Computergraphik_Hopp/Code/template_meshVisualisierung_textur.c
2018-11-28 15:48:19 +01:00

660 lines
22 KiB
C

#include <GL/glut.h>
#include <errno.h>
#include <math.h>
#include <stdio.h>
#include <string.h>
#define ORTHO 1
#define PERSPECTIVE 2
// Width & height of texture
#define HEIGHT 512
#define WIDTH 512
#pragma warning(disable : 4996)
void mouse(int button, int state, int x, int y);
void key(unsigned char key, int x, int y);
void init(void);
void reshape(int, int);
void display(void);
int main(int, char**);
void define_menu(void);
void idle(void);
void timer(int value);
void readcloud(char* filename);
void mouseactive(int x, int y);
void mouse(int button, int state, int x, int y);
void setProjection(int projType);
void setAntiAliasing(int state);
void readBitmap(void);
float cpoints[3 * 60000];
float cvnormals[3 * 60000];
float ccolors[3 * 60000];
int ccoord[10 * 3 * 60000];
float cnormals[10 * 3 * 60000];
int maxcoords = 0;
float cpointsmax[3];
float cpointsmin[3];
int cpoints_n = 0;
float xoff;
float yoff;
float zoff;
float zoom;
int angle1;
int angle2;
const float stepsize = 0.05;
const float anglestepsize = 0.01;
int displaymodus = 1;
int pressedbutton = 0;
int startx, starty, startz;
int startangle1;
int startangle2;
float startxoff;
float startyoff;
float startzoff;
GLubyte bitmapImage[HEIGHT][WIDTH][4];
// default values
int projType = PERSPECTIVE; // default: perspective projection
int lights = 0;
int shading = 0;
float shininess = 2;
int textureMode = 1;
float ambientLightColor[3] = { 0.1, 0.1, 0.1 };
float diffuseLightColor[3] = { 0.5, 0.5, 0.5 };
float specularLightColor[3] = { 1.0, 1.0, 1.0 };
float lightPosition[4] = { 0, 0, 1, 1 };
// short cut color white
float white[3] = { 0.5, 0.5, 0.5 };
char meshFile[] = "/home/andre/shares/Bachelor/DHBW_AI_16/4303_Computergraphik_Hopp/Code/bones.txt"; // change this in case the point cloud is saved somewhere else.
char textureFile[] = "/home/andre/shares/Bachelor/DHBW_AI_16/4303_Computergraphik_Hopp/Code/boneTexture.bmp"; // change this in case the texture is saved somewhere else.
int main(int argc, char** argv)
{
readcloud(meshFile);
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH); // Doublebuffer for animation
glutInitWindowSize(800, 800);
glutInitWindowPosition(400, 100);
glutCreateWindow("Mesh Visualization");
init();
glutMouseFunc(mouse);
glutMotionFunc(mouseactive);
glutDisplayFunc(display);
glutReshapeFunc(reshape);
glutKeyboardFunc(key);
printf("\n\nSTEUERUNG\nAnzeigemodi:\n");
printf("'0' nur Box\n'1' Points, Farbwerte nach Koordinate\n'2' Wireframe, Farbwerte nach Koordinate\n'3' Filled, Farbwerte nach Koordinate\n");
printf("'4' Points, Farbwerte aus Datei\n'5' Wireframe, Farbwerte aus Datei\n'6' Filled, Farbwerte aus Datei\n");
printf("'7' Texturmodus\n\n\n");
printf("Transformationen:\n linke Maustaste und x-y-Bewegung -> Rotation\n mittlere Maustaste und y-Richtung -> Zoom (entspricht einer Skalierung)\n");
printf(" rechte Maustaste und x-y-Bewegung -> Translation\n\n");
