Brush randomization (#123)

* feat: add brush density control

* feat: add brush ID randomization setting

* fix: fix brush undo being broken after upgrade to egui 0.26

Cargo.toml

@@ -132,6 +132,7 @@ rfd = "0.12.0"
 tempfile = "3.8.1"
 
 rand = "0.8.5"
+murmur3 = "0.5.2"
 
 alacritty_terminal = "0.22.0"
 

crates/components/Cargo.toml

@@ -48,3 +48,4 @@ fragile.workspace = true
 parking_lot.workspace = true
 
 fuzzy-matcher = "0.3.7"
+murmur3.workspace = true

crates/components/src/map_view.rs

@@ -352,7 +352,8 @@ impl MapView {
         );
         let pattern_rect = egui::Rect::from_min_size(
             map_rect.min + (self.cursor_pos.to_vec2() * tile_size),
-            if !force_show_pattern_rect && drawing_shape_pos.is_some() {
+            if tilepicker.brush_random || (!force_show_pattern_rect && drawing_shape_pos.is_some())
+            {
                 egui::Vec2::splat(tile_size)
             } else {
                 egui::vec2(

crates/components/src/tilepicker.rs

@@ -34,6 +34,11 @@ pub struct Tilepicker {
     resources: Arc<Resources>,
     viewport: Arc<luminol_graphics::viewport::Viewport>,
     ani_time: Option<f64>,
+
+    /// When true, brush tile ID randomization is enabled.
+    pub brush_random: bool,
+    /// Seed for the PRNG used for the brush when brush tile ID randomization is enabled.
+    brush_seed: [u8; 16],
 }
 
 struct Resources {
@@ -174,6 +179,18 @@ impl Tilepicker {
             &passages,
         );
 
+        let mut brush_seed = [0u8; 16];
+        brush_seed[0..8].copy_from_slice(
+            &update_state
+                .project_config
+                .as_ref()
+                .expect("project not loaded")
+                .project
+                .persistence_id
+                .to_le_bytes(),
+        );
+        brush_seed[8..16].copy_from_slice(&(map_id as u64).to_le_bytes());
+
         Ok(Self {
             resources: Arc::new(Resources {
                 tiles,
@@ -189,14 +206,44 @@ impl Tilepicker {
             coll_enabled: false,
             grid_enabled: true,
             drag_origin: None,
+            brush_seed,
+            brush_random: false,
         })
     }
 
-    pub fn get_tile_from_offset(&self, x: i16, y: i16) -> SelectedTile {
+    pub fn get_tile_from_offset(
+        &self,
+        absolute_x: i16,
+        absolute_y: i16,
+        absolute_z: i16,
+        relative_x: i16,
+        relative_y: i16,
+    ) -> SelectedTile {
         let width = self.selected_tiles_right - self.selected_tiles_left + 1;
         let height = self.selected_tiles_bottom - self.selected_tiles_top + 1;
-        let x = self.selected_tiles_left + x.rem_euclid(width);
-        let y = self.selected_tiles_top + y.rem_euclid(height);
+
+        let (x, y) = if self.brush_random {
+            let mut preimage = [0u8; 40];
+            preimage[0..16].copy_from_slice(&self.brush_seed);
+            preimage[16..24].copy_from_slice(&(absolute_x as u64).to_le_bytes());
+            preimage[24..32].copy_from_slice(&(absolute_y as u64).to_le_bytes());
+            preimage[32..40].copy_from_slice(&(absolute_z as u64).to_le_bytes());
+            let image = murmur3::murmur3_32(&mut std::io::Cursor::new(preimage), 5381).unwrap();
+            let x = (image & 0xffff) as i16;
+            let y = (image >> 16) as i16;
+            (
+                self.selected_tiles_left
+                    + (self.selected_tiles_left + x.rem_euclid(width)).rem_euclid(width),
+                self.selected_tiles_top
+                    + (self.selected_tiles_top + y.rem_euclid(height)).rem_euclid(height),
+            )
+        } else {
+            (
+                self.selected_tiles_left + relative_x.rem_euclid(width),
+                self.selected_tiles_top + relative_y.rem_euclid(height),
+            )
+        };
+
         match y {
             ..=0 => SelectedTile::Autotile(x),
             _ => SelectedTile::Tile(x + (y - 1) * 8 + 384),
@@ -209,6 +256,8 @@ impl Tilepicker {
         ui: &mut egui::Ui,
         scroll_rect: egui::Rect,
     ) -> egui::Response {
+        self.brush_random = update_state.toolbar.brush_random != ui.input(|i| i.modifiers.alt);
+
         let time = ui.ctx().input(|i| i.time);
         let graphics_state = update_state.graphics.clone();
 

crates/core/src/lib.rs

@@ -147,10 +147,14 @@ impl ModifiedState {
 }
 
 #[allow(missing_docs)]
-#[derive(Default)]
 pub struct ToolbarState {
     /// The currently selected pencil.
     pub pencil: Pencil,
+    /// Brush density between 0 and 1 inclusive; determines the proportion of randomly chosen tiles
+    /// the brush draws on if less than 1
+    pub brush_density: f32,
+    /// Whether or not brush tile ID randomization is active.
+    pub brush_random: bool,
 }
 
