Add SFML 3 support to the SFML backend

By default, CMake will now first look for SFML 3, and only if that is not found, it will look for SFML 2. To override the automatic selection, set `RMLUI_SFML_VERSION_MAJOR` to the desired version (2 or 3). Here, an empty value means default (automatic) behavior.

Backends/RmlUi_Backend_SFML_GL2.cpp

@@ -36,6 +36,13 @@
 #include <RmlUi/Debugger/Debugger.h>
 #include <SFML/Graphics.hpp>
 #include <SFML/Window.hpp>
+#include <cstdint>
+
+#if SFML_VERSION_MAJOR >= 3
+	#define SFML_COORDINATE(x, y) {x, y}
+#else
+	#define SFML_COORDINATE(x, y) x, y
+#endif
 
 /**
     Custom render interface example for the SFML/GL2 backend.
@@ -82,11 +89,11 @@ class RenderInterface_GL2_SFML : public RenderInterface_GL2 {
 		{
 			for (unsigned int y = 0; y < image.getSize().y; y++)
 			{
-				sf::Color color = image.getPixel(x, y);
-				color.r = (sf::Uint8)((color.r * color.a) / 255);
-				color.g = (sf::Uint8)((color.g * color.a) / 255);
-				color.b = (sf::Uint8)((color.b * color.a) / 255);
-				image.setPixel(x, y, color);
+				sf::Color color = image.getPixel(SFML_COORDINATE(x, y));
+				color.r = static_cast<std::uint8_t>((color.r * color.a) / 255);
+				color.g = static_cast<std::uint8_t>((color.g * color.a) / 255);
+				color.b = static_cast<std::uint8_t>((color.b * color.a) / 255);
+				image.setPixel(SFML_COORDINATE(x, y), color);
 			}
 		}
 
@@ -103,19 +110,22 @@ class RenderInterface_GL2_SFML : public RenderInterface_GL2 {
 		return (Rml::TextureHandle)texture;
 	}
 
-	Rml::TextureHandle GenerateTexture(Rml::Span<const Rml::byte> source, Rml::Vector2i source_dimensions) override
+	Rml::TextureHandle GenerateTexture(Rml::Span<const Rml::byte> source, Rml::Vector2i source_dimensions_i) override
 	{
-		sf::Texture* texture = new sf::Texture();
-		texture->setSmooth(true);
+		const auto source_dimensions = Rml::Vector2<unsigned int>(source_dimensions_i);
 
+#if SFML_VERSION_MAJOR >= 3
+		sf::Texture* texture = new sf::Texture(sf::Vector2u{source_dimensions.x, source_dimensions.y});
+#else
+		sf::Texture* texture = new sf::Texture();
 		if (!texture->create(source_dimensions.x, source_dimensions.y))
 		{
 			delete texture;
 			return false;
 		}
-
-		texture->update(source.data(), source_dimensions.x, source_dimensions.y, 0, 0);
-
+#endif
+		texture->setSmooth(true);
+		texture->update(source.data(), SFML_COORDINATE(source_dimensions.x, source_dimensions.y), SFML_COORDINATE(0, 0));
 		return (Rml::TextureHandle)texture;
 	}
 
@@ -131,7 +141,7 @@ static void UpdateWindowDimensions(sf::RenderWindow& window, RenderInterface_GL2
 	if (context)
 		context->SetDimensions(Rml::Vector2i(width, height));
 
-	sf::View view(sf::FloatRect(0.f, 0.f, (float)width, (float)height));
+	sf::View view(sf::FloatRect(SFML_COORDINATE(0.f, 0.f), SFML_COORDINATE((float)width, (float)height)));
 	window.setView(view);
 
 	render_interface.SetViewport(width, height);
@@ -156,17 +166,23 @@ bool Backend::Initialize(const char* window_name, int width, int height, bool al
 
 	data = Rml::MakeUnique<BackendData>();
 
