C++ Compiler throwing error with GLUT - c++

Question

The code was working fine but after I added the void projection(float), it's giving me unqaulified-id error inside the projection function. I'm using CodeBlocks IDE, MinGW. Please help me.
This is the error I'm getting:
||=== Build: Debug in L3 (compiler: GNU GCC Compiler) ===|
C:\Users\sos\Documents\Code Blocks c++\L3\src\CallbackFunctions.cpp||In function 'void projection(float)':|
C:\Users\sos\Documents\Code Blocks c++\L3\src\CallbackFunctions.cpp|56|error: expected unqualified-id before '=' token|
C:\Users\sos\Documents\Code Blocks c++\L3\src\CallbackFunctions.cpp|57|error: expected primary-expression before ',' token|
C:\Users\sos\Documents\Code Blocks c++\L3\src\CallbackFunctions.cpp| 57|error: expected primary-expression before ')' token|
C:\Users\sos\Documents\Code Blocks c++\L3\src\CallbackFunctions.cpp||In function 'void specialKeyboard(int, int, int)':|
||=== Build failed: 3 error(s), 15 warning(s) (0 minute(s), 0 second(s)) ===|
Moreover, if I comment everything inside projection, I get this error:
obj\Debug\src\Display.o||In function `glutInit_ATEXIT_HACK':|
C:\Program Files\CodeBlocks\MinGW\include\GL\freeglut_std.h|623|multiple definition of `keyboardKey'|
C:\Program Files\CodeBlocks\MinGW\include\GL\freeglut_std.h|623|multiple definition of `mouseX'|
C:\Program Files\CodeBlocks\MinGW\include\GL\freeglut_std.h|623|multiple definition of `mouseY'|
C:\Program Files\CodeBlocks\MinGW\include\GL\freeglut_std.h|623|multiple definition of `toggleProjection'|
CallbackFunctions.h
#ifndef CALLBACKFUNCTIONS_H
#define CALLBACKFUNCTIONS_H
#include "GL/freeglut.h"
unsigned char keyboardKey;
char *specialKeyboardKey ="";
char *modifier="";
char *mouseButtonPressed="";
char *mouseState="";
int mouseX, mouseY;
int toggleProjection=0;
char *view="";
/* Hardware Interrupts callback functions */
void display(); //called every single frame
void reshape(int width, int height); //called whenever the dimensions of the window are changed
void idle(); //when there is no interaction with the window
void keyboard(unsigned char key, int x, int y); //whenever a keyboard key is pressed/interrupt occurs
void specialKeyboard(int button, int x, int y); //captures special keys like: SHIFT ALT CTRL F1.....
void mouse(int button, int state, int x, int y); //captures the mouse clicks and their state
void mouseMotion(int x, int y); //captures the motion of the mouse pointer in the window
void projection(float asp);
#endif // CALLBACKFUNCTIONS_H
CallbackFunctions.cpp
#include "../include/CallbackFunctions.h"
#include "../include/Text.h"
extern int dim;
void display()
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glEnable(GL_DEPTH_TEST);
//Drawing stuff
glFlush();
glutSwapBuffers();
}
void idle()
{
display();
}
/* This callback function is called whenever the window is resized or reshaped */
void reshape(int width, int height)
{
//Width To Height Ratio
float w2h = (height>0)? (float)width/height : 1;
glViewport(0, 0, width, height);
projection(w2h);
}
void projection(float asp)
{
//Setting up the Viewing Matrix
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
if(toggleProjection==0)
{
glOrtho(-dim*asp, +dim*asp, -dim, +dim, -dim, +dim);
}
else
{
float fov = 55.0, near = asp/5, far = asp*5;
gluPerspective(fov, asp, near, far);
//To do
}
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}
/* This callback function is called when there is no activity in the window */
void keyboard(unsigned char key, int x, int y)
{
switch(key)
{
case 27:
exit(0);
break;
}
keyboardKey = key;
glutPostRedisplay();
}
/* This callback function is called whenever a keyboard interrupt is encountered */
void specialKeyboard(int key, int state, int a)
{
int currentModifier = glutGetModifiers();
switch(currentModifier)
{
case GLUT_ACTIVE_SHIFT:
modifier = "SHIFT";
break;
case GLUT_ACTIVE_CTRL:
modifier = "CTRL";
break;
case GLUT_ACTIVE_ALT:
modifier = "ALT";
break;
}
switch(key)
{
case GLUT_KEY_F1:
if(toggleProjection=0)
{
toggleProjection = 1;
view = "perspective";
break;
}
else
{
toggleProjection = 0;
view = "orthographic";
break;
}
}
glutPostRedisplay();
}
void mouse(int button, int state, int x, int y)
{
if(button == GLUT_LEFT_BUTTON)
mouseButtonPressed = "Left";
else if(button == GLUT_RIGHT_BUTTON)
mouseButtonPressed = "Right";
if(state == GLUT_DOWN)
mouseState = "down";
else if(state == GLUT_UP)
mouseState = "up";
}
void mouseMotion(int x, int y)
{
mouseX = x;
mouseY = y;
}
/*void info()
{
displayTextAt(-130, -40, 0, "mouseButton: %s", mouseButtonPressed);
displayTextAt(-130, -50, 0, "mouseButtonState: %s", mouseState);
displayTextAt(-130, -60, 0, "mouseX: %d", mouseX);
displayTextAt(-130, -70, 0, "mouseY: %d", mouseY);
displayTextAt(-130, -80, 0, "keyboard key: %c", keyboardKey);
displayTextAt(-130, -90, 0, "modifier: %s", modifier);
displayTextAt(70, -90, 0, view);
}*/

Answer 1

This is really a global variable declaration in a header problem. I've included the pastebin code (with fixes) for posterity.
/*This is the CallbackFunctions.h ------------------ */
#ifndef CALLBACKFUNCTIONS_H
#define CALLBACKFUNCTIONS_H
#include <GL/freeglut.h>
extern unsigned char keyboardKey;
/* Hardware Interrupts callback functions */
void display(); //called every single frame
void keyboard(unsigned char key, int x, int y); //whenever a keyboard key is pressed/interrupt occurs
#endif // CALLBACKFUNCTIONS_H
/*This is the CallbackFunctions.cpp ------------------ */
#include "CallbackFunctions.h"
unsigned char keyboardKey = 0;
void display()
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
}
void keyboard(unsigned char key, int x, int y)
{
keyboardKey = key;
}
/* --------------- This is the Main.cpp ---------------- */
#include <GL/freeglut.h>
#include "CallbackFunctions.h"
#define WIDTH 700
#define HEIGHT 400
void setupGlutWindow(int *argc, char **argv, int width, int height);
void setupCallbackFunctions();
int main(int argc, char** argv)
{
setupGlutWindow(&argc, argv, WIDTH, HEIGHT);
setupCallbackFunctions();
glutMainLoop();
}
void setupGlutWindow(int *argc, char **argv, int width, int height)
{
glutInit(argc, argv);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA | GLUT_DEPTH);
glutInitWindowSize(700, 500);
glutCreateWindow("Project L3");
glViewport(0, 0, width, height);
}
void setupCallbackFunctions()
{
glutDisplayFunc(display);
glutIdleFunc(display);
glutKeyboardFunc(keyboard);
}