implement in-game popups

25 files changed, 294 insertions, 33 deletions

diff --git a/app/mac/impl/display-spritekit.hh b/app/mac/impl/display-spritekit.hh
index 64e3b03..334d492 100644
--- a/app/mac/impl/display-spritekit.hh
+++ b/app/mac/impl/display-spritekit.hh
@@ -13,6 +13,7 @@ namespace nes::app::mac
 		NSMutableData* buffer_front_;
 		NSMutableData* buffer_back_;
 		u8* bytes_back_;
+		u8* bytes_front_;
 
 	public:
 		explicit display_spritekit(SKSpriteNode* node);
diff --git a/app/mac/impl/display-spritekit.mm b/app/mac/impl/display-spritekit.mm
index b6123d6..a5809c3 100644
--- a/app/mac/impl/display-spritekit.mm
+++ b/app/mac/impl/display-spritekit.mm
@@ -16,13 +16,14 @@ namespace nes::app::mac
 		, buffer_front_{ make_buffer() }
 		, buffer_back_{ make_buffer() }
 		, bytes_back_{ static_cast<u8*>([buffer_back_ mutableBytes]) }
+		, bytes_front_{ static_cast<u8*>([buffer_front_ mutableBytes]) }
 	{
 	}
 
 	auto display_spritekit::switch_buffers() -> void
 	{
 		std::swap(buffer_back_, buffer_front_);
-		bytes_back_ = static_cast<u8*>([buffer_back_ mutableBytes]);
+		std::swap(bytes_back_, bytes_front_);
 
 		auto texture = [SKTexture textureWithData:buffer_front_ size:CGSizeMake(width, height) flipped:YES];
 		[texture setFilteringMode:SKTextureFilteringNearest];
@@ -42,9 +43,9 @@ namespace nes::app::mac
 	{
 		auto const offset = (y * width + x) * 4;
 		auto res = rgb{};
-		res.r = bytes_back_[offset + 0];
-		res.g = bytes_back_[offset + 1];
-		res.b = bytes_back_[offset + 2];
+		res.r = bytes_front_[offset + 0];
+		res.g = bytes_front_[offset + 1];
+		res.b = bytes_front_[offset + 2];
 		return res;
 	}
 } // namespace nes::app::mac
\ No newline at end of file
diff --git a/lib/nes/app/action.hh b/lib/nes/app/action.hh
index f63c17d..cca7a35 100644
--- a/lib/nes/app/action.hh
+++ b/lib/nes/app/action.hh
@@ -17,6 +17,8 @@ namespace nes::app
 			go_to_settings,
 			go_to_help,
 			close_popup,
+			cancel_quit,
+			confirm_quit,
 			launch_game,
 			show_error,
 		};
@@ -35,6 +37,8 @@ namespace nes::app
 		static auto go_to_settings() -> action { return action{ type::go_to_settings }; }
 		static auto go_to_help() -> action { return action{ type::go_to_help }; }
 		static auto close_popup() -> action { return action{ type::close_popup }; }
+		static auto cancel_quit() -> action { return action{ type::cancel_quit }; }
+		static auto confirm_quit() -> action { return action{ type::confirm_quit }; }
 
 		static auto launch_game(std::string_view const file_name) -> action
 		{
diff --git a/lib/nes/app/application.cc b/lib/nes/app/application.cc
index ac81840..01d3f0b 100644
--- a/lib/nes/app/application.cc
+++ b/lib/nes/app/application.cc
@@ -4,7 +4,6 @@
 #include "nes/app/ui/screen.hh"
 #include "nes/app/graphics/renderer.hh"
 #include "nes/app/action.hh"
-#include <iostream>
 
 namespace nes::app
 {
@@ -32,6 +31,7 @@ namespace nes::app
 		, screen_title_{ keyboard }
 		, screen_browser_{ keyboard, file_browser }
 		, screen_error_{ keyboard }
+		, screen_confirm_quit_{ keyboard }
 	{
 		display_.screen = &screen_title_;
 	}
@@ -49,8 +49,29 @@ namespace nes::app
 			handle_action(a);
 		}
 
