A cross platform pre-configured C++ game development setup. It uses Meson to build a bouncing game using SFML, ImGUI, and Box2d in the smallest C++ example possible.
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#include "imgui.h"
#include "imgui-SFML.h"
#define _USE_MATH_DEFINES
#include <math.h>
#include <fmt/core.h>
#include <box2d/box2d.h>
#include <SFML/Graphics/Sprite.hpp>
#include <SFML/Graphics/Texture.hpp>
#include <SFML/Graphics/RenderWindow.hpp>
#include <SFML/System.hpp>
#include <SFML/Audio.hpp>
#include <SFML/Window/Event.hpp>
void ImGui_setup(sf::RenderWindow &window) {
int res = ImGui::SFML::Init(window);
if(res == 1) {
fmt::print("ImGui returned result {}\n", res);
} else {
fmt::print("ImGui returned an error code={}\n", res);
}
}
void ImGui_update(sf::RenderWindow &window, sf::Clock &deltaClock, sf::Time &tick) {
ImGui::SFML::Update(window, deltaClock.restart());
// ImGui::ShowDemoWindow();
ImGui::Begin("Clock");
sf::Vector2u size = window.getSize();
ImGui::SetWindowPos(ImVec2(size.x - 150, 0));
ImGui::SetWindowSize(ImVec2(150, 50));
std::string msg = fmt::format("Time: {}\n", tick.asSeconds());
ImGui::Button(msg.c_str());
ImGui::End();
}
void Window_update(sf::RenderWindow &window, sf::Sprite &player) {
window.clear();
window.draw(player);
ImGui::SFML::Render(window);
window.display();
}
struct BoxTest {
b2Body *groundBody;
b2Body *body;
};
struct BoxTest Box2d_setup(b2World &world) {
b2BodyDef groundBodyDef;
groundBodyDef.position.Set(0.0f, -10.0f);
b2Body *groundBody = world.CreateBody(&groundBodyDef);
b2PolygonShape groundBox;
groundBox.SetAsBox(50.0f, 10.0f);
groundBody->CreateFixture(&groundBox, 0.0f);
b2BodyDef bodyDef;
bodyDef.type = b2_dynamicBody;
bodyDef.position.Set(3.0f, 4.0f);
b2Body *body = world.CreateBody(&bodyDef);
b2PolygonShape dynamicBox;
dynamicBox.SetAsBox(1.0f, 1.0f);
b2FixtureDef fixtureDef;
fixtureDef.shape = &dynamicBox;
fixtureDef.density = 1.0f;
fixtureDef.friction = 0.3f;
body->CreateFixture(&fixtureDef);
BoxTest box {groundBody, body};
return box;
}
void Handle_events(sf::RenderWindow &window, BoxTest &box, sf::Sound &click) {
sf::Event event;
// is this a main event loop
while (window.pollEvent(event)) {
ImGui::SFML::ProcessEvent(window, event);
switch(event.type) {
case sf::Event::Closed:
fmt::print("Exiting...\n");
window.close();
break;
case sf::Event::KeyPressed:
if(sf::Keyboard::isKeyPressed(sf::Keyboard::Left)) {
b2Vec2 force(-200, 1000);
box.body->ApplyForceToCenter(force, true);
box.body->ApplyTorque(100.0f, true);
click.play();
} else if(sf::Keyboard::isKeyPressed(sf::Keyboard::Right)) {
b2Vec2 force(200, 1000);
box.body->ApplyForceToCenter(force, true);
box.body->ApplyTorque(-100.0f, true);
click.play();
}
break;
case sf::Event::MouseButtonPressed:
if(sf::Mouse::isButtonPressed(sf::Mouse::Left)) {
b2Vec2 force(-200, 1000);
box.body->ApplyForceToCenter(force, true);
box.body->ApplyTorque(100.0f, true);
click.play();
} else if (sf::Mouse::isButtonPressed(sf::Mouse::Right)) {
b2Vec2 force(200, 1000);
box.body->ApplyForceToCenter(force, true);
box.body->ApplyTorque(-100.0f, true);
click.play();
}
break;
}
}
}
sf::Time Update_entities(sf::RenderWindow &window, b2World &world, sf::Clock &clock, sf::Clock &deltaClock, sf::Time &tick, BoxTest &box, sf::Sprite &player) {
sf::Vector2u winSize = window.getSize();
float timeStep = 1.0f / 60.0f;
int velocityIterations = 6;
int positionIterations = 2;
sf::Time since = clock.getElapsedTime();
sf::Time nextTick = since - tick > sf::seconds(1) ? since : tick;
world.Step(timeStep, velocityIterations, positionIterations);
b2Vec2 position = box.body->GetPosition();
float angle = box.body->GetAngle();
player.setPosition(position.x * 100.0f, winSize.y - position.y * 100.0f);
player.setRotation(angle * 180.0f / M_PI);
ImGui_update(window, deltaClock, tick);
Window_update(window, player);
return nextTick;
}
void Create_player(sf::RenderWindow &window, sf::Sprite &player, sf::Texture &texture) {
if(!texture.loadFromFile("sprite.png")) {
fmt::print("Error loading sprite!");
}
texture.setSmooth(true);
player.setTexture(texture);
// position the prite
sf::Vector2u winSize = window.getSize();
player.setPosition(winSize.x / 2, winSize.y / 2);
player.setOrigin(50.f, 50.f);
}
int main() {
fmt::print("Setting up a window for you...\n");
sf::ContextSettings settings;
settings.antialiasingLevel = 8;
sf::RenderWindow window(sf::VideoMode(1920, 1080), "Simple Game Demo", sf::Style::Default, settings);
window.setFramerateLimit(60);
window.setVerticalSyncEnabled(true);
ImGui_setup(window);
sf::SoundBuffer buffer;
if(!buffer.loadFromFile("click.mp3")) {
fmt::print("Failed to load click.ogg!\n");
}
sf::Sound click;
click.setBuffer(buffer);
sf::Clock deltaClock;
sf::Clock clock;
sf::Time tick = clock.getElapsedTime();
sf::Sprite player;
sf::Texture texture;
Create_player(window, player, texture);
b2Vec2 gravity(0.0f, -10.0f);
b2World world(gravity);
BoxTest box = Box2d_setup(world);
while (window.isOpen()) {
Handle_events(window, box, click);
// preparing for refactoring this into a class or struct for everything
tick = Update_entities(window, world, clock, deltaClock, tick, box, player);
}
ImGui::SFML::Shutdown();
}