Merge pull request #181 from OpenVicProject/ui-state-style

UI polish

20 files changed, 438 insertions, 84 deletions

diff --git a/extension/deps/openvic-simulation b/extension/deps/openvic-simulation
-Subproject bff91f78f9c5339079c10adfbf8232e5159c1a2
+Subproject 0a425fbe05d6138b753c0e4a7c06f06695bde8a
diff --git a/extension/src/openvic-extension/classes/GFXButtonStateTexture.cpp b/extension/src/openvic-extension/classes/GFXButtonStateTexture.cpp
new file mode 100644
index 0000000..e6dff1f
--- /dev/null
+++ b/extension/src/openvic-extension/classes/GFXButtonStateTexture.cpp
@@ -0,0 +1,106 @@
+#include "GFXButtonStateTexture.hpp"
+
+#include "openvic-extension/utility/ClassBindings.hpp"
+
+using namespace OpenVic;
+using namespace godot;
+
+void GFXButtonStateTexture::_bind_methods() {
+	OV_BIND_METHOD(GFXButtonStateTexture::set_button_state, { "new_button_state" });
+	OV_BIND_METHOD(GFXButtonStateTexture::get_button_state);
+
+	OV_BIND_SMETHOD(get_generate_state_image_func_name);
+
+	OV_BIND_SMETHOD(button_state_to_theme_name, { "button_state" });
+	OV_BIND_METHOD(GFXButtonStateTexture::get_button_state_theme);
+
+	OV_BIND_METHOD(GFXButtonStateTexture::generate_state_image, { "source_image" });
+
+	BIND_ENUM_CONSTANT(HOVER);
+	BIND_ENUM_CONSTANT(PRESSED);
+	BIND_ENUM_CONSTANT(DISABLED);
+}
+
+GFXButtonStateTexture::GFXButtonStateTexture() : button_state { HOVER } {}
+
+Ref<GFXButtonStateTexture> GFXButtonStateTexture::make_gfx_button_state_texture(
+	ButtonState button_state, Ref<Image> const& source_image
+) {
+	Ref<GFXButtonStateTexture> button_state_texture;
+	button_state_texture.instantiate();
+	ERR_FAIL_NULL_V(button_state_texture, nullptr);
+	button_state_texture->set_button_state(button_state);
+	if (source_image.is_valid()) {
+		ERR_FAIL_COND_V(button_state_texture->generate_state_image(source_image) != OK, nullptr);
+	}
+	return button_state_texture;
+}
+
+void GFXButtonStateTexture::set_button_state(ButtonState new_button_state) {
+	ERR_FAIL_COND(new_button_state != HOVER && new_button_state != PRESSED && new_button_state != DISABLED);
+	button_state = new_button_state;
+}
+
+Error GFXButtonStateTexture::generate_state_image(Ref<Image> const& source_image) {
+	ERR_FAIL_COND_V(source_image.is_null() || source_image->is_empty(), FAILED);
+	/* Whether we've already set the ImageTexture to an image of the right dimensions and format,
+	* and so can update it without creating and setting a new image, or not. */
+	const bool can_update = state_image.is_valid() && state_image->get_size() == source_image->get_size()
+		&& state_image->get_format() == source_image->get_format();
+	if (!can_update) {
+		state_image = Image::create(source_image->get_width(), source_image->get_height(), false, source_image->get_format());
+		ERR_FAIL_NULL_V(state_image, FAILED);
+	}
+
+	static constexpr auto hover_colour = [](Color const& colour) -> Color {
+		return { std::min(colour.r + 0.1f, 1.0f), std::min(colour.g + 0.1f, 1.0f), std::min(colour.b + 0.1f, 1.0f), colour.a };
+	};
+	static constexpr auto pressed_colour = [](Color const& colour) -> Color {
+		return { std::max(colour.r - 0.1f, 0.0f), std::max(colour.g - 0.1f, 0.0f), std::max(colour.b - 0.1f, 0.0f), colour.a };
+	};
+	static constexpr auto disabled_colour = [](Color const& colour) -> Color {
+		const float luma = colour.get_luminance();
+		return { luma, luma, luma, colour.a };
+	};
+
+	const auto colour_func = button_state == HOVER ? hover_colour : button_state == PRESSED ? pressed_colour : disabled_colour;
+
+	for (Vector2i point { 0, 0 }; point.y < state_image->get_height(); ++point.y) {
+		for (point.x = 0; point.x < state_image->get_width(); ++point.x) {
+			state_image->set_pixelv(point, colour_func(source_image->get_pixelv(point)));
+		}
+	}
+
+	if (can_update) {
+		update(state_image);
+	} else {
+		set_image(state_image);
+	}
+	return OK;
+}
+
+StringName const& GFXButtonStateTexture::get_generate_state_image_func_name() {
+	static const StringName generate_state_image_func_name = "generate_state_image";
+	return generate_state_image_func_name;
+}
+
+StringName const& GFXButtonStateTexture::button_state_to_theme_name(ButtonState button_state) {
+	static const StringName theme_name_hover = "hover";
+	static const StringName theme_name_pressed = "pressed";
+	static const StringName theme_name_disabled = "disabled";
+	static const StringName theme_name_error = "";
+	switch (button_state) {
+		case HOVER:
+			return theme_name_hover;
+		case PRESSED:
+			return theme_name_pressed;
+		case DISABLED:
+			return theme_name_disabled;
+		default:
+			return theme_name_error;
+	}
+}
+
+StringName const& GFXButtonStateTexture::get_button_state_theme() const {
+	return button_state_to_theme_name(button_state);
+}
diff --git a/extension/src/openvic-extension/classes/GFXButtonStateTexture.hpp b/extension/src/openvic-extension/classes/GFXButtonStateTexture.hpp
new file mode 100644
index 0000000..32f4087
--- /dev/null
+++ b/extension/src/openvic-extension/classes/GFXButtonStateTexture.hpp
@@ -0,0 +1,46 @@
+#pragma once
+
+#include <godot_cpp/classes/image_texture.hpp>
+
+#include <openvic-simulation/utility/Getters.hpp>
+
+namespace OpenVic {
+	class GFXButtonStateTexture : public godot::ImageTexture {
+		GDCLASS(GFXButtonStateTexture, godot::ImageTexture)
+
+	public:
+		enum ButtonState {
+			HOVER,
+			PRESSED,
+			DISABLED
+		};
+
+	private:
+		ButtonState PROPERTY(button_state);
+		godot::Ref<godot::Image> state_image;
+
+	protected:
+		static void _bind_methods();
+
+	public:
+		GFXButtonStateTexture();
+
+		/* Create a GFXButtonStateTexture using the specified godot::Image. Returns nullptr if generate_state_image fails. */
+		static godot::Ref<GFXButtonStateTexture> make_gfx_button_state_texture(
+			ButtonState button_state, godot::Ref<godot::Image> const& source_image = nullptr
+		);
+
+		/* Set the ButtonState to be generated by this class (calling this does not trigger state image generation). */
+		void set_button_state(ButtonState new_button_state);
+
+		/* Generate a modified version of source_image and update the underlying godot::ImageTexture to use it. */
+		godot::Error generate_state_image(godot::Ref<godot::Image> const& source_image);
+
+		static godot::StringName const& get_generate_state_image_func_name();
+
+		static godot::StringName const& button_state_to_theme_name(ButtonState button_state);
+		godot::StringName const& get_button_state_theme() const;
+	};
+}
+
+VARIANT_ENUM_CAST(OpenVic::GFXButtonStateTexture::ButtonState);
diff --git a/extension/src/openvic-extension/classes/GFXIconTexture.cpp b/extension/src/openvic-extension/classes/GFXIconTexture.cpp
index 895bf6b..5d29c07 100644
--- a/extension/src/openvic-extension/classes/GFXIconTexture.cpp
+++ b/extension/src/openvic-extension/classes/GFXIconTexture.cpp
@@ -15,6 +15,11 @@ using OpenVic::Utilities::godot_to_std_string;
 using OpenVic::Utilities::std_view_to_godot_string;
 using OpenVic::Utilities::std_view_to_godot_string_name;
 
