Avoid unnecessary computation/cloning in renderer

src/vram.rs

@@ -1,5 +1,5 @@
 use std::{
-    collections::{hash_map::Entry, HashMap},
+    collections::{hash_map::Entry, HashMap, HashSet},
     hash::Hash,
     sync::{Arc, Mutex},
 };
@@ -11,12 +11,12 @@ use egui::{
 };
 use serde::{Deserialize, Serialize};
 
-pub trait VramResource: Sized + PartialEq + Eq + Hash {
+pub trait VramResource: Sized + Clone + PartialEq + Eq + Hash {
     fn to_uri(&self) -> String;
     fn from_uri(uri: &str) -> Option<Self>;
 }
 
-impl<T: Serialize + for<'a> Deserialize<'a> + PartialEq + Eq + Hash> VramResource for T {
+impl<T: Serialize + for<'a> Deserialize<'a> + Clone + PartialEq + Eq + Hash> VramResource for T {
     fn to_uri(&self) -> String {
         format!("vram://{}", serde_json::to_string(self).unwrap())
     }
@@ -28,7 +28,7 @@ impl<T: Serialize + for<'a> Deserialize<'a> + PartialEq + Eq + Hash> VramResourc
 }
 
 pub enum VramImage {
-    Unchanged(Arc<ColorImage>),
+    Unchanged(Option<Arc<ColorImage>>),
     Changed(ColorImage),
 }
 
@@ -40,11 +40,12 @@ impl VramImage {
     pub fn write(&mut self, coords: (usize, usize), shade: u8) {
         match self {
             Self::Unchanged(image) => {
-                let value = image[coords];
-                if value.r() == shade {
+                if image.as_ref().is_none_or(|i| i[coords].r() == shade) {
+                    return;
+                }
+                let Some(mut new_image) = image.take().map(Arc::unwrap_or_clone) else {
                     return;
                 };
-                let mut new_image = ColorImage::clone(image);
                 new_image[coords] = Color32::from_gray(shade);
                 *self = Self::Changed(new_image);
             }
@@ -59,7 +60,7 @@ impl VramImage {
             Self::Unchanged(_) => None,
             Self::Changed(image) => {
                 let arced = Arc::new(std::mem::take(image));
-                *self = Self::Unchanged(arced.clone());
+                *self = Self::Unchanged(Some(arced.clone()));
                 Some(arced)
             }
         }
@@ -81,6 +82,7 @@ pub struct VramTextureLoader<T: VramImageLoader> {
     id: String,
     loader: Mutex<T>,
     cache: Mutex<HashMap<T::Resource, (TextureHandle, VramImage)>>,
+    seen: Mutex<HashSet<T::Resource>>,
 }
 
 impl<T: VramImageLoader> VramTextureLoader<T> {
@@ -89,8 +91,16 @@ impl<T: VramImageLoader> VramTextureLoader<T> {
             id: loader.id().to_string(),
             loader: Mutex::new(loader),
             cache: Mutex::new(HashMap::new()),
+            seen: Mutex::new(HashSet::new()),
         }
     }
+
+    pub fn begin_pass(&self) {
+        let mut cache = self.cache.lock().unwrap();
+        let mut seen = self.seen.lock().unwrap();
+        cache.retain(|res, _| seen.contains(res));
+        seen.clear();
+    }
 }
 
 impl<T: VramImageLoader> TextureLoader for VramTextureLoader<T> {
@@ -113,8 +123,10 @@ impl<T: VramImageLoader> TextureLoader for VramTextureLoader<T> {
                 "Only TextureOptions::NEAREST are supported".into(),
             ));
         }
-        let loader = self.loader.lock().unwrap();
         let mut cache = self.cache.lock().unwrap();
+        let mut seen = self.seen.lock().unwrap();
+        seen.insert(resource.clone());
+        let loader = self.loader.lock().unwrap();
         let resources = cache.iter_mut().map(|(k, v)| (k, &mut v.1));
         loader.update(resources);
         for (handle, image) in cache.values_mut() {

