Generating hexagonal hex maps.

examples/hexagon_generation.rs

@@ -0,0 +1,240 @@
+use bevy::{prelude::*, render::texture::ImageSettings};
+use bevy_ecs_tilemap::prelude::*;
+mod helpers;
+use helpers::camera::movement as camera_movement;
+
+// Press SPACE to change map type. Hover over a tile to highlight its label (red) and those of its
+// neighbors (blue). Press and hold one of keys 0-5 to mark the neighbor in that direction (green).
+
+// You can increase the MAP_SIDE_LENGTH, in order to test larger maps but just make sure that you run
+// in release mode (`cargo run --release --example hexagon_generation`) otherwise things might be too
+// slow.
+const MAP_SIDE_LENGTH: u32 = 8;
+
+const TILE_SIZE_HEX_ROW: TilemapTileSize = TilemapTileSize { x: 50.0, y: 58.0 };
+const TILE_SIZE_HEX_COL: TilemapTileSize = TilemapTileSize { x: 58.0, y: 50.0 };
+const GRID_SIZE_HEX_ROW: TilemapGridSize = TilemapGridSize { x: 50.0, y: 58.0 };
+const GRID_SIZE_HEX_COL: TilemapGridSize = TilemapGridSize { x: 58.0, y: 50.0 };
+
+#[derive(Component, Deref)]
+pub struct TileHandleHexRow(Handle<Image>);
+
+#[derive(Component, Deref)]
+pub struct TileHandleHexCol(Handle<Image>);
+
+#[derive(Component, Deref)]
+pub struct TileHandleSquare(Handle<Image>);
+
+#[derive(Component, Deref)]
+pub struct TileHandleIso(Handle<Image>);
+
+// Spawns different tiles that are used for this example.
+fn spawn_assets(mut commands: Commands, asset_server: Res<AssetServer>) {
+    let tile_handle_hex_row: Handle<Image> = asset_server.load("bw-tile-hex-row.png");
+    let tile_handle_hex_col: Handle<Image> = asset_server.load("bw-tile-hex-col.png");
+    let font: Handle<Font> = asset_server.load("fonts/FiraSans-Bold.ttf");
+
+    commands.insert_resource(TileHandleHexCol(tile_handle_hex_col));
+    commands.insert_resource(TileHandleHexRow(tile_handle_hex_row));
+    commands.insert_resource(font);
+}
+
+// Generates the initial tilemap, which is a square grid.
+fn spawn_tilemap(mut commands: Commands, tile_handle_hex_row: Res<TileHandleHexRow>) {
+    commands.spawn_bundle(Camera2dBundle::default());
+
+    let total_size = TilemapSize {
+        x: MAP_SIDE_LENGTH,
+        y: MAP_SIDE_LENGTH,
+    };
+
+    let mut tile_storage = TileStorage::empty(total_size);
+    let tilemap_entity = commands.spawn().id();
+    let tilemap_id = TilemapId(tilemap_entity);
+
+    let hex_coord_system = HexCoordSystem::Row;
+
+    fill_tilemap_hexagon(
+        TileTexture(0),
+        TilePos {
+            x: MAP_SIDE_LENGTH / 2,
+            y: MAP_SIDE_LENGTH / 2,
+        },
+        MAP_SIDE_LENGTH / 2,
+        hex_coord_system,
+        tilemap_id,
+        &mut commands,
+        &mut tile_storage,
+    );
+
+    let tile_size = TILE_SIZE_HEX_ROW;
+    let grid_size = GRID_SIZE_HEX_ROW;
+
+    commands
+        .entity(tilemap_entity)
+        .insert_bundle(TilemapBundle {
+            grid_size,
+            size: total_size,
+            storage: tile_storage,
+            texture: TilemapTexture(tile_handle_hex_row.clone()),
+            tile_size,
+            map_type: TilemapType::Hexagon(hex_coord_system),
+            ..Default::default()
+        });
+}
+
+#[derive(Component)]
+pub struct MapTypeLabel;
+
+// Generates the map type label: e.g. `Square { diagonal_neighbors: false }`
+fn spawn_map_type_label(
+    mut commands: Commands,
+    font_handle: Res<Handle<Font>>,
+    windows: Res<Windows>,
+    map_type_q: Query<&TilemapType>,
+) {
+    let text_style = TextStyle {
+        font: font_handle.clone(),
+        font_size: 20.0,
+        color: Color::BLACK,
+    };
+    let text_alignment = TextAlignment::CENTER;
+
+    for window in windows.iter() {
+        for map_type in map_type_q.iter() {
+            // Place the map type label somewhere in the top left side of the screen
+            let transform = Transform {
+                translation: Vec2::new(-0.5 * window.width() / 2.0, 0.8 * window.height() / 2.0)
+                    .extend(1.0),
+                ..Default::default()
+            };
+            commands
+                .spawn_bundle(Text2dBundle {
+                    text: Text::from_section(format!("{map_type:?}"), text_style.clone())
+                        .with_alignment(text_alignment),
+                    transform,
+                    ..default()
+                })
+                .insert(MapTypeLabel);
+        }
+    }
+}
+