 #[derive(Default, strum::EnumIter, strum::Display, PartialEq, Eq, Clone, Copy)]
@@ -163,6 +167,16 @@ pub enum Pencil {
     Fill,
 }
 
+impl Default for ToolbarState {
+    fn default() -> Self {
+        Self {
+            pencil: Default::default(),
+            brush_density: 1.,
+            brush_random: false,
+        }
+    }
+}
+
 impl<'res> UpdateState<'res> {
     pub(crate) fn reborrow_with_edit_window<'this>(
         &'this mut self,

crates/ui/Cargo.toml

@@ -55,5 +55,7 @@ color-eyre.workspace = true
 
 wgpu.workspace = true
 
+murmur3.workspace = true
+
 [target.'cfg(not(target_arch = "wasm32"))'.dependencies]
 luminol-term = { version = "0.4.0", path = "../term/" }

crates/ui/src/tabs/map/brush.rs

@@ -46,13 +46,19 @@ impl super::Tab {
 
         match pencil {
             luminol_core::Pencil::Pen => {
+                let (rect_width, rect_height) = if self.tilepicker.brush_random {
+                    (1, 1)
+                } else {
+                    (width, height)
+                };
+
                 let drawing_shape_pos = if let Some(drawing_shape_pos) = self.drawing_shape_pos {
                     drawing_shape_pos
                 } else {
                     self.drawing_shape_pos = Some(map_pos);
                     map_pos
                 };
-                for (y, x) in (0..height).cartesian_product(0..width) {
+                for (y, x) in (0..rect_height).cartesian_product(0..rect_width) {
                     let absolute_x = map_x + x as usize;
                     let absolute_y = map_y + y as usize;
 
@@ -64,6 +70,9 @@ impl super::Tab {
                     self.set_tile(
                         map,
                         self.tilepicker.get_tile_from_offset(
+                            absolute_x as i16,
+                            absolute_y as i16,
+                            tile_layer as i16,
                             x + (map_x as f32 - drawing_shape_pos.x) as i16,
                             y + (map_y as f32 - drawing_shape_pos.y) as i16,
                         ),
@@ -87,6 +96,9 @@ impl super::Tab {
                     self.set_tile(
                         map,
                         self.tilepicker.get_tile_from_offset(
+                            position.0 as i16,
+                            position.1 as i16,
+                            tile_layer as i16,
                             position.0 as i16 - drawing_shape_pos.x as i16,
                             position.1 as i16 - drawing_shape_pos.y as i16,
                         ),
@@ -159,6 +171,9 @@ impl super::Tab {
                             self.set_tile(
                                 map,
                                 self.tilepicker.get_tile_from_offset(
+                                    x as i16,
+                                    y as i16,
+                                    tile_layer as i16,
                                     x as i16 - drawing_shape_pos.x as i16,
                                     y as i16 - drawing_shape_pos.y as i16,
                                 ),
@@ -202,6 +217,9 @@ impl super::Tab {
                         self.set_tile(
                             map,
                             self.tilepicker.get_tile_from_offset(
+                                map_x as i16,
+                                map_y as i16,
+                                tile_layer as i16,
                                 map_x as i16 - drawing_shape_pos.x as i16,
                                 map_y as i16 - drawing_shape_pos.y as i16,
                             ),
@@ -250,6 +268,9 @@ impl super::Tab {
                                     self.set_tile(
                                         map,
                                         self.tilepicker.get_tile_from_offset(
+                                            x as i16,
+                                            y as i16,
+                                            tile_layer as i16,
                                             x as i16 - drawing_shape_pos.x as i16,
                                             y as i16 - drawing_shape_pos.y as i16,
                                         ),
@@ -292,6 +313,9 @@ impl super::Tab {
                                     self.set_tile(
                                         map,
                                         self.tilepicker.get_tile_from_offset(
+                                            x as i16,
+                                            y as i16,
+                                            tile_layer as i16,
                                             x as i16 - drawing_shape_pos.x as i16,
                                             y as i16 - drawing_shape_pos.y as i16,
                                         ),

crates/ui/src/tabs/map/mod.rs

@@ -85,6 +85,12 @@ pub struct Tab {
     /// This stores the passage values for every position on the map so that we can figure out
     /// which passage values have changed in the current frame
     passages: luminol_data::Table2,
+
+    /// Brush density between 0 and 1 inclusive; determines the proportion of randomly chosen tiles
+    /// the brush draws on if less than 1
+    brush_density: f32,
+    /// Seed for the PRNG used for the brush when brush density is less than 1
+    brush_seed: [u8; 16],
 }
 