printf("Projektionsart aendern:\n");
printf("'o' orthographische Projektion, 'p' perspektivische Projektion \n\n");
printf("Licht Optionen\n");
printf(" 's' : Shading Modus aendern (Flat / Gouraud)\n");
printf(" 'l' : Licht ein-/ausschalten\n");
printf(" '+'/'-' : Spekular-Exponent aendern\n\n");
printf("Textur Optionen\n");
printf(" 't' : Automatische Texturkoordinaten aesndern (Object Linear / Eye Linear)\n\n");
glutMainLoop();
return 0;
}
void readBitmap(void)
{
int i, j, k;
GLubyte c;
FILE* img;
img = fopen(textureFile, "rb");
fseek(img, sizeof(unsigned char) * 54, 0); // offset to pixel data
for (i = 0; i < HEIGHT; i++) {
for (j = 0; j < WIDTH; j++) {
for (k = 0; k < 3; k++) {
fread(&c, sizeof(GLubyte), 1, img);
bitmapImage[i][j][k] = (GLubyte)c;
}
bitmapImage[i][j][3] = (GLubyte)255;
}
}
fclose(img);
}
void displaycloud(int modus)
{
int i = 0;
float range[3];
float directionVector[3][2];
float n[3];
float currentColor[3];
int counter = 0;
glEnable(GL_NORMALIZE);
glFrontFace(GL_CW);
for (i = 0; i < 3; i++)
range[i] = cpointsmax[i] - cpointsmin[i];
////////////////////////////////////////////////////////////////////////////////////
// Switch on/off Texture mode
if (modus == 7) {
glEnable(GL_TEXTURE_2D);
} else {
glDisable(GL_TEXTURE_2D);
}
///////////////////////////////////////////////////////////////////////////////////
if (modus > 0) {
if (modus == 1 || modus == 4) { // Darstellung von Punkten
glPolygonMode(GL_FRONT_AND_BACK, GL_POINT);
}
if (modus == 2 || modus == 5) { // Darstellung des Drahtgittermodells
glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
}
if (modus == 3 || modus == 6 || modus == 7) { // Darstellung gefüllter Polygone
glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
}
glBegin(GL_TRIANGLES);
for (i = 0; i < maxcoords + 1; i++) {
if (modus > 3) { // Darstellung der Farben aus dem Mesh-File
currentColor[0] = ccolors[ccoord[i] * 3];
currentColor[1] = ccolors[ccoord[i] * 3 + 1];
currentColor[2] = ccolors[ccoord[i] * 3 + 2];
} else { // Darstellung der interpolierten Farben entsprechend der Koordinaten
currentColor[0] = (cpoints[ccoord[i] * 3] - cpointsmin[0]) / range[0];
currentColor[1] = (cpoints[ccoord[i] * 3 + 1] - cpointsmin[1]) / range[1];
currentColor[2] = (cpoints[ccoord[i] * 3 + 2] - cpointsmin[2]) / range[2];
}
if (lights == 1) {
glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT, currentColor);
glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, currentColor);
glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, currentColor);
glMaterialf(GL_FRONT_AND_BACK, GL_SHININESS, shininess);
} else {
glColor3f(currentColor[0], currentColor[1], currentColor[2]);
}
// for flat shading: one normal per triangle (before defintion of vertices) is sufficient
// cnormals contains the surface normal
if (counter == 0) {
if (shading == 0) {
glNormal3f(cnormals[i], cnormals[i + 1], cnormals[i + 2]);
}
}
counter++;
if (counter == 3) {
counter = 0;
}
// for gouraud shading we need the normal of each vertex
