Tile drawing implementation and bug fixes (#38)

* Fix off-by-one when the layer number is displayed

* Basic tile drawing for non-autotiles

* Fix tilepicker default width being too small

* Fix `Table3` indexing implementation

Co-authored-by: Speak2Erase <lily@nowaffles.com>

* Fix tilepicker showing incorrect autotile graphics

RPG Maker XP displays autotile index 47 for autotiles in the tilepicker,
not 0.

* Tile drawing now works with autotiles as well

* Fix bottom-right corner of map not rendering

* Blank tiles should always have ID 0

---------

Co-authored-by: Speak2Erase <lily@nowaffles.com>

rmxp-types/src/rgss_structs.rs

@@ -434,12 +434,12 @@ impl Index<(usize, usize, usize)> for Table3 {
     type Output = i16;
 
     fn index(&self, index: (usize, usize, usize)) -> &Self::Output {
-        &self.data[index.0 + (index.1 * self.xsize) + (index.2 * self.ysize)]
+        &self.data[index.0 + self.xsize * (index.1 + self.ysize * index.2)]
     }
 }
 
 impl IndexMut<(usize, usize, usize)> for Table3 {
     fn index_mut(&mut self, index: (usize, usize, usize)) -> &mut Self::Output {
-        &mut self.data[index.0 + (index.1 * self.xsize) + (index.2 * self.ysize)]
+        &mut self.data[index.0 + self.xsize * (index.1 + self.ysize * index.2)]
     }
 }

src/components/tilepicker.rs

@@ -22,9 +22,10 @@ use std::time::{Duration, Instant};
 
 #[derive(Debug)]
 pub struct Tilepicker {
+    pub selected_tile: SelectedTile,
+
     resources: Arc<Resources>,
     ani_instant: Instant,
-    selected_tile: SelectedTile,
 }
 
 #[derive(Debug)]
@@ -50,7 +51,7 @@ impl Tilepicker {
     pub fn new(tileset: &rpg::Tileset) -> Result<Tilepicker, String> {
         let atlas = state!().atlas_cache.load_atlas(tileset)?;
 
-        let tilepicker_data = (0..384)
+        let tilepicker_data = (47..(384 + 47))
             .step_by(48)
             .chain(384..(atlas.tileset_height as i16 / 32 * 8 + 384))
             .collect_vec();

src/graphics/map.rs

@@ -100,6 +100,10 @@ impl Map {
         })
     }
 
+    pub fn set_tile(&self, tile_id: i16, position: (usize, usize, usize)) {
+        self.resources.tiles.set_tile(tile_id, position);
+    }
+
     pub fn paint(&mut self, painter: &egui::Painter, rect: egui::Rect) {
         if self.ani_instant.elapsed() >= Duration::from_secs_f32((1. / 60.) * 16.) {
             self.ani_instant = Instant::now();

src/graphics/primitives/tiles/instance.rs

@@ -114,7 +114,7 @@ impl Instances {
 
         // Calculate the start and end index of the buffer, as well as the amount of instances.
         let start_index = layer * self.map_width * self.map_height;
-        let end_index = (layer + 1) * self.map_width * self.map_height - 1;
+        let end_index = (layer + 1) * self.map_width * self.map_height;
         let count = (end_index - start_index) as u32;
 
         // Convert the indexes into actual offsets.