-		if (console_)
+		if (display_.screen)
 		{
+			// Directly let the scene render itself without rendering any gameplay (the scene is responsible for
+			// clearing the buffer).
+			display_.switch_buffers();
+		}
+		else if (console_)
+		{
+			// Handle escape key.
+			while (auto const event = input_manager_.get_keyboard().poll_event())
+			{
+				if (event == input_event::key_down(key::escape))
+				{
+					screen_freeze_.freeze(display_);
+					screen_confirm_quit_.set_confirm(false);
+					display_.screen = &screen_freeze_;
+					display_.popup = &screen_confirm_quit_;
+					display_.switch_buffers();
+					return;
+				}
+			}
+
+			// Forward current input state to the NES.
 			console_->ref_controller_1().set_pressed(input_manager_.get_input_1().read_buttons());
 			console_->ref_controller_2().set_pressed(input_manager_.get_input_2().read_buttons());
 
@@ -60,22 +81,15 @@ namespace nes::app
 
 			if (console_->get_status() != status::success)
 			{
-				// TODO: Present as error popup
-				std::cerr << "Invalid state: " << to_string(console_->get_status()) << std::endl;
-				std::abort();
+				screen_freeze_.freeze(display_);
+				display_.screen = &screen_freeze_;
+				show_error("Runtime error", console_->get_status(), action::go_to_browser());
+				console_.clear();
 			}
-
-			// TODO: Handle escape key
-		}
-		else
-		{
-			// Directly let the scene render itself without rendering any gameplay (the scene is responsible for
-			// clearing the buffer).
-			display_.switch_buffers();
 		}
 	}
 
-	auto application::handle_action(action const a) -> void
+	auto application::handle_action(action const& a) -> void
 	{
 		switch (a.get_type())
 		{
@@ -112,6 +126,19 @@ namespace nes::app
 				display_.popup = nullptr;
 				break;
 			}
+			case action::type::cancel_quit:
+			{
+				display_.popup = nullptr;
+				display_.screen = nullptr;
+				break;
+			}
+			case action::type::confirm_quit:
+			{
+				display_.popup = nullptr;
+				display_.screen = &screen_browser_;
+				console_.clear();
+				break;
+			}
 			case action::type::launch_game:
 			{
 				u8 buffer[sys::cartridge::max_file_size];
@@ -142,11 +169,11 @@ namespace nes::app
 		}
 	}
 
-	auto application::show_error(std::string_view const message, status const error) -> void
+	auto application::show_error(std::string_view const message, status const error, action const& action) -> void
 	{
 		screen_error_.set_message(message);
 		screen_error_.set_error(error);
+		screen_error_.set_action(action);
 		display_.popup = &screen_error_;
 	}
-
 } // namespace nes::app
\ No newline at end of file
diff --git a/lib/nes/app/application.hh b/lib/nes/app/application.hh
index 81e6516..ddeff85 100644
--- a/lib/nes/app/application.hh
+++ b/lib/nes/app/application.hh
@@ -3,7 +3,9 @@
 #include "nes/app/input/input-manager.hh"
 #include "nes/app/ui/screen-title.hh"
 #include "nes/app/ui/screen-browser.hh"
+#include "nes/app/ui/screen-freeze.hh"
 #include "nes/app/ui/screen-error.hh"
+#include "nes/app/ui/screen-confirm-quit.hh"
 #include "nes/sys/nes.hh"
 #include "nes/common/box.hh"
 #include "nes/common/display.hh"
@@ -47,7 +49,9 @@ namespace nes::app
 		box<sys::nes> console_{};
 		screen_title screen_title_;
 		screen_browser screen_browser_;
+		screen_freeze screen_freeze_;
 		screen_error screen_error_;
+		screen_confirm_quit screen_confirm_quit_;
 
 	public:
 		explicit application(display&, input_device_keyboard&, file_browser& file_browser);
@@ -64,7 +68,7 @@ namespace nes::app
 		auto remove_controller(input_device_controller& c) -> void { input_manager_.remove_controller(c); }
 
 	private:
-		auto handle_action(action) -> void;
-		auto show_error(std::string_view message, status error) -> void;
+		auto handle_action(action const&) -> void;
+		auto show_error(std::string_view message, status error, action const& action = action::close_popup()) -> void;
 	};
 } // namespace nes::app
\ No newline at end of file
diff --git a/lib/nes/app/graphics/renderer.cc b/lib/nes/app/graphics/renderer.cc
index d512e71..564125b 100644
--- a/lib/nes/app/graphics/renderer.cc
+++ b/lib/nes/app/graphics/renderer.cc
@@ -5,6 +5,7 @@
 #include "nes/app/graphics/image-view.hh"
 #include "nes/app/graphics/text-attributes.hh"
 #include "nes/app/graphics/tiles/characters.hh"
+#include "nes/app/graphics/tiles/borders.hh"
 #include "nes/common/display.hh"
 