+	const std::uint32_t style = (allow_resize ? sf::Style::Default : (sf::Style::Titlebar | sf::Style::Close));
+	constexpr unsigned int anti_aliasing_level = 2;
+
 	// Create the window.
 	sf::RenderWindow out_window;
 	sf::ContextSettings context_settings;
 	context_settings.stencilBits = 8;
-	context_settings.antialiasingLevel = 2;
-
-	const sf::Uint32 style = (allow_resize ? sf::Style::Default : (sf::Style::Titlebar | sf::Style::Close));
 
+#if SFML_VERSION_MAJOR >= 3
+	context_settings.antiAliasingLevel = anti_aliasing_level;
+	data->window.create(sf::VideoMode({(unsigned int)width, (unsigned int)height}), window_name, style, sf::State::Windowed, context_settings);
+#else
+	context_settings.antialiasingLevel = anti_aliasing_level;
 	data->window.create(sf::VideoMode(width, height), window_name, style, context_settings);
-	data->window.setVerticalSyncEnabled(true);
+#endif
 
+	data->window.setVerticalSyncEnabled(true);
 	if (!data->window.isOpen())
 	{
 		data.reset();
@@ -209,34 +225,57 @@ bool Backend::ProcessEvents(Rml::Context* context, KeyDownCallback key_down_call
 	bool result = data->running;
 	data->running = true;
 
+	auto handle_key_pressed = [&](const sf::Event& ev, sf::Keyboard::Key key_pressed_code) {
+		const Rml::Input::KeyIdentifier key = RmlSFML::ConvertKey(key_pressed_code);
+		const int key_modifier = RmlSFML::GetKeyModifierState();
+		const float native_dp_ratio = 1.f;
+
+		// See if we have any global shortcuts that take priority over the context.
+		if (key_down_callback && !key_down_callback(context, key, key_modifier, native_dp_ratio, true))
+			return;
+		// Otherwise, hand the event over to the context by calling the input handler as normal.
+		if (!RmlSFML::InputHandler(context, ev))
+			return;
+		// The key was not consumed by the context either, try keyboard shortcuts of lower priority.
+		if (key_down_callback && !key_down_callback(context, key, key_modifier, native_dp_ratio, false))
+			return;
+	};
+
+#if SFML_VERSION_MAJOR >= 3
+	while (const std::optional ev = data->window.pollEvent())
+	{
+		if (ev->is<sf::Event::Resized>())
+		{
+			UpdateWindowDimensions(data->window, data->render_interface, context);
+		}
+		else if (auto key_pressed = ev->getIf<sf::Event::KeyPressed>())
+		{
+			handle_key_pressed(*ev, key_pressed->code);
+		}
+		else if (ev->is<sf::Event::Closed>())
+		{
+			result = false;
+		}
+		else
+		{
+			RmlSFML::InputHandler(context, *ev);
+		}
+	}
+
+#else
+
 	sf::Event ev;
 	while (data->window.pollEvent(ev))
 	{
 		switch (ev.type)
 		{
 		case sf::Event::Resized: UpdateWindowDimensions(data->window, data->render_interface, context); break;
-		case sf::Event::KeyPressed:
-		{
-			const Rml::Input::KeyIdentifier key = RmlSFML::ConvertKey(ev.key.code);
-			const int key_modifier = RmlSFML::GetKeyModifierState();
-			const float native_dp_ratio = 1.f;
-
-			// See if we have any global shortcuts that take priority over the context.
-			if (key_down_callback && !key_down_callback(context, key, key_modifier, native_dp_ratio, true))
-				break;
-			// Otherwise, hand the event over to the context by calling the input handler as normal.
-			if (!RmlSFML::InputHandler(context, ev))
-				break;
-			// The key was not consumed by the context either, try keyboard shortcuts of lower priority.
-			if (key_down_callback && !key_down_callback(context, key, key_modifier, native_dp_ratio, false))
-				break;
-		}
-		break;
+		case sf::Event::KeyPressed: handle_key_pressed(ev, ev.key.code); break;
 		case sf::Event::Closed: result = false; break;
 		default: RmlSFML::InputHandler(context, ev); break;
 		}
 	}
-
+#endif
 	return result;
 }