example_rectangle.cpp

This example shows a very basic application that renders a lime green rectangle at a fixed size in the middle of a resizable window.

 
#include <donut/aliases.hpp>
#include <donut/donut.hpp>
 
namespace {
 
class RectangleApplication final : public app::Application {
public:
    RectangleApplication() {
        resize();
    }
 
protected:
    void update(app::FrameInfo /*frameInfo*/) override {
        for (const events::Event& event : eventPump.pollEvents()) {
            if (event.is<events::ApplicationQuitRequestedEvent>()) {
                quit();
            } else if (event.is<events::WindowSizeChangedEvent>()) {
                resize();
            }
        }
    }
 
    void display(app::TickInfo /*tickInfo*/, app::FrameInfo /*frameInfo*/) override {
        constexpr vec2 RECTANGLE_SIZE{100.0f, 60.0f};
 
        gfx::Framebuffer& framebuffer = window.getFramebuffer();
 
        renderer.clearFramebufferColor(framebuffer, Color::BLACK);
 
        gfx::RenderPass renderPass{};
        renderPass.draw(gfx::RectangleInstance{
            .position = vec2{viewport.size / 2} - RECTANGLE_SIZE * 0.5f,
            .size = RECTANGLE_SIZE,
            .tintColor = Color::LIME,
        });
 
        renderer.render(framebuffer, renderPass, viewport, camera);
 
        window.present();
    }
 
private:
    void resize() {
        const ivec2 size = window.getDrawableSize();
        viewport = {.position{0, 0}, .size = size};
        camera = gfx::Camera::createOrthographic({.offset{0.0f, 0.0f}, .size = size});
    }
 
    events::EventPump eventPump{};
    gfx::Window window{{.title = "Rectangle"}};
    gfx::Viewport viewport{};
    gfx::Camera camera{};
    gfx::Renderer renderer{};
};
 
} // namespace
 
int main() {
    RectangleApplication application{};
    application.run();
}