+// Swaps the map type, when user presses SPACE
+#[allow(clippy::too_many_arguments)]
+fn swap_map_type(
+    mut commands: Commands,
+    mut tilemap_query: Query<(
+        Entity,
+        &mut TilemapType,
+        &mut TilemapGridSize,
+        &mut TilemapTexture,
+        &mut TilemapTileSize,
+        &mut TileStorage,
+    )>,
+    keyboard_input: Res<Input<KeyCode>>,
+    mut map_type_label_q: Query<
+        (&mut Text, &mut Transform),
+        (With<MapTypeLabel>, Without<TilemapType>),
+    >,
+    tile_handle_hex_row: Res<TileHandleHexRow>,
+    tile_handle_hex_col: Res<TileHandleHexCol>,
+    font_handle: Res<Handle<Font>>,
+    windows: Res<Windows>,
+) {
+    if keyboard_input.just_pressed(KeyCode::Space) {
+        for (
+            map_id,
+            mut map_type,
+            mut grid_size,
+            mut map_texture,
+            mut tile_size,
+            mut tile_storage,
+        ) in tilemap_query.iter_mut()
+        {
+            // Remove all previously spawned tiles.
+            for possible_entity in tile_storage.iter_mut() {
+                // see documentation for take to understand how it works:
+                // https://doc.rust-lang.org/std/option/enum.Option.html#method.take
+                if let Some(entity) = possible_entity.take() {
+                    commands.entity(entity).despawn_recursive();
+                }
+            }
+
+            let new_coord_sys = match map_type.as_ref() {
+                TilemapType::Hexagon(HexCoordSystem::Row) => HexCoordSystem::Column,
+                TilemapType::Hexagon(HexCoordSystem::Column) => HexCoordSystem::Row,
+                _ => unreachable!(),
+            };
+
+            *map_type = TilemapType::Hexagon(new_coord_sys);
+
+            if new_coord_sys == HexCoordSystem::Column {
+                *map_texture = TilemapTexture((*tile_handle_hex_col).clone());
+                *tile_size = TILE_SIZE_HEX_COL;
+                *grid_size = GRID_SIZE_HEX_COL;
+            } else if new_coord_sys == HexCoordSystem::Row {
+                *map_texture = TilemapTexture((*tile_handle_hex_row).clone());
+                *tile_size = TILE_SIZE_HEX_ROW;
+                *grid_size = GRID_SIZE_HEX_ROW;
+            }
+
+            // Re-generate tiles in a hexagonal pattern.
+            fill_tilemap_hexagon(
+                TileTexture(0),
+                TilePos {
+                    x: MAP_SIDE_LENGTH / 2,
+                    y: MAP_SIDE_LENGTH / 2,
+                },
+                MAP_SIDE_LENGTH / 2,
+                new_coord_sys,
+                TilemapId(map_id),
+                &mut commands,
+                &mut tile_storage,
+            );
+
+            for window in windows.iter() {
+                for (mut label_text, mut label_transform) in map_type_label_q.iter_mut() {
+                    *label_transform = Transform {
+                        translation: Vec2::new(
+                            -0.5 * window.width() / 2.0,
+                            0.8 * window.height() / 2.0,
+                        )
+                        .extend(1.0),
+                        ..Default::default()
+                    };
+                    *label_text = Text::from_section(
+                        format!("{:?}", map_type.as_ref()),
+                        TextStyle {
+                            font: font_handle.clone(),
+                            font_size: 20.0,
+                            color: Color::BLACK,
+                        },
+                    )
+                    .with_alignment(TextAlignment::CENTER);
+                }
+            }
+        }
+    }
+}
+
+fn main() {
+    App::new()
+        .insert_resource(WindowDescriptor {
+            width: 1270.0,
+            height: 720.0,
+            title: String::from(
+                "Hexagon Neighbors - Hover over a tile, and then press 0-5 to mark neighbors",
+            ),
+            ..Default::default()
+        })
+        .insert_resource(ImageSettings::default_nearest())
+        .add_plugins(DefaultPlugins)
+        .add_plugin(TilemapPlugin)
+        .add_startup_system_to_stage(StartupStage::PreStartup, spawn_assets)
+        .add_startup_system_to_stage(StartupStage::Startup, spawn_tilemap)
+        .add_startup_system_to_stage(StartupStage::PostStartup, spawn_map_type_label)
+        .add_system(camera_movement)
+        .add_system(swap_map_type)
+        .run();
+}

