update DosLike system resource with variable screen size support

also re-did DosLikeConfig at the same time, making usage a bit clearer

ggdt/src/system/framebuffer.rs

@@ -0,0 +1,123 @@
+use byte_slice_cast::AsByteSlice;
+use thiserror::Error;
+
+use crate::graphics::bitmap::indexed::IndexedBitmap;
+use crate::graphics::bitmap::rgb::RgbaBitmap;
+use crate::graphics::palette::Palette;
+
+pub fn calculate_logical_screen_size(window_width: u32, window_height: u32, scale_factor: u32) -> (u32, u32) {
+	let logical_width = (window_width as f32 / scale_factor as f32).ceil() as u32;
+	let logical_height = (window_height as f32 / scale_factor as f32).ceil() as u32;
+	(logical_width, logical_height)
+}
+
+const SCREEN_TEXTURE_PIXEL_SIZE: usize = 4; // 32-bit ARGB format
+
+#[derive(Error, Debug)]
+pub enum SdlFramebufferError {
+	#[error("SdlFramebufferError SDL error: {0}")]
+	SDLError(String),
+}
+
+/// Internal structure to manager the SDL renderer/canvas and texture bits surrounding how we display our
+/// [`SystemResources`] implementation managed [`Bitmap`][Bitmap] backbuffer to the actual screen.
+///
+/// [Bitmap]: crate::graphics::bitmap::Bitmap
+pub struct SdlFramebuffer {
+	sdl_texture: sdl2::render::Texture,
+	sdl_texture_pitch: usize,
+	intermediate_texture: Option<Box<[u32]>>,
+}
+
+// TODO: i'm not totally happy with this implementation. i don't like the two display methods and how the caller
+//       can technically call the wrong method. while i'm quite sure this won't happen in practice, it still feels
+//       like a bad design which we could do better. but this is simple for now, so i'll leave it for the time being.
+//       since this is all not in a public module, that seems like less of a big deal to me as well. for now.
+impl SdlFramebuffer {
+	pub fn new(
+		canvas: &mut sdl2::render::WindowCanvas,
+		logical_screen_width: u32,
+		logical_screen_height: u32,
+		create_intermediate_texture: bool,
+	) -> Result<Self, SdlFramebufferError> {
+		// this sets up screen/window resolution independant rendering on the SDL-side of things
+		// which we may or may not actually need, but this ALSO changes the way that SDL reports things
+		// like mouse cursor coordinates. so we benefit from setting the canvas logical screen size
+		// to always match our window size, even when we are using variable screen sizes.
+		if let Err(error) = canvas.set_logical_size(logical_screen_width, logical_screen_height) {
+			return Err(SdlFramebufferError::SDLError(error.to_string()));
+		}
+
+		let sdl_texture = match canvas.create_texture_streaming(
+			Some(sdl2::pixels::PixelFormatEnum::ARGB8888),
+			logical_screen_width,
+			logical_screen_height,
+		) {
+			Ok(texture) => texture,
+			Err(error) => return Err(SdlFramebufferError::SDLError(error.to_string())),
+		};
+		let sdl_texture_pitch = sdl_texture.query().width as usize * SCREEN_TEXTURE_PIXEL_SIZE;
+
+		let intermediate_texture = if create_intermediate_texture {
+			// create a raw 32-bit RGBA buffer that will be used as the temporary source for
+			// SDL texture uploads each frame. necessary as applications are dealing with 8-bit indexed
+			// bitmaps, not 32-bit RGBA pixels, so this temporary buffer is where we convert the final
+			// application framebuffer to 32-bit RGBA pixels before it is uploaded to the SDL texture
+			let texture_pixels_size =
+				(logical_screen_width * logical_screen_height) as usize * SCREEN_TEXTURE_PIXEL_SIZE;
+			Some(vec![0u32; texture_pixels_size].into_boxed_slice())
+		} else {
+			None
+		};
+
+		Ok(SdlFramebuffer { sdl_texture, sdl_texture_pitch, intermediate_texture })
+	}
+
+	pub fn display_indexed_bitmap(
+		&mut self,
+		canvas: &mut sdl2::render::WindowCanvas,
+		src: &IndexedBitmap,
+		palette: &Palette,
+	) -> Result<(), SdlFramebufferError> {
+		let intermediate_texture = &mut self.intermediate_texture.as_mut().expect(
+			"Calls to display_indexed_bitmap should only occur on SdlFramebuffers with an intermediate_texture",
+		);
+
+		src.copy_as_argb_to(intermediate_texture, palette);
+
+		let texture_pixels = intermediate_texture.as_byte_slice();
+		if let Err(error) = self.sdl_texture.update(None, texture_pixels, self.sdl_texture_pitch) {
+			return Err(SdlFramebufferError::SDLError(error.to_string()));
+		}
+		canvas.clear();
+		if let Err(error) = canvas.copy(&self.sdl_texture, None, None) {
+			return Err(SdlFramebufferError::SDLError(error));
+		}
+		canvas.present();
+
+		Ok(())
+	}
+
+	pub fn display(
+		&mut self,
+		canvas: &mut sdl2::render::WindowCanvas,
+		src: &RgbaBitmap,
+	) -> Result<(), SdlFramebufferError> {
+		assert!(
+			self.intermediate_texture.is_none(),
+			"Calls to display should only occur on SdlFramebuffers without an intermediate_texture"
+		);
+
+		let texture_pixels = src.pixels().as_byte_slice();
+		if let Err(error) = self.sdl_texture.update(None, texture_pixels, self.sdl_texture_pitch) {
+			return Err(SdlFramebufferError::SDLError(error.to_string()));
+		}
+		canvas.clear();
+		if let Err(error) = canvas.copy(&self.sdl_texture, None, None) {
+			return Err(SdlFramebufferError::SDLError(error));
+		}
+		canvas.present();
+
+		Ok(())
+	}
+}