 // TODO: If we add support for changing event IDs, these need to be added as history entries
@@ -133,6 +139,18 @@ impl Tab {
             |x, y, passage| passages[(x, y)] = passage,
         );
 
+        let mut brush_seed = [0u8; 16];
+        brush_seed[0..8].copy_from_slice(
+            &update_state
+                .project_config
+                .as_ref()
+                .expect("project not loaded")
+                .project
+                .persistence_id
+                .to_le_bytes(),
+        );
+        brush_seed[8..16].copy_from_slice(&(id as u64).to_le_bytes());
+
         Ok(Self {
             id,
 
@@ -157,6 +175,9 @@ impl Tab {
             tilemap_undo_cache_layer: 0,
 
             passages,
+
+            brush_density: 1.,
+            brush_seed,
         })
     }
 }
@@ -190,6 +211,8 @@ impl luminol_core::Tab for Tab {
         update_state: &mut luminol_core::UpdateState<'_>,
         is_focused: bool,
     ) {
+        self.brush_density = update_state.toolbar.brush_density;
+
         // Display the toolbar.
         egui::TopBottomPanel::top(format!("map_{}_toolbar", self.id)).show_inside(ui, |ui| {
             ui.horizontal_wrapped(|ui| {
@@ -377,7 +400,9 @@ impl luminol_core::Tab for Tab {
                     }
                 }
 
-                if !response.dragged_by(egui::PointerButton::Primary) {
+                if !response.is_pointer_button_down_on()
+                    || ui.input(|i| !i.pointer.button_down(egui::PointerButton::Primary))
+                {
                     if self.drawing_shape {
                         self.drawing_shape = false;
                     }
@@ -406,24 +431,20 @@ impl luminol_core::Tab for Tab {
                 if let luminol_components::SelectedLayer::Tiles(tile_layer) =
                     self.view.selected_layer
                 {
-                    // Before drawing tiles, save the state of the current layer so we can undo it
-                    // later if we need to
-                    if response.drag_started_by(egui::PointerButton::Primary)
-                        && !ui.input(|i| i.modifiers.command)
-                    {
-                        self.tilemap_undo_cache_layer = tile_layer;
-                        for i in 0..self.layer_cache.len() {
-                            self.tilemap_undo_cache[i] = self.layer_cache[i];
-                        }
-                    }
-
                     // Tile drawing
                     if response.is_pointer_button_down_on()
                         && ui.input(|i| {
                             i.pointer.button_down(egui::PointerButton::Primary)
                                 && !i.modifiers.command
                         })
                     {
+                        if self.drawing_shape_pos.is_none() {
+                            // Before drawing tiles, save the state of the current layer so we can
+                            // undo it later if we need to
+                            self.tilemap_undo_cache_layer = tile_layer;
+                            self.tilemap_undo_cache.copy_from_slice(&self.layer_cache);
+                        }
+
                         self.handle_brush(
                             map_x as usize,
                             map_y as usize,

crates/ui/src/tabs/map/util.rs

@@ -148,6 +148,27 @@ impl super::Tab {
         tile: luminol_components::SelectedTile,
         position: (usize, usize, usize),
     ) {
+        if self.brush_density != 1. {
+            if self.brush_density == 0. {
+                return;
+            }
+
+            // Pick a pseudorandom normal f32 uniformly in the interval [0, 1)
+            let mut preimage = [0u8; 40];
+            preimage[0..16].copy_from_slice(&self.brush_seed);
+            preimage[16..24].copy_from_slice(&(position.0 as u64).to_le_bytes());
+            preimage[24..32].copy_from_slice(&(position.1 as u64).to_le_bytes());
+            preimage[32..40].copy_from_slice(&(position.2 as u64).to_le_bytes());
+            let image = (murmur3::murmur3_32(&mut std::io::Cursor::new(preimage), 1729).unwrap()
+                & 16777215) as f32
+                / 16777216f32;
+
+            // Set the tile only if that's less than the brush density
+            if image >= self.brush_density {
+                return;
+            }
+        }
+
         map.data[position] = tile.to_id();
 
         for y in -1i8..=1i8 {