+StringName const& GFXIconTexture::_signal_image_updated() {
+	static const StringName signal_image_updated = "image_updated";
+	return signal_image_updated;
+}
+
 void GFXIconTexture::_bind_methods() {
 	OV_BIND_METHOD(GFXIconTexture::clear);
 
@@ -26,16 +31,32 @@ void GFXIconTexture::_bind_methods() {
 	OV_BIND_METHOD(GFXIconTexture::get_icon_count);
 
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "icon_index"), "set_icon_index", "get_icon_index");
+
+	ADD_SIGNAL(
+		MethodInfo(_signal_image_updated(), PropertyInfo(Variant::OBJECT, "source_image", PROPERTY_HINT_RESOURCE_TYPE, "Image"))
+	);
 }
 
 GFXIconTexture::GFXIconTexture()
 	: gfx_texture_sprite { nullptr }, icon_index { GFX::NO_FRAMES }, icon_count { GFX::NO_FRAMES } {}
 
-Ref<GFXIconTexture> GFXIconTexture::make_gfx_icon_texture(GFX::TextureSprite const* gfx_texture_sprite, GFX::frame_t icon) {
+Ref<GFXIconTexture> GFXIconTexture::make_gfx_icon_texture(
+	GFX::TextureSprite const* gfx_texture_sprite, GFX::frame_t icon,
+	std::vector<Ref<GFXButtonStateTexture>> const& button_state_textures
+) {
 	Ref<GFXIconTexture> icon_texture;
 	icon_texture.instantiate();
 	ERR_FAIL_NULL_V(icon_texture, nullptr);
-	icon_texture->set_gfx_texture_sprite(gfx_texture_sprite, icon);
+
+	for (Ref<GFXButtonStateTexture> const& button_state_texture : button_state_textures) {
+		icon_texture->connect(
+			_signal_image_updated(),
+			Callable { *button_state_texture, GFXButtonStateTexture::get_generate_state_image_func_name() },
+			CONNECT_PERSIST
+		);
+	}
+
+	ERR_FAIL_COND_V(icon_texture->set_gfx_texture_sprite(gfx_texture_sprite, icon) != OK, nullptr);
 	return icon_texture;
 }
 
@@ -57,9 +78,15 @@ Error GFXIconTexture::set_gfx_texture_sprite(GFX::TextureSprite const* new_gfx_t
 		ERR_FAIL_NULL_V(asset_manager, FAILED);
 
 		const StringName texture_file = std_view_to_godot_string_name(new_gfx_texture_sprite->get_texture_file());
+
+		/* Needed for GFXButtonStateTexture, AssetManager::get_texture will re-use this image from its internal cache. */
+		const Ref<Image> image = asset_manager->get_image(texture_file);
+		ERR_FAIL_NULL_V_MSG(image, FAILED, vformat("Failed to load image: %s", texture_file));
+
 		const Ref<ImageTexture> texture = asset_manager->get_texture(texture_file);
 		ERR_FAIL_NULL_V_MSG(texture, FAILED, vformat("Failed to load texture: %s", texture_file));
 
+		sprite_image = image;
 		gfx_texture_sprite = new_gfx_texture_sprite;
 		set_atlas(texture);
 		icon_index = GFX::NO_FRAMES;
@@ -98,6 +125,7 @@ Error GFXIconTexture::set_icon_index(int32_t new_icon_index) {
 		}
 		icon_index = GFX::NO_FRAMES;
 		set_region({ {}, size });
+		emit_signal(_signal_image_updated(), sprite_image);
 		return OK;
 	}
 	if (GFX::NO_FRAMES < new_icon_index && new_icon_index <= icon_count) {
@@ -111,5 +139,6 @@ Error GFXIconTexture::set_icon_index(int32_t new_icon_index) {
 		}
 	}
 	set_region({ (icon_index - 1) * size.x / icon_count, 0, size.x / icon_count, size.y });
+	emit_signal(_signal_image_updated(), sprite_image->get_region(get_region()));
 	return OK;
 }
diff --git a/extension/src/openvic-extension/classes/GFXIconTexture.hpp b/extension/src/openvic-extension/classes/GFXIconTexture.hpp
index 176d855..06dac34 100644
--- a/extension/src/openvic-extension/classes/GFXIconTexture.hpp
+++ b/extension/src/openvic-extension/classes/GFXIconTexture.hpp
@@ -4,6 +4,8 @@
 
 #include <openvic-simulation/interface/GFX.hpp>
 
+#include "openvic-extension/classes/GFXButtonStateTexture.hpp"
+
 namespace OpenVic {
 	class GFXIconTexture : public godot::AtlasTexture {
 		GDCLASS(GFXIconTexture, godot::AtlasTexture)
@@ -16,14 +18,22 @@ namespace OpenVic {
 		GFX::frame_t PROPERTY(icon_index);
 		GFX::frame_t PROPERTY(icon_count);
 
+		godot::Ref<godot::Image> sprite_image;
+
+		static godot::StringName const& _signal_image_updated();
+
 	protected:
 		static void _bind_methods();
 
 	public:
 		GFXIconTexture();
 