 namespace nes::app
@@ -125,11 +126,9 @@ namespace nes::app
 		}
 	}
 
-	auto renderer::render_rect(
-		i32 const x, i32 const y, u32 const width, u32 const height, color const c) -> void
+	auto renderer::render_rect(i32 const x, i32 const y, u32 const width, u32 const height, color const c) -> void
 	{
 		if (c == color::transparent) { return; }
-		if (x >= static_cast<i32>(renderer::width) || y >= static_cast<i32>(renderer::height)) { return; }
 
 		auto const resolved = resolve_color(c);
 		auto const x_stop = std::min(x + static_cast<i32>(width), static_cast<i32>(renderer::width));
@@ -145,6 +144,55 @@ namespace nes::app
 		}
 	}
 
+	auto renderer::render_border(i32 const x, i32 const y, u32 const width, u32 const height, color const c) -> void
+	{
+		if (width <= 1 || height <= 1) { return; }
+
+		auto const x_last = std::min(x + static_cast<i32>(width), static_cast<i32>(renderer::width)) - 1;
+		auto const y_last = std::min(y + static_cast<i32>(height), static_cast<i32>(renderer::height)) - 1;
+		auto const x_start = std::max(x, 0);
+		auto const y_start = std::max(y, 0);
+		for (auto border_y = i32{ y_start }; border_y <= y_last; ++border_y)
+		{
+			for (auto border_x = i32{ x_start }; border_x <= x_last; ++border_x)
+			{
+				if (border_x == x_start && border_y == y_start)
+				{
+					render_mask_tile(border_x, border_y, tiles::border_top_left, c);
+				}
+				else if (border_x == x_last && border_y == y_start)
+				{
+					render_mask_tile(border_x, border_y, tiles::border_top_right, c);
+				}
+				else if (border_x == x_last && border_y == y_last)
+				{
+					render_mask_tile(border_x, border_y, tiles::border_bottom_right, c);
+				}
+				else if (border_x == x_start && border_y == y_last)
+				{
+					render_mask_tile(border_x, border_y, tiles::border_bottom_left, c);
+				}
+				else if (border_x == x_start)
+				{
+					render_mask_tile(border_x, border_y, tiles::border_left, c);
+				}
+				else if (border_x == x_last)
+				{
+					render_mask_tile(border_x, border_y, tiles::border_right, c);
+				}
+				else if (border_y == y_start)
+				{
+					render_mask_tile(border_x, border_y, tiles::border_top, c);
+				}
+				else if (border_y == y_last)
+				{
+					render_mask_tile(border_x, border_y, tiles::border_bottom, c);
+				}
+			}
+		}
+	}
+
+
 	auto renderer::render_fill(color const c) -> void
 	{
 		render_rect(0, 0, width, height, c);
diff --git a/lib/nes/app/graphics/renderer.hh b/lib/nes/app/graphics/renderer.hh
index 9b764a6..83cafb3 100644
--- a/lib/nes/app/graphics/renderer.hh
+++ b/lib/nes/app/graphics/renderer.hh
@@ -37,6 +37,8 @@ namespace nes::app
 		auto operator=(renderer const&) -> renderer& = delete;
 		auto operator=(renderer&&) -> renderer& = delete;
 
+		auto get_display() const -> display& { return display_; }
+
 		/// Render a colored tile at the given tile coordinates.
 		auto render_image_tile(i32 x, i32 y, image_tile const&) -> void;
 		/// Render an alpha-only tile at the given tile coordinates with the given color.
@@ -66,6 +68,8 @@ namespace nes::app
 
