1 files changed, 116 insertions, 0 deletions
diff --git a/src/display/systems.rs b/src/display/systems.rs
new file mode 100644
index 0000000..a768af5
--- /dev/null
+++ b/src/display/systems.rs
@@ -0,0 +1,116 @@
+use bevy::{
+    prelude::*,
+    render::render_resource::{Extent3d, TextureFormat},
+};
+use crossterm::event::Event;
+use bevy_framebuffer_extract::{
+    components::FramebufferExtractDestination, render_assets::FramebufferExtractSource,
+};
+use ratatui::{
+    style::Stylize,
+    widgets::{Paragraph, Wrap},
+};
+
+use crate::input::events::TerminalInputEvent;
+
+use super::resources::Terminal;
+
+const BRAILLE_CODE_MIN: u16 = 0x2800;
+const BRAILLE_CODE_MAX: u16 = 0x28FF;
+
+/// 0 3
+/// 1 4
+/// 2 5
+/// 6 7
+const BRAILLE_DOT_BIT_POSITIONS: [u8; 8] = [0, 1, 2, 6, 3, 4, 5, 7];
+
+/// Prints out the contents of a render image to the terminal as braille characters
+pub fn print_to_terminal(
+    mut terminal: ResMut<Terminal>,
+    image_exports: Query<&FramebufferExtractDestination>,
+) {
+    for image_export in image_exports.iter() {
+        let mut image = image_export
+            .0
+            .lock()
+            .expect("Failed to get lock on output texture");
+        if image.texture_descriptor.format != TextureFormat::R8Unorm {
+            warn_once!("Extracted framebuffer texture is not R8Unorm format. Will attempt conversion, but consider changing your render texture's format.");
+            info_once!("{:?}", image);
+            match image.convert(TextureFormat::R8Unorm) {
+                Some(img) => *image = img,
+                None => error_once!(
+                    "Could not convert to R8Unorm texture format. Unexpected output may occur."
+                ),
+            };
+        }
+
+        let mut output_buffer = Vec::<char>::new();
+        let width = image.width();
+        let height = image.height();
+        let data = &image.data;
+        for character_y in (0..height).step_by(4) {
+            for character_x in (0..width).step_by(2) {
+                let mut mask: u8 = 0;
+                for offset_x in 0..2 {
+                    for offset_y in 0..4 {
+                        let x = character_x + offset_x;
+                        let y = character_y + offset_y;
+                        if x < width && y < height && data[(y * width + x) as usize] == 0xFF {
+                            mask |= 1
+                                << (BRAILLE_DOT_BIT_POSITIONS[(offset_x * 4 + offset_y) as usize]);
+                        }
+                    }
+                }
+                output_buffer.push(braille_char(mask));
+            }
+        }
+
+        let string = output_buffer.into_iter().collect::<String>();
+        terminal
+            .0
+            .draw(|frame| {
+                frame.render_widget(
+                    Paragraph::new(string)
+                        .white()
+                        .bold()
+                        .wrap(Wrap { trim: true }),
+                    frame.size(),
+                );
+            })
+            .expect("Failed to draw terminal frame");
+    }
+}
+
+/// Utility function to convert a u8 into the corresponding braille character
+fn braille_char(mask: u8) -> char {
+    match char::from_u32((BRAILLE_CODE_MIN + mask as u16) as u32) {
+        Some(character) => {
+            if character as u16 > BRAILLE_CODE_MAX {
+                panic!("Number too big!")
+            }
+            character
+        }
+        None => panic!("Error converting character!"),
+    }
+}
+
+/// Watches for terminal resize events and resizes the render image accordingly
+pub fn resize_handling(
+    mut images: ResMut<Assets<Image>>,
+    mut sources: ResMut<Assets<FramebufferExtractSource>>,
+    mut event_reader: EventReader<TerminalInputEvent>,
+) {
+    for event in event_reader.read() {
+        if let Event::Resize(w, h) = event.0 {
+            for source in sources.iter_mut() {
+                let image = images.get_mut(&source.1 .0).unwrap();
+                image.resize(Extent3d {
+                    width: w as u32 * 2,
+                    height: h as u32 * 4,
+                    depth_or_array_layers: 1,
+                });
+            }
+        }
+    }
+}