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const std = @import("std");
const ecs = @import("ecs");
// override the EntityTraits used by ecs
pub const EntityTraits = ecs.EntityTraitsType(.small);
pub const Velocity = struct { x: f32, y: f32 };
pub const Position = struct { x: f32, y: f32 };
pub fn main() !void {
var reg = ecs.Registry.init(std.heap.c_allocator);
defer reg.deinit();
var e1 = reg.create();
reg.add(e1, Position{ .x = 0, .y = 0 });
reg.add(e1, Velocity{ .x = 5, .y = 7 });
var e2 = reg.create();
reg.add(e2, Position{ .x = 10, .y = 10 });
reg.add(e2, Velocity{ .x = 15, .y = 17 });
var view = reg.view(.{ Velocity, Position }, .{});
var iter = view.iterator();
while (iter.next()) |entity| {
var pos = view.get(Position, entity);
const vel = view.getConst(Velocity, entity);
std.debug.print(
"entity: {}, pos: (x = {d}, y = {d}), vel: (x = {d}, y = {d})\n",
.{ entity, pos.x, pos.y, vel.x, vel.y },
);
pos.*.x += vel.x;
pos.*.y += vel.y;
}
std.debug.print("---- resetting iter\n", .{});
iter.reset();
while (iter.next()) |entity| {
const pos = view.getConst(Position, entity);
const vel = view.getConst(Velocity, entity);
std.debug.print(
"entity: {}, pos: (x = {d}, y = {d}), vel: (x = {d}, y = {d})\n",
.{ entity, pos.x, pos.y, vel.x, vel.y },
);
}
}