+		/* Create a GFXIconTexture using the specified GFX::TextureSprite and icon index. Returns nullptr if
+		 * set_gfx_texture_sprite fails. Connects the provided GFXButtonStateTextures (if any) to the
+		* GFXIconTexture's image_updated signal. */
 		static godot::Ref<GFXIconTexture> make_gfx_icon_texture(
-			GFX::TextureSprite const* gfx_texture_sprite, GFX::frame_t icon = GFX::NO_FRAMES
+			GFX::TextureSprite const* gfx_texture_sprite, GFX::frame_t icon = GFX::NO_FRAMES,
+			std::vector<godot::Ref<GFXButtonStateTexture>> const& button_state_textures = {}
 		);
 
 		/* Discard the GFX::TextureSprite, atlas texture and icon index. */
diff --git a/extension/src/openvic-extension/classes/GFXMaskedFlagTexture.cpp b/extension/src/openvic-extension/classes/GFXMaskedFlagTexture.cpp
index 424be33..0a44e56 100644
--- a/extension/src/openvic-extension/classes/GFXMaskedFlagTexture.cpp
+++ b/extension/src/openvic-extension/classes/GFXMaskedFlagTexture.cpp
@@ -13,15 +13,22 @@ using OpenVic::Utilities::godot_to_std_string;
 using OpenVic::Utilities::std_view_to_godot_string;
 using OpenVic::Utilities::std_view_to_godot_string_name;
 
+StringName const& GFXMaskedFlagTexture::_signal_image_updated() {
+	static const StringName signal_image_updated = "image_updated";
+	return signal_image_updated;
+}
+
 Error GFXMaskedFlagTexture::_generate_combined_image() {
 	ERR_FAIL_NULL_V(overlay_image, FAILED);
-	bool can_update = true;
-	if (combined_image.is_null() || combined_image->get_size() != overlay_image->get_size()) {
+	/* Whether we've already set the ImageTexture to an image of the right dimensions and format,
+	 * and so can update it without creating and setting a new image, or not. */
+	const bool can_update = combined_image.is_valid() && combined_image->get_size() == overlay_image->get_size()
+		&& combined_image->get_format() == overlay_image->get_format();
+	if (!can_update) {
 		combined_image = Image::create(
 			overlay_image->get_width(), overlay_image->get_height(), false, overlay_image->get_format()
 		);
 		ERR_FAIL_NULL_V(combined_image, FAILED);
-		can_update = false;
 	}
 
 	if (mask_image.is_valid() && flag_image.is_valid()) {
@@ -55,6 +62,7 @@ Error GFXMaskedFlagTexture::_generate_combined_image() {
 	} else {
 		set_image(combined_image);
 	}
+	emit_signal(_signal_image_updated(), combined_image);
 	return OK;
 }
 
@@ -68,14 +76,29 @@ void GFXMaskedFlagTexture::_bind_methods() {
 	OV_BIND_METHOD(GFXMaskedFlagTexture::set_flag_country_name, { "new_flag_country_name" });
 	OV_BIND_METHOD(GFXMaskedFlagTexture::get_flag_country_name);
 	OV_BIND_METHOD(GFXMaskedFlagTexture::get_flag_type);
+
+	ADD_SIGNAL(
+		MethodInfo(_signal_image_updated(), PropertyInfo(Variant::OBJECT, "source_image", PROPERTY_HINT_RESOURCE_TYPE, "Image"))
+	);
 }
 
 GFXMaskedFlagTexture::GFXMaskedFlagTexture() : gfx_masked_flag { nullptr }, flag_country { nullptr } {}
 
-Ref<GFXMaskedFlagTexture> GFXMaskedFlagTexture::make_gfx_masked_flag_texture(GFX::MaskedFlag const* gfx_masked_flag) {
+Ref<GFXMaskedFlagTexture> GFXMaskedFlagTexture::make_gfx_masked_flag_texture(
+	GFX::MaskedFlag const* gfx_masked_flag, std::vector<Ref<GFXButtonStateTexture>> const& button_state_textures
+) {
 	Ref<GFXMaskedFlagTexture> masked_flag_texture;
 	masked_flag_texture.instantiate();
 	ERR_FAIL_NULL_V(masked_flag_texture, nullptr);
+
+	for (Ref<GFXButtonStateTexture> const& button_state_texture : button_state_textures) {
+		masked_flag_texture->connect(
+			_signal_image_updated(),
+			Callable { *button_state_texture, GFXButtonStateTexture::get_generate_state_image_func_name() },
+			CONNECT_PERSIST
+		);
+	}
+
 	ERR_FAIL_COND_V(masked_flag_texture->set_gfx_masked_flag(gfx_masked_flag) != OK, nullptr);
 	return masked_flag_texture;
 }
diff --git a/extension/src/openvic-extension/classes/GFXMaskedFlagTexture.hpp b/extension/src/openvic-extension/classes/GFXMaskedFlagTexture.hpp
index f71a1d7..294b842 100644
--- a/extension/src/openvic-extension/classes/GFXMaskedFlagTexture.hpp
+++ b/extension/src/openvic-extension/classes/GFXMaskedFlagTexture.hpp
@@ -5,6 +5,8 @@
 #include <openvic-simulation/country/Country.hpp>
 #include <openvic-simulation/interface/GFX.hpp>
 
+#include "openvic-extension/classes/GFXButtonStateTexture.hpp"
+
 namespace OpenVic {
 	class GFXMaskedFlagTexture : public godot::ImageTexture {
 		GDCLASS(GFXMaskedFlagTexture, godot::ImageTexture)
@@ -15,6 +17,8 @@ namespace OpenVic {
 
 		godot::Ref<godot::Image> overlay_image, mask_image, flag_image, combined_image;
 
+		static godot::StringName const& _signal_image_updated();
+
 		godot::Error _generate_combined_image();
 
 	protected:
@@ -23,9 +27,12 @@ namespace OpenVic {
 	public:
 		GFXMaskedFlagTexture();
 
-		/* Create a GFXMaskedFlagTexture using the specific GFX::MaskedFlag.
-		 * Returns nullptr if setting gfx_masked_flag fails. */
-		static godot::Ref<GFXMaskedFlagTexture> make_gfx_masked_flag_texture(GFX::MaskedFlag const* gfx_masked_flag);
+		/* Create a GFXMaskedFlagTexture using the specified GFX::MaskedFlag. Returns nullptr if gfx_masked_flag fails.
+		 * Connects the provided GFXButtonStateTextures (if any) to the GFXMaskedFlagTexture's image_updated signal. */
+		static godot::Ref<GFXMaskedFlagTexture> make_gfx_masked_flag_texture(
+			GFX::MaskedFlag const* gfx_masked_flag,
+			std::vector<godot::Ref<GFXButtonStateTexture>> const& button_state_textures = {}
+		);
 