 		/// Render a rectangle at the given tile coordinates with a given size (measured in tiles).
 		auto render_rect(i32 x, i32 y, u32 width, u32 height, color) -> void;
+		/// Render a border around a rectangle with the given size (measured in tiles).
+		auto render_border(i32 x, i32 y, u32 width, u32 height, color) -> void;
 		/// Completely fill the screen.
 		auto render_fill(color) -> void;
 
diff --git a/lib/nes/app/graphics/tiles/CMakeLists.txt b/lib/nes/app/graphics/tiles/CMakeLists.txt
index 144b9da..eced5ca 100644
--- a/lib/nes/app/graphics/tiles/CMakeLists.txt
+++ b/lib/nes/app/graphics/tiles/CMakeLists.txt
@@ -74,6 +74,20 @@ nes_generate_tiles(
 
 nes_generate_tiles(
 	nes
+	borders
+	TYPE mask
+	FILES
+		border_top.png
+		border_top_left.png
+		border_top_right.png
+		border_left.png
+		border_right.png
+		border_bottom.png
+		border_bottom_left.png
+		border_bottom_right.png)
+
+nes_generate_tiles(
+	nes
 	banner
 	TYPE image
 	FILES banner.png)
\ No newline at end of file
diff --git a/lib/nes/app/graphics/tiles/border_bottom.png b/lib/nes/app/graphics/tiles/border_bottom.png
new file mode 100644
index 0000000..05ac7a7
--- /dev/null
+++ b/lib/nes/app/graphics/tiles/border_bottom.png
diff --git a/lib/nes/app/graphics/tiles/border_bottom_left.png b/lib/nes/app/graphics/tiles/border_bottom_left.png
new file mode 100644
index 0000000..974b1b1
--- /dev/null
+++ b/lib/nes/app/graphics/tiles/border_bottom_left.png
diff --git a/lib/nes/app/graphics/tiles/border_bottom_right.png b/lib/nes/app/graphics/tiles/border_bottom_right.png
new file mode 100644
index 0000000..2fa6822
--- /dev/null
+++ b/lib/nes/app/graphics/tiles/border_bottom_right.png
diff --git a/lib/nes/app/graphics/tiles/border_left.png b/lib/nes/app/graphics/tiles/border_left.png
new file mode 100644
index 0000000..ba5ecb6
--- /dev/null
+++ b/lib/nes/app/graphics/tiles/border_left.png
diff --git a/lib/nes/app/graphics/tiles/border_right.png b/lib/nes/app/graphics/tiles/border_right.png
new file mode 100644
index 0000000..801bd7d
--- /dev/null
+++ b/lib/nes/app/graphics/tiles/border_right.png
diff --git a/lib/nes/app/graphics/tiles/border_top.png b/lib/nes/app/graphics/tiles/border_top.png
new file mode 100644
index 0000000..94d5cf5
--- /dev/null
+++ b/lib/nes/app/graphics/tiles/border_top.png
diff --git a/lib/nes/app/graphics/tiles/border_top_left.png b/lib/nes/app/graphics/tiles/border_top_left.png
new file mode 100644
index 0000000..f67b585
--- /dev/null
+++ b/lib/nes/app/graphics/tiles/border_top_left.png
diff --git a/lib/nes/app/graphics/tiles/border_top_right.png b/lib/nes/app/graphics/tiles/border_top_right.png
new file mode 100644
index 0000000..0b8613c
--- /dev/null
+++ b/lib/nes/app/graphics/tiles/border_top_right.png
diff --git a/lib/nes/app/ui/CMakeLists.txt b/lib/nes/app/ui/CMakeLists.txt
index de42744..37720c1 100644
--- a/lib/nes/app/ui/CMakeLists.txt
+++ b/lib/nes/app/ui/CMakeLists.txt
@@ -7,5 +7,9 @@ target_sources(
 		screen-title.cc
 		screen-browser.hh
 		screen-browser.cc
+		screen-freeze.hh
+		screen-freeze.cc
 		screen-error.hh
-		screen-error.cc)
\ No newline at end of file
+		screen-error.cc
+		screen-confirm-quit.hh
+		screen-confirm-quit.cc)
\ No newline at end of file
