Update to most recent version (old initial commit)

12 files changed, 1032 insertions, 0 deletions

diff --git a/src/client/window/basic_window.cc b/src/client/window/basic_window.cc
new file mode 100644
index 0000000..c96f94a
--- /dev/null
+++ b/src/client/window/basic_window.cc
@@ -0,0 +1,33 @@
+#include "client/window/basic_window.hh"
+
+namespace client {
+namespace window {
+
+using bw = basic_window;
+
+bool bw::is_inside(const glm::vec2& v, const glm::vec2& p,
+                   const glm::vec2& s) noexcept {
+    if (v.x < p.x || v.x > p.x + s.x) {
+        return false;
+    }
+    if (v.y < p.y || v.y > p.y + s.y) {
+        return false;
+    }
+    return true;
+}
+
+bool bw::is_inside(const glm::vec2& v) const noexcept {
+    return is_inside(v, this->pos, this->size);
+}
+
+void bw::draw() noexcept {
+    client::render::draw_rectangle({.pos = {.offset = this->pos + 6.0f},
+                                    .size = {.offset = this->size},
+                                    .colour = {this->tertiary_clr, 0.9f}});
+    client::render::draw_rectangle({.pos = {.offset = this->pos},
+                                    .size = {.offset = this->size},
+                                    .colour = {this->primary_clr, 1.0f}});
+}
+
+} // namespace window
+} // namespace client
diff --git a/src/client/window/basic_window.hh b/src/client/window/basic_window.hh
new file mode 100644
index 0000000..292cc64
--- /dev/null
+++ b/src/client/window/basic_window.hh
@@ -0,0 +1,52 @@
+#ifndef CLIENT_WINDOW_BASIC_WINDOW_HH_
+#define CLIENT_WINDOW_BASIC_WINDOW_HH_
+
+#include <glm/glm.hpp>
+
+#include "client/entity/player.hh"
+#include "client/render/render.hh"
+#include "client/render/struct.hh"
+
+namespace client {
+namespace window {
+
+// All window objects should derive from basic_window, and make use of multiple
+// inheritance for specific behaviours.
+class basic_window {
+protected:
+    // Colours borrowed from arc-dark(er).
+    static constexpr glm::vec3 primary_clr{0.21f, 0.23f, 0.29f};   // dark
+    static constexpr glm::vec3 secondary_clr{0.29f, 0.32f, 0.38f}; // less dark
+    static constexpr glm::vec3 tertiary_clr{0.48, 0.50, 0.54};  // less dark ^2
+    static constexpr glm::vec3 highlight_clr{0.32, 0.58, 0.88}; // light blue
+    static constexpr glm::vec3 font_colour{0.88, 0.88, 0.88};   // light grey
+
+protected:
+    static constexpr float OUTLINE_WIDTH = 2.0f;
+    float get_item_size() const noexcept { return this->size.x / 10.0f; }
+
+protected:
+    glm::vec2 pos;
+    glm::vec2 size;
+
+public:
+    // Test if a vec2 v is inside a square starting at position p with size s.
+    static bool is_inside(const glm::vec2& v, const glm::vec2& p,
+                          const glm::vec2& s) noexcept;
+    // Test if v is inside this->pos, this->size
+    bool is_inside(const glm::vec2& v) const noexcept;
+
+public:
+    basic_window(const client::render::relative_arg& pos,
+                 const client::render::relative_arg& size) noexcept
+        : pos(pos.to_vec2()), size(size.to_vec2()) {}
+    virtual ~basic_window() noexcept {}
+
+    virtual bool maybe_handle_event(const SDL_Event&) noexcept { return false; }
+    virtual void draw() noexcept;
+};
+
+} // namespace window
+} // namespace client
+
+#endif
diff --git a/src/client/window/button_window.cc b/src/client/window/button_window.cc
new file mode 100644
index 0000000..4743c0a
--- /dev/null
+++ b/src/client/window/button_window.cc
@@ -0,0 +1,71 @@
+#include "client/window/button_window.hh"
+
+namespace client {
+namespace window {
+
+using bw = class button_window;
+
+void bw::handle_mousebuttondown(const SDL_Event& event) noexcept {
+    if (event.button.button != SDL_BUTTON_LEFT) {
+        return;
+    }
+    this->is_pressed = true;
+}
+
+void bw::handle_mousebuttonup(const SDL_Event& event) noexcept {
+    if (event.button.button != SDL_BUTTON_LEFT) {
+        return;
+    }
+    if (!this->is_pressed) {
+        return;
+    }
+    this->is_pressed = false;
+    std::invoke(this->callback); // edge
+}
+
+const glm::vec3& bw::get_draw_colour() noexcept {
+    if (!this->is_inside(client::input::state.mouse_pos)) {
+        this->is_pressed = false;
+        return this->primary_clr;
+    }
+
+    if (!this->is_pressed) {
+        return this->secondary_clr;
