zflecs

Getting started

pub fn build(b: *std.Build) void {
 const exe = b.addExecutable(.{ ... });
 const zflecs = b.dependency("zflecs", .{});
 exe.root_module.addImport("zflecs", zflecs.module("root"));
 exe.linkLibrary(zflecs.artifact("flecs"));
}

const std = @import("std");
const ecs = @import("zflecs");
const Position = struct { x: f32, y: f32 };
const Velocity = struct { x: f32, y: f32 };
const Eats = struct {};
const Apples = struct {};
fn move_system(positions: []Position, velocities: []const Velocity) void {
 for (positions, velocities) |*p, v| {
 p.x += v.x;
 p.y += v.y;
 }
}
//Optionally, systems can receive the components iterator (usually not necessary)
fn move_system_with_it(it: *ecs.iter_t, positions: []Position, velocities: []const Velocity) void {
 const type_str = ecs.table_str(it.world, it.table).?;
 std.debug.print("Move entities with [{s}]\n", .{type_str});
 defer ecs.os.free(type_str);
 for (positions, velocities) |*p, v| {
 p.x += v.x;
 p.y += v.y;
 }
}
pub fn main() !void {
 const world = ecs.init();
 defer _ = ecs.fini(world);
 ecs.COMPONENT(world, Position);
 ecs.COMPONENT(world, Velocity);
 ecs.TAG(world, Eats);
 ecs.TAG(world, Apples);
 _ = ecs.ADD_SYSTEM(world, "move system", ecs.OnUpdate, move_system);
 _ = ecs.ADD_SYSTEM(world, "move system with iterator", ecs.OnUpdate, move_system_with_it);
 const bob = ecs.new_entity(world, "Bob");
 _ = ecs.set(world, bob, Position, .{ .x = 0, .y = 0 });
 _ = ecs.set(world, bob, Velocity, .{ .x = 1, .y = 2 });
 ecs.add_pair(world, bob, ecs.id(Eats), ecs.id(Apples));
 _ = ecs.progress(world, 0);
 _ = ecs.progress(world, 0);
 const p = ecs.get(world, bob, Position).?;
 std.debug.print("Bob's position is ({d}, {d})\n", .{ p.x, p.y });
}

Move entities with [main.Position, main.Velocity, (Identifier,Name), (main.Eats,main.Apples)]
Move entities with [main.Position, main.Velocity, (Identifier,Name), (main.Eats,main.Apples)]
Bob's position is (4, 8)