 		/* Reset gfx_masked_flag, flag_country and flag_type to nullptr/an empty string, and unreference all images.
 		 * This does not affect the godot::ImageTexture, which cannot be reset to a null or empty image. */
diff --git a/extension/src/openvic-extension/classes/GFXPieChartTexture.cpp b/extension/src/openvic-extension/classes/GFXPieChartTexture.cpp
index 63deeda..c9a2a72 100644
--- a/extension/src/openvic-extension/classes/GFXPieChartTexture.cpp
+++ b/extension/src/openvic-extension/classes/GFXPieChartTexture.cpp
@@ -12,6 +12,19 @@ using OpenVic::Utilities::godot_to_std_string;
 using OpenVic::Utilities::std_view_to_godot_string;
 using OpenVic::Utilities::std_view_to_godot_string_name;
 
+StringName const& GFXPieChartTexture::_slice_identifier_key() {
+	static StringName const slice_identifier_key = "identifier";
+	return slice_identifier_key;
+}
+StringName const& GFXPieChartTexture::_slice_colour_key() {
+	static StringName const slice_colour_key = "colour";
+	return slice_colour_key;
+}
+StringName const& GFXPieChartTexture::_slice_weight_key() {
+	static StringName const slice_weight_key = "weight";
+	return slice_weight_key;
+}
+
 static constexpr float PI = std::numbers::pi_v<float>;
 
 Error GFXPieChartTexture::_generate_pie_chart_image() {
@@ -21,14 +34,13 @@ Error GFXPieChartTexture::_generate_pie_chart_image() {
 		vformat("Invalid GFX::PieChart size for GFXPieChartTexture - %d", gfx_pie_chart->get_size())
 	);
 	const int32_t pie_chart_size = 2 * gfx_pie_chart->get_size();
-	bool can_update = true;
-	if (
-		pie_chart_image.is_null() || pie_chart_image->get_width() != pie_chart_size ||
-		pie_chart_image->get_height() != pie_chart_size
-	) {
+	/* Whether we've already set the ImageTexture to an image of the right dimensions,
+	 * and so can update it without creating and setting a new image, or not. */
+	const bool can_update = pie_chart_image.is_valid() && pie_chart_image->get_width() == pie_chart_size
+		&& pie_chart_image->get_height() == pie_chart_size;
+	if (!can_update) {
 		pie_chart_image = Image::create(pie_chart_size, pie_chart_size, false, Image::FORMAT_RGBA8);
 		ERR_FAIL_NULL_V(pie_chart_image, FAILED);
-		can_update = false;
 	}
 
 	static const Color background_colour { 0.0f, 0.0f, 0.0f, 0.0f };
@@ -74,17 +86,14 @@ Error GFXPieChartTexture::_generate_pie_chart_image() {
 }
 
 Error GFXPieChartTexture::set_slices_array(TypedArray<Dictionary> const& new_slices) {
-	static const StringName colour_key = "colour";
-	static const StringName weight_key = "weight";
-
 	slices.clear();
 	total_weight = 0.0f;
 	for (int32_t i = 0; i < new_slices.size(); ++i) {
 		Dictionary const& slice_dict = new_slices[i];
 		ERR_CONTINUE_MSG(
-			!slice_dict.has(colour_key) || !slice_dict.has(weight_key), vformat("Invalid slice keys at index %d", i)
+			!slice_dict.has(_slice_colour_key()) || !slice_dict.has(_slice_weight_key()), vformat("Invalid slice keys at index %d", i)
 		);
-		const slice_t slice = std::make_pair(slice_dict[colour_key], slice_dict[weight_key]);
+		slice_t slice = std::make_pair(slice_dict[_slice_colour_key()], slice_dict[_slice_weight_key()]);
 		ERR_CONTINUE_MSG(slice.second <= 0.0f, vformat("Invalid slice values at index %d", i));
 		total_weight += slice.second;
 		slices.emplace_back(std::move(slice));
diff --git a/extension/src/openvic-extension/classes/GFXPieChartTexture.hpp b/extension/src/openvic-extension/classes/GFXPieChartTexture.hpp
index ad8e751..f8279e4 100644
--- a/extension/src/openvic-extension/classes/GFXPieChartTexture.hpp
+++ b/extension/src/openvic-extension/classes/GFXPieChartTexture.hpp
@@ -17,6 +17,10 @@ namespace OpenVic {
 		float total_weight;
 		godot::Ref<godot::Image> pie_chart_image;
 
+		static godot::StringName const& _slice_identifier_key();
+		static godot::StringName const& _slice_colour_key();
+		static godot::StringName const& _slice_weight_key();
+
 		godot::Error _generate_pie_chart_image();
 
 	protected:
@@ -34,34 +38,31 @@ namespace OpenVic {
 		 * The resulting Array of Dictionaries can be used as an argument for set_slices_array. */
 		template<std::derived_from<HasIdentifierAndColour> T>
 		static godot::TypedArray<godot::Dictionary> distribution_to_slices_array(fixed_point_map_t<T const*> const& dist) {
+			using namespace godot;
 			using entry_t = std::pair<T const*, fixed_point_t>;
 			std::vector<entry_t> sorted_dist;
 			sorted_dist.reserve(dist.size());
 			for (entry_t const& entry : dist) {
 				ERR_CONTINUE_MSG(
-					entry.first == nullptr, godot::vformat("Null distribution key with value %f", entry.second.to_float())
+					entry.first == nullptr, vformat("Null distribution key with value %f", entry.second.to_float())
 				);
 				sorted_dist.push_back(entry);
 			}
 			std::sort(sorted_dist.begin(), sorted_dist.end(), [](entry_t const& lhs, entry_t const& rhs) -> bool {
 				return lhs.second < rhs.second;
 			});
-			static const godot::StringName identifier_key = "identifier";
-			static const godot::StringName colour_key = "colour";
-			static const godot::StringName weight_key = "weight";
-			godot::TypedArray<godot::Dictionary> array;
+			TypedArray<Dictionary> array;
 			for (auto const& [key, val] : sorted_dist) {
-				godot::Dictionary sub_dict;
-				sub_dict[identifier_key] = Utilities::std_view_to_godot_string(key->get_identifier());
-				sub_dict[colour_key] = Utilities::to_godot_color(key->get_colour());
-				sub_dict[weight_key] = val.to_float();
+				Dictionary sub_dict;
+				sub_dict[_slice_identifier_key()] = Utilities::std_view_to_godot_string(key->get_identifier());
+				sub_dict[_slice_colour_key()] = Utilities::to_godot_color(key->get_colour());
+				sub_dict[_slice_weight_key()] = val.to_float();
 				array.push_back(sub_dict);
 			}
 			return array;
 		}
 