// cvnormals contains the vertex normals
if (shading == 1) {
glNormal3f(cvnormals[ccoord[i] * 3], cvnormals[ccoord[i] * 3 + 1], cvnormals[ccoord[i] * 3 + 2]);
}
glVertex3f(cpoints[ccoord[i] * 3], cpoints[ccoord[i] * 3 + 1], cpoints[ccoord[i] * 3 + 2]);
}
glEnd();
glDisable(GL_TEXTURE_2D);
}
}
void display(void)
{
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// automatic generation of texture coordinates (object/eye linear)
// Define s and t planes
GLfloat s_plane[] = { 0, 0, 1, 0 };
GLfloat t_plane[] = { 0, 1, 0, 0 };
if (textureMode == 1) { // OBJECT LINEAR
glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR);
glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR);
} else if (textureMode == 2) { // EYE LINEAR
glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR);
glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR);
}
glTexGenfv(GL_S, GL_OBJECT_PLANE, s_plane);
glTexGenfv(GL_T, GL_OBJECT_PLANE, t_plane);
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////
if (lights == 1) {
glEnable(GL_LIGHT0);
glLightfv(GL_LIGHT0, GL_AMBIENT, ambientLightColor);
glLightfv(GL_LIGHT0, GL_DIFFUSE, diffuseLightColor);
glLightfv(GL_LIGHT0, GL_SPECULAR, specularLightColor);
glLightfv(GL_LIGHT0, GL_POSITION, lightPosition);
glEnable(GL_LIGHTING);
if (shading == 0) { // Flat Shading
glShadeModel(GL_FLAT);
} else if (shading == 1) { // Gouraud Shading
glShadeModel(GL_SMOOTH);
}
} else {
glDisable(GL_LIGHTING);
}
// projection switch
switch (projType) {
case ORTHO:
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(-2 - zoff, 2 + zoff, -2 - zoff, 2 + zoff, -2, 10);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
gluLookAt(0.0, 0.0, 0.01, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);
break;
case PERSPECTIVE:
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(45.0, 1.0, 3.0, 7.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
gluLookAt(0, 0, 5 + zoff, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);
break;
}
glPushMatrix();
// enable depth buffer and clear color/depth buffer
glClearDepth(1); // Default: 1
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LESS); // Default: GL_LESS
glColor3f(0.0, 0.0, 0.0);
// center and rotate
glTranslatef(xoff, yoff, 0);
glRotatef(angle2, 1.0, 0.0, 0.0);
glRotatef(angle1, 0.0, 1.0, 0.0);
//display
displaycloud(displaymodus);
// draw box
glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT, white);
glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, white);
glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, white);
glMaterialf(GL_FRONT_AND_BACK, GL_SHININESS, shininess);
glColor3f(0.0, 0.0, 0.0);
glBegin(GL_LINE_LOOP);
glVertex3f(cpointsmax[0], cpointsmax[1], cpointsmax[2]);
glVertex3f(cpointsmin[0], cpointsmax[1], cpointsmax[2]);
glVertex3f(cpointsmin[0], cpointsmin[1], cpointsmax[2]);
glVertex3f(cpointsmax[0], cpointsmin[1], cpointsmax[2]);
glEnd();
glBegin(GL_LINE_LOOP);
glVertex3f(cpointsmax[0], cpointsmax[1], cpointsmin[2]);
