feat: add a new TilemapRenderSettings to control chunks RenderOrder

examples/3d_iso.rs

@@ -14,7 +14,8 @@ fn startup(mut commands: Commands, asset_server: Res<AssetServer>) {
             // Map size is 12x12 so we'll have render chunks that are:
             // 12 tiles wide and 1 tile tall.
             render_chunk_size: UVec2::new(3, 1),
-            y_sort: true,
+            y_sort: true, // equivalent to render_order: RenderOrder::YReverseThenX
+            ..Default::default()
         },
         ..Default::default()
     });

src/map.rs

@@ -4,13 +4,80 @@ use bevy::ecs::reflect::ReflectMapEntities;
 use bevy::prelude::{ReflectComponent, Res, ResMut};
 use bevy::render::render_resource::TextureUsages;
 use bevy::{
-    math::{UVec2, Vec2},
+    math::{UVec2, Vec2, Vec3},
     prelude::{Component, Deref, DerefMut, Entity, Handle, Image, Reflect},
 };
 
 /// The default chunk_size (in tiles) used per mesh.
 pub const CHUNK_SIZE_2D: UVec2 = UVec2::from_array([64, 64]);
 
+/// The order in which we want to perform the render
+#[derive(Clone, Debug, Copy, Default)]
+pub enum RenderOrder {
+    #[default]
+    None,
+    XThenY,
+    XReverseThenY,
+    XThenYReverse,
+    XReverseThenYReverse,
+    YThenX,
+    YReverseThenX,
+    YThenXReverse,
+    YReverseThenXReverse,
+}
+
+impl RenderOrder {
+    /// Compute a new Z translation value based upon the selected render order
+    /// Returned Z value will have an offset between 0 and 11
+    pub fn compute_z_translation(
+        &self,
+        translation: &Vec3,
+        tilemap_size: TilemapSize,
+        tile_size: TilemapTileSize,
+    ) -> f32 {
+        let scaling_factor = 10.;
+        let map_size_x = tilemap_size.x as f32 * tile_size.x;
+        let map_size_y = tilemap_size.y as f32 * tile_size.y;
+        let mut z_value = translation.z;
+        match self {
+            Self::XThenY => {
+                z_value += scaling_factor * (translation.x / map_size_x);
+                z_value += translation.y / map_size_y;
+            },
+            Self::XReverseThenY => {
+                z_value += scaling_factor * (1. - (translation.x / map_size_x));
+                z_value += translation.y / map_size_y;
+            },
+            Self::XThenYReverse => {
+                z_value += scaling_factor * (translation.x / map_size_x);
+                z_value += 1. - (translation.y / map_size_y);
+            },
+            Self::XReverseThenYReverse => {
+                z_value += scaling_factor * (1. - (translation.x / map_size_x));
+                z_value += 1. - (translation.y / map_size_y);
+            },
+            Self::YThenX => {
+                z_value += translation.x / map_size_x;
+                z_value += scaling_factor * (translation.y / map_size_y);
+            },
+            Self::YReverseThenX => {
+                z_value += translation.x / map_size_x;
+                z_value += scaling_factor * (1. - (translation.y / map_size_y));
+            },
+            Self::YThenXReverse => {
+                z_value += 1. - (translation.x / map_size_x);
+                z_value += scaling_factor * (translation.y / map_size_y);
+            },
+            Self::YReverseThenXReverse => {
+                z_value += 1. - (translation.x / map_size_x);
+                z_value += scaling_factor * (1. - (translation.y / map_size_y));
+            },
+            _ => {},
+        };
+        z_value
+    }
+}
+
 /// Custom parameters for the render pipeline.
 ///
 /// It must be added as a component to the tilemap entity.
@@ -30,13 +97,16 @@ pub struct TilemapRenderSettings {
     ///
     /// `render_chunk_size`'s `z` value should be `1` when using this for 3d isometric tilemaps.
     pub y_sort: bool,
+    /// The order in which we will render each chunk relative to each other
+    pub render_chunk_order: RenderOrder,
 }
 
 impl Default for TilemapRenderSettings {
     fn default() -> Self {
         Self {
             render_chunk_size: CHUNK_SIZE_2D,
             y_sort: false,
+            render_chunk_order: RenderOrder::None,
         }
     }
 }

src/render/chunk.rs

@@ -18,6 +18,7 @@ use bevy::{
     render::mesh::MeshVertexBufferLayouts,
 };
 
+use crate::map::RenderOrder;
 use crate::prelude::helpers::transform::{chunk_aabb, chunk_index_to_world_space};
 use crate::render::extract::ExtractedFrustum;
 use crate::{
@@ -59,6 +60,7 @@ impl RenderChunk2dStorage {
         frustum_culling: &FrustumCulling,
         render_size: RenderChunkSize,
         y_sort: bool,
+        render_order: RenderOrder,
     ) -> &mut RenderChunk2d {
         let pos = position.xyz();
 
@@ -96,6 +98,7 @@ impl RenderChunk2dStorage {
                 **frustum_culling,
                 render_size,
                 y_sort,
+                render_order,
             );
             self.entity_to_chunk.insert(chunk_entity, pos);
             chunk_storage.insert(pos, chunk);
@@ -220,6 +223,7 @@ pub struct RenderChunk2d {
     pub frustum_culling: bool,
     pub render_size: RenderChunkSize,
     pub y_sort: bool,
+    pub render_chunk_order: RenderOrder,
 }
 
 impl RenderChunk2d {
@@ -241,6 +245,7 @@ impl RenderChunk2d {
         frustum_culling: bool,
         render_size: RenderChunkSize,
         y_sort: bool,
+        render_chunk_order: RenderOrder,
     ) -> Self {
         let position = chunk_index_to_world_space(index.xy(), size_in_tiles, &grid_size, &map_type);
         let local_transform = Transform::from_translation(position.extend(0.0));
@@ -277,6 +282,7 @@ impl RenderChunk2d {
             frustum_culling,
             render_size,
             y_sort,
+            render_chunk_order,
         }
     }
 

src/render/material.rs

@@ -470,7 +470,10 @@ pub fn queue_material_tilemap_meshes<M: MaterialTilemap>(
                             - (transform.translation.y
                                 / (chunk.map_size.y as f32 * chunk.tile_size.y)))
                 } else {
-                    transform.translation.z
+                    chunk.render_chunk_order.compute_z_translation(
+                        &transform.translation,
+                        chunk.map_size,
+                        chunk.tile_size)
                 };
                 transparent_phase.add(Transparent2d {
                     entity,

src/render/prepare.rs

@@ -114,6 +114,7 @@ pub(crate) fn prepare(
             frustum_culling,
             chunk_size,
             tilemap_render_settings.y_sort,
+            tilemap_render_settings.render_chunk_order,
         );
         chunk.set(
             &in_chunk_tile_index.into(),