C++ make sprite appear every 3 seconds - c++

Question

I'm making a whack-a-mole game for class and i'm trying to make my mole1 sprite appear every 3 seconds but I can't figure out how to get it to work. Right now i Have the game to just run for 5 seconds, in the end it will be 60. Here is the main for the project. I need to change the mole1.visible to to true so he shows up. After I get this I will add the 5 other moles to each hole.
EDIT
For some reason I can't get chrono to compile but i figured out how to first make the mole appear but I can't ge thim to disappear after. I used modulo to make it false and I thought doig the opposite would make it disappear but it doesn't
if((60-now)%4==3){
mole1.visible=true;
mole1.paint_sprite(myscreen);
}
if ((60-now)%4!=3){
mole1.visible=false;
mole1.paint_sprite(myscreen);
}
Rest of code:
using namespace std; // allows us to avoid std::cout
#include <iostream> // standard C++ include
#include <curses.h> // this is required to use the Unix curses libraries
#include "screen.cpp" // screen class
#include "sprite2.cpp" // generic sprite class
#include "nonblocking.h" // facilitates non-blocking keyboard events
#include <unistd.h> // used by sleep
#include <time.h>
long start_time, now;
int i;
main() // main function
{
char c; // used to get character input from keyboard
screen myscreen; // screen data structure declaration
char aimage[80][24]={' '}; // fills in entire array with spaces
long start_time, now;
int i; // used for counters
int loop=0;
aimage[1][0]='_';
aimage[2][0]='_';
aimage[0][1]='(';
aimage[1][1]='_';
aimage[2][1]='(';
aimage[3][1]=')';
aimage[1][2]='|';
aimage[2][2]='|';
char bgimage[80][24]={' '}; // fills in entire array with spaces
bgimage[3][0]='"';
bgimage[4][0]='"';
bgimage[5][0]='"';
bgimage[2][0]='-';
bgimage[6][0]='-';
bgimage[1][0]='.';
bgimage[7][0]='.';
bgimage[0][1]='/';
bgimage[8][1]='\\';
bgimage[0][2]='|';
bgimage[8][2]='|';
bgimage[0][3]='\\';
bgimage[8][3]='/';
bgimage[1][4]='"';
bgimage[2][4]='-';
bgimage[3][4]='.';
bgimage[4][4]='.';
bgimage[5][4]='.';
bgimage[6][4]='-';
bgimage[7][4]='"';
char cimage[80][24]={' '}; // fills in entire array with spaces
cimage[1][0]='c';
cimage[2][0]='.';
cimage[3][0]='_';
cimage[4][1]='\'';
cimage[5][1]='-';
cimage[6][1]='.';
cimage[0][1]='C';
cimage[3][1]='o';
cimage[5][2]='\'';
cimage[4][2]='.';
cimage[3][2]='.';
cimage[2][3]='-';
cimage[1][3]='-';
cimage[0][2]='(';
char dimage[80][24]={' '}; // fills in entire array with spaces
dimage[0][0]='6';
dimage[1][0]='0';
sprite hammer(22,10,3,4,aimage,&myscreen);
sprite hole1(20,3,5,9,bgimage,&myscreen);
sprite hole2(40,3,5,9,bgimage,&myscreen);
sprite hole3(60,3,5,9,bgimage,&myscreen);
sprite hole4(20,15,5,9,bgimage,&myscreen);
sprite hole5(40,15,5,9,bgimage,&myscreen);
sprite hole6(60,15,5,9,bgimage,&myscreen);
sprite mole1(21,4,4,7,cimage,&myscreen);
sprite timer(5,10,1,2,dimage, &myscreen);
mole1.visible=false; // bullet should be false until the player shoots
hole1.paint_sprite(myscreen);
hole2.paint_sprite(myscreen);
hole3.paint_sprite(myscreen);
hole4.paint_sprite(myscreen);
hole5.paint_sprite(myscreen);
hole6.paint_sprite(myscreen);
hammer.paint_sprite(myscreen);
mole1.paint_sprite(myscreen);
timer.paint_sprite(myscreen);
myscreen.display(); // cause the screen to paint for the first time
start_time=(unsigned)time(NULL);
for(;;) // infinite loop
{
now = (unsigned)time(NULL)-start_time;
if((5-now)<=0) //ends game after 60 seconds
{
endwin(); // clean up curses (really never executed)
return(1);
}
loop++;
if (kbhit())
{
c=getchar(); // get one character from the keyboard
tcflush(0, TCIFLUSH); // system call to flush the keyboard buffer
if (c=='a') // if z, move ship left
{
hammer.move_sprite(-20,0,myscreen);
}
if (c=='d') // if a, move ship right
{
hammer.move_sprite(20,0,myscreen);
}
if (c=='s') // if z, move ship down
{
hammer.move_sprite(0,10,myscreen);
}
if (c=='w') // if z, move ship up
{
hammer.move_sprite(0,-10,myscreen);
}
}
myscreen.display(); // refresh the screen
}
endwin(); // clean up curses (really never executed)
return(1); // end program (also, never executed)
}