glVertex3f(cpointsmin[0], cpointsmax[1], cpointsmin[2]);
glVertex3f(cpointsmin[0], cpointsmin[1], cpointsmin[2]);
glVertex3f(cpointsmax[0], cpointsmin[1], cpointsmin[2]);
glEnd();
glBegin(GL_LINES);
glVertex3f(cpointsmax[0], cpointsmax[1], cpointsmax[2]);
glVertex3f(cpointsmax[0], cpointsmax[1], cpointsmin[2]);
glVertex3f(cpointsmin[0], cpointsmax[1], cpointsmax[2]);
glVertex3f(cpointsmin[0], cpointsmax[1], cpointsmin[2]);
glVertex3f(cpointsmin[0], cpointsmin[1], cpointsmax[2]);
glVertex3f(cpointsmin[0], cpointsmin[1], cpointsmin[2]);
glVertex3f(cpointsmax[0], cpointsmin[1], cpointsmax[2]);
glVertex3f(cpointsmax[0], cpointsmin[1], cpointsmin[2]);
glEnd();
glPopMatrix();
glPopMatrix();
glutSwapBuffers(); // Buffer for animation needs to be swapped
}
void init(void)
{
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glHint(GL_LINE_SMOOTH_HINT, GL_NICEST);
glHint(GL_POINT_SMOOTH_HINT, GL_NICEST);
glHint(GL_POLYGON_SMOOTH_HINT, GL_NICEST);
glClearColor(0.99f, 0.99f, 0.99f, 0.0);
glLoadIdentity();
xoff = 0.0;
yoff = 0.0;
zoff = 0.0;
zoom = 1;
angle1 = 45;
angle2 = 45;
//////////////////////////////////////////////////////////////////////////////////////////////////////
// Read bitmap file
readBitmap();
// Texture wrap settings
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
// Filter settings
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
// Connecting lighting and texture
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
// Initialize texture
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, WIDTH, HEIGHT, 0, GL_RGBA, GL_UNSIGNED_BYTE, bitmapImage);
// enable automatic texture generation
glEnable(GL_TEXTURE_GEN_S);
glEnable(GL_TEXTURE_GEN_T);
//////////////////////////////////////////////////////////////////////////////////////////////////////
}
void reshape(int w, int h)
{
glViewport(0, 0, w, h);
glClear(GL_COLOR_BUFFER_BIT);
}
void idle()
{
}
void timer(int value)
{
}
void readcloud(char* filename)
{
int i = 0;
int j = 0;
int k = 0;
int numVertices = 0;
int counter = 0;
float directionVector[3][2];
float n[3];
float x, y, z;
float temp;
int index;
int indexBegin;
int numNeighbouringFaces = 0;
FILE* f;
int abbruch = 0;
char str[200] = "";
printf("Lese '%s' ein\n", filename);
f = fopen(filename, "r");
printf("Ueberspringe Kopf...\n");
// Kopf Überspringen
while (!feof(f) && str[0] != '[')
fscanf(f, "%s", str);
printf("Lese Punkte ein...\n");
//Punkte einlesen
while (!feof(f) && abbruch == 0) {
//einlesen
if (((i + 1) % 3) == 0)
fscanf(f, "%f %c", &cpoints[i], str);
else
fscanf(f, "%f", &cpoints[i]);
// Extremalwerte initialisieren
if (i < 3) {
cpointsmax[i % 3] = cpoints[i];
cpointsmin[i % 3] = cpoints[i];
}
//Abbruch, wenn alle Punkte 0 sind, (nicht ganz sauber, aber funktioniert, wenn nicht zufällig der Urspung ein gültiger Punkt ist)
if (i > 3 && cpoints[i - 2] == 0 && cpoints[i - 1] == 0 && cpoints[i] == 0)
abbruch = 1;
//Extremalwerte gegebenenfalls erneuern
if (cpoints[i] > cpointsmax[i % 3] && cpoints[i] != 0)
cpointsmax[i % 3] = cpoints[i];