diff --git a/lib/nes/app/ui/screen-confirm-quit.cc b/lib/nes/app/ui/screen-confirm-quit.cc
new file mode 100644
index 0000000..3c7a337
--- /dev/null
+++ b/lib/nes/app/ui/screen-confirm-quit.cc
@@ -0,0 +1,68 @@
+#include "nes/app/ui/screen-confirm-quit.hh"
+#include "nes/app/graphics/renderer.hh"
+#include "nes/app/graphics/color.hh"
+#include "nes/app/input/input-device-keyboard.hh"
+
+namespace nes::app
+{
+	screen_confirm_quit::screen_confirm_quit(input_device_keyboard& keyboard)
+		: keyboard_{ keyboard }
+	{
+	}
+
+	auto screen_confirm_quit::render(renderer& renderer) -> void
+	{
+		renderer.render_rect(2, 8, 28, 10, color::background_secondary);
+		renderer.render_border(2, 8, 28, 10, color::foreground_primary);
+
+		auto const attrs = text_attributes{}
+			.set_alignment(text_alignment::center)
+			.set_ellipsize_mode(ellipsize_mode::end)
+			.set_max_width(26);
+		renderer.render_text(16, 10, "Are you sure?", color::foreground_primary, attrs);
+		renderer.render_text(16, 12, "All progress is lost.", color::foreground_primary, attrs);
+		if (confirm_)
+		{
+			renderer.render_text(10, 15, "Cancel", color::foreground_secondary);
+			renderer.render_text(18, 15, "> OK <", color::accent_primary);
+		}
+		else
+		{
+			renderer.render_text(8, 15, "> Cancel <", color::accent_primary);
+			renderer.render_text(20, 15, "OK", color::foreground_secondary);
+		}
+	}
+
+	auto screen_confirm_quit::process_events() -> action
+	{
+		while (auto const event = keyboard_.poll_event())
+		{
+			// Use key-up so the enter key is not immediately captured by the game.
+			if (event == input_event::key_up(key::enter))
+			{
+				if (confirm_)
+				{
+					return action::confirm_quit();
+				}
+				else
+				{
+					return action::cancel_quit();
+				}
+			}
+			else if (event == input_event::key_down(key::space))
+			{
+				confirm_ = !confirm_;
+			}
+			else if (event == input_event::key_down(key::arrow_left))
+			{
+				confirm_ = false;
+			}
+			else if (event == input_event::key_down(key::arrow_right))
+			{
+				confirm_ = true;
+			}
+		}
+
+		return action{};
+	}
+} // namespace nes::app
\ No newline at end of file
diff --git a/lib/nes/app/ui/screen-confirm-quit.hh b/lib/nes/app/ui/screen-confirm-quit.hh
new file mode 100644
index 0000000..c176f4b
--- /dev/null
+++ b/lib/nes/app/ui/screen-confirm-quit.hh
@@ -0,0 +1,24 @@
+#pragma once
+
+#include "nes/app/ui/screen.hh"
+
+namespace nes::app
+{
+	class input_device_keyboard;
+
+	/// A popup asking the user if they really want to quit the game.
+	class screen_confirm_quit final : public screen
+	{
+		input_device_keyboard& keyboard_;
+		bool confirm_{ false };
+
+	public:
+		explicit screen_confirm_quit(input_device_keyboard&);
+
+		auto get_confirm() const -> bool { return confirm_; }
+		auto set_confirm(bool const v) -> void { confirm_ = v; }
+
+		auto render(renderer&) -> void override;
+		auto process_events() -> action override;
+	};
+} // namespace nes::app
\ No newline at end of file
diff --git a/lib/nes/app/ui/screen-error.cc b/lib/nes/app/ui/screen-error.cc
index 67a3244..9375012 100644
--- a/lib/nes/app/ui/screen-error.cc
+++ b/lib/nes/app/ui/screen-error.cc
@@ -12,8 +12,8 @@ namespace nes::app
 
