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ecs: add type-safe module wrapper/helper

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Signed-off-by: Stephen Gutekanst <stephen@hexops.com>
This commit is contained in:
Stephen Gutekanst 2023-03-26 21:23:44 -07:00 • committed by Stephen Gutekanst
parent 5c1414efb5
commit 0bae4b00bd
2 changed files with 95 additions and 36 deletions
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111
libs/ecs/src/systems.zig
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@ -8,6 +8,7 @@ const EnumField = std.builtin.Type.EnumField;
const UnionField = std.builtin.Type.UnionField;
const Entities = @import("entities.zig").Entities;
const EntityID = @import("entities.zig").EntityID;
/// Validates that a module matches the expected type layout.
///
@ -224,6 +225,79 @@ pub fn World(comptime modules: anytype) type {
const Self = @This();
pub fn Module(comptime module_tag: anytype) type {
return struct {
world: *Self,
/// Gets a state value called `.state_tag` from the module.
pub inline fn getState(m: @This(), comptime state_tag: anytype) @TypeOf(@field(
@field(m.world.state, @tagName(module_tag)),
@tagName(state_tag),
)) {
return comptime @field(
@field(m.world.state, @tagName(module_tag)),
@tagName(state_tag),
);
}
/// Sets a state value called `.state_tag` in the module.
pub inline fn setState(
m: *@This(),
comptime state_tag: anytype,
value: @TypeOf(@field(
@field(m.world.state, @tagName(module_tag)),
@tagName(state_tag),
)),
) void {
comptime @field(
@field(m.world.state, @tagName(module_tag)),
@tagName(state_tag),
) = value;
}
/// 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 inline fn set(
m: *@This(),
entity: EntityID,
comptime component_name: std.meta.FieldEnum(@TypeOf(@field(all_components, @tagName(module_tag)))),
component: @field(
@field(all_components, @tagName(module_tag)),
@tagName(component_name),
),
) !void {
try m.world.entities.setComponent(entity, module_tag, component_name, component);
}
/// 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 inline fn get(
m: *@This(),
entity: EntityID,
comptime component_name: std.meta.FieldEnum(@TypeOf(@field(all_components, @tagName(module_tag)))),
) ?@field(
@field(all_components, @tagName(module_tag)),
@tagName(component_name),
) {
return m.world.entities.getComponent(entity, module_tag, component_name);
}
/// Removes the named component from the entity, or noop if it doesn't have such a component.
pub inline fn remove(
m: *@This(),
entity: EntityID,
comptime component_name: std.meta.FieldEnum(@TypeOf(@field(all_components, @tagName(module_tag)))),
) !void {
try m.world.entities.removeComponent(entity, module_tag, component_name);
}
};
}
pub inline fn mod(world: *Self, comptime module_tag: anytype) Self.Module(module_tag) {
return .{ .world = world };
}
pub fn init(allocator: Allocator) !Self {
return Self{
.allocator = allocator,
@ -236,33 +310,6 @@ pub fn World(comptime modules: anytype) type {
world.entities.deinit();
}
/// Gets a state value called `.state_tag` from the module named `.module_tag`
pub fn get(world: *Self, comptime module_tag: anytype, comptime state_tag: anytype) @TypeOf(@field(
@field(world.state, @tagName(module_tag)),
@tagName(state_tag),
)) {
return comptime @field(
@field(world.state, @tagName(module_tag)),
@tagName(state_tag),
);
}
/// Sets a state value called `.state_tag` in the module named `.module_tag`
pub fn set(
world: *Self,
comptime module_tag: anytype,
comptime state_tag: anytype,
value: @TypeOf(@field(
@field(world.state, @tagName(module_tag)),
@tagName(state_tag),
)),
) void {
comptime @field(
@field(world.state, @tagName(module_tag)),
@tagName(state_tag),
) = value;
}
/// Broadcasts a state message to all modules that are subscribed to it.
pub fn send(world: *Self, comptime msg_tag: anytype) !void {
inline for (std.meta.fields(@TypeOf(modules))) |module_field| {
@ -273,5 +320,15 @@ pub fn World(comptime modules: anytype) type {
}
}
}
/// Returns a new entity.
pub inline fn newEntity(world: *Self) !EntityID {
return try world.entities.new();
}
/// Removes an entity.
pub inline fn remove(world: *Self, entity: EntityID) !void {
try world.entities.remove(entity);
}
};
}