if (cpoints[i] < cpointsmin[i % 3] && cpoints[i] != 0)
cpointsmin[i % 3] = cpoints[i];
i++;
}
cpoints_n = i - 1;
printf("Es wurden %i Vertices gelesen\n", cpoints_n / 3);
printf("Koordinaten sind in den Intervallen [%f,%f] [%f,%f] [%f,%f]\n\n", cpointsmin[0], cpointsmax[0], cpointsmin[1], cpointsmax[1], cpointsmin[2], cpointsmax[2]);
abbruch = 0;
i = 0;
//warten, bis es zu den colors geht
while (!feof(f) && str[0] != '[')
fscanf(f, "%s", str);
printf("Lese Farben ein...\n");
// Farben einlesen
while (!feof(f) && abbruch == 0) {
//einlesen
if (((i + 1) % 3) == 0)
fscanf(f, "%f %c", &ccolors[i], str);
else
fscanf(f, "%f", &ccolors[i]);
//Abbruch, wenn alle farben 0 sind, (nicht ganz sauber, aber funktioniert, wenn nicht zufällig schwarz eine gültige Farbe ist)
if (i > 3 && ccolors[i - 2] == 0 && ccolors[i - 1] == 0 && ccolors[i] == 0)
abbruch = 1;
i++;
}
printf("Es wurden %i Farben eingelesen\n\n", (i - 1) / 3);
abbruch = 0;
i = 0;
//warten, bis es zu den koordinaten geht
while (!feof(f) && str[0] != '[')
fscanf(f, "%s", str);
printf("Lese Koordinaten fuer die Dreiecke ein...\n");
// Koordinaten einlesen
while (!feof(f) && abbruch < 2) {
//einlesen
fscanf(f, "%i %c", &ccoord[i], str);
//printf("%i\n",ccoord[i]);
//Abbruch, wenn alle Dreiecke 0 sind, (nicht ganz sauber, aber funktioniert, wenn nicht zufällig der Urspung ein gültiger Punkt ist)
if (ccoord[i] == -1) {
i--;
abbruch++;
} else
abbruch = 0;
i++;
}
maxcoords = i - 1;
printf("Es wurden %i Dreiecke eingelesen\n", (maxcoords + 1) / 3); // drei Punkte bilden ein Dreieck
fclose(f);
printf("Einlesen beendet\n\n");
for (j = 0; j < cpoints_n; j++) {
// normalize
cpoints[j] = cpoints[j] - cpointsmin[j % 3];
cpoints[j] = 2 * cpoints[j] / (cpointsmax[j % 3] - cpointsmin[j % 3]);
cpoints[j] = cpoints[j] - 1;
}
cpointsmin[0] = -1;
cpointsmin[1] = -1;
cpointsmin[2] = -1;
cpointsmax[0] = 1;
cpointsmax[1] = 1;
cpointsmax[2] = 1;
for (j = 0; j < cpoints_n; j++) {
if (j % 3 == 1) { // y-coordinate change with z-coordinate
temp = cpoints[j];
cpoints[j] = cpoints[j + 1];
cpoints[j + 1] = temp;
}
}
printf("Berechne Flächen- und Vertexnormalen...\n");
counter = 0;
for (i = 0; i < maxcoords + 1; i++) {
if (counter == 0) {
// Richtungsvektoren der Ebene aus jeweils zwei Seiten des Dreiecks
directionVector[0][0] = cpoints[ccoord[i + 1] * 3] - cpoints[ccoord[i] * 3];
directionVector[1][0] = cpoints[ccoord[i + 1] * 3 + 1] - cpoints[ccoord[i] * 3 + 1];
directionVector[2][0] = cpoints[ccoord[i + 1] * 3 + 2] - cpoints[ccoord[i] * 3 + 2];
directionVector[0][1] = cpoints[ccoord[i + 2] * 3] - cpoints[ccoord[i] * 3];
directionVector[1][1] = cpoints[ccoord[i + 2] * 3 + 1] - cpoints[ccoord[i] * 3 + 1];
directionVector[2][1] = cpoints[ccoord[i + 2] * 3 + 2] - cpoints[ccoord[i] * 3 + 2];
// Normalenvektor als Kreuzprodukt der beiden Seiten
n[0] = (directionVector[1][0] * directionVector[2][1]) - (directionVector[2][0] * directionVector[1][1]);
n[1] = (directionVector[2][0] * directionVector[0][1]) - (directionVector[0][0] * directionVector[2][1]);
