Proper input system

1 files changed, 116 insertions, 0 deletions

diff --git a/src/Input.hpp b/src/Input.hpp
new file mode 100644
index 0000000..683ee55
--- /dev/null
+++ b/src/Input.hpp
@@ -0,0 +1,116 @@
+#pragma once
+
+#include "Time.hpp"
+#include "Common/Casts.hpp"
+#include "Common/Sizes.hpp"
+#include "Common/Pure.hpp"
+#include "GFX/Window.hpp"
+#include "Math/Vector.hpp"
+
+namespace MC {
+
+// TODO: Add some more keys.
+// TODO: I think some of these keys are "modifiers" under GLFW, and should be handled differently.
+enum class Key {
+    A, B, C, D, E, F, G, H, I, J, K, L, M,
+    N, O, P, Q, R, S, T, U, V, W, X, Y, Z,
+    Zero, One, Two, Three, Four, Five, Six, Seven, Eight, Nine,
+    Escape, Enter, Tab, Backspace, Insert, Delete, Right, Left, Down, Up,
+    LeftShift, RightShift, LeftControl, RightControl, LeftAlt, RightAlt,
+    Space, F1, F2, F3, F4, F5, F6, F7, F8, F9, F10, F11, F12,
+};
+
+constexpr USize KeyCount = 65;
+static_assert(KeyCount == TO(USize, Key::F12) + 1, "Key count mismatch.");
+
+enum class Mouse {
+    Left, Right, Middle,
+};
+
+constexpr USize MouseCount = 3;
+static_assert(MouseCount == TO(USize, Mouse::Middle) + 1, "Mouse count mismatch.");
+
+// The simple input system.
+// All methods are thread safe, except the initial registration of the input callbacks
+// and the state update. Both must be called from the main thread.
+class Input {
+public:
+    explicit Input() = default;
+
+    // Registers the input callbacks for the given window.
+    // This function must be called from the main thread.
+    static void register_callbacks(GFX::Window const& window);
+
+    // Updates the input state from the callback buffers.
+    // This function must be called from the main thread.
+    void update(Time::Timestamp current_time);
+
+    // Returns true if the key was pressed during the last frame.
+    PURE Bool pressed(Key key) const;
+    // Returns true if the mouse button was pressed during the last frame.
+    PURE Bool pressed(Mouse button) const;
+
+    // Returns true if the key is currently held down.
+    PURE Bool held(Key key) const;
+    // Returns true if the mouse button is currently held down.
+    PURE Bool held(Mouse button) const;
+
+    // Returns true if the key was released during the last frame.
+    PURE Bool released(Key key) const;
+    // Returns true if the mouse button was released during the last frame.
+    PURE Bool released(Mouse button) const;
+
+    // Returns true if the key was double pressed during the last frame.
+    // A double press is defined as two presses within a certain time frame.
+    PURE Bool double_pressed(Key key) const;
+    // Returns true if the mouse button was double pressed during the last frame.
+    // A double press is defined as two presses within a certain time frame.
+    PURE Bool double_pressed(Mouse button) const;
+
+    // Returns the position of the mouse cursor in the window.
+    PURE Vector<2> mouse_position() const;
+
+    // Returns the change in the position of the mouse cursor since the last frame.
+    PURE Vector<2> mouse_movement() const;
+
+private:
+    template <typename T>
+    struct ButtonMap {
+        T keys[KeyCount] = { 0 };
+        T mouse_buttons[MouseCount] = { 0 };
+    };
+
+    struct FrameState {
+        ButtonMap<Bool> map;
+        Vec2 mouse_position = { 0, 0 };
+    };
+
+    std::unique_ptr<FrameState> m_state = std::make_unique<FrameState>();
+    std::unique_ptr<FrameState> m_previous_state = std::make_unique<FrameState>();
+
+    std::unique_ptr<ButtonMap<Time::Timestamp>> m_last_key_release = std::make_unique<ButtonMap<Time::Timestamp>>();
+    std::unique_ptr<ButtonMap<Bool>> m_double_press = std::make_unique<ButtonMap<Bool>>();
+
+    static Bool key_pressed(std::unique_ptr<FrameState> const& current, std::unique_ptr<FrameState> const& previous, Key key);
+    static Bool mouse_button_pressed(std::unique_ptr<FrameState> const& current, std::unique_ptr<FrameState> const& previous, Mouse mouse);
+    static Bool key_released(std::unique_ptr<FrameState> const& current, std::unique_ptr<FrameState> const& previous, Key key);
+    static Bool mouse_button_released(std::unique_ptr<FrameState> const& current, std::unique_ptr<FrameState> const& previous, Mouse mouse);
+
+    static Bool s_key_buffer[KeyCount];
+    static Bool s_mouse_buffer[MouseCount];
+    static Vec2 s_mouse_position;
+    enum class MouseEventType { None, First, Subsequent };
+    static MouseEventType s_mouse_event_type;
+
+    static USize key_value(Key key);
+    static USize mouse_button_value(Mouse button);
+
+    static Key from_glfw_key(I32 key);
+    static Mouse from_glfw_mouse(I32 button);
+
+    static void key_callback(GLFWwindow* _window, I32 key, I32 _scancode, I32 action, I32 _mods);
+    static void cursor_position_callback(GLFWwindow* _window, F64 x, F64 y);
+    static void mouse_button_callback(GLFWwindow* _window, I32 button, I32 action, I32 _mods);
+};
+
+}