX/0.6);
            }
            glutPostRedisplay();
            break;
        case 's':
        case 'S':
            if(flag==0){
                glutIdleFunc(spinDisplay);
                flag=1;
            }
            else{
                glutIdleFunc(NULL);
                flag=0;
            }
            break;
        case 'z':
        case 'Z':
            sumbu_z=1;
            sumbu_x=0;
            sumbu_y=0;
            break;
        case 'x':
        case 'X':
            sumbu_z=0;
            sumbu_x=1;
            sumbu_y=0;
            break;
        case 'y':
        case 'Y':
            sumbu_z=0;
            sumbu_x=0;
            sumbu_y=1;
            break;
        case 27:
        case 'q':
        case 'Q':
            exit(0);
            break;
        case '1':
            glLoadIdentity();
            glutDisplayFunc(display_soal_satu);
            glutPostRedisplay();
            break;
        case '2':
            glLoadIdentity();
            glutDisplayFunc(display_soal_dua);
            glutPostRedisplay();
            break;
    }
}

void handleSpecialKeyReleased(int key, int x, int y) {
    switch (key) {
        case GLUT_KEY_UP:
            isupKeyPressed = false;
            break;
        case GLUT_KEY_DOWN:
            isdownKeyPressed = false;
            break;
    }
}

int main(int argc, char** argv)
{
    printf("Welcome,\n");
    printf("Press Keyboard\n");
    printf("(1) for Star (Case 1)\n");
    printf("(2) for Square Animation(Case 2)\n");
    printf("for case 1, press up and down arrow to change color\n");
    printf("and for case 2, press s/S to start rotation\n");
    printf("then x/X to rotate on X\n");
    printf("then y/Y to rotate on Y\n");
    printf("then z/Z to rotate on Z\n");
    printf("<press esc/q to exit>\n");
    glutInit(&argc, argv);
    glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
    glutInitWindowSize (400, 400);
    glutCreateWindow (argv[0]);
    init();
    glutSpecialFunc(handleSpecialKeypress);
    glutSpecialUpFunc(handleSpecialKeyReleased);
    glutDisplayFunc (display);
    glutMainLoop();
    return 0;
}