Question

I have two exact same codes OpenGL C++ , compiled using VS2008 in different project , but when i compile them, it behaves differently. One of them can recognize the condition if ( mod == GLUT_ACTIVE_CTRL && button == GLUT_WHEEL_UP ) and one of them is not.

Here is the complete function:

void mouse(int button, int state, int x, int y) {

int mod = glutGetModifiers();
mouseState = state;
mouseButton = button;
double modelview[16], projection[16];

int viewport[4];
float z = 0 ;

/*Read the projection, modelview and viewport matrices
using the glGet functions.*/
glGetIntegerv( GL_VIEWPORT, viewport );
glGetDoublev( GL_MODELVIEW_MATRIX, modelview );
//glGetDoublev( GL_PROJECTION_MATRIX, projection );

//Read the window z value from the z-buffer 
glReadPixels( x, viewport[3]-y, 1, 1, GL_DEPTH_COMPONENT, GL_FLOAT, &z );   

// Used for wheels, has to be up    
if (state == GLUT_UP )  {       
    if ( mod == GLUT_ACTIVE_CTRL && button == GLUT_WHEEL_UP ){                  
        printf("Wheel Up\n");
        zoom += 0.1;
    }
    else if (mod == GLUT_ACTIVE_CTRL &&  button == GLUT_WHEEL_DOWN ){
        printf("Wheel Down\n"); 
        zoom -= 0.1;
    }


    else if (mod == GLUT_ACTIVE_ALT && button == GLUT_WHEEL_UP) {
        //printf("Z++\n");
        translation_z = translation_z + 0.1;
        //printf("Z = %f", translation_z);
    }

    else if (mod == GLUT_ACTIVE_ALT && button == GLUT_WHEEL_DOWN) {
        //printf("Z--\n");
        translation_z = translation_z - 0.1;
    }

    else if (mod == GLUT_ACTIVE_SHIFT && button == GLUT_WHEEL_UP) {
        //printf("Shift Wheel Up. Z axis rotation goes here.\n");
        zrotation += (5*(z - oldZ)); // about x-axis
    }

    else if (mod == GLUT_ACTIVE_SHIFT && button == GLUT_WHEEL_DOWN) {
        //printf("Shift Wheel Down. Z Axis rotation goes here\n");
        zrotation -= (5*(z - oldZ)); // about x-axis
        //translation_z = translation_z - 0.1;
    }


}
else if (state == GLUT_DOWN) {
    //printf("Glut Down before z processing\n");

    if (button == GLUT_LEFT_BUTTON){
        cursorX = x;
        cursorY = y;
        mode = SELECT;
        //printf("Left is down\n");
    }

    oldX = x;
    oldY = y;
}
}

`

and I uploaded both of the project here.

Answer 1

I found the problem, In the project that can not recognize wheel up/down condition (despite that it should), I included:

freeglut.lib glut32.lib opengl32.lib user32.lib

This can be solved by including only the following libs:

opengl32.lib user32.lib

Thank you @melak47 for suggesting to check the project settings.