add excludes to Views

zig-ecs/examples/simple.zig

@@ -19,7 +19,7 @@ pub fn main() !void {
     reg.add(e2, Position{ .x = 10, .y = 10 });
     reg.add(e2, Velocity{ .x = 15, .y = 17 });
 
-    var view = reg.view(.{ Velocity, Position });
+    var view = reg.view(.{ Velocity, Position }, .{});
 
     var iter = view.iterator();
     while (iter.next()) |entity| {

zig-ecs/src/ecs/registry.zig

@@ -254,24 +254,34 @@ pub const Registry = struct {
             null;
     }
 
-    pub fn view(self: *Registry, comptime includes: var) ViewType(includes) {
+    pub fn view(self: *Registry, comptime includes: var, comptime excludes: var) ViewType(includes, excludes) {
+        if (@typeInfo(@TypeOf(includes)) != .Struct)
+            @compileError("Expected tuple or struct argument, found " ++ @typeName(@TypeOf(args)));
+        if (@typeInfo(@TypeOf(excludes)) != .Struct)
+            @compileError("Expected tuple or struct argument, found " ++ @typeName(@TypeOf(excludes)));
         std.debug.assert(includes.len > 0);
 
-        if (includes.len == 1)
+        if (includes.len == 1 and excludes.len == 0)
             return BasicView(includes[0]).init(self.assure(includes[0]));
 
-        var arr: [includes.len]u32 = undefined;
+        var includes_arr: [includes.len]u32 = undefined;
         inline for (includes) |t, i| {
             _ = self.assure(t);
-            arr[i] = @as(u32, self.typemap.get(t));
+            includes_arr[i] = @as(u32, self.typemap.get(t));
         }
 
-        return BasicMultiView(includes.len).init(arr, self);
+        var excludes_arr: [excludes.len]u32 = undefined;
+        inline for (excludes) |t, i| {
+            _ = self.assure(t);
+            excludes_arr[i] = @as(u32, self.typemap.get(t));
         }
 
-    fn ViewType(comptime includes: var) type {
+        return BasicMultiView(includes.len, excludes.len).init(includes_arr, excludes_arr, self);
-        if (includes.len == 1) return BasicView(includes[0]);
+    }
-        return BasicMultiView(includes.len);
+
+    fn ViewType(comptime includes: var, comptime excludes: var) type {
+        if (includes.len == 1 and excludes.len == 0) return BasicView(includes[0]);
+        return BasicMultiView(includes.len, excludes.len);
     }
 };
 

zig-ecs/src/ecs/view.zig

@@ -5,7 +5,6 @@ const Registry = @import("registry.zig").Registry;
 const Storage = @import("registry.zig").Storage;
 const Entity = @import("registry.zig").Entity;
 
-
 /// single item view. Iterating raw() directly is the fastest way to get at the data.
 pub fn BasicView(comptime T: type) type {
     return struct {
@@ -37,14 +36,19 @@ pub fn BasicView(comptime T: type) type {
         pub fn get(self: Self, entity: Entity) *T {
             return self.storage.get(entity);
         }
+
+        pub fn getConst(self: *Self, comptime T: type, entity: Entity) T {
+            return self.storage.getConst(entity);
+        }
     };
 }
 
-pub fn BasicMultiView(comptime n: usize) type {
+pub fn BasicMultiView(comptime n_includes: usize, comptime n_excludes: usize) type {
     return struct {
         const Self = @This();
 
