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ecs: make [set/remove/get]Component globally type safe

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Signed-off-by: Stephen Gutekanst <stephen@hexops.com>
This commit is contained in:
Stephen Gutekanst 2022-06-10 20:37:25 -07:00 • committed by Stephen Gutekanst
parent 1f7ea529f4
commit 25afe5ccf4
2 changed files with 51 additions and 28 deletions
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66
ecs/src/entities.zig
View file

@ -497,7 +497,14 @@ pub fn Entities(all_components: anytype) type {
/// Sets the named component to the specified value for the given entity,
/// moving the entity from it's current archetype table to the new archetype
/// table if required.
pub fn setComponent(entities: *Self, entity: EntityID, comptime name: []const u8, component: anytype) !void {
pub fn setComponent(
entities: *Self,
entity: EntityID,
comptime component_name: std.meta.FieldEnum(@TypeOf(all_components)),
component: @field(all_components, std.meta.tagName(component_name)),
) !void {
const name = std.meta.tagName(component_name);
var archetype = entities.archetypeByID(entity);
// Determine the old hash for the archetype.
@ -595,7 +602,13 @@ pub fn Entities(all_components: anytype) type {
/// gets the named component of the given type (which must be correct, otherwise undefined
/// behavior will occur). Returns null if the component does not exist on the entity.
pub fn getComponent(entities: *Self, entity: EntityID, name: []const u8, comptime Component: type) ?Component {
pub fn getComponent(
entities: *Self,
entity: EntityID,
comptime component_name: std.meta.FieldEnum(@TypeOf(all_components)),
) ?@field(all_components, std.meta.tagName(component_name)) {
const Component = comptime @field(all_components, std.meta.tagName(component_name));
const name = std.meta.tagName(component_name);
var archetype = entities.archetypeByID(entity);
const ptr = entities.entities.get(entity).?;
@ -603,7 +616,12 @@ pub fn Entities(all_components: anytype) type {
}
/// Removes the named component from the entity, or noop if it doesn't have such a component.
pub fn removeComponent(entities: *Self, entity: EntityID, name: []const u8) !void {
pub fn removeComponent(
entities: *Self,
entity: EntityID,
comptime component_name: std.meta.FieldEnum(@TypeOf(all_components)),
) !void {
const name = std.meta.tagName(component_name);
var archetype = entities.archetypeByID(entity);
if (!archetype.hasComponent(name)) return;
@ -712,45 +730,47 @@ test "entity ID size" {
test "example" {
const allocator = testing.allocator;
const all_components = .{};
const Location = struct {
x: f32 = 0,
y: f32 = 0,
z: f32 = 0,
};
const Rotation = struct { degrees: f32 };
const all_components = .{
.location = Location,
.name = []const u8,
.rotation = Rotation,
};
//-------------------------------------------------------------------------
// Create a world.
var world = try Entities(all_components).init(allocator);
defer world.deinit();
//-------------------------------------------------------------------------
// Define component types, any Zig type will do!
// A location component.
const Location = struct {
x: f32 = 0,
y: f32 = 0,
z: f32 = 0,
};
//-------------------------------------------------------------------------
// Create first player entity.
var player1 = try world.new();
try world.setComponent(player1, "name", "jane"); // add Name component
try world.setComponent(player1, "location", Location{}); // add Location component
try world.setComponent(player1, .name, "jane"); // add Name component
try world.setComponent(player1, .location, .{}); // add Location component
// Create second player entity.
var player2 = try world.new();
try testing.expect(world.getComponent(player2, "location", Location) == null);
try testing.expect(world.getComponent(player2, "name", []const u8) == null);
try testing.expect(world.getComponent(player2, .location) == null);
try testing.expect(world.getComponent(player2, .name) == null);
//-------------------------------------------------------------------------
// We can add new components at will.
const Rotation = struct { degrees: f32 };
try world.setComponent(player2, "rotation", Rotation{ .degrees = 90 });
try testing.expect(world.getComponent(player1, "rotation", Rotation) == null); // player1 has no rotation
try world.setComponent(player2, .rotation, .{ .degrees = 90 });
try testing.expect(world.getComponent(player1, .rotation) == null); // player1 has no rotation
//-------------------------------------------------------------------------
// Remove a component from any entity at will.
// TODO: add a way to "cleanup" truly unused archetypes
try world.removeComponent(player1, "name");
try world.removeComponent(player1, "location");
try world.removeComponent(player1, "location"); // doesn't exist? no problem.
try world.removeComponent(player1, .name);
try world.removeComponent(player1, .location);
try world.removeComponent(player1, .location); // doesn't exist? no problem.
//-------------------------------------------------------------------------
// Introspect things.

13
ecs/src/main.zig
View file

@ -46,7 +46,10 @@ test "inclusion" {
test "example" {
const allocator = testing.allocator;
const all_components = .{};
const all_components = .{
.physics = u16,
.geometry = u16,
};
//-------------------------------------------------------------------------
// Create a world.
@ -56,11 +59,11 @@ test "example" {
const player1 = try world.entities.new();
const player2 = try world.entities.new();
const player3 = try world.entities.new();
try world.entities.setComponent(player1, "physics", @as(u16, 1234));
try world.entities.setComponent(player1, "geometry", @as(u16, 1234));
try world.entities.setComponent(player1, .physics, 1234);
try world.entities.setComponent(player1, .geometry, 1234);
try world.entities.setComponent(player2, "physics", @as(u16, 1234));
try world.entities.setComponent(player3, "physics", @as(u16, 1234));
try world.entities.setComponent(player2, .physics, 1234);
try world.entities.setComponent(player3, .physics, 1234);
const physics = (struct {
pub fn physics(adapter: *Adapter(all_components)) void {