src/tabs/map.rs

@@ -57,6 +57,156 @@ impl Tab {
             force_close: false,
         })
     }
+
+    fn recompute_autotile(&self, map: &rpg::Map, position: (usize, usize, usize)) -> i16 {
+        if map.data[position] >= 384 {
+            return map.data[position];
+        }
+
+        let autotile = map.data[position] / 48;
+        if autotile == 0 {
+            return 0;
+        }
+
+        let x_array: [i8; 8] = [-1, 0, 1, 1, 1, 0, -1, -1];
+        let y_array: [i8; 8] = [-1, -1, -1, 0, 1, 1, 1, 0];
+
+        /*
+         * 765
+         * 0 4
+         * 123
+         */
+        let mut bitfield = 0u8;
+
+        // Loop through the 8 neighbors of this position
+        for (x, y) in x_array.into_iter().zip(y_array.into_iter()) {
+            bitfield <<= 1;
+            // Out-of-bounds tiles always count as valid neighbors
+            if ((x == -1 && position.0 == 0) || (x == 1 && position.0 + 1 == map.data.xsize()))
+                || ((y == -1 && position.1 == 0) || (y == 1 && position.1 + 1 == map.data.ysize()))
+            {
+                bitfield |= 1;
+            }
+            // Otherwise, we only consider neighbors that are autotiles of the same type
+            else if map.data[(
+                if x == -1 {
+                    position.0 - 1
+                } else {
+                    position.0 + x as usize
+                },
+                if y == -1 {
+                    position.1 - 1
+                } else {
+                    position.1 + y as usize
+                },
+                position.2,
+            )] / 48
+                == autotile
+            {
+                bitfield |= 1;
+            }
+        }
+
+        // Check how many edges have valid neighbors
+        autotile * 48
+            + match (bitfield & 0b01010101).count_ones() {
+                4 => {
+                    // If the autotile is surrounded on all 4 edges,
+                    // then the autotile variant is one of the first 16,
+                    // depending on which corners are surrounded
+                    let tl = (bitfield & 0b10000000 == 0) as u8;
+                    let tr = (bitfield & 0b00100000 == 0) as u8;
+                    let br = (bitfield & 0b00001000 == 0) as u8;
+                    let bl = (bitfield & 0b00000010 == 0) as u8;
+                    tl | (tr << 1) | (br << 2) | (bl << 3)
+                }
+
+                3 => {
+                    // Rotate the bitfield 90 degrees counterclockwise until
+                    // the one edge that is not surrounded is at the left
+                    let mut bitfield = bitfield;
+                    let mut i = 16u8;
+                    while bitfield & 0b00000001 != 0 {
+                        bitfield = bitfield.rotate_left(2);
+                        i += 4;
+                    }
+                    // Now, the variant is one of the next 16
+                    let tr = (bitfield & 0b00100000 == 0) as u8;
+                    let br = (bitfield & 0b00001000 == 0) as u8;
+                    i + (tr | (br << 1))
+                }
+
+                // Top and bottom edges
+                2 if bitfield & 0b01000100 == 0b01000100 => 32,
+
+                // Left and right edges
+                2 if bitfield & 0b00010001 == 0b00010001 => 33,
+
+                2 => {
+                    // Rotate the bitfield 90 degrees counterclockwise until
+                    // the two edges that are surrounded are at the right and bottom
+                    let mut bitfield = bitfield;
+                    let mut i = 34u8;
+                    while bitfield & 0b00010100 != 0b00010100 {
+                        bitfield = bitfield.rotate_left(2);
+                        i += 2;
+                    }
+                    let br = (bitfield & 0b00001000 == 0) as u8;
+                    i + br
+                }
+
+                1 => {
+                    // Rotate the bitfield 90 degrees clockwise until
+                    // the edge is at the bottom
+                    let mut bitfield = bitfield;
+                    let mut i = 42u8;
+                    while bitfield & 0b00000100 == 0 {
+                        bitfield = bitfield.rotate_right(2);
+                        i += 1;
+                    }
+                    i
+                }
+
+                0 => 46,
+
+                _ => unreachable!(),
+            } as i16
+    }
+
+    fn set_tile(&self, map: &mut rpg::Map, tile: SelectedTile, position: (usize, usize, usize)) {
+        map.data[position] = match tile {
+            SelectedTile::Autotile(i) => i * 48,
+            SelectedTile::Tile(i) => i,
+        };
+
+        for y in -1i8..=1i8 {
+            for x in -1i8..=1i8 {
+                // Don't check tiles that are out of bounds
+                if ((x == -1 && position.0 == 0) || (x == 1 && position.0 + 1 == map.data.xsize()))
+                    || ((y == -1 && position.1 == 0)
+                        || (y == 1 && position.1 + 1 == map.data.ysize()))
+                {
+                    continue;
+                }
+                let position = (
+                    if x == -1 {
+                        position.0 - 1
+                    } else {
+                        position.0 + x as usize
+                    },
+                    if y == -1 {
+                        position.1 - 1
+                    } else {
+                        position.1 + y as usize
+                    },
+                    position.2,
+                );
+                let tile_id = self.recompute_autotile(map, position);
+                map.data[position] = tile_id;
+                self.view.map.set_tile(tile_id, position);
+            }
+        }
+    }
 }
 
 impl tab::Tab for Tab {
@@ -94,7 +244,7 @@ impl tab::Tab for Tab {
                     // Format the text based on what layer is selected.
                     match self.view.selected_layer {
                         SelectedLayer::Events => "Events ⏷".to_string(),
-                        SelectedLayer::Tiles(layer) => format!("Layer {layer} ⏷"),
+                        SelectedLayer::Tiles(layer) => format!("Layer {} ⏷", layer + 1),
                     },
                     |ui| {
                         // TODO: Add layer enable button
@@ -153,11 +303,19 @@ impl tab::Tab for Tab {
         });
 
         // Display the tilepicker.
+        let spacing = ui.spacing();
+        let tilepicker_default_width = 256.
+            + 3. * spacing.window_margin.left
+            + spacing.scroll_bar_inner_margin
+            + spacing.scroll_bar_width
+            + spacing.scroll_bar_outer_margin;
         egui::SidePanel::left(format!("map_{}_tilepicker", self.id))
-            .default_width(256.)
+            .default_width(tilepicker_default_width)
+            .max_width(tilepicker_default_width)
             .show_inside(ui, |ui| {
                 egui::ScrollArea::both().show(ui, |ui| {
                     self.tilepicker.ui(ui);
+                    ui.separator();
                 });
             });
 
@@ -169,6 +327,18 @@ impl tab::Tab for Tab {
                 let map_x = self.view.cursor_pos.x as i32;
                 let map_y = self.view.cursor_pos.y as i32;
 
+                if let SelectedLayer::Tiles(tile_layer) = self.view.selected_layer {
+                    if response.dragged_by(egui::PointerButton::Primary)
+                        && !ui.input(|i| i.modifiers.command)
+                    {
+                        self.set_tile(
+                            &mut map,
+                            self.tilepicker.selected_tile,
+                            (map_x as usize, map_y as usize, tile_layer),
+                        );
+                    }
+                }
+
                 if ui.input(|i| {
                     i.key_pressed(egui::Key::Delete) || i.key_pressed(egui::Key::Backspace)
                 }) {