-        type_ids: [n]u32,
+        type_ids: [n_includes]u32,
+        exclude_type_ids: [n_excludes]u32,
         registry: *Registry,
 
         pub const Iterator = struct {
@@ -69,10 +73,19 @@ pub fn BasicMultiView(comptime n: usize) type {
                     // entity must be in all other Storages
                     for (it.view.type_ids) |tid| {
                         const ptr = it.view.registry.components.getValue(@intCast(u8, tid)).?;
-                        if (!@intToPtr(*Storage(u8), ptr).contains(entity)) {
+                        if (!@intToPtr(*Storage(u1), ptr).contains(entity)) {
                             break :blk;
                         }
                     }
+
+                    // entity must not be in all other excluded Storages
+                    for (it.view.exclude_type_ids) |tid| {
+                        const ptr = it.view.registry.components.getValue(@intCast(u8, tid)).?;
+                        if (@intToPtr(*Storage(u1), ptr).contains(entity)) {
+                            break :blk;
+                        }
+                    }
+
                     it.index += 1;
                     return entity;
                 }
@@ -86,9 +99,10 @@ pub fn BasicMultiView(comptime n: usize) type {
             }
         };
 
-        pub fn init(type_ids: [n]u32, registry: *Registry) Self {
+        pub fn init(type_ids: [n_includes]u32, exclude_type_ids: [n_excludes]u32, registry: *Registry) Self {
             return Self{
                 .type_ids = type_ids,
+                .exclude_type_ids = exclude_type_ids,
                 .registry = registry,
             };
         }
@@ -97,8 +111,6 @@ pub fn BasicMultiView(comptime n: usize) type {
             const type_id = self.registry.typemap.get(T);
             const ptr = self.registry.components.getValue(type_id).?;
             const store = @intToPtr(*Storage(T), ptr);
-
-            std.debug.assert(store.contains(entity));
             return store.get(entity);
         }
 
@@ -106,14 +118,12 @@ pub fn BasicMultiView(comptime n: usize) type {
             const type_id = self.registry.typemap.get(T);
             const ptr = self.registry.components.getValue(type_id).?;
             const store = @intToPtr(*Storage(T), ptr);
-
-            std.debug.assert(store.contains(entity));
             return store.getConst(entity);
         }
 
         fn sort(self: *Self) void {
             // get our component counts in an array so we can sort the type_ids based on how many entities are in each
-            var sub_items: [n]usize = undefined;
+            var sub_items: [n_includes]usize = undefined;
             for (self.type_ids) |tid, i| {
                 const ptr = self.registry.components.getValue(@intCast(u8, tid)).?;
                 const store = @intToPtr(*Storage(u8), ptr);
@@ -130,7 +140,6 @@ pub fn BasicMultiView(comptime n: usize) type {
     };
 }
 
-
 test "single basic view" {
     var store = Storage(f32).init(std.testing.allocator);
     defer store.deinit();
@@ -194,8 +203,8 @@ test "basic multi view" {
     reg.add(e0, @as(u32, 0));
     reg.add(e2, @as(u32, 2));
 
-    var single_view = reg.view(.{u32});
+    var single_view = reg.view(.{u32}, .{});
-    var view = reg.view(.{ i32, u32 });
+    var view = reg.view(.{ i32, u32 }, .{});
 
     var iterated_entities: usize = 0;
     var iter = view.iterator();
@@ -215,3 +224,41 @@ test "basic multi view" {
 
     std.testing.expectEqual(iterated_entities, 1);
 }
+
+test "basic multi view with excludes" {
+    var reg = Registry.init(std.testing.allocator);
+    defer reg.deinit();
+
+    var e0 = reg.create();
+    var e1 = reg.create();
+    var e2 = reg.create();
+
+    reg.add(e0, @as(i32, -0));
+    reg.add(e1, @as(i32, -1));
+    reg.add(e2, @as(i32, -2));
+
+    reg.add(e0, @as(u32, 0));
+    reg.add(e2, @as(u32, 2));
+
+    reg.add(e2, @as(u8, 255));
+
+    var view = reg.view(.{ i32, u32 }, .{u8});
+
+    var iterated_entities: usize = 0;
+    var iter = view.iterator();
+    while (iter.next()) |entity| {
+        iterated_entities += 1;
+    }
+
+    std.testing.expectEqual(iterated_entities, 1);
+    iterated_entities = 0;
+
+    reg.remove(u8, e2);
+
+    iter.reset();
+    while (iter.next()) |entity| {
+        iterated_entities += 1;
+    }
+
+    std.testing.expectEqual(iterated_entities, 2);
+}