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

#include <GL/glut.h>

// Zustandsvariablen
// Mausbewewung
int mousemotion;
int mousex, mousey;
int draw_type = 1;

// Initialisierung Modellorientierung
GLfloat xangle = 4;		/* in Drehung um */
GLfloat yangle = 120;
//Modellposition
GLfloat posx = 0, posy = 0, posz = -400;

//Callback Funktion: Reaktion auf Mausclicks
void mouse(int button, int state, int x, int y)
{
   if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN) {
      mousemotion = 1;
      mousex = x;
      mousey = y;
   }
   if (button == GLUT_LEFT_BUTTON && state == GLUT_UP) {
      mousemotion = 0;
   }
}

//Callback Funktion: Reaktion auf Mausbewegung
void motion(int x, int y)
{
   if (mousemotion) {
      xangle = xangle - (y - mousey);
      yangle = yangle - (x - mousex);
      mousex = x;
      mousey = y;

      // Szene neu zeichnen
      glutPostRedisplay();
   }
}

//Callback Funktion: Reaktion auf Tastendruck
void keyb(unsigned char keyPressed, int x, int y)
{
   switch (keyPressed) {
   case '1':
      draw_type = 1;
      break;
   case '2':
      draw_type = 2;
      break;
   case '3':
      draw_type = 3;
      break;
   case '4':
      draw_type = 4;
      break;
   case '5':
      draw_type = 5;
      break;
   case '6':
      draw_type = 6;
      break;
   case '7':
      draw_type = 7;
      break;
   case '8':
      draw_type = 8;
      break;
   case '9':
      draw_type = 9;
      break;

   }
}

//neue Modellposition berechnen
void recalcModelPos(void)
{
   glLoadIdentity();
   glTranslatef(posx, posy, posz);
   glRotatef(xangle, 1.0, 0.0, 0.0);
   glRotatef(yangle, 0.0, 1.0, 0.0);
}

void DrawScene(void)
{
   // Puffer löschen
   glClearColor(0.0, 0.0, 0.0, 0.0);
   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

   // neue Modellkoordinaten berechnen     
   recalcModelPos();