+    }
+
+    return this->highlight_clr;
+}
+
+bool bw::maybe_handle_event(const SDL_Event& event) noexcept {
+    if (this->is_inside(client::input::state.mouse_pos)) {
+        switch (event.type) {
+        case SDL_MOUSEBUTTONDOWN:
+            this->handle_mousebuttondown(event);
+            return true;
+        case SDL_MOUSEBUTTONUP:
+            this->handle_mousebuttonup(event);
+            return true;
+        }
+    }
+
+    return basic_window::maybe_handle_event(event);
+}
+
+void bw::draw() noexcept {
+    basic_window::draw();
+
+    client::render::draw_rectangle({.pos = {.offset = this->pos},
+                                    .size = {.offset = this->size},
+                                    .colour = {this->get_draw_colour(), 1.0f}});
+    client::render::draw_text(
+        this->name, {.pos = {.extent = {0.0f, 0.0f},
+                             .offset = this->pos + (this->size / 2.0f)},
+                     .offset_height = this->size.y / 2.0f,
+                     .colour = {this->font_colour, 1.0f},
+                     .has_backing = false,
+                     .is_centered = true,
+                     .is_vcentered = true});
+};
+
+} // namespace window
+} // namespace client
diff --git a/src/client/window/button_window.hh b/src/client/window/button_window.hh
new file mode 100644
index 0000000..6847696
--- /dev/null
+++ b/src/client/window/button_window.hh
@@ -0,0 +1,40 @@
+#ifndef CLIENT_WINDOW_BUTTON_WINDOW_HH_
+#define CLIENT_WINDOW_BUTTON_WINDOW_HH_
+
+#include <functional>
+#include <string>
+
+#include "client/input.hh"
+#include "client/render/render.hh"
+#include "client/window/basic_window.hh"
+
+namespace client {
+namespace window {
+
+class button_window : public basic_window {
+protected:
+    std::string name;
+    std::function<void()> callback;
+    bool is_pressed;
+
+private:
+    void handle_mousebuttondown(const SDL_Event& event) noexcept;
+    void handle_mousebuttonup(const SDL_Event& event) noexcept;
+    const glm::vec3& get_draw_colour() noexcept;
+
+public:
+    template <typename... Args>
+    button_window(const std::string_view n, const decltype(callback)& c,
+                  Args&&... args) noexcept
+        : basic_window(std::forward<Args>(args)...), name(n), callback(c),
+          is_pressed(false) {}
+    virtual ~button_window() noexcept {}
+
+    virtual bool maybe_handle_event(const SDL_Event& event) noexcept override;
+    virtual void draw() noexcept override;
+};
+
+} // namespace window
+} // namespace client
+
+#endif
diff --git a/src/client/window/hud_window.cc b/src/client/window/hud_window.cc
new file mode 100644
index 0000000..52995ca
--- /dev/null
+++ b/src/client/window/hud_window.cc
@@ -0,0 +1,88 @@
+#include "client/window/hud_window.hh"
+
+namespace client {
+namespace window {
+
+using hw = class hud_window;
+bool hw::maybe_handle_keydown(const SDL_Event& event) noexcept {
+    const auto& sym = event.key.keysym.sym;
+    const auto index = static_cast<int>(sym);
+
+    const auto min = static_cast<int>(SDLK_0);
+    const auto max = static_cast<int>(SDLK_9);
+    if (index < min || index > max) {
+        return false;
+    }
+
+    const auto active =
+        static_cast<std::uint32_t>((((sym - min) - 1) + 10) % 10);
+    client::get_localplayer().get_mutable_active_item() = active;
+    return true;
+}
+
+bool hw::maybe_handle_event(const SDL_Event& event) noexcept {
+    if (is_open()) {
+        return false;
+    }
+
+    switch (event.type) {
+    case SDL_KEYDOWN:
+        return this->maybe_handle_keydown(event);
+    default:
+        break;
+    }
+    return false;
+}
+
+void hw::draw() noexcept {
+    this->basic_window::draw();
+
+    const float item_size = this->get_item_size();
+
+    const auto& localplayer = client::get_localplayer();
+    client::render::draw_rectangle(
+        {.pos = {.offset = {this->pos.x + static_cast<float>(
+                                              localplayer.get_active_item()) *
+                                              item_size,
+                            this->pos.y}},
+         .size = {.offset = {item_size, item_size}},
+         .colour = {this->secondary_clr, 1.0f}});
+
+    for (int i = 1; i < shared::player::INVENTORY_COLS; ++i) {
+        const float off = item_size * static_cast<float>(i);