-		/* Create a GFXPieChartTexture using the specific GFX::PieChart.
-		 * Returns nullptr if setting gfx_pie_chart fails. */
+		/* Create a GFXPieChartTexture using the specified GFX::PieChart. Returns nullptr if gfx_pie_chart fails. */
 		static godot::Ref<GFXPieChartTexture> make_gfx_pie_chart_texture(GFX::PieChart const* gfx_pie_chart);
 
 		/* Reset gfx_pie_chart, flag_country and flag_type to nullptr/an empty string, and unreference all images.
diff --git a/extension/src/openvic-extension/classes/GUINode.cpp b/extension/src/openvic-extension/classes/GUINode.cpp
index 043f65d..89701e0 100644
--- a/extension/src/openvic-extension/classes/GUINode.cpp
+++ b/extension/src/openvic-extension/classes/GUINode.cpp
@@ -49,6 +49,9 @@ void GUINode::_bind_methods() {
 }
 
 GUINode::GUINode() {
+	set_anchors_and_offsets_preset(PRESET_FULL_RECT);
+	set_h_grow_direction(GROW_DIRECTION_BOTH);
+	set_v_grow_direction(GROW_DIRECTION_BOTH);
 	set_mouse_filter(MOUSE_FILTER_IGNORE);
 }
 
diff --git a/extension/src/openvic-extension/classes/GUIOverlappingElementsBox.cpp b/extension/src/openvic-extension/classes/GUIOverlappingElementsBox.cpp
index ff88781..921f633 100644
--- a/extension/src/openvic-extension/classes/GUIOverlappingElementsBox.cpp
+++ b/extension/src/openvic-extension/classes/GUIOverlappingElementsBox.cpp
@@ -120,6 +120,15 @@ Error GUIOverlappingElementsBox::set_child_count(int32_t new_count) {
 					name, child_count, new_count
 				)
 			);
+
+			static const StringName set_z_index_func_name = "set_z_index";
+			static const StringName mouse_entered_signal_name = "mouse_entered";
+			static const StringName mouse_exited_signal_name = "mouse_exited";
+
+			/* Move the child element in front of its neighbours when moused-over. */
+			child->connect(mouse_entered_signal_name, Callable { child, set_z_index_func_name }.bind(1), CONNECT_PERSIST);
+			child->connect(mouse_exited_signal_name, Callable { child, set_z_index_func_name }.bind(0), CONNECT_PERSIST);
+
 			add_child(child);
 			child_count++;
 		} while (child_count < new_count);
diff --git a/extension/src/openvic-extension/register_types.cpp b/extension/src/openvic-extension/register_types.cpp
index 278365e..046bc60 100644
--- a/extension/src/openvic-extension/register_types.cpp
+++ b/extension/src/openvic-extension/register_types.cpp
@@ -2,6 +2,7 @@
 
 #include <godot_cpp/classes/engine.hpp>
 
+#include "openvic-extension/classes/GFXButtonStateTexture.hpp"
 #include "openvic-extension/classes/GFXIconTexture.hpp"
 #include "openvic-extension/classes/GFXMaskedFlagTexture.hpp"
 #include "openvic-extension/classes/GFXPieChartTexture.hpp"
@@ -43,6 +44,7 @@ void initialize_openvic_types(ModuleInitializationLevel p_level) {
 	Engine::get_singleton()->register_singleton("AssetManager", AssetManager::get_singleton());
 
 	ClassDB::register_class<MapMesh>();
+	ClassDB::register_class<GFXButtonStateTexture>();
 	ClassDB::register_class<GFXIconTexture>();
 	ClassDB::register_class<GFXMaskedFlagTexture>();
 	ClassDB::register_class<GFXPieChartTexture>();
diff --git a/extension/src/openvic-extension/singletons/GameSingleton.cpp b/extension/src/openvic-extension/singletons/GameSingleton.cpp
index 7ad0db0..e10efb3 100644
--- a/extension/src/openvic-extension/singletons/GameSingleton.cpp
+++ b/extension/src/openvic-extension/singletons/GameSingleton.cpp
@@ -25,6 +25,21 @@ using OpenVic::Utilities::std_view_to_godot_string;
 /* Maximum width or height a GPU texture can have. */
 static constexpr int32_t GPU_DIM_LIMIT = 0x3FFF;
 
+/* StringNames cannot be constructed until Godot has called StringName::setup(),
+ * so we must use these wrapper functions to delay their initialisation. */
+StringName const& GameSingleton::_signal_gamestate_updated() {
+	static const StringName signal_gamestate_updated = "gamestate_updated";
+	return signal_gamestate_updated;
+}
+StringName const& GameSingleton::_signal_province_selected() {
+	static const StringName signal_province_selected = "province_selected";
+	return signal_province_selected;
+}
+StringName const& GameSingleton::_signal_clock_state_changed() {
+	static const StringName signal_clock_state_changed = "clock_state_changed";
+	return signal_clock_state_changed;
+}
+
 void GameSingleton::_bind_methods() {
 	OV_BIND_SMETHOD(setup_logger);
 
@@ -70,24 +85,31 @@ void GameSingleton::_bind_methods() {
 	OV_BIND_METHOD(GameSingleton::get_longform_date);
 	OV_BIND_METHOD(GameSingleton::try_tick);
 
-	ADD_SIGNAL(MethodInfo("state_updated"));
-	ADD_SIGNAL(MethodInfo("province_selected", PropertyInfo(Variant::INT, "index")));
+	ADD_SIGNAL(MethodInfo(_signal_gamestate_updated()));
+	ADD_SIGNAL(MethodInfo(_signal_province_selected(), PropertyInfo(Variant::INT, "index")));
+	ADD_SIGNAL(MethodInfo(_signal_clock_state_changed()));
 }
 
 GameSingleton* GameSingleton::get_singleton() {
 	return singleton;
 }
 
-void GameSingleton::_on_state_updated() {
+void GameSingleton::_on_gamestate_updated() {
 	_update_colour_image();
-	emit_signal("state_updated");
+	emit_signal(_signal_gamestate_updated());
+}
+
+void GameSingleton::_on_clock_state_changed() {
+	emit_signal(_signal_clock_state_changed());
 }
 