ggdt/src/system/mod.rs

@@ -8,6 +8,7 @@ pub mod event;
 pub mod input_devices;
 pub mod res;
 
+mod framebuffer;
 pub mod prelude;
 
 fn is_x11_compositor_skipping_problematic() -> bool {

ggdt/src/system/res/dos_like.rs

@@ -26,14 +26,14 @@
 //! ```
 //!
 
-use byte_slice_cast::AsByteSlice;
-
 use crate::audio::queue::AudioQueue;
 use crate::audio::{Audio, TARGET_AUDIO_CHANNELS, TARGET_AUDIO_FREQUENCY};
 use crate::graphics::bitmap::indexed::IndexedBitmap;
 use crate::graphics::font::BitmaskFont;
 use crate::graphics::palette::Palette;
+use crate::prelude::WindowEvent;
 use crate::system::event::{SystemEvent, SystemEventHandler};
+use crate::system::framebuffer::{calculate_logical_screen_size, SdlFramebuffer};
 use crate::system::input_devices::keyboard::Keyboard;
 use crate::system::input_devices::mouse::cursor::CustomMouseCursor;
 use crate::system::input_devices::mouse::Mouse;
@@ -48,22 +48,48 @@ const DEFAULT_SCALE_FACTOR: u32 = 3;
 pub struct DosLikeConfig {
 	screen_width: u32,
 	screen_height: u32,
+	fixed_screen_size: bool,
 	initial_scale_factor: u32,
 	integer_scaling: bool,
 }
 
-impl DosLikeConfig {
+impl Default for DosLikeConfig {
 	/// Returns a new [`DosLikeConfig`] with a default configuration.
-	pub fn new() -> Self {
+	fn default() -> Self {
+		DosLikeConfig::fixed_screen_size(DEFAULT_SCREEN_WIDTH, DEFAULT_SCREEN_HEIGHT, false)
+	}
+}
+
+impl DosLikeConfig {
+	/// Creates a configuration that will use a fixed screen size at a set scaling factor. Any window resizing
+	/// will simply scale up or down the final image on screen, but the application will always use the same
+	/// logical screen resolution, `screen_width` and `screen_height`, at runtime.
+	pub fn fixed_screen_size(screen_width: u32, screen_height: u32, integer_scaling: bool) -> Self {
 		DosLikeConfig {
-			screen_width: DEFAULT_SCREEN_WIDTH,
-			screen_height: DEFAULT_SCREEN_HEIGHT,
+			screen_width,
+			screen_height,
 			initial_scale_factor: DEFAULT_SCALE_FACTOR,
-			integer_scaling: false,
+			integer_scaling,
+			fixed_screen_size: true,
 		}
 	}
 