+        client::render::draw_rectangle(
+            {.pos = {.offset = {this->pos.x + off,
+                                this->pos.y + OUTLINE_WIDTH}},
+             .size = {.offset = {OUTLINE_WIDTH,
+                                 item_size - 2.0f * OUTLINE_WIDTH}},
+             .colour = {this->tertiary_clr, 1.0f}});
+    }
+
+    const auto& inventory = localplayer.inventory;
+    for (int x = 0; x < shared::player::INVENTORY_COLS; ++x) {
+        const auto& item = inventory.contents[static_cast<unsigned long>(x)];
+        if (item == nullptr) {
+            continue;
+        }
+
+        const glm::vec2 off{glm::vec2{x, 0} * item_size};
+        const auto item_ptr = dynamic_cast<client::item::item*>(&*item);
+        if (item_ptr == nullptr) {
+            continue;
+        }
+        item_ptr->draw(this->pos + off, glm::vec2{item_size, item_size});
+
+        client::render::draw_text(
+            std::to_string(item->quantity),
+            {.pos = {.offset = this->pos + off +
+                               glm::vec2{item_size * 0.75f, item_size * 0.2f}},
+             .offset_height = item_size * 0.40f,
+             .colour = {this->font_colour, 1.0f},
+             .has_backing = false,
+             .is_centered = true,
+             .is_vcentered = true});
+    }
+}
+
+} // namespace window
+} // namespace client
diff --git a/src/client/window/hud_window.hh b/src/client/window/hud_window.hh
new file mode 100644
index 0000000..7c03e0e
--- /dev/null
+++ b/src/client/window/hud_window.hh
@@ -0,0 +1,32 @@
+#ifndef CLIENT_WINDOW_HUD_WINDOW_HH_
+#define CLIENT_WINDOW_HUD_WINDOW_HH_
+
+#include "client/render/struct.hh"
+#include "client/window/basic_window.hh"
+#include "client/window/window.hh"
+#include "shared/entity/player.hh"
+
+namespace client {
+namespace window {
+
+class hud_window : public basic_window {
+
+private:
+    bool maybe_handle_keydown(const SDL_Event& event) noexcept;
+
+public:
+    template <typename... Args>
+    hud_window(const float size) noexcept
+        : basic_window(
+              client::render::relative_arg{.extent = {0.5f, 0.0f},
+                                           .offset = {-size / 2.0f, 0.0f}},
+              client::render::relative_arg{.offset = {size, size / 10.0f}}) {}
+
+    virtual void draw() noexcept override;
+    virtual bool maybe_handle_event(const SDL_Event& event) noexcept override;
+};
+
+} // namespace window
+} // namespace client
+
+#endif
diff --git a/src/client/window/inventory_window.cc b/src/client/window/inventory_window.cc
new file mode 100644
index 0000000..5023f1d
--- /dev/null
+++ b/src/client/window/inventory_window.cc
@@ -0,0 +1,196 @@
+#include "client/window/inventory_window.hh"
+
+namespace client {
+namespace window {
+
+using iw = class inventory_window;
+
+bool iw::maybe_handle_mousebuttondown(const SDL_Event& event) noexcept {
+
+    if (event.button.button != SDL_BUTTON_LEFT) {
+        return false;
+    }
+    if (!this->is_inside(client::input::state.mouse_pos)) {
+        return false;
+    }
+
+    const auto index =
+        this->maybe_get_inventory_index(client::input::state.mouse_pos);
+    if (!index.has_value()) {
+        return false;
+    }
+
+    const auto& inventory = client::get_localplayer().inventory;
+    if (inventory.contents[*index] != nullptr) {
+        this->grabbed.emplace(*index);
+    }
+    return true;
+}
+
+static proto::packet make_swap_packet(const std::uint32_t& a,
+                                      const std::uint32_t& b) noexcept {
+    proto::packet ret;
+    const auto packet = ret.mutable_item_swap_packet();
+    packet->set_index_a(a);
+    packet->set_index_b(b);
+    return ret;
+}
+
+bool iw::maybe_handle_mousebuttonup(const SDL_Event& event) noexcept {
+
+    if (event.button.button != SDL_BUTTON_LEFT) {
+        return false;
+    }
+    if (!this->grabbed.has_value()) {
+        return false;
+    }
+
+    if (const auto index =
+            this->maybe_get_inventory_index(input::state.mouse_pos);
+        index.has_value() && index != *grabbed) {
+
+        auto& inventory = client::get_localplayer().inventory;
+        std::swap(inventory.contents[*grabbed], inventory.contents[*index]);
+
+        // replicate on server
+        state::connection->rsend_packet(