 /* REQUIREMENTS:
  * MAP-21, MAP-23, MAP-25, MAP-32, MAP-33, MAP-34
  */
 GameSingleton::GameSingleton()
-	: game_manager { std::bind(&GameSingleton::_on_state_updated, this) } {
+	: game_manager {
+		std::bind(&GameSingleton::_on_gamestate_updated, this), std::bind(&GameSingleton::_on_clock_state_changed, this)
+	} {
 	ERR_FAIL_COND(singleton != nullptr);
 	singleton = this;
 }
@@ -360,7 +382,7 @@ int32_t GameSingleton::get_selected_province_index() const {
 void GameSingleton::set_selected_province(int32_t index) {
 	game_manager.get_map().set_selected_province(index);
 	_update_colour_image();
-	emit_signal("province_selected", index);
+	emit_signal(_signal_province_selected(), index);
 }
 
 int32_t GameSingleton::get_province_building_count() const {
@@ -411,35 +433,35 @@ String GameSingleton::float_to_formatted_string(float val) {
 }
 
 void GameSingleton::set_paused(bool paused) {
-	game_manager.get_clock().is_paused = paused;
+	game_manager.get_simulation_clock().set_paused(paused);
 }
 
 void GameSingleton::toggle_paused() {
-	game_manager.get_clock().is_paused = !game_manager.get_clock().is_paused;
+	game_manager.get_simulation_clock().toggle_paused();
 }
 
 bool GameSingleton::is_paused() const {
-	return game_manager.get_clock().is_paused;
+	return game_manager.get_simulation_clock().is_paused();
 }
 
 void GameSingleton::increase_speed() {
-	game_manager.get_clock().increase_simulation_speed();
+	game_manager.get_simulation_clock().increase_simulation_speed();
 }
 
 void GameSingleton::decrease_speed() {
-	game_manager.get_clock().decrease_simulation_speed();
+	game_manager.get_simulation_clock().decrease_simulation_speed();
 }
 
 int32_t GameSingleton::get_speed() const {
-	return game_manager.get_clock().get_simulation_speed();
+	return game_manager.get_simulation_clock().get_simulation_speed();
 }
 
 bool GameSingleton::can_increase_speed() const {
-	return game_manager.get_clock().can_increase_simulation_speed();
+	return game_manager.get_simulation_clock().can_increase_simulation_speed();
 }
 
 bool GameSingleton::can_decrease_speed() const {
-	return game_manager.get_clock().can_decrease_simulation_speed();
+	return game_manager.get_simulation_clock().can_decrease_simulation_speed();
 }
 
 String GameSingleton::get_longform_date() const {
@@ -447,7 +469,7 @@ String GameSingleton::get_longform_date() const {
 }
 
 void GameSingleton::try_tick() {
-	game_manager.get_clock().conditionally_advance_game();
+	game_manager.get_simulation_clock().conditionally_advance_game();
 }
 
 Error GameSingleton::_load_map_images(bool flip_vertical) {
diff --git a/extension/src/openvic-extension/singletons/GameSingleton.hpp b/extension/src/openvic-extension/singletons/GameSingleton.hpp
index 56f3c25..5622688 100644
--- a/extension/src/openvic-extension/singletons/GameSingleton.hpp
+++ b/extension/src/openvic-extension/singletons/GameSingleton.hpp
@@ -25,6 +25,10 @@ namespace OpenVic {
 		godot::Ref<godot::Texture2DArray> terrain_texture;
 		std::map<Country const*, std::map<godot::StringName, godot::Ref<godot::Image>>> flag_image_map;
 
+		static godot::StringName const& _signal_gamestate_updated();
+		static godot::StringName const& _signal_province_selected();
+		static godot::StringName const& _signal_clock_state_changed();
+
 		godot::Error _generate_terrain_texture_array();
 		godot::Error _load_map_images(bool flip_vertical);
 		godot::Error _load_terrain_variants();
@@ -32,7 +36,8 @@ namespace OpenVic {
 
 		/* Generate the province_colour_texture from the current mapmode. */
 		godot::Error _update_colour_image();
-		void _on_state_updated();
+		void _on_gamestate_updated();
+		void _on_clock_state_changed();
 
 	protected:
 		static void _bind_methods();
diff --git a/extension/src/openvic-extension/singletons/LoadLocalisation.cpp b/extension/src/openvic-extension/singletons/LoadLocalisation.cpp
index 6469820..8860105 100644
--- a/extension/src/openvic-extension/singletons/LoadLocalisation.cpp
+++ b/extension/src/openvic-extension/singletons/LoadLocalisation.cpp
@@ -30,7 +30,7 @@ LoadLocalisation::~LoadLocalisation() {
 	_singleton = nullptr;
 }
 
-Error LoadLocalisation::_load_file(String const& file_path, Ref<Translation> translation) const {
+Error LoadLocalisation::_load_file(String const& file_path, Ref<Translation> const& translation) const {
 	const Ref<FileAccess> file = FileAccess::open(file_path, FileAccess::ModeFlags::READ);
 	Error err = FileAccess::get_open_error();
 	ERR_FAIL_COND_V_MSG(
diff --git a/extension/src/openvic-extension/singletons/LoadLocalisation.hpp b/extension/src/openvic-extension/singletons/LoadLocalisation.hpp
index aeee076..9e39746 100644
--- a/extension/src/openvic-extension/singletons/LoadLocalisation.hpp
+++ b/extension/src/openvic-extension/singletons/LoadLocalisation.hpp
@@ -12,7 +12,7 @@ namespace OpenVic {
 
 		godot::Ref<godot::Translation> translations[Dataloader::_LocaleCount];
 
-		godot::Error _load_file(godot::String const& file_path, godot::Ref<godot::Translation> translation) const;
+		godot::Error _load_file(godot::String const& file_path, godot::Ref<godot::Translation> const& translation) const;
 		godot::Ref<godot::Translation> _get_translation(godot::String const& locale) const;
 
 	protected:
diff --git a/extension/src/openvic-extension/utility/UITools.cpp b/extension/src/openvic-extension/utility/UITools.cpp
index 67ea8f5..409a3ba 100644
--- a/extension/src/openvic-extension/utility/UITools.cpp
+++ b/extension/src/openvic-extension/utility/UITools.cpp
@@ -11,6 +11,7 @@
 #include <godot_cpp/classes/theme.hpp>
 #include <godot_cpp/variant/utility_functions.hpp>
 
+#include "openvic-extension/classes/GFXButtonStateTexture.hpp"
 #include "openvic-extension/classes/GFXIconTexture.hpp"
 #include "openvic-extension/classes/GFXMaskedFlagTexture.hpp"
 #include "openvic-extension/classes/GFXPieChartTexture.hpp"
@@ -138,28 +139,75 @@ static bool generate_icon(generate_gui_args_t&& args) {
 				godot_progress_bar, false, vformat("Failed to create TextureProgressBar for GUI icon %s", icon_name)
 			);
 