-	// TODO: add customization ability for setting different screen dimensions instead of it being hardcoded
+	/// Creates a configuration that allows the screen size to be automatically updated at runtime to match the
+	/// current window size, including any arbitrary user window resizing. The final image on screen will always be
+	/// scaled up by the factor given. The logical screen size at runtime (as seen by the application code) is
+	/// always based on:
+	///
+	/// `logical_screen_width = ceil(window_width / scale_factor)`  
+	/// `logical_screen_height = ceil(window_height / scale_factor)`
+	pub fn variable_screen_size(initial_width: u32, initial_height: u32) -> Self {
+		DosLikeConfig {
+			screen_width: initial_width,
+			screen_height: initial_height,
+			initial_scale_factor: DEFAULT_SCALE_FACTOR,
+			integer_scaling: false,
+			fixed_screen_size: false,
+		}
+	}
 
 	/// Sets an integer scaling factor for the [`System`] being built to up-scale the virtual
 	/// framebuffer to when displaying it on screen.
@@ -71,13 +97,6 @@ impl DosLikeConfig {
 		self.initial_scale_factor = scale_factor;
 		self
 	}
-
-	/// Enables or disables restricting the final rendered output to always be integer scaled,
-	/// even if that result will not fully fill the area of the window.
-	pub fn integer_scaling(mut self, enable: bool) -> Self {
-		self.integer_scaling = enable;
-		self
-	}
 }
 
 impl SystemResourcesConfig for DosLikeConfig {
@@ -89,8 +108,6 @@ impl SystemResourcesConfig for DosLikeConfig {
 		audio_subsystem: &sdl2::AudioSubsystem,
 		mut window: sdl2::video::Window,
 	) -> Result<Self::SystemResourcesType, SystemResourcesError> {
-		let texture_pixel_size = 4; // 32-bit ARGB format
-
 		let window_width = self.screen_width * self.initial_scale_factor;
 		let window_height = self.screen_height * self.initial_scale_factor;
 		if let Err(error) = window.set_size(window_width, window_height) {
@@ -104,9 +121,6 @@ impl SystemResourcesConfig for DosLikeConfig {
 			Ok(canvas) => canvas,
 			Err(error) => return Err(SystemResourcesError::SDLError(error.to_string())),
 		};
-		if let Err(error) = sdl_canvas.set_logical_size(self.screen_width, self.screen_height) {
-			return Err(SystemResourcesError::SDLError(error.to_string()));
-		};
 
 		// TODO: newer versions of rust-sdl2 support this directly off the WindowCanvas struct
 		unsafe {
@@ -120,30 +134,14 @@ impl SystemResourcesConfig for DosLikeConfig {
 			);
 		}
 
-		// create an SDL texture which we will be uploading to every frame to display the
-		// application's framebuffer
+		// create the SDL framebuffer at the initial logical screen size
 
-		let sdl_texture = match sdl_canvas.create_texture_streaming(
-			Some(sdl2::pixels::PixelFormatEnum::ARGB8888),
-			self.screen_width,
-			self.screen_height,
-		) {
-			Ok(texture) => texture,
-			Err(error) => return Err(SystemResourcesError::SDLError(error.to_string())),
-		};
-		let sdl_texture_pitch = (sdl_texture.query().width * texture_pixel_size) as usize;
-
-		// create a raw 32-bit RGBA buffer that will be used as the temporary source for
-		// SDL texture uploads each frame. necessary as applications are dealing with 8-bit indexed
-		// bitmaps, not 32-bit RGBA pixels, so this temporary buffer is where we convert the final
-		// application framebuffer to 32-bit RGBA pixels before it is uploaded to the SDL texture
-		let texture_pixels_size = (self.screen_width * self.screen_height * texture_pixel_size) as usize;
-		let texture_pixels = vec![0u32; texture_pixels_size].into_boxed_slice();
+		let framebuffer = SdlFramebuffer::new(&mut sdl_canvas, self.screen_width, self.screen_height, true)?;
 
 		// create the Bitmap object that will be exposed to the application acting as the system
 		// backbuffer
 
-		let framebuffer = match IndexedBitmap::new(self.screen_width, self.screen_height) {
+		let screen_bitmap = match IndexedBitmap::new(self.screen_width, self.screen_height) {
 			Ok(bmp) => bmp,
 			Err(error) => return Err(SystemResourcesError::SDLError(error.to_string())),
 		};
@@ -182,13 +180,13 @@ impl SystemResourcesConfig for DosLikeConfig {
 