+            make_swap_packet(static_cast<std::uint32_t>(*grabbed),
+                             static_cast<std::uint32_t>(*index)));
+    }
+
+    this->grabbed.reset();
+    return true;
+}
+
+std::optional<unsigned long>
+iw::maybe_get_inventory_index(const glm::vec2& pos) const noexcept {
+
+    const float item_size = this->get_item_size();
+    for (int x = 0; x < shared::player::INVENTORY_COLS; ++x) {
+        for (int y = 0; y < shared::player::INVENTORY_ROWS; ++y) {
+            const glm::vec2 off{this->pos +
+                                glm::vec2{OUTLINE_WIDTH, OUTLINE_WIDTH} +
+                                glm::vec2{x, y} * item_size};
+            if (!basic_window::is_inside(pos, off,
+                                         glm::vec2{item_size, item_size})) {
+                continue;
+            }
+            return x + y * shared::player::INVENTORY_COLS;
+        }
+    }
+    return std::nullopt;
+}
+
+bool iw::maybe_handle_event(const SDL_Event& event) noexcept {
+    switch (event.type) {
+    case SDL_MOUSEBUTTONDOWN:
+        return this->maybe_handle_mousebuttondown(event);
+    case SDL_MOUSEBUTTONUP:
+        return this->maybe_handle_mousebuttonup(event);
+    }
+
+    return basic_window::maybe_handle_event(event);
+}
+
+void iw::draw() noexcept {
+    basic_window::draw();
+
+    const float item_size = this->get_item_size();
+
+    const auto& localplayer = client::get_localplayer();
+    client::render::draw_rectangle(
+        {.pos = {.offset = {this->pos.x + static_cast<float>(
+                                              localplayer.get_active_item()) *
+                                              item_size,
+                            this->pos.y}},
+         .size = {.offset = {item_size, item_size}},
+         .colour = {this->secondary_clr, 1.0f}});
+    for (int i = 1; i < shared::player::INVENTORY_COLS; ++i) {
+        const float off = item_size * static_cast<float>(i);
+        client::render::draw_rectangle(
+            {.pos = {.offset = {this->pos.x + off,
+                                this->pos.y + OUTLINE_WIDTH}},
+             .size = {.offset = {OUTLINE_WIDTH,
+                                 item_size * shared::player::INVENTORY_ROWS -
+                                     OUTLINE_WIDTH}},
+             .colour = {this->tertiary_clr, 1.0f}});
+
+        if (i <= shared::player::INVENTORY_ROWS) {
+            client::render::draw_rectangle(
+                {.pos = {.offset = {pos.x + OUTLINE_WIDTH, pos.y + off}},
+                 .size = {.offset = {this->size.x - 2.0f * OUTLINE_WIDTH,
+                                     OUTLINE_WIDTH}},
+                 .colour = {this->tertiary_clr, 1.0f}});
+        }
+    }
+
+    const auto& inventory = localplayer.inventory;
+    if (const auto index =
+            this->maybe_get_inventory_index(client::input::state.mouse_pos);
+        index.has_value()) {
+        const glm::vec2 off{glm::vec2{*index % shared::player::INVENTORY_COLS,
+                                      *index / shared::player::INVENTORY_COLS} *
+                            item_size};
+        client::render::draw_rectangle(
+            {.pos = {.offset = this->pos + off +
+                               glm::vec2{OUTLINE_WIDTH, OUTLINE_WIDTH}},
+             .size = {.offset = glm::vec2{item_size, item_size} -
+                                glm::vec2{OUTLINE_WIDTH, OUTLINE_WIDTH}},
+             .colour = {this->secondary_clr, 1.0f}});
+    }
+
+    for (int x = 0; x < shared::player::INVENTORY_COLS; ++x) {
+        for (int y = 0; y < shared::player::INVENTORY_ROWS; ++y) {
+            const auto index = static_cast<unsigned long>(
+                x + y * shared::player::INVENTORY_COLS);
+            const auto& item = inventory.contents[index];
+            if (item == nullptr) {
+                continue;
+            }
+            if (this->grabbed.has_value() && *this->grabbed == index) {
+                continue;
+            }
+
+            const glm::vec2 off{glm::vec2{x, y} * item_size};
+            const auto item_ptr = dynamic_cast<client::item::item*>(&*item);
+            if (item_ptr == nullptr) {
+                continue;
+            }
+            item_ptr->draw(this->pos + off, glm::vec2{item_size, item_size});
+
+            client::render::draw_text(
