broken GUI impl + Broken PPU scrolling

src/render.rs

@@ -1,15 +1,17 @@
+use eframe::egui;
+use crate::input::{key_to_button, Controller, Key};
 use crate::palette::index_to_rgb;
 
 pub trait Renderer {
     fn present(&mut self, framebuffer: &[u8], width: u16, height: u16);
+    fn should_close(&self) -> bool { false }                              // headless never closes
+    fn poll_input(&mut self, _controller: &mut Controller) {}             // headless: no input
 }
 
 pub struct PpmRenderer {
     frame: u32,
 }
 
-
-
 impl PpmRenderer {
     pub fn new() -> Self {
         Self { frame: 0 }
@@ -26,6 +28,71 @@ impl Renderer for PpmRenderer {
     }
 }
 
+// The GUI renderer: egui window, texture upload, keyboard -> controller.
+pub struct WindowRenderer {
+    ctx: egui::Context,
+    texture: Option<egui::TextureHandle>,
+    rgb: Vec<u8>,          // reusable RGB buffer (palette indices -> RGB)
+    width: usize,
+    height: usize,
+}
+
+impl WindowRenderer {
+    pub fn new(cc: &eframe::CreationContext<'_>, width: u16, height: u16) -> Self {
+        Self {
+            ctx: cc.egui_ctx.clone(),
+            texture: None,
+            rgb: vec![0; width as usize * height as usize * 3],
+            width: width as usize,
+            height: height as usize,
+        }
+    }
+
+    // Called from eframe::App::ui: draws the texture filling the window.
+    pub fn draw(&mut self, ui: &mut egui::Ui) {
+        if let Some(tex) = &self.texture {
+            let avail = ui.available_size();
+            ui.add(egui::Image::new(tex).fit_to_exact_size(avail));
+        }
+    }
+}
+
+impl Renderer for WindowRenderer {
+    fn present(&mut self, framebuffer: &[u8], width: u16, height: u16) {
+        // palette indices -> RGB
+        for (i, &idx) in framebuffer.iter().enumerate() {
+            let (r, g, b) = index_to_rgb(idx);
+            self.rgb[i * 3] = r;
+            self.rgb[i * 3 + 1] = g;
+            self.rgb[i * 3 + 2] = b;
+        }
+        let image = egui::ColorImage::from_rgb([self.width, self.height], &self.rgb);
+        match &mut self.texture {
+            Some(t) => t.set(image, egui::TextureOptions::NEAREST),
+            None => {
+                let t = self.ctx.load_texture("nes-screen", image, egui::TextureOptions::NEAREST);
+                self.texture = Some(t);
+            }
+        }
+    }
+
+    fn poll_input(&mut self, controller: &mut Controller) {
+        let buttons = self.ctx.input(|i| {
+            let mut b = 0u8;
+            if i.key_down(egui::Key::Z)          { b |= key_to_button(Key::A); }
+            if i.key_down(egui::Key::X)          { b |= key_to_button(Key::B); }
+            if i.modifiers.shift                 { b |= key_to_button(Key::Select); }
+            if i.key_down(egui::Key::Enter)      { b |= key_to_button(Key::Start); }
+            if i.key_down(egui::Key::ArrowUp)    { b |= key_to_button(Key::Up); }
+            if i.key_down(egui::Key::ArrowDown)  { b |= key_to_button(Key::Down); }
+            if i.key_down(egui::Key::ArrowLeft)  { b |= key_to_button(Key::Left); }
+            if i.key_down(egui::Key::ArrowRight) { b |= key_to_button(Key::Right); }
+            b
+        });
+        controller.set_buttons(buttons);
+    }
+}
+
 pub fn ppm_bytes(framebuffer: &[u8], width: u16, height: u16) -> Vec<u8> {
     let mut out = format!("P6\n{width} {height}\n255\n").into_bytes();
     for &idx in framebuffer {