basic group sorting

zig-ecs/src/ecs.zig

@@ -8,6 +8,8 @@ pub const Entity = @import("ecs/registry.zig").Entity;
 pub const Registry = @import("ecs/registry.zig").Registry;
 pub const BasicView = @import("ecs/views.zig").BasicView;
 pub const BasicMultiView = @import("ecs/views.zig").BasicMultiView;
+pub const BasicGroup = @import("ecs/groups.zig").BasicGroup;
+pub const OwningGroup = @import("ecs/groups.zig").OwningGroup;
 
 // signals
 pub const Signal = @import("signals/signal.zig").Signal;

zig-ecs/src/ecs/component_storage.zig

@@ -162,9 +162,11 @@ pub fn ComponentStorage(comptime Component: type, comptime Entity: type) type {
 
         pub usingnamespace if (is_empty_struct)
             struct {
-                /// Sort Entities according to the given comparison function
-                pub fn sort(self: Self, comptime sortFn: fn (void, Entity, Entity) bool) void {
-                    self.set.sort(sortFn);
+                /// Sort Entities according to the given comparison function. Only T == Entity is allowed. The constraint param only exists for
+                /// parity with non-empty Components
+                pub fn sort(self: Self, comptime T: type, context: var, comptime lessThan: fn (@TypeOf(context), T, T) bool) void {
+                    std.debug.assert(T == Entity);
+                    self.set.sort(context, lessThan);
                 }
             }
         else
@@ -200,16 +202,12 @@ pub fn ComponentStorage(comptime Component: type, comptime Entity: type) type {
                 }
 
                 /// Sort Entities or Components according to the given comparison function
-                pub fn sort(self: *Self, comptime T: type, comptime lessThan: fn (void, T, T) bool) void {
+                pub fn sort(self: Self, comptime T: type, context: var, comptime lessThan: fn (@TypeOf(context), T, T) bool) void {
                     std.debug.assert(T == Entity or T == Component);
                     if (T == Entity) {
-                        self.set.sortSub(lessThan, Component, self.instances.items);
+                        self.set.sortSub(context, lessThan, Component, self.instances.items);
                     } else if (T == Component) {
-                        self.set.sortSubSub({}, Component, lessThan, self.instances.items);
-                        // fn sorter(self: Self, a: T, b: T, sortFn) bool {
-                        //      return sortFn(self.instances[a], self.instances[b]);
-                        // }
-                        //return compare(std::as_const(instances[underlying_type::index(lhs)]), std::as_const(instances[underlying_type::index(rhs)]));
+                        self.set.sortSubSub(context, Component, lessThan, self.instances.items);
                     }
                 }
             };
@@ -339,13 +337,13 @@ test "sort empty component" {
     store.add(0, Empty{});
 
     comptime const asc_u32 = std.sort.asc(u32);
-    store.sort(asc_u32);
+    store.sort(u32, {}, asc_u32);
     for (store.data()) |e, i| {
         std.testing.expectEqual(@intCast(u32, i), e);
     }
 
     comptime const desc_u32 = std.sort.desc(u32);
-    store.sort(desc_u32);
+    store.sort(u32, {}, desc_u32);
     var counter: u32 = 2;
     for (store.data()) |e, i| {
         std.testing.expectEqual(counter, e);
@@ -353,7 +351,7 @@ test "sort empty component" {
     }
 }
 
-test "sort component" {
+test "sort by entity" {
     std.debug.warn("\n", .{});
 
     var store = ComponentStorage(f32, u32).initPtr(std.testing.allocator);
@@ -363,8 +361,37 @@ test "sort component" {
     store.add(11, @as(f32, 1.1));
     store.add(33, @as(f32, 3.3));
 
