ASGE
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Rendering · Getting Started
Background Changer
About the smallest ASGE program
About as small as an ASGE program gets: one component holding an RGBA color, cleared to the screen every frame, randomized on a keypress.
A good first file to read before anything involving ECS or the asset pipeline.
Controls
- SPACE Randomize the background color
Run it yourself
build just this example
cmake --build --preset windows-debug --target background_changer
# binary lands under bin/ (e.g. bin/Debug/background_changer.exe on Windows)See Installation for the full build setup.
Source
examples/background_changer/Game.hpp
#pragma once
#include <ASGE/ASGE.hpp>
#include "Component.hpp"
class BackgroundChangingState final : public asge::game::state::IGameState<int>
{
BackgroundComponent m_BackgroundComponent{ BackgroundComponent::GetRandomColor() };
public:
[[nodiscard]] std::optional<asge::game::state::Transition<int>>
Update(float inDeltaTime, asge::input::InputState const& inInput) override;
void Render(asge::video::IRenderer& inRenderer) override;
void OnSystemEvent(asge::event::SystemEvent const& inSysEvent) override;
};
class BackgroundChangingGame final : public asge::game::Game<int>
{
public:
explicit BackgroundChangingGame(asge::video::IRenderer& inRenderer, asge::audio::AudioDevice& inAudioDev);
protected:
[[nodiscard]] std::unique_ptr<StateType> CreateState(int inId) override;
};
examples/background_changer/Game.cpp
#include "Game.hpp"
std::optional<asge::game::state::Transition<int>> BackgroundChangingState::Update(
[[maybe_unused]] float inDeltaTime, [[maybe_unused]] asge::input::InputState const& inInput)
{
return std::nullopt;
}
void BackgroundChangingState::Render(asge::video::IRenderer &inRenderer)
{
inRenderer.Clear(m_BackgroundComponent.GetColor());
}
void BackgroundChangingState::OnSystemEvent(asge::event::SystemEvent const &inSysEvent)
{
if ( auto const* keyEvent = inSysEvent.TryGet<asge::event::KeyboardEvent>() )
{
if ( keyEvent->s_Down && keyEvent->s_Keycode == asge::input::Keycode::SPACE )
{
m_BackgroundComponent.SetColor( BackgroundComponent::GetRandomColor() );
}
}
}
BackgroundChangingGame::BackgroundChangingGame(asge::video::IRenderer& inRenderer, asge::audio::AudioDevice& inAudioDev)
: Game(inRenderer, inAudioDev)
{
SetInitialState(0);
}
std::unique_ptr<BackgroundChangingGame::StateType>
BackgroundChangingGame::CreateState([[maybe_unused]] int inId)
{
return std::make_unique<BackgroundChangingState>();
}
examples/background_changer/Component.hpp
#pragma once
#include <random>
#include <ASGE/ASGE.hpp>
namespace asge_g = asge::graphics;
class BackgroundComponent
{
private:
using color_type = asge_g::RGBA_Color;
color_type m_Color;
public:
BackgroundComponent( color_type const& initColor )
: m_Color( initColor )
{}
color_type const& GetColor() const noexcept;
static color_type GetRandomColor() noexcept;
void SetColor( color_type const& inColor );
};