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ecs: temporarily fix bug around updating component values

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Signed-off-by: Stephen Gutekanst <stephen@hexops.com>
This commit is contained in:
Stephen Gutekanst 2023-04-27 18:39:55 -07:00 • committed by Stephen Gutekanst
parent 5e2ee3fed5
commit da851bdd1a
1 changed files with 31 additions and 6 deletions
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37
libs/ecs/src/entities.zig
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@ -129,7 +129,7 @@ pub const ArchetypeStorage = struct {
/// Asserts `new_capacity >= storage.len`, if you want to shrink capacity then change the len
/// yourself first.
pub fn setCapacity(storage: *ArchetypeStorage, gpa: Allocator, new_capacity: usize) !void {
assert(storage.capacity >= storage.len);
assert(new_capacity >= storage.len);
// TODO: ensure columns are sorted by type_id
for (storage.columns) |*column| {
@ -161,6 +161,8 @@ pub const ArchetypeStorage = struct {
/// Sets the value of the named components (columns) for the given row in the table.
pub fn set(storage: *ArchetypeStorage, gpa: Allocator, row_index: u32, name: []const u8, component: anytype) void {
assert(storage.len != 0 and storage.len >= row_index);
const ColumnType = @TypeOf(component);
if (@sizeOf(ColumnType) == 0) return;
@ -436,7 +438,7 @@ pub fn Entities(comptime all_components: anytype) type {
// Determine the new hash for the archetype + new component
var have_already = archetype.hasComponent(name);
const new_hash = if (have_already) old_hash else old_hash ^ std.hash_map.hashString(name);
var new_hash = if (have_already) old_hash else old_hash ^ std.hash_map.hashString(name);
// Find the archetype storage for this entity. Could be a new archetype storage table (if a
// new component was added), or the same archetype storage table (if just updating the
@ -449,6 +451,8 @@ pub fn Entities(comptime all_components: anytype) type {
if (!archetype_entry.found_existing) {
const columns = entities.allocator.alloc(Column, archetype.columns.len + 1) catch |err| {
// Note: this removal doesn't break index accesses performed by archetypeByID
// since our archetype is guaranteed to be the last index right now.
assert(entities.archetypes.swapRemove(new_hash));
return err;
};
@ -472,6 +476,23 @@ pub fn Entities(comptime all_components: anytype) type {
.hash = undefined,
};
archetype_entry.value_ptr.calculateHash();
// TODO: because hashing approach is poor, and specifically because columns are sorted,
// new_hash can actually not equal the result of .calculateHash which means the archetypes
// hashmap entry is under the wrong key now!
const old_hash_2 = new_hash;
new_hash = archetype_entry.value_ptr.hash;
var new_entry = archetype_entry.value_ptr.*;
// We rely on entities.archetypes access by array index (archetypeByID); but since
// it is guaranteed the item we're replacing is the last item in the array it's fine.
_ = entities.archetypes.orderedRemove(old_hash_2);
archetype_entry = try entities.archetypes.getOrPut(entities.allocator, new_hash);
if (archetype_entry.found_existing) {
// oops! our bad hashing means we did extra work
new_entry.deinit(entities.allocator);
} else {
archetype_entry.value_ptr.* = new_entry;
}
}
// Either new storage (if the entity moved between storage tables due to having a new
@ -579,6 +600,8 @@ pub fn Entities(comptime all_components: anytype) type {
if (!archetype_entry.found_existing) {
const columns = entities.allocator.alloc(Column, archetype.columns.len - 1) catch |err| {
// Note: this removal doesn't break index accesses performed by archetypeByID
// since our archetype is guaranteed to be the last index right now.
assert(entities.archetypes.swapRemove(new_hash));
return err;
};
@ -686,8 +709,9 @@ test "example" {
//-------------------------------------------------------------------------
// Create first player entity.
var player1 = try world.new();
try world.setComponent(player1, .game, .name, "jane"); // add Name component
try world.setComponent(player1, .game, .location, .{}); // add Location component
try world.setComponent(player1, .game, .name, "jane"); // add .name component
try world.setComponent(player1, .game, .name, "joe"); // update .name component
try world.setComponent(player1, .game, .location, .{}); // add .location component
// Create second player entity.
var player2 = try world.new();
@ -697,6 +721,7 @@ test "example" {
//-------------------------------------------------------------------------
// We can add new components at will.
try world.setComponent(player2, .game, .rotation, .{ .degrees = 90 });
try world.setComponent(player2, .game, .rotation, .{ .degrees = 91 }); // update .rotation component
try testing.expect(world.getComponent(player1, .game, .rotation) == null); // player1 has no rotation
//-------------------------------------------------------------------------
@ -714,9 +739,9 @@ test "example" {
var archetypes = world.archetypes.keys();
try testing.expectEqual(@as(usize, 6), archetypes.len);
try testing.expectEqual(@as(u64, void_archetype_hash), archetypes[0]);
try testing.expectEqual(@as(u64, 10567852867187873021), archetypes[1]);
try testing.expectEqual(@as(u64, 5804575476291452713), archetypes[1]);
try testing.expectEqual(@as(u64, 14072552683119202344), archetypes[2]);
try testing.expectEqual(@as(u64, 17945105277702244199), archetypes[3]);
try testing.expectEqual(@as(u64, 4263961864502127795), archetypes[3]);
try testing.expectEqual(@as(u64, 12546098194442238762), archetypes[4]);
try testing.expectEqual(@as(u64, 4457032469566706731), archetypes[5]);