src/window/vram/bgmap.rs

@@ -18,7 +18,7 @@ use super::utils::{parse_palette, CharacterGrid, GENERIC_PALETTE};
 
 pub struct BgMapWindow {
     sim_id: SimId,
-    loader: Option<BgMapLoader>,
+    loader: Arc<VramTextureLoader<BgMapLoader>>,
     bgmaps: MemoryView,
     cell_index: usize,
     cell_index_str: String,
@@ -31,7 +31,7 @@ impl BgMapWindow {
     pub fn new(sim_id: SimId, memory: &mut MemoryMonitor) -> Self {
         Self {
             sim_id,
-            loader: Some(BgMapLoader::new(sim_id, memory)),
+            loader: Arc::new(VramTextureLoader::new(BgMapLoader::new(sim_id, memory))),
             bgmaps: memory.view(sim_id, 0x00020000, 0x1d800),
             cell_index: 0,
             cell_index_str: "0".into(),
@@ -188,11 +188,11 @@ impl AppWindow for BgMapWindow {
     }
 
     fn on_init(&mut self, ctx: &Context, _render_state: &egui_wgpu::RenderState) {
-        let loader = self.loader.take().unwrap();
-        ctx.add_texture_loader(Arc::new(VramTextureLoader::new(loader)));
+        ctx.add_texture_loader(self.loader.clone());
     }
 
     fn show(&mut self, ctx: &Context) {
+        self.loader.begin_pass();
         CentralPanel::default().show(ctx, |ui| {
             ui.horizontal_top(|ui| {
                 StripBuilder::new(ui)
@@ -219,7 +219,7 @@ fn parse_cell(cell: u16) -> (usize, bool, bool, usize) {
     (char_index, vflip, hflip, palette_index)
 }
 
-#[derive(Serialize, Deserialize, PartialEq, Eq, Hash)]
+#[derive(Serialize, Deserialize, Clone, PartialEq, Eq, Hash)]
 enum BgMapResource {
     BgMap { index: usize, generic_palette: bool },
     Cell { index: usize, generic_palette: bool },

src/window/vram/chardata.rs

@@ -77,7 +77,7 @@ impl Display for VramPalette {
 
 pub struct CharacterDataWindow {
     sim_id: SimId,
-    loader: Option<CharDataLoader>,
+    loader: Arc<VramTextureLoader<CharDataLoader>>,
     brightness: MemoryView,
     palettes: MemoryView,
     palette: VramPalette,
@@ -91,7 +91,7 @@ impl CharacterDataWindow {
     pub fn new(sim_id: SimId, memory: &mut MemoryMonitor) -> Self {
         Self {
             sim_id,
-            loader: Some(CharDataLoader::new(sim_id, memory)),
+            loader: Arc::new(VramTextureLoader::new(CharDataLoader::new(sim_id, memory))),
             brightness: memory.view(sim_id, 0x0005f824, 8),
             palettes: memory.view(sim_id, 0x0005f860, 16),
             palette: VramPalette::Generic,
@@ -250,11 +250,11 @@ impl AppWindow for CharacterDataWindow {
     }
 
     fn on_init(&mut self, ctx: &Context, _render_state: &egui_wgpu::RenderState) {
-        let loader = self.loader.take().unwrap();
-        ctx.add_texture_loader(Arc::new(VramTextureLoader::new(loader)));
+        ctx.add_texture_loader(self.loader.clone());
     }
 
     fn show(&mut self, ctx: &Context) {
+        self.loader.begin_pass();
         CentralPanel::default().show(ctx, |ui| {
             ui.horizontal_top(|ui| {
                 StripBuilder::new(ui)
@@ -273,7 +273,7 @@ impl AppWindow for CharacterDataWindow {
     }
 }
 
-#[derive(Serialize, Deserialize, PartialEq, Eq, Hash)]
+#[derive(Serialize, Deserialize, Clone, PartialEq, Eq, Hash)]
 enum CharDataResource {
     Character { palette: VramPalette, index: usize },
     CharacterData { palette: VramPalette },