Hi.
I have a weird a problem - I can't get a smooth movement. Like from the first steps from tutorials - by multiplying velocity on GetFrameTime(), and then every possible variants - fixed timesteps, variable, fixed with interpolation - there is always some stuttering. Later variant though(implementation of deWitters game loop) works better than others - really smooth, but motion freezes for a frame or two every few seconds. It's actually barely noticeable with small sprites, but with view scrolling over tilemap (no matter vertexaray or big sprite) this is quiet observably.
I use Netbeans with gcc 4.6 on Ubuntu 12.04 and build of the latest SFML snapshot, and i had the same perfomance with 2.0rc and 1.6 versions. Recently i tried the same code on Windows with visual studio 2010 and had no problems with no vsync and some similiar drops(but fewer) with vsync on. So I think now, that it is actually my system/hardware perfomance problem rather than something wrong with my code, but I want to be sure. I tried some opengl benchmarks on ubuntu and they worked slick, is there any common SFML test ? And it may be helpfull if someone could run my code and tell how it performs. Also I open to any suggestion which helps to improve this situation. Thanks.
Here is the code:
#include <SFML/Window.hpp>
#include <SFML/Graphics.hpp>
#include <math.h>
struct Focus{
sf::RectangleShape drawable;
sf::Vector2f velocity;
sf::Vector2f coord;
sf::Vector2f previous_coord;
};
#define VELOCITY 250.f
int main(int argc, char** argv) {
sf::RenderWindow window;
sf::View view;
sf::Texture texture;
sf::Sprite tiles;
sf::Clock timer;
window.create(sf::VideoMode(800,600,32),"Test Scrolling",sf::Style::Default);
//window.setFramerateLimit(60);
//window.setVerticalSyncEnabled(true);
Focus focus;
focus.velocity = sf::Vector2f(0.f, 0.f);
focus.coord = sf::Vector2f(0.f, 0.f);
focus.drawable.setSize(sf::Vector2f(32,32));
focus.drawable.setFillColor(sf::Color(255,100,100));
view.setCenter(0.f, 0.f);
view.setSize(800,600);
texture.loadFromFile("8OtUK.png");
tiles.setTexture(texture);
const float TIMESTEP = 0.04f;
const int MAX_FRAMESKIP = 5;
float nexttick = 0;
bool running = true;
while(running){
int frameskips = 0;
while(timer.getElapsedTime().asSeconds() > nexttick && frameskips < MAX_FRAMESKIP){
sf::Event event;
while (window.pollEvent(event)){
if (event.type == sf::Event::Closed)
running = false;
if(event.type == sf::Event::KeyPressed)
switch(event.key.code){
case sf::Keyboard::Up :
focus.velocity.y = -VELOCITY;
break;
case sf::Keyboard::Down :
focus.velocity.y = VELOCITY;
break;
case sf::Keyboard::Left :
focus.velocity.x = -VELOCITY;
break;
case sf::Keyboard::Right :
focus.velocity.x = VELOCITY;
break;
}
}
sf::Time frametime = timer.getElapsedTime();
//Update coordinates
focus.previous_coord = focus.coord;
focus.coord += focus.velocity * TIMESTEP;
//
frameskips++;
nexttick += TIMESTEP;
}
sf::Time startdraw = timer.getElapsedTime();
float interpolation = (timer.getElapsedTime().asSeconds() + TIMESTEP - nexttick) / TIMESTEP;
//Draw
window.clear(sf::Color(0,0,0));
sf::Vector2f draw_coord = focus.previous_coord + ((focus.coord - focus.previous_coord) * interpolation);
focus.drawable.setPosition(floor(draw_coord.x + 0.5f), floor(draw_coord.y + 0.5f));
view.setCenter(focus.drawable.getPosition());
window.setView(view);
window.draw(tiles);
window.draw(focus.drawable);
window.display();
//
sf::Time frametime = timer.getElapsedTime() - startdraw;
if(timer.getElapsedTime().asSeconds() > 2){
nexttick = 0;
timer.restart();
}
//sf::sleep(sf::microseconds(16666) - frametime);
}
window.close();
return 0;
}
link to image -
http://i.imgur.com/8OtUK.png(There are commented lines - options which I tried(independently of each other), but it seems now that there is less stuttering without them)
Also my specs: Core2DuoE7400 @ 2.80GHz × 2, GeForce9600Gt, 2Gb Ram DDR2, on ubuntu latest beta drivers (310), also tried on current recommended version and (173),on Windows Xp - latest nvidia driver.
Also to note, I run this code in release mode, without output anything to console, and I tried to increase process priority on both systems, without visible success.
