Rotating around the origin in 3d space using GLUT - c

Question

I am stuck trying to get this code to work in Visual Studio 2012 using glut. It renders a 10/10 3D grid but it will not respond to my input from the keyboard. I am trying to get the camera to rotate around the origin when i hit the left arrow key.
// This example shows how to create a camera for 3D graphics.
#ifdef __APPLE__
#include <GLUT/glut.h>
#else
#include <GL/glut.h>
#endif
#include <iostream>
#include <cmath>
#include <math.h>
using namespace std;
int g_winWidth = 1024;
int g_winHeight = 512;
bool keyStatus[256];
float angle = 0.0f; //angle for rotating camera
float beginning_angle = 0.0f;
float cx = 10.0, cy = 10.0, cz = -10.0;
void initialGL()
{
glEnable(GL_DEPTH_TEST);
glClearColor (1.0f, 1.0f, 1.0f, 0.0f);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glMatrixMode (GL_MODELVIEW);
glLoadIdentity();
}
//initialize the keyboard keys
void initialization()
{
for(int i =0; i<256; i++)
keyStatus[i] = false;
}
//function to draw the colored x,y, and z axis
void drawCS()
{
glMatrixMode(GL_MODELVIEW);
glPushMatrix();
glScalef(10.0f, 10.0f, 10.0f);
glLineWidth(2.5f);
glBegin(GL_LINES);
//axis x
glColor3f(1.0f, 0.0f, 0.0f);
glVertex3f(0.0f, 0.0f, 0.0f);
glVertex3f(0.3f, 0.0f, 0.0f);
//text x
glVertex3f(0.4f, 0.05f, 0.0f);
glVertex3f(0.5f, -0.05f, 0.0f);
glVertex3f(0.4f, -0.05f, 0.0f);
glVertex3f(0.5f, 0.05f, 0.0f);
//axis y
glColor3f(0.0f, 1.0f, 0.0f);
glVertex3f(0.0f, 0.0f, 0.0f);
glVertex3f(0.0f, 0.3f, 0.0f);
//text y
glVertex3f(0.0f, 0.5f, 0.0f);
glVertex3f(0.0f, 0.4f, 0.0f);
glVertex3f(-0.05f, 0.55f, 0.0f);
glVertex3f(0.0f, 0.5f, 0.0f);
glVertex3f(0.05f, 0.55f, 0.0f);
glVertex3f(0.0f, 0.5f, 0.0f);
//axis z
glColor3f(0.0f, 0.0f, 1.0f);
glVertex3f(0.0f, 0.0f, 0.0f);
glVertex3f(0.0f, 0.0f, 0.3f);
//text z
glVertex3f(-0.025f, 0.025f, 0.4f);
glVertex3f(0.025f, 0.025f, 0.4f);
glVertex3f(0.025f, 0.025f, 0.4f);
glVertex3f(-0.025f, -0.025f, 0.4f);
glVertex3f(-0.025f, -0.025f, 0.4f);
glVertex3f(0.025f, -0.025f, 0.4f);
glEnd();
glLineWidth(1.0f);
glPopMatrix();
}
//function to draw the grid
void drawGrid()
{
int size = 10; // determining the grid size and the numbers of cells
if(size%2 != 0) ++size;
glMatrixMode(GL_MODELVIEW);
glPushMatrix();
//glScalef(30.0f, 30.0f, 30.0f);
glBegin(GL_LINES);
for (int i =0; i<size+1; i++) {
if((float)i == size/2.0f) {
glColor3f(0.0f, 0.0f, 0.0f);
} else {
glColor3f(0.8f, 0.8f, 0.8f);
}
glVertex3f(-size/2.0f, 0.0f, -size/2.0f+i);
glVertex3f(size/2.0f, 0.0f, -size/2.0f+i);
glVertex3f(-size/2.0f+i, 0.0f, -size/2.0f);
glVertex3f(-size/2.0f+i, 0.0f, size/2.0f);
}
glEnd();
glPopMatrix();
}
//function to display everything that is happening in window
void display(void)
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
drawGrid();// call to function to draw the grid
drawCS();//call to function to draw the x,y,z axis
glutSwapBuffers();
}
void reshape(int w, int h)
{
g_winWidth = w;
g_winHeight = h;
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
//this function sets the initial position of the camera in 3D space
/*
Need to find a way to rotate around the origin from left to right
*/
gluLookAt( cx, cy, cz, //camera position
0.0f, 0.0f, 0.0f, //what camera looks at
0.0f, 1.0f, 0.0f); //
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(45, g_winWidth/g_winHeight, 0.1, 100);//specifies the view for the scene
glViewport(0, 0, w, h);
//angle += 0.1f;
}
//keyboard function for the exit key
void keyboard(unsigned char key, int x, int y)
{
keyStatus[key] = true;
switch (key) {
case 27:
exit(0);
break;
default:
break;
}
}
//sets the keyboard callback to the current window
void keyboardUp(unsigned char key, int x, int y)
{
keyStatus[key] = false;
}
//function for arrow keys output
void processSpecialKeys(int key, int xx, int yy) {
switch(key) {
case GLUT_KEY_LEFT :
//What the left arrow key does
angle -= 0.01f;
cx = sin(angle);
cz = -cos(angle);
break;
case GLUT_KEY_RIGHT :
//What the right arrow key does
break;
case GLUT_KEY_UP :
//What the up arrow key does
break;
case GLUT_KEY_DOWN :
//What the down arrow key does
break;
}
}
int main(int argc, char **argv)
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGB);
glutInitWindowSize(g_winWidth, g_winHeight);
glutInitWindowPosition(0, 0);
glutCreateWindow("Camera");
initialGL();
glutDisplayFunc(display);
glutReshapeFunc(reshape);
glutIdleFunc(display);
glutKeyboardFunc(keyboard);
glutKeyboardUpFunc(keyboardUp);
glutSpecialFunc(processSpecialKeys);
glEnable(GL_DEPTH_TEST);
initialization();
glutMainLoop();
return 1;//changed from EXIT_SUCCESS
}