n[2] = (directionVector[0][0] * directionVector[1][1]) - (directionVector[1][0] * directionVector[0][1]);
// Normalenvektor in Array speichern
cnormals[i] = n[0];
cnormals[i + 1] = n[1];
cnormals[i + 2] = n[2];
// Aufaddieren der Normalen an den Betroffenen Vertices, die das Dreieck bilden
cvnormals[ccoord[i] * 3] = cvnormals[ccoord[i] * 3] + n[0];
cvnormals[ccoord[i] * 3 + 1] = cvnormals[ccoord[i] * 3 + 1] + n[1];
cvnormals[ccoord[i] * 3 + 2] = cvnormals[ccoord[i] * 3 + 2] + n[2];
cvnormals[ccoord[i + 1] * 3] = cvnormals[ccoord[i + 1] * 3] + n[0];
cvnormals[ccoord[i + 1] * 3 + 1] = cvnormals[ccoord[i + 1] * 3 + 1] + n[1];
cvnormals[ccoord[i + 1] * 3 + 2] = cvnormals[ccoord[i + 1] * 3 + 2] + n[2];
cvnormals[ccoord[i + 2] * 3] = cvnormals[ccoord[i + 2] * 3] + n[0];
cvnormals[ccoord[i + 2] * 3 + 1] = cvnormals[ccoord[i + 2] * 3 + 1] + n[1];
cvnormals[ccoord[i + 2] * 3 + 2] = cvnormals[ccoord[i + 2] * 3 + 2] + n[2];
}
counter++;
if (counter == 3) {
counter = 0;
}
}
printf("... beendet.\n");
}
void key(unsigned char k, int x, int y);
void mouseactive(int x, int y)
{
if (pressedbutton == GLUT_LEFT_BUTTON) {
angle1 = startangle1 + (x - startx) / 10;
angle2 = startangle2 + (y - starty) / 10;
}
if (pressedbutton == GLUT_RIGHT_BUTTON) {
xoff = startxoff + (float)(x - startx) / 100;
yoff = startyoff + (float)(y - starty) / 100;
}
if (pressedbutton == GLUT_MIDDLE_BUTTON) {
zoff = startzoff + ((float)(y - startz) / 100);
}
glutPostRedisplay();
}
void mouse(int button, int state, int x, int y)
{
if (state == GLUT_DOWN) {
pressedbutton = button;
startx = x;
starty = y;
startz = y;
startangle1 = angle1;
startangle2 = angle2;
startxoff = xoff;
startyoff = yoff;
startzoff = zoff;
} else
pressedbutton = 0;
}
void MainMenu(int value)
{
switch (value) {
case 2:
key('q', 0, 0);
break;
}
}
void submenu1(int value)
{
}
void define_menu()
{
}
void key(unsigned char k, int x, int y)
{
switch (k) {
case 8: //BACKSPACE
init();
break;
case 27:
case 'q':
case 'Q':
exit(0);
case 'o':
projType = ORTHO;
printf("Projektion: ORTHOGRAPHIC\n");
glutPostRedisplay();
break;
case 'p':
projType = PERSPECTIVE;
printf("Projektion: PERSPECTIVE\n");
glutPostRedisplay();
break;
case 'l':
if (lights == 0)
lights = 1;
else
lights = 0;
break;
case '+':
shininess = shininess + 0.1;
printf(" Shininess: %f\n", shininess);
break;
case '-':
shininess = shininess - 0.1;
printf(" Shininess: %f\n", shininess);
break;
case 's':
if (shading == 1) {
shading = 0;
printf(" Shading = FLAT\n");
} else if (shading == 0) {
shading = 1;
printf(" Shading = GOURAUD\n");
}
break;
case 't':
if (textureMode == 1) {
textureMode = 2;
printf(" Texture Mode = EYE LINEAR\n");
} else if (textureMode == 2) {
textureMode = 1;
printf(" Texture Mode = OBJECT LINEAR\n");
}
break;
default:
if (k > '0' - 1 && k < '8') {
displaymodus = k - '0';
printf("Display-Modus: %i\n", displaymodus);
} else {
printf("Taste %c mit Steuerzeichen %i nicht belegt\n", k, k);
}
break;
}
glutPostRedisplay();
}