-			const StringName back_texture_file =
-				std_view_to_godot_string_name(icon.get_sprite()->cast_to<GFX::ProgressBar>()->get_back_texture_file());
-			const Ref<ImageTexture> back_texture = args.asset_manager.get_texture(back_texture_file);
+			GFX::ProgressBar const* progress_bar = icon.get_sprite()->cast_to<GFX::ProgressBar>();
+
+			Ref<ImageTexture> back_texture;
+			if (!progress_bar->get_back_texture_file().empty()) {
+				const StringName back_texture_file = std_view_to_godot_string_name(progress_bar->get_back_texture_file());
+				back_texture = args.asset_manager.get_texture(back_texture_file);
+				if (back_texture.is_null()) {
+					UtilityFunctions::push_error(
+						"Failed to load progress bar sprite back texture ", back_texture_file, " for GUI icon ", icon_name
+					);
+					ret = false;
+				}
+			}
+			if (back_texture.is_null()) {
+				const Color back_colour = Utilities::to_godot_color(progress_bar->get_back_colour());
+				back_texture = Utilities::make_solid_colour_texture(
+					back_colour, progress_bar->get_size().x, progress_bar->get_size().y
+				);
+				if (back_texture.is_null()) {
+					UtilityFunctions::push_error(
+						"Failed to generate progress bar sprite ", back_colour, " back texture for GUI icon ", icon_name
+					);
+					ret = false;
+				}
+			}
 			if (back_texture.is_valid()) {
 				godot_progress_bar->set_under_texture(back_texture);
 			} else {
-				UtilityFunctions::push_error("Failed to load progress bar base sprite ", back_texture_file, " for GUI icon ", icon_name);
+				UtilityFunctions::push_error(
+					"Failed to create and set progress bar sprite back texture for GUI icon ", icon_name
+				);
 				ret = false;
 			}
 
-			const StringName progress_texture_file =
-				std_view_to_godot_string_name(icon.get_sprite()->cast_to<GFX::ProgressBar>()->get_progress_texture_file());
-			const Ref<ImageTexture> progress_texture = args.asset_manager.get_texture(progress_texture_file);
+			Ref<ImageTexture> progress_texture;
+			if (!progress_bar->get_progress_texture_file().empty()) {
+				const StringName progress_texture_file = std_view_to_godot_string_name(progress_bar->get_progress_texture_file());
+				progress_texture = args.asset_manager.get_texture(progress_texture_file);
+				if (progress_texture.is_null()) {
+					UtilityFunctions::push_error(
+						"Failed to load progress bar sprite progress texture ", progress_texture_file, " for GUI icon ", icon_name
+					);
+					ret = false;
+				}
+			}
+			if (progress_texture.is_null()) {
+				const Color progress_colour = Utilities::to_godot_color(progress_bar->get_progress_colour());
+				progress_texture = Utilities::make_solid_colour_texture(
+					progress_colour, progress_bar->get_size().x, progress_bar->get_size().y
+				);
+				if (progress_texture.is_null()) {
+					UtilityFunctions::push_error(
+						"Failed to generate progress bar sprite ", progress_colour, " progress texture for GUI icon ", icon_name
+					);
+					ret = false;
+				}
+			}
 			if (progress_texture.is_valid()) {
 				godot_progress_bar->set_progress_texture(progress_texture);
 			} else {
 				UtilityFunctions::push_error(
-					"Failed to load progress bar base sprite ", progress_texture_file, " for GUI icon ", icon_name
+					"Failed to create and set progress bar sprite progress texture for GUI icon ", icon_name
 				);
 				ret = false;
 			}
 
+			// TODO - work out why progress bar is missing bottom border pixel (e.g. province building expansion bar)
+			godot_progress_bar->set_custom_minimum_size(Utilities::to_godot_fvec2(static_cast<fvec2_t>(progress_bar->get_size())));
+
 			args.result = godot_progress_bar;
 		} else if (icon.get_sprite()->is_type<GFX::PieChart>()) {
 			TextureRect* godot_texture_rect = new_control<TextureRect>(icon, args.name);
@@ -202,23 +250,43 @@ static bool generate_button(generate_gui_args_t&& args) {
 	Button* godot_button = new_control<Button>(button, args.name);
 	ERR_FAIL_NULL_V_MSG(godot_button, false, vformat("Failed to create Button for GUI button %s", button_name));
 
+	godot_button->set_mouse_filter(Control::MOUSE_FILTER_PASS);
+
 	if (!button.get_text().empty()) {
 		godot_button->set_text(std_view_to_godot_string(button.get_text()));
 	}
 
 	bool ret = true;
+
+	using enum GFXButtonStateTexture::ButtonState;
+	static constexpr std::array<GFXButtonStateTexture::ButtonState, 3> button_states { HOVER, PRESSED, DISABLED };
+
+	std::vector<Ref<GFXButtonStateTexture>> button_state_textures;
+	for (GFXButtonStateTexture::ButtonState button_state : button_states) {
+		Ref<GFXButtonStateTexture> button_state_texture = GFXButtonStateTexture::make_gfx_button_state_texture(button_state);
+		if (button_state_texture.is_valid()) {
+			button_state_textures.push_back(button_state_texture);
+		} else {
+			UtilityFunctions::push_error(
+				"Failed to make ", GFXButtonStateTexture::button_state_to_theme_name(button_state),
+				" GFXButtonStateTexture for GUI button ", button_name
+			);
+			ret = false;
+		}
+	}
+
 	if (button.get_sprite() != nullptr) {
 		Ref<Texture2D> texture;
 		if (button.get_sprite()->is_type<GFX::TextureSprite>()) {
 			GFX::TextureSprite const* texture_sprite = button.get_sprite()->cast_to<GFX::TextureSprite>();
-			texture = GFXIconTexture::make_gfx_icon_texture(texture_sprite);
+			texture = GFXIconTexture::make_gfx_icon_texture(texture_sprite, 0, button_state_textures);
 			if (texture.is_null()) {
 				UtilityFunctions::push_error("Failed to make GFXIconTexture for GUI button ", button_name);
 				ret = false;
 			}
 		} else if (button.get_sprite()->is_type<GFX::MaskedFlag>()) {
 			GFX::MaskedFlag const* masked_flag = button.get_sprite()->cast_to<GFX::MaskedFlag>();
-			texture = GFXMaskedFlagTexture::make_gfx_masked_flag_texture(masked_flag);
+			texture = GFXMaskedFlagTexture::make_gfx_masked_flag_texture(masked_flag, button_state_textures);
 			if (texture.is_null()) {
 				UtilityFunctions::push_error("Failed to make GFXMaskedFlagTexture for GUI button ", button_name);
 				ret = false;
@@ -231,15 +299,21 @@ static bool generate_button(generate_gui_args_t&& args) {
 
