When i began my journey with SFML, i wanted to create something simple. I chose 2D car game. For this moment it's quite simple: press up to accelerate, left+up or right+up to go in the other directions(i also added some more functions but it doesn't matter right now). The problem is, whenever i press any key, a small delay occurs. It's very annoying, for example, i press up for accelerate. The car moves for 1 pixel, stays for a while and then runs smoothly. Then i press left too to rotate. The car moves to left for one pixel, stays for a while and then turns left until i release left key. I made a video to show this more clearly. Could anybody tell me what should i change in my code to make this issue go away?
https://www.youtube.com/watch?v=5VURSQyqJwA&feature=youtu.be <- the video
#include <SFML/Graphics.hpp>
#include <iostream>
#include <random>
#include <string>
#include <sstream>
// Converts an int into a string
static inline std::string int2Str(int x)
{
std::stringstream type;
type << x;
return type.str();
}
struct Car
{
sf::RectangleShape vehicleShape;
double carPositionX = 10;
double carPositionY = 10;
int carSizeX = 20;
int carSizeY = 10;
int carRotation = 0.;
int carVelocity = 1.;
};
int main()
{
srand(time(0)); // used for random background color
sf::RenderWindow window(sf::VideoMode(800, 600), "drive");
sf::Event event;
sf::Color color(sf::Color::Green);
Car skoda;
skoda.vehicleShape.setSize(sf::Vector2f(skoda.carSizeX,skoda.carSizeY)); //setting size of car
skoda.vehicleShape.setOrigin((skoda.carSizeX/2),(skoda.carSizeY/2)); //setting origin(center point) of the car
skoda.vehicleShape.setFillColor(sf::Color::Blue); //setting color of the car
sf::Font font;
if(!font.loadFromFile("ComicSans.ttf"))
{
skoda.vehicleShape.setFillColor(sf::Color::Black); //changes color of car when compilator can't find the font
}
sf::Text text; //displays car rotation
sf::Text debug; //currently changes color to red whether up is pressed or not, doesn't work
debug.setFont(font);
debug.setCharacterSize(50);
debug.setPosition(40,20);
debug.setFillColor(sf::Color::Yellow);
text.setFont(font);
text.setString(int2Str(skoda.carRotation));
text.setCharacterSize(10);
text.setFillColor(sf::Color::Red);
text.setStyle(sf::Text::Bold | sf::Text::Underlined);
while(window.isOpen())
{
skoda.vehicleShape.setPosition(sf::Vector2f(skoda.carPositionX,skoda.carPositionY)); // sets position of car
debug.setString("is up pressed"); //as mentioned, doesn't work
while(window.pollEvent(event))
{
if(event.type == sf::Event::Closed)
window.close();
if(event.type == sf::Event::KeyPressed)
{
if(sf::Keyboard::isKeyPressed(sf::Keyboard::Space)) //random background while pressing space
//it has the delay too
{
color.g = rand();
color.r = rand();
color.b = rand();
}
if(sf::Keyboard::isKeyPressed(sf::Keyboard::Up))
{
if(sf::Keyboard::isKeyPressed(sf::Keyboard::Left))
skoda.vehicleShape.setRotation(skoda.carRotation-=5);
if(sf::Keyboard::isKeyPressed(sf::Keyboard::Right))
skoda.vehicleShape.setRotation(skoda.carRotation+=5);
debug.setFillColor(sf::Color::Red);
/*it should only be red when up is pressed, but instead it stays red until i
press other key*/
if(skoda.carRotation>=0 && skoda.carRotation<=90)
{
skoda.carPositionX += ((90. - skoda.carRotation)/(90./skoda.carVelocity));
skoda.carPositionY += (skoda.carRotation/(90./skoda.carVelocity));
}
else if(skoda.carRotation>90 && skoda.carRotation<=180)
{
skoda.carPositionX -= ((skoda.carRotation-90)/(90./skoda.carVelocity));
skoda.carPositionY += ((90. - (skoda.carRotation-90))/(90./skoda.carVelocity));
}
else if(skoda.carRotation>180 && skoda.carRotation<=270)
{
skoda.carPositionX -= ((90. - (skoda.carRotation - 180))/(90./skoda.carVelocity));
skoda.carPositionY -= ((skoda.carRotation-180)/(90./skoda.carVelocity));
}
else if(skoda.carRotation>270 && skoda.carRotation<360)
{
skoda.carPositionX += ((skoda.carRotation-270)/(90./skoda.carVelocity));
skoda.carPositionY -= ((90. - (skoda.carRotation-270))/(90./skoda.carVelocity));
}
}
else
debug.setFillColor(sf::Color::Yellow);
if(sf::Keyboard::isKeyPressed(sf::Keyboard::Down))
{
if(sf::Keyboard::isKeyPressed(sf::Keyboard::Left))
skoda.vehicleShape.setRotation(skoda.carRotation-=5);
if(sf::Keyboard::isKeyPressed(sf::Keyboard::Right))
skoda.vehicleShape.setRotation(skoda.carRotation+=5);
if(skoda.carRotation>=0 && skoda.carRotation<=90)
{
skoda.carPositionX -= ((90. - skoda.carRotation)/(90./skoda.carVelocity));
skoda.carPositionY -= (skoda.carRotation/(90./skoda.carVelocity));
}
else if(skoda.carRotation>90 && skoda.carRotation<=180)
{
skoda.carPositionX += ((skoda.carRotation-90)/(90./skoda.carVelocity));
skoda.carPositionY -= ((90. - (skoda.carRotation-90))/(90./skoda.carVelocity));
}
else if(skoda.carRotation>180 && skoda.carRotation<=270)
{
skoda.carPositionX += ((90. - (skoda.carRotation - 180))/(90./skoda.carVelocity));
skoda.carPositionY += ((skoda.carRotation-180)/(90./skoda.carVelocity));
}
else if(skoda.carRotation>270 && skoda.carRotation<360)
{
skoda.carPositionX -= ((skoda.carRotation-270)/(90./skoda.carVelocity));
skoda.carPositionY += ((90. - (skoda.carRotation-270))/(90./skoda.carVelocity));
}
}
if(sf::Keyboard::isKeyPressed(sf::Keyboard::D)) //temporary mechanism to set velocity of the car
skoda.carVelocity += 1;
if(sf::Keyboard::isKeyPressed(sf::Keyboard::A))
skoda.carVelocity -= 1;
}
if(skoda.carRotation>=360) //making sure that the rotation value won't go beyond 360
skoda.carRotation = 0;
if(skoda.carRotation<0) //and under 0
skoda.carRotation = 359;
}
text.setString(int2Str(skoda.carRotation));
window.clear(color);
window.draw(skoda.vehicleShape);
window.draw(text);
window.draw(debug);
window.display();
}
}