+                std::to_string(item->quantity),
+                {.pos = {.offset =
+                             this->pos + off +
+                             glm::vec2{item_size * 0.75f, item_size * 0.2f}},
+                 .offset_height = item_size * 0.40f,
+                 .colour = {this->font_colour, 1.0f},
+                 .has_backing = false,
+                 .is_centered = true,
+                 .is_vcentered = true});
+        }
+    }
+
+    if (this->grabbed.has_value()) {
+        const auto item_ptr =
+            dynamic_cast<client::item::item*>(&*inventory.contents[*grabbed]);
+        if (item_ptr != nullptr) {
+            item_ptr->draw(client::input::state.mouse_pos -
+                               glm::vec2{item_size, item_size} * 0.5f,
+                           glm::vec2{item_size, item_size});
+            client::render::draw_text(
+                std::to_string(item_ptr->quantity),
+                {.pos = {.offset =
+                             client::input::state.mouse_pos +
+                             glm::vec2{item_size * 0.25f, item_size * -0.3f}},
+                 .offset_height = item_size * 0.40f,
+                 .colour = {this->font_colour, 1.0f},
+                 .has_backing = false,
+                 .is_centered = true,
+                 .is_vcentered = true});
+        }
+    }
+}
+
+} // namespace window
+} // namespace client
diff --git a/src/client/window/inventory_window.hh b/src/client/window/inventory_window.hh
new file mode 100644
index 0000000..a77ae2f
--- /dev/null
+++ b/src/client/window/inventory_window.hh
@@ -0,0 +1,40 @@
+#ifndef CLIENT_WINDOW_INVENTORY_WINDOW_HH_
+#define CLIENT_WINDOW_INVENTORY_WINDOW_HH_
+
+#include <cstdint>
+#include <optional>
+
+#include "client/item/item.hh"
+#include "client/render/draw.hh"
+#include "client/state/state.hh"
+#include "client/window/basic_window.hh"
+
+namespace client {
+namespace window {
+
+class inventory_window : public basic_window {
+private:
+    std::optional<unsigned long> grabbed;
+
+private:
+    std::optional<unsigned long>
+    maybe_get_inventory_index(const glm::vec2& pos) const noexcept;
+
+private:
+    bool maybe_handle_mousebuttondown(const SDL_Event& event) noexcept;
+    bool maybe_handle_mousebuttonup(const SDL_Event& event) noexcept;
+
+public:
+    template <typename... Args>
+    inventory_window(Args&&... args) noexcept
+        : basic_window(std::forward<Args>(args)...) {}
+    virtual ~inventory_window() noexcept {}
+
+    virtual bool maybe_handle_event(const SDL_Event& event) noexcept override;
+    virtual void draw() noexcept override;
+};
+
+} // namespace window
+} // namespace client
+
+#endif
diff --git a/src/client/window/text_input_window.cc b/src/client/window/text_input_window.cc
new file mode 100644
index 0000000..0d556a4
--- /dev/null
+++ b/src/client/window/text_input_window.cc
@@ -0,0 +1,81 @@
+#include "client/window/text_input_window.hh"
+
+namespace client {
+namespace window {
+
+using tiw = class text_input_window;
+
+const std::string& tiw::get_send_text() noexcept {
+    auto& text = client::input::state.text_input;
+    text = std::string{std::begin(text),
+                       std::begin(text) +
+                           static_cast<long>(std::min(std::size(text),
+                                                      shared::MAX_SAY_LENGTH))};
+    return text;
+}
+
+proto::packet tiw::make_say_packet() noexcept {
+    proto::packet packet;
+
+    const auto sub_say_packet = packet.mutable_say_packet();
+    sub_say_packet->set_text(get_send_text());
+
+    return packet;
+}
+
+bool tiw::maybe_handle_keydown(const SDL_Event& event) noexcept {
+    if (event.key.keysym.sym == SDLK_BACKSPACE) {
+        if (!client::input::state.text_input.empty()) {
+            client::input::state.text_input.pop_back();
+        }
+        return true;
+    }
+
+    if (event.key.keysym.sym != SDLK_RETURN || event.key.repeat) {
+        return false;
+    }
+
+    if (!client::input::state.text_input.empty()) {
+        client::state::connection->rsend_packet(make_say_packet());
+    }
+
+    pop_window();
+    return true;
+}
+
+const glm::vec3& tiw::get_draw_colour() noexcept {
+    if (client::input::state.text_input.length() >= shared::MAX_SAY_LENGTH) {
+        return basic_window::highlight_clr;