 		if (texture.is_valid()) {
 			godot_button->set_custom_minimum_size(texture->get_size());
-			Ref<StyleBoxTexture> stylebox;
-			stylebox.instantiate();
-			if (stylebox.is_valid()) {
-				static const StringName theme_name_normal = "normal";
+
+			const auto add_stylebox = [godot_button, &button_name](StringName const& theme_name, Ref<Texture2D> const& texture) -> bool {
+				Ref<StyleBoxTexture> stylebox;
+				stylebox.instantiate();
+				ERR_FAIL_NULL_V(stylebox, false);
 				stylebox->set_texture(texture);
-				godot_button->add_theme_stylebox_override(theme_name_normal, stylebox);
-			} else {
-				UtilityFunctions::push_error("Failed to load instantiate texture stylebox for GUI button ", button_name);
-				ret = false;
+				godot_button->add_theme_stylebox_override(theme_name, stylebox);
+				return true;
+			};
+
+			static const StringName theme_name_normal = "normal";
+			ret &= add_stylebox(theme_name_normal, texture);
+
+			for (Ref<GFXButtonStateTexture> const& button_state_texture : button_state_textures) {
+				ret &= add_stylebox(button_state_texture->get_button_state_theme(), button_state_texture);
 			}
 		}
 	} else {
@@ -256,8 +330,14 @@ static bool generate_button(generate_gui_args_t&& args) {
 			UtilityFunctions::push_error("Failed to load font for GUI button ", button_name);
 			ret = false;
 		}
+
+		static const std::vector<StringName> button_font_themes {
+			"font_color", "font_hover_color", "font_hover_pressed_color", "font_pressed_color", "font_disabled_color"
+		};
 		const Color colour = Utilities::to_godot_color(button.get_font()->get_colour());
-		godot_button->add_theme_color_override("font_color", colour);
+		for (StringName const& theme_name : button_font_themes) {
+			godot_button->add_theme_color_override(theme_name, colour);
+		}
 	}
 
 	args.result = godot_button;
diff --git a/game/src/Game/GameSession/GameSession.tscn b/game/src/Game/GameSession/GameSession.tscn
index a3a5f38..c7a8003 100644
--- a/game/src/Game/GameSession/GameSession.tscn
+++ b/game/src/Game/GameSession/GameSession.tscn
@@ -27,19 +27,11 @@ _game_session_menu = NodePath("GameSessionMenu")
 [node name="ProvinceOverviewPanel" type="GUINode" parent="."]
 layout_mode = 1
 anchors_preset = 15
-anchor_right = 1.0
-anchor_bottom = 1.0
-grow_horizontal = 2
-grow_vertical = 2
 script = ExtResource("5_lfv8l")
 
 [node name="Topbar" type="GUINode" parent="."]
 layout_mode = 1
 anchors_preset = 15
-anchor_right = 1.0
-anchor_bottom = 1.0
-grow_horizontal = 2
-grow_vertical = 2
 script = ExtResource("4_2kbih")
 
 [node name="MapControlPanel" parent="." instance=ExtResource("3_afh6d")]
diff --git a/game/src/Game/GameSession/ProvinceOverviewPanel.gd b/game/src/Game/GameSession/ProvinceOverviewPanel.gd
index 6ffc906..8920b26 100644
--- a/game/src/Game/GameSession/ProvinceOverviewPanel.gd
+++ b/game/src/Game/GameSession/ProvinceOverviewPanel.gd
@@ -119,7 +119,7 @@ var _province_info : Dictionary
 
 func _ready() -> void:
 	GameSingleton.province_selected.connect(_on_province_selected)
-	GameSingleton.state_updated.connect(_update_info)
+	GameSingleton.gamestate_updated.connect(_update_info)
 
 	if add_gui_element("province_interface.gui", "province_view") != OK:
 		push_error("Failed to generate province overview panel!")
diff --git a/game/src/Game/GameSession/Topbar.gd b/game/src/Game/GameSession/Topbar.gd
index 4de9474..b6a170f 100644
--- a/game/src/Game/GameSession/Topbar.gd
+++ b/game/src/Game/GameSession/Topbar.gd
@@ -8,7 +8,8 @@ var _date_label : Label
 var _country_name_label : Label
 
 func _ready() -> void:
-	GameSingleton.state_updated.connect(_update_info)
+	GameSingleton.gamestate_updated.connect(_update_info)
+	GameSingleton.clock_state_changed.connect(_update_speed_controls)
 
 	add_gui_element("topbar.gui", "topbar")
 
@@ -42,13 +43,25 @@ func _ready() -> void:
 		_country_name_label.text = player_country
 
 	_speed_indicator_button = get_button_from_nodepath(^"./topbar/speed_indicator")
-	_speed_indicator_texture = get_gfx_icon_texture_from_nodepath(^"./topbar/speed_indicator")
+	if _speed_indicator_button:
+		_speed_indicator_button.pressed.connect(_on_play_pause_button_pressed)
+		_speed_indicator_texture = get_gfx_icon_texture_from_node(_speed_indicator_button)
+
+	_update_info()
+	_update_speed_controls()
+
+func _notification(what : int) -> void:
+	match what:
+		NOTIFICATION_TRANSLATION_CHANGED:
+			_update_info()
 
 func _update_info() -> void:
 	if _date_label:
 		_date_label.text = GameSingleton.get_longform_date()
 
-	#  TODO - add disabled state textures so this doesn't hide the buttons
+func _update_speed_controls() -> void:
+	#  TODO - decide whether to disable these or not
+	# (they don't appear to get disabled in the base game)
 	#if _speed_up_button:
 	#	_speed_up_button.disabled = not GameSingleton.can_increase_speed()
 
@@ -67,18 +80,15 @@ func _update_info() -> void:
 func _on_play_pause_button_pressed() -> void:
 	print("Toggling pause!")
 	GameSingleton.toggle_paused()
-	_update_info()
 
 # REQUIREMENTS:
 # * UIFUN-72
 func _on_increase_speed_button_pressed() -> void:
 	print("Speed up!")
 	GameSingleton.increase_speed()
-	_update_info()
 
 # REQUIREMENTS:
 # * UIFUN-73
 func _on_decrease_speed_button_pressed() -> void:
 	print("Speed down!")
 	GameSingleton.decrease_speed()
-	_update_info()