I just can't seem to solve this.

Heres what I want to do:
I want my program to calculate movement, from one point to another.

The function _updatepos is the main function, where I have troubles. It is supposed to, as the name says, update the position (posx and posy), and move it a bit closer to the destination (desx and desy);

I would be very thankful if you could help me, thanks in advance!

#include <iostream>
#include <windows.h>
#include <time.h>
using namespace std;

time_t current_time;

double posx = 10000;
double posy = 10000;

double desx = 0;
double desy = 0;

int speed = 520;


double getDistance(double x1, double y1, double x2, double y2) {
return (((x2-x1)*(x2-x1))+((y2-y1)*(y2-y1))/((x2-x1)*(x2-x1))+((y2-y1)*(y2-y1))); //no need for maths.h....
}

double timeNeeded() {
    return getDistance(posx,posy,desx,desy)/speed;
}

void _updatepos() { //******THIS*********
    if((desx>0)&&(desy>0)) {
        //just cant think of a way to solve this....
        double timeneeded = timeNeeded();
        double xleft = desx-posx;
        double yleft = desy-posy;
        double incx = xleft/timeneeded;
        double incy = yleft/timeneeded;
        time_t isthere = clock();
        posx = posx + (incx*(isthere-current_time));
        posy = posy + (incy*(isthere-current_time));
    }
}

void stopmov() {
    if((posx==desx)&&(posy==desy)) {
        desx = 0;
        desy = 0;
    }
}

void updatePos() {
    current_time = clock();
    _updatepos();
    stopmov();
}

void moveTo(int x, int y) {
    desx = x;
    desy = y;
}


int main() {
    moveTo(2000,1000);
    while(true) {
        updatePos();
        //cout << posx << ", " << posy << endl;
    }
    cin.get();
return 0;
}

Things happen so fast inside the computer these days that the difference between isthere and current_time may be effectively zero making the update to posx and posy essentially zero as well.

If it's the source of your problem then you have several options. I'd probably have the program do something inane for a period of time, then come back for the real thing.

double incy = yleft/timeneeded;        
long i = 0;
long target = 10000;
while(i < target)
   ++i;
time_t isthere = clock();

Make the pause long enough to make a difference and "prove" it's the problem. Then cut the duration down to meet your needs.

You could also look into sleep() or pause(), or versions thereof.

Edited 6 Years Ago by Lerner: n/a

Ok, thanks alot for your help and reply, but it seems like i had so solve it in a different way.

This code works perfectly + it can update the movement of up to 200 npcs and palyers (can be increased t any time), and if the desx and desy change while moving it will re-calculate accordingly :D.

This might come in handy for some game developers, (or bot makers like myself).

So heres the Code:

#include <iostream>
#include <windows.h>
#include <time.h>
using namespace std;
 
time_t current_time;
 
time_t isthere[100];
double posx[200];
double posy[200];
double posxbuf[200];
double posybuf[200];
double desx[200];
double desy[200];
double desxbuf[200];
double desybuf[200];
double incx[200];
double incy[200];
bool moving[200];

double timeneeded[200];

int speed[200];
 
 
double getDistance(double x1, double y1, double x2, double y2) {
return (((x2-x1)*(x2-x1))+((y2-y1)*(y2-y1))/((x2-x1)*(x2-x1))+((y2-y1)*(y2-y1))); //no need for maths.h....
}
 
double timeNeeded(double x1, double y1, double x2, double y2,double speed) {
    return (getDistance(x1,y1,x2,y2)/(speed*10));
}
 
DWORD WINAPI thread(LPVOID lpData) {
    while(true) {
        for(int i = 0; i<200; i++) {
            if((desx[i]!=0)&&(desy[i]!=0)) {
                if(moving[i] == true) {
                    posx[i] = posx[i] + (incx[i]*(current_time-isthere[i]));
                    posy[i] = posy[i] + (incy[i]*(current_time-isthere[i]));
                }
                timeneeded[i] = timeNeeded(posx[i],posy[i],desx[i],desy[i],speed[i]);
                desxbuf[i] = desx[i];
                desybuf[i] = desy[i];
                incx[i] = (desxbuf[i]-posx[i])/timeneeded[i];
                incy[i] = (desybuf[i]-posy[i])/timeneeded[i];
                isthere[i] = clock();
                desx[i] = 0;
                desy[i] = 0;
                moving[i] = true;
            }
            if(moving[i] == true) {
                posxbuf[i] = posx[i]+(incx[i]*(current_time-isthere[i]));
                posybuf[i] = posy[i]+(incy[i]*(current_time-isthere[i]));
                if((current_time-isthere[i])>=timeneeded[i]) {
                    moving[i] = false;
                    cout << posxbuf[i] << ", " << posybuf[i] << endl;
                }
            }
        }
        Sleep(5);
    }
    return 0;
}
 
int main() {
    CreateThread(NULL,0,thread,NULL,0,0);
    posx[0] = 1000;
    posy[0] = 1000;
    desx[0] = 12000;
    desy[0] = 6000;
    speed[0] = 540;
    moving[0] = false;
    
    posx[1] = 5000;
    posy[1] = 6200;
    desx[1] = 4080;
    desy[1] = 7000;
    speed[1] = 320;
    moving[1] = false;

    
    while(true) {
        current_time = clock();
        Sleep(5);
    }
    cin.get();
return 0;
}
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