-    comptime const desc_u32 = std.sort.desc(f32);
-    store.sort(f32, desc_u32);
+    const SortContext = struct{
+        store: *ComponentStorage(f32, u32),
+
+        fn sort(this: @This(), a: u32, b: u32) bool {
+            const real_a = this.store.getConst(a);
+            const real_b = this.store.getConst(b);
+            return real_a > real_b;
+        }
+    };
+    const context = SortContext{.store = store};
+    store.sort(u32, context, SortContext.sort);
+
+    var compare: f32 = 5;
+    for (store.raw()) |val, i| {
+        std.testing.expect(compare > val);
+        compare = val;
+    }
+}
+
+test "sort by component" {
+    std.debug.warn("\n", .{});
+
+    var store = ComponentStorage(f32, u32).initPtr(std.testing.allocator);
+    defer store.deinit();
+
+    store.add(22, @as(f32, 2.2));
+    store.add(11, @as(f32, 1.1));
+    store.add(33, @as(f32, 3.3));
+
+    comptime const desc_f32 = std.sort.desc(f32);
+    store.sort(f32, {}, desc_f32);
 
     var compare: f32 = 5;
     for (store.raw()) |val, i| {

zig-ecs/src/ecs/groups.zig

@@ -9,40 +9,59 @@ const Entity = @import("registry.zig").Entity;
 /// BasicGroups do not own any components. Internally, they keep a SparseSet that is always kept up-to-date with the matching
 /// entities.
 pub const BasicGroup = struct {
-    const Self = @This();
-
     registry: *Registry,
     group_data: *Registry.GroupData,
 
-    pub fn init(registry: *Registry, group_data: *Registry.GroupData) Self {
-        return Self{
+    pub fn init(registry: *Registry, group_data: *Registry.GroupData) BasicGroup {
+        return .{
             .registry = registry,
             .group_data = group_data,
         };
     }
 
-    pub fn len(self: Self) usize {
+    pub fn len(self: BasicGroup) usize {
         return self.group_data.entity_set.len();
     }
 
     /// Direct access to the array of entities
-    pub fn data(self: Self) []const Entity {
+    pub fn data(self: BasicGroup) []const Entity {
         return self.group_data.entity_set.data();
     }
 
-    pub fn get(self: *Self, comptime T: type, entity: Entity) *T {
+    pub fn get(self: *BasicGroup, comptime T: type, entity: Entity) *T {
         return self.registry.assure(T).get(entity);
     }
 
-    pub fn getConst(self: *Self, comptime T: type, entity: Entity) T {
+    pub fn getConst(self: *BasicGroup, comptime T: type, entity: Entity) T {
         return self.registry.assure(T).getConst(entity);
     }
 
     /// iterates the matched entities backwards, so the current entity can always be removed safely
     /// and newly added entities wont affect it.
-    pub fn iterator(self: Self) utils.ReverseSliceIterator(Entity) {
+    pub fn iterator(self: BasicGroup) utils.ReverseSliceIterator(Entity) {
         return self.group_data.entity_set.reverseIterator();
     }
+
+    pub fn sort(self: *BasicGroup, comptime T: type, context: var, comptime lessThan: fn (@TypeOf(context), T, T) bool) void {
+        if (T == Entity) {
+            self.group_data.entity_set.sort(context, lessThan);
+        } else {
+            // TODO: in debug mode, validate that T is present in the group
+            const SortContext = struct{
+                group: *BasicGroup,
+                wrapped_context: @TypeOf(context),
+                lessThan: fn (@TypeOf(context), T, T) bool,
+
+                fn sort(this: @This(), a: Entity, b: Entity) bool {
+                    const real_a = this.group.getConst(T, a);
+                    const real_b = this.group.getConst(T, b);
+                    return this.lessThan(this.wrapped_context, real_a, real_b);
+                }
+            };
+            var wrapper = SortContext{.group = self, .wrapped_context = context, .lessThan = lessThan};
+            self.group_data.entity_set.sort(wrapper, SortContext.sort);
+        }
+    }
 };
 
 pub const OwningGroup = struct {

zig-ecs/src/ecs/registry.zig

@@ -412,10 +412,10 @@ pub const Registry = struct {
         return self.singletons;
     }
 