   // Verschiedene Objekte zeichnen
   switch (draw_type) {
   case 1:			// ZWEI PUNKTE
      glBegin(GL_POINTS);
      // 1. PUNKT 
      glColor3f(1.0f, 0.0f, 0.0f);
      glVertex3f(-100.0f, 0.0f, -100.0f);
      // 2. PUNKT
      glColor3f(0.0f, 1.0f, 0.0f);
      glVertex3f(-100.0f, 100.0f, -100.0f);
      glEnd();
      break;
   case 2:			// EINE LINIE
      glBegin(GL_LINES);
      glColor3f(1.0f, 0.0f, 0.0f);
      glVertex3f(-100.0f, 0.0f, -100.0f);
      glColor3f(0.0f, 1.0f, 0.0f);
      glVertex3f(-100.0f, 100.0f, -100.0f);
      glEnd();
      break;
   case 3:			// ZWEI LINIEN
      glBegin(GL_LINE_STRIP);
      glColor3f(1.0f, 0.0f, 0.0f);
      glVertex3f(-100.0f, 0.0f, -100.0f);
      glColor3f(0.0f, 1.0f, 0.0f);
      glVertex3f(-100.0f, 100.0f, -100.0f);
      glColor3f(0.0f, 0.0f, 1.0f);
      glVertex3f(0.0f, 100.0f, -100.0f);
      glEnd();
      break;
   case 4:			// EIN LINIENZUG
      glBegin(GL_LINE_LOOP);
      glColor3f(1.0f, 0.0f, 0.0f);
      glVertex3f(-100.0f, 0.0f, -100.0f);
      glColor3f(0.0f, 1.0f, 0.0f);
      glVertex3f(-100.0f, 100.0f, -100.0f);
      glColor3f(0.0f, 0.0f, 1.0f);
      glVertex3f(0.0f, 100.0f, -100.0f);
      glEnd();
      break;
   case 5:			// EIN DREICK
      glBegin(GL_TRIANGLES);
      glColor3f(1.0f, 0.0f, 0.0f);
      glVertex3f(-100.0f, 0.0f, -100.0f);
      glVertex3f(-100.0f, 100.0f, -100.0f);
      glVertex3f(0.0f, 100.0f, -100.0f);
      glEnd();
      break;
   case 6:			// ZWEI DREIECKE
      glBegin(GL_TRIANGLE_STRIP);
      glColor3f(1.0f, 0.0f, 0.0f);
      glVertex3f(-100.0f, 0.0f, -100.0f);
      glVertex3f(-100.0f, 100.0f, -100.0f);
      glColor3f(0.0f, 0.0f, 1.0f);
      glVertex3f(0.0f, 0.0f, -100.0f);
      glVertex3f(0.0f, 100.0f, -100.0f);
      glEnd();
      break;
   case 7:			// ZWEI DREIECKE
      glBegin(GL_TRIANGLE_FAN);
      glColor3f(1.0f, 0.0f, 0.0f);
      glVertex3f(0.0f, 0.0f, -100.0f);
      glColor3f(1.0f, 0.03, 0.0f);
      glVertex3f(-100.0f, 0.0f, -100.0f);
      glColor3f(.0f, 1.0f, 0.0f);
      glVertex3f(-100.0f, 100.0f, -100.0f);
      glColor3f(.0f, 0.0f, 1.0f);
      glVertex3f(50.0f, 50.0f, -100.0f);
      glEnd();
      break;
   case 8:			// EIN VIERECK
      glBegin(GL_QUADS);
      glColor3f(1.0f, 0.0f, 0.0f);
      glVertex3f(0.0f, 0.0f, -100.0f);
      glVertex3f(100.0f, 0.0f, -100.0f);
      glVertex3f(100.0f, 100.0f, -100.0f);
      glVertex3f(0.0f, 100.0f, -100.0f);
      glEnd();
      break;
   case 9:			// EIN FÜNFECK
      glBegin(GL_POLYGON);
      glColor3f(1.0f, 0.0f, 0.0f);
      glVertex3f(0.0f, 0.0f, -100.0f);
      glVertex3f(100.0f, 0.0f, -100.0f);
      glVertex3f(50.0f, 100.0f, -100.0f);
      glVertex3f(100.0f, 100.0f, -100.0f);
      glVertex3f(0.0f, 100.0f, -100.0f);
      glEnd();
      break;
   }

   // Szene neu zeichnen
   glutPostRedisplay();
   // Vordergrund- und Hintergrundpuffer wechseln
   glutSwapBuffers();
}

//eigene Initialisierungsfunktion
void myinit()
{
   GLfloat light_position[] = { 0.0, 0.0, -1.0, 1.0 };

   //erstes GL-Light setzen
   glLightfv(GL_LIGHT0, GL_POSITION, light_position);
   glEnable(GL_LIGHT0);

   //Z-Puffer aktivieren
   glDepthFunc(GL_LEQUAL);
   glEnable(GL_DEPTH_TEST);

   // Matritzen setzen
   glMatrixMode(GL_PROJECTION);
   // Sichtpyramide erstellen
   gluPerspective(60.0, 1.0, 1.0, 1000.0);
   glMatrixMode(GL_MODELVIEW);
   gluLookAt(0.0, 0.0, 5.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.);

}

int main(int argc, char *argv[])
{
   //GLUT initialisieren, Fenster setzen
   glutInit(&argc, argv);
   glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
   glutInitWindowSize(500, 500);
   glutInitWindowPosition(100, 100);
   glutCreateWindow(argv[0]);

   // eigene Initialisierungen
   myinit();

   //Callbacks setzen: Reaktion auf Mausklicks und -bewegungen, Tastaturaktivitäten
   glutMouseFunc(mouse);
   glutMotionFunc(motion);
   glutKeyboardFunc(keyb);

   //Callback zum Zeichnen der GL-Funktion
   glutDisplayFunc(DrawScene);

   glutMainLoop();

   return EXIT_SUCCESS;
}