src/helpers/filling.rs

@@ -1,4 +1,7 @@
+use crate::helpers::hex_grid::axial::AxialPos;
+use crate::helpers::hex_grid::neighbors::{HexDirection, HEX_DIRECTIONS};
 use crate::map::TilemapId;
+use crate::prelude::HexCoordSystem;
 use crate::tiles::{TileBundle, TileColor, TilePos, TileTexture};
 use crate::{TileStorage, TilemapSize};
 use bevy::hierarchy::BuildChildren;
@@ -97,3 +100,78 @@ pub fn fill_tilemap_rect_color(
         }
     }
 }
+
+/// Generates a vector of hex positions that form a ring of given `radius` around the specified
+/// `origin`.
+///
+/// If `radius` is zero, `origin` is the only position in the returned vector.
+pub fn generate_hex_ring(origin: AxialPos, radius: u32) -> Vec<AxialPos> {
+    if radius == 0 {
+        vec![origin]
+    } else {
+        let mut ring = Vec::with_capacity((radius * 6) as usize);
+        let corners = HEX_DIRECTIONS
+            .iter()
+            .map(|direction| origin + radius * AxialPos::from(direction))
+            .collect::<Vec<AxialPos>>();
+        // The "tangent" is the direction we must travel in to reach the next corner
+        let tangents = (0..6)
+            .map(|ix| HexDirection::from(ix + 2).into())
+            .collect::<Vec<AxialPos>>();
+
+        for (&corner, &tangent) in corners.iter().zip(tangents.iter()) {
+            for k in 0..radius {
+                ring.push(corner + k * tangent);
+            }
+        }
+
+        ring
+    }
+}
+
+/// Generates a vector of hex positions that form a hexagon of given `radius` around the specified
+/// `origin`.
+pub fn generate_hexagon(origin: AxialPos, radius: u32) -> Vec<AxialPos> {
+    let mut hexagon = Vec::with_capacity((6 * radius * (radius + 1) / 2) as usize);
+    for r in 0..radius {
+        hexagon.extend(generate_hex_ring(origin, r));
+    }
+    hexagon
+}
+
+/// Fills a hexagonal region with the given `tile_texture`.
+///
+/// The rectangular region is defined by an `origin` in [`TilePos`](crate::tiles::TilePos), and a
+/// `radius`.
+///
+/// Tiles that do not fit in the tilemap will not be created.
+pub fn fill_tilemap_hexagon(
+    tile_texture: TileTexture,
+    origin: TilePos,
+    radius: u32,
+    hex_coord_system: HexCoordSystem,
+    tilemap_id: TilemapId,
+    commands: &mut Commands,
+    tile_storage: &mut TileStorage,
+) {
+    let tile_positions = generate_hexagon(
+        AxialPos::from_tile_pos_given_coord_system(&origin, hex_coord_system),
+        radius,
+    )
+    .into_iter()
+    .map(|axial_pos| axial_pos.as_tile_pos_given_coord_system(hex_coord_system))
+    .collect::<Vec<TilePos>>();
+
+    for tile_pos in tile_positions {
+        let tile_entity = commands
+            .spawn()
+            .insert_bundle(TileBundle {
+                position: tile_pos,
+                tilemap_id,
+                texture: tile_texture,
+                ..Default::default()
+            })
+            .id();
+        tile_storage.checked_set(&tile_pos, tile_entity)
+    }
+}

src/helpers/hex_grid/axial.rs

@@ -82,6 +82,17 @@ impl Mul<AxialPos> for i32 {
     }
 }
 
+impl Mul<AxialPos> for u32 {
+    type Output = AxialPos;
+
+    fn mul(self, rhs: AxialPos) -> Self::Output {
+        AxialPos {
+            q: (self as i32) * rhs.q,
+            r: (self as i32) * rhs.r,
+        }
+    }
+}
+
 fn ceiled_division_by_2(x: i32) -> i32 {
     if x < 0 {
         (x - 1) / 2
@@ -365,3 +376,12 @@ impl From<Vec2> for FractionalAxialPos {
         FractionalAxialPos { q: v.x, r: v.y }
     }
 }
+
+impl From<AxialPos> for FractionalAxialPos {
+    fn from(axial_pos: AxialPos) -> Self {
+        FractionalAxialPos {
+            q: axial_pos.q as f32,
+            r: axial_pos.r as f32,
+        }
+    }
+}

src/helpers/hex_grid/cube.rs

@@ -76,6 +76,18 @@ impl Mul<CubePos> for i32 {
     }
 }
 
+impl Mul<CubePos> for u32 {
+    type Output = CubePos;
+
+    fn mul(self, rhs: CubePos) -> Self::Output {
+        CubePos {
+            q: (self as i32) * rhs.q,
+            r: (self as i32) * rhs.r,
+            s: (self as i32) * rhs.s,
+        }
+    }
+}
+
 impl CubePos {
     /// The magnitude of a cube position is its distance away from the `[0, 0, 0]` hex_grid.
     ///

src/helpers/hex_grid/neighbors.rs

@@ -44,6 +44,18 @@ pub const HEX_OFFSETS: [AxialPos; 6] = [
     AxialPos { q: 1, r: -1 },
 ];
 
+impl From<HexDirection> for AxialPos {
+    fn from(direction: HexDirection) -> Self {
+        HEX_OFFSETS[direction as usize]
+    }
+}
+
+impl From<&HexDirection> for AxialPos {
+    fn from(direction: &HexDirection) -> Self {
+        AxialPos::from(*direction)
+    }
+}
+
 impl From<usize> for HexDirection {
     fn from(choice: usize) -> Self {
         let ix = choice % 6;