 		Ok(DosLike {
 			sdl_canvas,
-			sdl_texture,
-			sdl_texture_pitch,
-			texture_pixels,
+			framebuffer,
+			scale_factor: self.initial_scale_factor,
+			fixed_screen_size: self.fixed_screen_size,
 			audio,
 			audio_queue,
 			palette,
-			video: framebuffer,
+			video: screen_bitmap,
 			font,
 			keyboard,
 			mouse,
@@ -201,9 +199,9 @@ impl SystemResourcesConfig for DosLikeConfig {
 /// audio via [`Audio`] and keyboard/mouse input.
 pub struct DosLike {
 	sdl_canvas: sdl2::render::WindowCanvas,
-	sdl_texture: sdl2::render::Texture,
-	sdl_texture_pitch: usize,
-	texture_pixels: Box<[u32]>,
+	framebuffer: SdlFramebuffer,
+	scale_factor: u32,
+	fixed_screen_size: bool,
 
 	/// An [`Audio`] instance that allows interacting with the system's audio output device.
 	pub audio: Audio,
@@ -267,24 +265,8 @@ impl SystemResources for DosLike {
 	/// to fill the window (preserving aspect ratio of course).
 	fn display(&mut self) -> Result<(), SystemResourcesError> {
 		self.cursor.render(&mut self.video);
-
-		// convert application framebuffer to 32-bit RGBA pixels, and then upload it to the SDL
-		// texture so it will be displayed on screen
-
-		self.video.copy_as_argb_to(&mut self.texture_pixels, &self.palette);
-
-		let texture_pixels = self.texture_pixels.as_byte_slice();
-		if let Err(error) = self.sdl_texture.update(None, texture_pixels, self.sdl_texture_pitch) {
-			return Err(SystemResourcesError::SDLError(error.to_string()));
-		}
-		self.sdl_canvas.clear();
-		if let Err(error) = self.sdl_canvas.copy(&self.sdl_texture, None, None) {
-			return Err(SystemResourcesError::SDLError(error));
-		}
-		self.sdl_canvas.present();
-
+		self.framebuffer.display_indexed_bitmap(&mut self.sdl_canvas, &self.video, &self.palette)?;
 		self.cursor.hide(&mut self.video);
-
 		Ok(())
 	}
 
@@ -295,6 +277,13 @@ impl SystemResources for DosLike {
 	}
 
 	fn handle_event(&mut self, event: &SystemEvent) -> Result<bool, SystemResourcesError> {
+		if let SystemEvent::Window(WindowEvent::SizeChanged(width, height)) = event {
+			if !self.fixed_screen_size {
+				self.resize_screen(*width as u32, *height as u32)?;
+			}
+			return Ok(true);
+		}
+
 		if self.keyboard.handle_event(event) {
 			return Ok(true);
 		}
@@ -314,3 +303,21 @@ impl SystemResources for DosLike {
 		self.video.height()
 	}
 }
+
+impl DosLike {
+	fn resize_screen(&mut self, new_width: u32, new_height: u32) -> Result<(), SystemResourcesError> {
+		let (logical_width, logical_height) = calculate_logical_screen_size(new_width, new_height, self.scale_factor);
+
+		let framebuffer = SdlFramebuffer::new(&mut self.sdl_canvas, logical_width, logical_height, true)?;
+
+		let screen_bitmap = match IndexedBitmap::new(logical_width, logical_height) {
+			Ok(bmp) => bmp,
+			Err(error) => return Err(SystemResourcesError::SDLError(error.to_string())),
+		};
+
+		self.framebuffer = framebuffer;
+		self.video = screen_bitmap;
+
+		Ok(())
+	}
+}

ggdt/src/system/res/mod.rs

@@ -3,6 +3,7 @@ use thiserror::Error;
 use crate::audio::device::AudioDeviceError;
 use crate::audio::AudioError;
 use crate::system::event::SystemEvent;
+use crate::system::framebuffer::SdlFramebufferError;
 
 pub mod dos_like;
 pub mod standard;
@@ -12,6 +13,9 @@ pub enum SystemResourcesError {
 	#[error("SystemResources SDL error: {0}")]
 	SDLError(String),
 
+	#[error("SdlFramebufferError: {0}")]
+	SdlFramebufferError(#[from] SdlFramebufferError),
+
 	#[error("System audioerror: {0}")]
 	AudioError(#[from] AudioError),