This is a simple game I'm writing to test the idea of using games to teach C++. https://learncodethehardway.com/
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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/CircleShape.hpp>
#include <SFML/Graphics/RenderWindow.hpp>
#include <SFML/System.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::Shape &shape) {
window.clear();
window.draw(shape);
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;
}
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::CircleShape shape(50.f, 4);
sf::Vector2u winSize = window.getSize();
shape.setPosition(winSize.x / 2, winSize.y / 2);
shape.setOrigin(50.f, 50.f);
shape.setFillColor(sf::Color(150, 50, 250));
shape.setOutlineThickness(10.f);
shape.setOutlineColor(sf::Color(250, 150, 100));
sf::Clock deltaClock;
sf::Clock clock;
sf::Time tick = clock.getElapsedTime();
// very cool, c++11 lambdas doing a 1 second slept thread
sf::Thread thread([](){
for(int i = 0; i < 10; i++) {
fmt::print("I'm a thread. {}\n", i);
sf::sleep(sf::seconds(1));
}
});
thread.launch();
b2Vec2 gravity(0.0f, -10.0f);
b2World world(gravity);
BoxTest box = Box2d_setup(world);
float timeStep = 1.0f / 60.0f;
int velocityIterations = 6;
int positionIterations = 2;
while (window.isOpen()) {
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();
thread.terminate();
break;
case sf::Event::KeyPressed:
if(sf::Keyboard::isKeyPressed(sf::Keyboard::Left)) {
b2Vec2 force(-200, 1000);
box.body->ApplyForceToCenter(force, true);
} else if(sf::Keyboard::isKeyPressed(sf::Keyboard::Right)) {
b2Vec2 force(200, 1000);
box.body->ApplyForceToCenter(force, true);
}
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);
} else if (sf::Mouse::isButtonPressed(sf::Mouse::Right)) {
b2Vec2 force(200, 1000);
box.body->ApplyForceToCenter(force, true);
box.body->ApplyTorque(-100.0f, true);
}
break;
}
}
// should this move up to the pollEvent loop?
sf::Time since = clock.getElapsedTime();
if(since - tick > sf::seconds(1)) {
tick = since;
}
world.Step(timeStep, velocityIterations, positionIterations);
b2Vec2 position = box.body->GetPosition();
float angle = box.body->GetAngle();
shape.setPosition(position.x * 100.0f, winSize.y - position.y * 100.0f);
shape.setRotation(angle * 180.0f / M_PI);
ImGui_update(window, deltaClock, tick);
Window_update(window, shape);
}
ImGui::SFML::Shutdown();
}