+    }
+    return basic_window::primary_clr;
+}
+
+bool tiw::maybe_handle_event(const SDL_Event& event) noexcept {
+    switch (event.type) {
+    case SDL_KEYDOWN:
+        return this->maybe_handle_keydown(event);
+    }
+
+    return basic_window::maybe_handle_event(event);
+}
+
+void tiw::draw() noexcept {
+    basic_window::draw();
+
+    client::render::draw_rectangle({.pos = {.offset = this->pos},
+                                    .size = {.offset = this->size},
+                                    .colour = {this->get_draw_colour(), 1.0f}});
+
+    client::render::draw_text(
+        this->get_send_text(),
+        {.pos = {.extent = {0.0f, 0.0f},
+                 .offset = this->pos + (this->size / 2.0f)},
+         .offset_height = this->size.y / 2.0f,
+         .colour = {this->font_colour, 1.0f},
+         .has_backing = false,
+         .is_centered = true,
+         .is_vcentered = true});
+};
+
+} // namespace window
+} // namespace client
diff --git a/src/client/window/text_input_window.hh b/src/client/window/text_input_window.hh
new file mode 100644
index 0000000..edff672
--- /dev/null
+++ b/src/client/window/text_input_window.hh
@@ -0,0 +1,43 @@
+#ifndef CLIENT_WINDOW_TEXT_INPUT_WINDOW_HH_
+#define CLIENT_WINDOW_TEXT_INPUT_WINDOW_HH_
+
+#include <string>
+
+#include "client/input.hh"
+#include "client/shared.hh"
+#include "client/state/state.hh"
+#include "client/window/basic_window.hh"
+#include "shared/net/proto.hh"
+
+namespace client {
+namespace window {
+
+void pop_window() noexcept; // forward declaration
+
+class text_input_window : public basic_window {
+private:
+    // text restricted to a size of 32.
+    static const std::string& get_send_text() noexcept;
+    static proto::packet make_say_packet() noexcept;
+
+    static bool maybe_handle_keydown(const SDL_Event& event) noexcept;
+    static const glm::vec3& get_draw_colour() noexcept;
+
+public:
+    template <typename... Args>
+    text_input_window(Args&&... args) noexcept
+        : basic_window(std::forward<Args>(args)...) {
+        client::input::set_text_input(true);
+    }
+    virtual ~text_input_window() noexcept {
+        client::input::set_text_input(false);
+    }
+    virtual bool maybe_handle_event(const SDL_Event& event) noexcept override;
+
+    virtual void draw() noexcept override;
+};
+
+} // namespace window
+} // namespace client
+
+#endif
diff --git a/src/client/window/window.cc b/src/client/window/window.cc
new file mode 100644
index 0000000..648997f
--- /dev/null
+++ b/src/client/window/window.cc
@@ -0,0 +1,318 @@
+#include "window.hh"
+
+namespace client {
+namespace window {
+
+// TODO
+
+// Sliders are for numerical values of some type T.
+// TODO
+/*
+template <typename T>
+class slider_window : public basic_window {
+protected:
+    std::string name;
+    T min;
+    T cur;
+    T max;
+    T& var;
+
+private:
+    void handle_mousebuttondown(const SDL_Event& event) noexcept {}
+    void handle_mousebuttonup(const SDL_Event& event) noexcept {}
+
+public:
+    template <typename... Args>
+    slider_window(const std::string_view name, const T& min, const T& cur,
+                  const T& max, T& var, Args&&... args) noexcept
+        : basic_window(std::forward<Args>(args)...), name(name), min(min),
+          cur(cur), max(max), var(var) {}
+
+    // slider_window(
+    virtual bool maybe_handle_event(const SDL_Event& event) noexcept
+override { switch (event.type) { case SDL_MOUSEBUTTONDOWN:
+            this->handle_mousebuttondown(event);
+            return true;
+        case SDL_MOUSEBUTTONUP:
+            this->handle_mousebuttonup(event);
+            return true;
+        }
+        return basic_window::maybe_handle_event(event);
+    }
+    virtual void draw() noexcept override { basic_window::draw(); }
+};
+*/
+
+static void handle_event(const SDL_Event& event) noexcept; // ignore
+
+static hud_window& get_hud_window() noexcept {
+    static hud_window ret = []() {
+        const auto& window = client::render::get_window_size();
+        const float size = std::min(static_cast<float>(window.x) / 2.0f,
+                                    static_cast<float>(window.y) / 2.0f);
+        client::window::hud_window ret{size};
+        return ret;
+    }();
+    return ret;
+}
+
+// All dynamic windows go in this list!