-    pub fn sort(self: *Registry, comptime T: type) void {
+    pub fn sort(self: *Registry, comptime T: type, comptime lessThan: fn (void, T, T) bool) void {
         const comp = self.assure(T);
         std.debug.assert(comp.super == 0);
-        unreachable;
+        comp.sort(T, lessThan);
     }
 
     /// Checks whether the given component belongs to any group. If so, it is not sortable directly.
@@ -563,7 +563,8 @@ pub const Registry = struct {
                 new_group_data.entity_set.add(entity);
             }
         } else {
-            // ??? why not? we cannot iterate backwards because we want to leave behind valid entities in case of owned types
+            // we cannot iterate backwards because we want to leave behind valid entities in case of owned types
+            // ??? why not?
             var first_owned_storage = self.assure(owned[0]);
             for (first_owned_storage.data()) |entity| {
                 new_group_data.maybeValidIf(entity);

zig-ecs/src/ecs/sparse_set.zig

@@ -143,8 +143,8 @@ pub fn SparseSet(comptime SparseT: type) type {
         }
 
         /// Sort elements according to the given comparison function
-        pub fn sort(self: *Self, comptime sortFn: fn (void, SparseT, SparseT) bool) void {
-            std.sort.insertionSort(SparseT, self.dense.items, {}, sortFn);
+        pub fn sort(self: *Self, context: var, comptime lessThan: fn (@TypeOf(context), SparseT, SparseT) bool) void {
+            std.sort.insertionSort(SparseT, self.dense.items, context, lessThan);
 
             for (self.dense.items) |sparse, i| {
                 // sparse[page(packed[pos])][offset(packed[pos])] = entity_type(pos);
@@ -153,12 +153,20 @@ pub fn SparseSet(comptime SparseT: type) type {
         }
 
         /// Sort elements according to the given comparison function and keeps sub_items with the same sort
-        pub fn sortSub(self: *Self, comptime sortFn: fn (void, SparseT, SparseT) bool, comptime T: type, sub_items: []T) void {
-            utils.sortSub(SparseT, T, self.dense.items, sub_items, sortFn);
+        pub fn sortSub(self: *Self, context: var, comptime lessThan: fn (@TypeOf(context), SparseT, SparseT) bool, comptime T: type, sub_items: []T) void {
+            std.sort.insertionSort(SparseT, self.dense.items, context, lessThan);
 
-            for (self.dense.items) |sparse, i| {
-                // sparse[page(packed[pos])][offset(packed[pos])] = entity_type(pos);
-                self.sparse.items[self.dense.items[self.page(@intCast(SparseT, i))]] = @intCast(SparseT, i);
+            for (self.dense.items) |sparse, pos| {
+                var curr = @intCast(SparseT, pos);
+                var next = self.index(self.dense.items[curr]);
+
+                while (curr != next) {
+                    std.mem.swap(T, &sub_items[self.index(self.dense.items[curr])], &sub_items[self.index(self.dense.items[next])]);
+                    self.sparse.items[self.dense.items[self.page(@intCast(SparseT, curr))]] = @intCast(SparseT, curr);
+
+                    curr = next;
+                    next = self.index(self.dense.items[curr]);
+                }
             }
         }
 
@@ -323,7 +331,7 @@ test "respect 2" {
     set.add(1);
     set.add(3);
 
-    set.sort(desc_u32);
+    set.sort({}, desc_u32);
 
     for (set.dense.items) |item, i| {
         if (i < set.dense.items.len - 1) {

zig-ecs/tests/groups_test.zig

@@ -2,6 +2,7 @@ const std = @import("std");
 const warn = std.debug.warn;
 const ecs = @import("ecs");
 const Registry = @import("ecs").Registry;
+const BasicGroup = @import("ecs").BasicGroup;
 