 	auto screen_error::render(renderer& renderer) -> void
 	{
-		// TODO: Nicer box
-		renderer.render_rect(2, 9, 28, 5, color::background_secondary);
+		renderer.render_rect(2, 8, 28, 10, color::background_secondary);
+		renderer.render_border(2, 8, 28, 10, color::foreground_primary);
 
 		auto const attrs = text_attributes{}
 			.set_alignment(text_alignment::center)
@@ -21,6 +21,7 @@ namespace nes::app
 			.set_max_width(26);
 		renderer.render_text_format(16, 10, color::foreground_primary, attrs, "{}:", message_);
 		renderer.render_text(16, 12, to_string(error_), color::foreground_primary, attrs);
+		renderer.render_text(16, 15, "> OK <", color::accent_primary, attrs);
 	}
 
 	auto screen_error::process_events() -> action
@@ -29,7 +30,7 @@ namespace nes::app
 		{
 			if (event == input_event::key_down(key::enter))
 			{
-				return action::close_popup();
+				return action_;
 			}
 		}
 
diff --git a/lib/nes/app/ui/screen-error.hh b/lib/nes/app/ui/screen-error.hh
index ec877e1..4559942 100644
--- a/lib/nes/app/ui/screen-error.hh
+++ b/lib/nes/app/ui/screen-error.hh
@@ -12,14 +12,17 @@ namespace nes::app
 		input_device_keyboard& keyboard_;
 		std::string_view message_;
 		status error_{ status::success };
+		action action_{};
 
 	public:
 		explicit screen_error(input_device_keyboard&);
 
 		auto get_message() const -> std::string_view { return message_; }
 		auto get_error() const -> status { return error_; }
-		auto set_message(std::string_view const v) { message_ = v; }
-		auto set_error(status const v) { error_ = v; }
+		auto get_action() const -> action { return action_; }
+		auto set_message(std::string_view const v) -> void { message_ = v; }
+		auto set_error(status const v) -> void { error_ = v; }
+		auto set_action(action const& v) -> void { action_ = v; }
 
 		auto render(renderer&) -> void override;
 		auto process_events() -> action override;
diff --git a/lib/nes/app/ui/screen-freeze.cc b/lib/nes/app/ui/screen-freeze.cc
new file mode 100644
index 0000000..60410dd
--- /dev/null
+++ b/lib/nes/app/ui/screen-freeze.cc
@@ -0,0 +1,33 @@
+#include "nes/app/ui/screen-freeze.hh"
+#include "nes/app/graphics/renderer.hh"
+
+namespace nes::app
+{
+	auto screen_freeze::freeze(display const& disp) -> void
+	{
+		for (auto y = u32{ 0 }; y < display::height; ++y)
+		{
+			for (auto x = u32{ 0 }; x < display::width; ++x)
+			{
+				frozen_data_[y * display::width + x] = disp.get(x, y);
+			}
+		}
+	}
+
+	auto screen_freeze::render(renderer& renderer) -> void
+	{
+		auto& disp = renderer.get_display();
+		for (auto y = u32{ 0 }; y < display::height; ++y)
+		{
+			for (auto x = u32{ 0 }; x < display::width; ++x)
+			{
+				disp.set(x, y, frozen_data_[y * display::width + x]);
+			}
+		}
+	}
+
+	auto screen_freeze::process_events() -> action
+	{
+		return action{};
+	}
+} // namespace nes::app
\ No newline at end of file
diff --git a/lib/nes/app/ui/screen-freeze.hh b/lib/nes/app/ui/screen-freeze.hh
new file mode 100644
index 0000000..fe67aad
--- /dev/null
+++ b/lib/nes/app/ui/screen-freeze.hh
@@ -0,0 +1,25 @@
+#pragma once
+
+#include "nes/app/ui/screen.hh"
+#include "nes/common/rgb.hh"
+#include "nes/common/display.hh"
+
+namespace nes::app
+{
+	/// Freeze screen which preserves the display buffer at a certain state.
+	///
+	/// This is usually used to preserve the image from the console when the game should not continue.
+	class screen_freeze final : public screen
+	{
+		rgb frozen_data_[display::width * display::height]{};
+
+	public:
+		explicit screen_freeze() = default;
+
+		auto render(renderer&) -> void override;
+		auto process_events() -> action override;
+
+		/// Update the image shown to the back buffer of the given display.
+		auto freeze(display const&) -> void;
+	};
+} // namespace nes::app
\ No newline at end of file
diff --git a/lib/nes/common/display.hh b/lib/nes/common/display.hh
index eb35366..f7d53c1 100644
--- a/lib/nes/common/display.hh
+++ b/lib/nes/common/display.hh
@@ -25,7 +25,7 @@ namespace nes
 		virtual auto switch_buffers() -> void = 0;
 		/// Update the pixel at the given position in the back buffer.
 		virtual auto set(u32 x, u32 y, rgb value) -> void = 0;
-		/// Load the pixel value at the given position in the back buffer.
+		/// Load the pixel value at the given position in the front buffer.
 		virtual auto get(u32 x, u32 y) const -> rgb = 0;
 
 	protected:
diff --git a/lib/nes/common/rgb.hh b/lib/nes/common/rgb.hh
index 0b8ec1c..b8cd0f3 100644
--- a/lib/nes/common/rgb.hh
+++ b/lib/nes/common/rgb.hh
@@ -8,7 +8,7 @@ namespace nes
 	class rgb
 	{
 	public:
-		explicit rgb() = default;
+		rgb() = default;
 
 		explicit rgb(u8 const r, u8 const g, u8 const b)
 			: r{ r }