+using layer = std::forward_list<std::unique_ptr<basic_window>>;
+using layers = std::forward_list<layer>;
+static layers& get_layers() noexcept {
+    // We callbacks for our window manager are initialised here too.
+    static layers ret = []() -> layers {
+        client::input::register_event_handler(&handle_event);
+        client::input::set_text_input(false);
+        client::input::set_mouse_relative(true);
+        return {};
+    }();
+    return ret;
+}
+
+void pop_window() noexcept {
+    if (!get_layers().empty()) {
+        get_layers().pop_front();
+    }
+    // Our windows might be empty here, so set our mouse mode accordingly.
+    if (!client::window::is_open()) {
+        client::input::set_mouse_relative(true);
+    }
+}
+
+// Constants used for uniform ui sizes.
+constexpr glm::vec2 lsize_extent{0.4, 0.075};
+constexpr glm::vec2 ssize_extent{0.15, 0.075};
+
+static void center_mouse_position() noexcept {
+    const glm::vec2& window = client::render::get_window_size();
+    client::input::set_mouse_position({window.x / 2.0f, window.y / 2.0f});
+}
+
+template <typename T, typename... Args>
+void push_window(Args&&... args) noexcept {
+    get_layers().front().push_front(
+        std::make_unique<T>(std::forward<Args>(args)...));
+}
+
+constexpr glm::vec2 center_extent(const glm::vec2 pos,
+                                  const glm::vec2 size) noexcept {
+    return {pos.x, pos.y - size.y / 2.0f};
+}
+
+static void make_options_menu() noexcept {
+    get_layers().push_front({});
+
+    /*
+    push_window<::slider_window<float>>(
+        "Field of Vision", 0.0f,
+        settings::get(std::make_pair("gameplay", "fov"), 100.0f), 145.0f,
+        pop_window,
+        client::draw::relative_arg{.extent =
+                                       center_extent({0.3, 0.7},
+    lsize_extent)}, client::draw::relative_arg{.extent = lsize_extent});
+        */
+
+    push_window<button_window>(
+        "Back", pop_window,
+        client::render::relative_arg{
+            .extent = center_extent({0.3, 0.3}, ssize_extent)},
+        client::render::relative_arg{.extent = ssize_extent});
+}
+
+static void make_main_menu() noexcept {
+    get_layers().push_front({});
+
+    push_window<button_window>(
+        "Return to Game", pop_window,
+        client::render::relative_arg{
+            .extent = center_extent({0.3, 0.7}, lsize_extent)},
+        client::render::relative_arg{.extent = lsize_extent});
+
+    push_window<button_window>(
+        "Options", make_options_menu,
+        client::render::relative_arg{
+            .extent = center_extent({0.55, 0.6}, ssize_extent)},
+        client::render::relative_arg{.extent = ssize_extent});
+
+    push_window<button_window>(
+        "?", pop_window,
+        client::render::relative_arg{
+            .extent = center_extent({0.55, 0.5}, ssize_extent)},
+        client::render::relative_arg{.extent = ssize_extent});
+
+    push_window<button_window>(
+        "?", pop_window,
+        client::render::relative_arg{
+            .extent = center_extent({0.55, 0.4}, ssize_extent)},
+        client::render::relative_arg{.extent = ssize_extent});
+
+    push_window<button_window>(
+        "Exit Game", [] { shared::should_exit = true; },
+        client::render::relative_arg{
+            .extent = center_extent({0.3, 0.3}, lsize_extent)},
+        client::render::relative_arg{.extent = lsize_extent});
+
+    client::input::set_mouse_relative(false);
+    center_mouse_position();
+}
+
+static void make_chat_window() noexcept {
+    get_layers().push_front({});
+
+    push_window<text_input_window>(
+        client::render::relative_arg{
+            .extent = center_extent({0.3, 0.3}, lsize_extent)},
+        client::render::relative_arg{.extent = lsize_extent});
+
+    client::input::set_mouse_relative(false);
+    center_mouse_position();
+}
+
+static void make_inventory_window() noexcept {
+    get_layers().push_front({});
+
+    const glm::vec2& window = client::render::get_window_size();
+
+    const float size = std::min(window.x / 2.0f, window.y / 2.0f);
+    const glm::vec2 pos{(window - size) / 2.0f};
+
+    push_window<inventory_window>(
+        client::render::relative_arg{.offset = pos},
+        client::render::relative_arg{.offset = glm::vec2{size, size}});
+    client::input::set_mouse_relative(false);
+    center_mouse_position();
+}
+
+static void handle_meta_return() noexcept {
+    if (!is_open()) {
+        make_chat_window();
+        return;
+    }
+}
+
+static void handle_meta_escape() noexcept {
+    if (!is_open()) {
+        make_main_menu();
+        return;
+    }
+
+    pop_window();
+}
+
+static void handle_meta_e() noexcept {
+    if (!is_open()) {
+        make_inventory_window();
+        return;
+    }
+
+    // The inventory window must be open.