 const Velocity = struct { x: f32 = 0, y: f32 = 0 };
 const Position = struct { x: f32 = 0, y: f32 = 0 };
@@ -14,31 +15,79 @@ const Rotation = struct { x: f32 = 0 };
 fn printStore(store: var, name: []const u8) void {
     warn("--- {} ---\n", .{name});
     for (store.set.dense.items) |e, i| {
-        warn("e[{}] s[{}]{}", .{e, store.set.page(store.set.dense.items[i]), store.set.sparse.items[store.set.page(store.set.dense.items[i])]});
+        warn("e[{}] s[{}]{}", .{ e, store.set.page(store.set.dense.items[i]), store.set.sparse.items[store.set.page(store.set.dense.items[i])] });
         warn(" ({d:.2})   ", .{store.instances.items[i]});
     }
     warn("\n", .{});
 }
 
+test "sort BasicGroup by Entity" {
+    var reg = Registry.init(std.testing.allocator);
+    defer reg.deinit();
+
+    var group = reg.group(.{}, .{Sprite, Renderable}, .{});
+
+    var i: usize = 0;
+    while (i < 5) : (i += 1) {
+        var e = reg.create();
+        reg.add(e, Sprite{ .x = @intToFloat(f32, i) });
+        reg.add(e, Renderable{ .x = @intToFloat(f32, i) });
+    }
+
+    const SortContext = struct{
+        group: BasicGroup,
+
+        fn sort(this: *@This(), a: ecs.Entity, b: ecs.Entity) bool {
+            const real_a = this.group.getConst(Sprite, a);
+            const real_b = this.group.getConst(Sprite, b);
+            return real_a.x > real_b.x;
+        }
+    };
+
+    var context = SortContext{.group = group};
+    group.sort(ecs.Entity, &context, SortContext.sort);
+
+    var val: f32 = 0;
+    var iter = group.iterator();
+    while (iter.next()) |entity| {
+        std.testing.expectEqual(val, group.getConst(Sprite, entity).x);
+        val += 1;
+    }
+}
 
-test "sort component" {
-    var store = ecs.ComponentStorage(f32, u32).initPtr(std.testing.allocator);
-    defer store.deinit();
+test "sort BasicGroup by Component" {
+    var reg = Registry.init(std.testing.allocator);
+    defer reg.deinit();
 
-    store.add(22, @as(f32, 2.2));
-    store.add(11, @as(f32, 1.1));
-    store.add(33, @as(f32, 3.3));
+    var group = reg.group(.{}, .{Sprite, Renderable}, .{});
 
-    comptime const desc_u32 = std.sort.desc(f32);
-    store.sort(f32, desc_u32);
+    var i: usize = 0;
+    while (i < 5) : (i += 1) {
+        var e = reg.create();
+        reg.add(e, Sprite{ .x = @intToFloat(f32, i) });
+        reg.add(e, Renderable{ .x = @intToFloat(f32, i) });
+    }
 
-    var compare: f32 = 5;
-    for (store.raw()) |val, i| {
-        std.testing.expect(compare > val);
-        compare = val;
+    const SortContext = struct{
+        fn sort(this: void, a: Sprite, b: Sprite) bool {
+            return a.x > b.x;
+        }
+    };
+    group.sort(Sprite, {}, SortContext.sort);
+
+    var val: f32 = 0;
+    var iter = group.iterator();
+    while (iter.next()) |entity| {
+        std.testing.expectEqual(val, group.getConst(Sprite, entity).x);
+        val += 1;
     }
 }
 
+test "sort OwningGroup by Entity" {
+    var reg = Registry.init(std.testing.allocator);
+    defer reg.deinit();
+}
+
 test "nested OwningGroups add/remove components" {
     var reg = Registry.init(std.testing.allocator);
     defer reg.deinit();
@@ -87,7 +136,7 @@ test "nested OwningGroups entity order" {
     var transform_store = reg.assure(Transform);
     // printStore(sprite_store, "Sprite");
 
-    reg.add(1, Transform{.x = 1});
+    reg.add(1, Transform{ .x = 1 });
 
     // printStore(sprite_store, "Sprite");
     // printStore(transform_store, "Transform");