Answer 1

You can use global loop to calculate time difference and then set visible=true; after passing 3.0 seconds.
Like here:
#include <iostream>
#include <chrono>
#include <unistd.h>
const float TIME_TO_SHOW = 3.0f;
//Function to update all objects
void Update( float dt )
{
static float DeltaCounter = 0.0f;
DeltaCounter+= dt;
if ( DeltaCounter > TIME_TO_SHOW )
{
DeltaCounter -= TIME_TO_SHOW; //Keep overflow
//Set object visible here. For example your mole1.visible=true;
}
}
int main()
{
typedef std::chrono::duration<float> FloatSeconds;
auto OldMs = std::chrono::system_clock::now().time_since_epoch();
const uint32_t SleepMicroseconds = 100;
//Global loop
while (true)
{
auto CurMs = std::chrono::system_clock::now().time_since_epoch();
auto DeltaMs = CurMs - OldMs;
OldMs = CurMs;
//Cast delta time to float seconds
auto DeltaFloat = std::chrono::duration_cast<FloatSeconds>(DeltaMs);
std::cout << "Seconds passed since last update: " << DeltaFloat.count() << " seconds" << std::endl;
//Update all object by time as float value.
Update( DeltaFloat.count() );
// Sleep to give time for system interaction
usleep(SleepMicroseconds);
// Any other actions to calculate can be here
//...
}
return 0;
}
If you have constant behavior you can use simple loop with sleep function. It sleeps your process for given seconds:
const int32_t CountObjectToShow = 10;
const unsigned int TIME_TO_SHOW = 3;
for ( int32_t i = 0; i < CountObjectToShow; i++ )
{
sleep(TIME_TO_SHOW);
//Set object visible here. For example your mole1.visible=true;
std::cout << "Object showed" << std::endl;
}
Code with global loop is more flexible and allows to do many others useful things.

Answer 2

Well, in order to show something every certain amount of seconds you need to have a variable referencing the start time. Then, you check if the delta between the current time and the stored time is greater than a certain amount.
A good tool to make this for kind of task would be a clock class.
Clock.h
#ifndef CLOCK_H
#define CLOCK_H
#include <chrono>
template<typename Clock_t = std::chrono::steady_clock>
class Clock
{
public:
using TimePoint = decltype(Clock_t::now());
private:
TimePoint m_start;
public:
Clock() : m_start(Clock_t::now()) {
}
~Clock() {
}
void reset() {
m_start = Clock_t::now():
}
float getSeconds() const {
return std::chrono::duration_cast<std::chrono::duration<float>>(Clock_t::now() - m_start).count();
}
long long getMilliseconds() const {
return std::chrono::duration_cast<std::chrono::milliseconds>(ClockType::now() - m_start).count();
}
};
#endif
Example
#include <iostream>
#include "Clock.h"
int main() {
Clock<> clock;
constexpr long long spawnRate = 3000;
while (true) {
if (clock.getMilliseconds() >= spawnRate) {
std::cout << "SPAWN\n";
clock.reset();
}
}
}
Thus, for your case you would have a clock for the game, a clock for the mole spawner, etc.
During the game you would just simply check if the clock's current elapsed time is greater than a certain delta. If that is the case, do some other things.
Also, make sure to correctly reset the clocks, such as when you are resetting the mole spawn timer, and when starting the game.
This should handle the timing of things. If you have other problems, then you should ask about those.