+    if (!dynamic_cast<inventory_window*>(&*get_layers().front().front())) {
+        return;
+    }
+
+    pop_window();
+}
+
+static void handle_meta_keydown(const SDL_Event& event) noexcept {
+    if (event.key.repeat) { // only handle keypresses
+        return;
+    }
+
+    switch (event.key.keysym.sym) {
+    case SDLK_ESCAPE:
+        handle_meta_escape();
+        break;
+    case SDLK_RETURN:
+        handle_meta_return();
+        break;
+    case SDLK_e:
+        handle_meta_e();
+        break;
+    case SDLK_0:
+    case SDLK_1:
+    case SDLK_2:
+    case SDLK_3:
+    case SDLK_4:
+    case SDLK_5:
+    case SDLK_6:
+    case SDLK_7:
+    case SDLK_8:
+    case SDLK_9:
+        get_hud_window().maybe_handle_event(event);
+    default:
+        break;
+    }
+}
+
+static void handle_meta_mousemotion(const SDL_Event& event) noexcept {
+    // We convert SDL's weird coordinates into useful ones (0,0 = bottom
+    // left).
+    client::input::state.mouse_pos = {
+        event.motion.x,
+        static_cast<int>(client::render::get_window_size().y) - event.motion.y};
+}
+
+static void handle_meta_windowevent(const SDL_Event& event) noexcept {
+    if (event.window.event == SDL_WINDOWEVENT_FOCUS_LOST) {
+        if (!is_open()) {
+            make_main_menu();
+            return;
+        }
+    }
+}
+
+static void handle_meta_event(const SDL_Event& event) noexcept {
+    switch (event.type) {
+    case SDL_KEYDOWN:
+        handle_meta_keydown(event);
+        break;
+    case SDL_MOUSEMOTION:
+        handle_meta_mousemotion(event);
+        break;
+    case SDL_WINDOWEVENT:
+        handle_meta_windowevent(event);
+        break;
+    }
+}
+
+static void handle_event(const SDL_Event& event) noexcept {
+    // We ALWAYS update our mouse position.
+    if (event.type == SDL_MOUSEMOTION) {
+        handle_meta_mousemotion(event);
+    }
+
+    // Either a window consumes our event, or no window does - so we send
+    // the event to our "meta handler" which does things like closing
+    // windows etc.
+    if (is_open()) {
+        for (const auto& window : get_layers().front()) {
+            if (window->maybe_handle_event(event)) {
+                return;
+            }
+        }
+    }
+
+    handle_meta_event(event);
+}
+
+void draw() noexcept {
+    if (!is_open()) {
+
+        if (!client::input::is_key_toggled(SDLK_F1)) {
+            get_hud_window().draw();
+        }
+
+        return;
+    }
+
+    client::render::draw_colour({0.0f, 0.0f, 0.0f, 0.10f}); // very light shade
+    for (const auto& window : get_layers().front()) {
+        window->draw();
+    }
+}
+
+bool is_open() noexcept { return !get_layers().empty(); }
+
+} // namespace window
+} // namespace client
diff --git a/src/client/window/window.hh b/src/client/window/window.hh
new file mode 100644
index 0000000..d112d18
--- /dev/null
+++ b/src/client/window/window.hh
@@ -0,0 +1,38 @@
+#ifndef CLIENT_WINDOW_WINDOW_HH_
+#define CLIENT_WINDOW_WINDOW_HH_
+
+#include <algorithm>
+#include <forward_list>
+#include <functional>
+#include <memory>
+#include <optional>
+#include <string>
+#include <utility>
+
+#include <SDL2/SDL.h>
+#include <glm/glm.hpp>
+
+#include "client/client.hh"
+#include "client/input.hh"
+#include "client/render/render.hh"
+#include "client/settings.hh"
+#include "client/window/basic_window.hh"
+#include "client/window/button_window.hh"
+#include "client/window/hud_window.hh"
+#include "client/window/inventory_window.hh"
+#include "client/window/text_input_window.hh"
+#include "shared/shared.hh"
+
+namespace client {
+namespace window {
+
+// removes the topmost window
+void pop_window() noexcept;
+bool is_open() noexcept;
+
+void draw() noexcept;
+
+} // namespace window
+} // namespace client
+
+#endif