   Keyboard Input problem
  I was originally studying lighting. I made a blue sphere that was lit at the top to make it appear more REAL. Then I thought it would be cool if I could see the lights move. Unfortunately, the light positions are fixed (as far as i know). So, the code below tries to move the blue sphere to observe light reflections from various angles.The Problem?I use two variables x and y to store the translational values and increase or decrease them depending on the key pressed. Well, nothing is happening. You can see that i use cout<<x<<y in the SpecialFunction(...) to see the values of x and y. However, the variables seem to be stuck with a fixed value (oddly x=230, y=71 or something) and no keypress changes it.Please help!!!//This is the common framework required for all GLUT programs#include <gl/glut.h>#include <windows.h>#define STEP 0.05#include <iostream>using namespace std;GLint Width, Height; GLfloat x=0.0f,y=0.0f;GLfloat diffused[]={0.0f,0.9f,0.1f,1.0f};GLfloat ambient[]={1.0f,1.0f,1.0f,1.0f};GLfloat lightpos[]={0.0f,1.0f,1.0f,1.0f};void RenderScene(){glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);    glMatrixMode(GL_MODELVIEW);glLoadIdentity();glTranslatef(x,y,0.0f);glColor3f(0.0f,0.0f,1.0f);glutSolidSphere(0.5f,20,20);glutSwapBuffers();}void SetupRC(){glEnable(GL_DEPTH_TEST);glEnable(GL_LIGHTING);glEnable(GL_CULL_FACE);glLightfv(GL_LIGHT0,GL_DIFFUSE,diffused);glLightModelfv(GL_LIGHT_MODEL_AMBIENT,ambient);glLightfv(GL_LIGHT0,GL_POSITION,lightpos);glEnable(GL_LIGHT0);glEnable(GL_COLOR_MATERIAL);glColorMaterial(GL_FRONT,GL_AMBIENT);glClearColor(0.0f,0.0f,0.0f,1.0f);}void TimerFunction(int value){glutPostRedisplay(); //Refresh the screen    glutTimerFunc(33,TimerFunction,1);}void ChangeSize(int width,int height) {    /* Save the new width and height */    Width  = width;    Height = height;    /* Reset the viewport... */    glViewport(0, 0, width, height);    glMatrixMode(GL_PROJECTION);    glLoadIdentity();    gluPerspective(45.0, (float)width / (float)height, 0.1, 1000.0);    glMatrixMode(GL_MODELVIEW);}void SpecialFunction(int key,int x,int y){cout<<x<<","<<y<<" ";if(key == GLUT_KEY_UP)y += STEP;if(key == GLUT_KEY_DOWN)y -= STEP;if(key == GLUT_KEY_RIGHT)x += STEP;if(key == GLUT_KEY_LEFT)x -= STEP;glutPostRedisplay();}int main(){glutInitDisplayMode(GLUT_DOUBLE|GLUT_RGB);glutCreateWindow("Simple");glutDisplayFunc(RenderScene);    glutTimerFunc(33,TimerFunction,1); glutSpecialFunc(SpecialFunction);SetupRC();glutMainLoop();return 0;}
  Hey,if you take a look at the names of your variables you'll see that it's logic that you get this error.Your SpecialFunction has two arguments called x and y, and you have two global variables called the same. But because of namespaces within the SpecialFunction you can only acces the arguments though.This should work:...//Renamed argument variables here:void SpecialFunction(int key,int mouse_x,int mouse_y){cout<<x<<","<<y<<" ";if(key == GLUT_KEY_UP)y += STEP;if(key == GLUT_KEY_DOWN)y -= STEP;if(key == GLUT_KEY_RIGHT)x += STEP;if(key == GLUT_KEY_LEFT)x -= STEP;glutPostRedisplay();}...;  Hey, thanks a lot!But I still have to ask myself: When will I stop making these STUPID mistakes???   