////////////////////////////////
//~ Sim accel

SimAccel AcquireSimAccel(void)
{
    SimAccel accel = ZI;
    accel.space = space_acquire(SPACE_CELL_SIZE, SPACE_CELL_BINS_SQRT);
    return accel;
}

void ReleaseSimAccel(SimAccel *accel)
{
    space_release(accel->space);
}

void ResetSimAccel(Snapshot *ss, SimAccel *accel)
{
    space_reset(accel->space);

    /* Reset ent space handles */
    for (u64 sim_ent_index = 0; sim_ent_index < ss->num_ents_reserved; ++sim_ent_index) {
        Entity *ent = &ss->ents[sim_ent_index];
        if (ent->valid) {
            ZeroStruct(&ent->space_handle);
        }
    }
}

////////////////////////////////
//~ Spawn test operations

/* TODO: Remove this */

Entity *SpawnTestSmg(Entity *parent)
{
    Entity *e = AcquireSyncSrc(parent);
    e->sprite = S_TagFromPath(Lit("sprite/gun.ase"));

    EnableProp(e, Prop_Attached);
    e->attach_slice = Lit("attach.wep");
    e->layer = SIM_LAYER_RELATIVE_WEAPON;

    EnableProp(e, Prop_Smg);
    e->primary_fire_delay = 1.0f / 10.0f;
    e->secondary_fire_delay = 1.0f / 10.0f;

    return e;
}

Entity *SpawnTestLauncher(Entity *parent)
{
    Entity *e = AcquireSyncSrc(parent);
    e->sprite = S_TagFromPath(Lit("sprite/gun.ase"));

    EnableProp(e, Prop_Attached);
    e->attach_slice = Lit("attach.wep");
    e->layer = SIM_LAYER_RELATIVE_WEAPON;

    EnableProp(e, Prop_Launcher);
    e->primary_fire_delay = 1.0f / 10.0f;
    e->secondary_fire_delay = 1.0f / 10.0f;

    return e;
}

Entity *SpawnTestChucker(Entity *parent)
{
    Entity *chucker = AcquireSyncSrc(parent);
    chucker->sprite = S_TagFromPath(Lit("sprite/gun.ase"));

    EnableProp(chucker, Prop_Attached);
    chucker->attach_slice = Lit("attach.wep");
    chucker->layer = SIM_LAYER_RELATIVE_WEAPON;

    EnableProp(chucker, Prop_Chucker);
    chucker->primary_fire_delay = 1.0f / 10.0f;
    chucker->secondary_fire_delay = 1.0f / 2.0f;

    /* Chucker zone */
    {
        Entity *zone = AcquireSyncSrc(chucker);

        EnableProp(zone, Prop_ChuckerZone);

        EnableProp(zone, Prop_Attached);
        zone->attach_slice = Lit("out");

        EnableProp(zone, Prop_Sensor);
        CLD_Shape collider = ZI;
        collider.count = 2;
        collider.points[1] = VEC2(0, -0.5);
        collider.radius = 0.1f;
        zone->local_collider = collider;

        chucker->chucker_zone = zone->id;
    }

    return chucker;
}

Entity *SpawnTestEmployee(Entity *parent)
{
    /* Player */
    Entity *employee = NilEntity();
    {

        Entity *e = AcquireSyncSrc(parent);

        Vec2 pos = VEC2(1, -1);

        //Vec2 size = VEC2(0.5, 0.5);
        //Vec2 size = VEC2(0.5, 0.25);
        Vec2 size = VEC2(1.0, 1.0);

        //f32 r = Pi / 4;
        f32 r = 0;

        {
            EnableProp(e, Prop_Test);
            e->sprite = S_TagFromPath(Lit("sprite/tim.ase"));
            e->mass_unscaled = 10;
            e->inertia_unscaled = 5;
        }

        //e->sprite = S_TagFromPath(Lit("sprite/box_rounded.ase"));
        //e->sprite_span_name = Lit("idle.unarmed");
        //e->sprite_span_name = Lit("idle.one_handed");
        e->sprite_span_name = Lit("idle.two_handed");
        e->layer = SIM_LAYER_SHOULDERS;

        e->local_collider.points[0] = VEC2(0, 0);
        e->local_collider.count = 1;
        e->local_collider.radius = 0.25f;

        Xform xf = XformFromTrs(TRS(.t = pos, .r = r, .s = size));
        //xf.bx.y = -1.f;

        SetXform(e, xf);

        e->linear_ground_friction = 250;
        e->angular_ground_friction = 200;

        e->friction = 0;




        EnableProp(e, Prop_LightTest);
        e->sprite_emittance = VEC3(1, 1, 1);






        //e->control_force = 500;
        e->control_force = 1200;
        e->control_force_max_speed = 7;

        //e->control_torque = 5000;
        e->control_torque = F32Infinity;

        EnableProp(e, Prop_Dynamic);
        EnableProp(e, Prop_Solid);

        employee = e;
    }

    /* Player weapon */
    if (employee->valid) {
        LAX SpawnTestSmg;
        LAX SpawnTestLauncher;
        LAX SpawnTestChucker;

        Entity *e = SpawnTestChucker(employee);
        employee->equipped = e->id;

        EnableProp(e, Prop_LightTest);
        e->sprite_emittance = VEC3(1, 1, 1);
    }

    return employee;
}

Entity *SpawnTestCamera(Entity *parent, Entity *follow)
{
    Entity *camera_ent = NilEntity();
    if (follow->valid) {
        camera_ent = AcquireSyncSrc(parent);
        SetXform(camera_ent, XformIdentity);

        EnableProp(camera_ent, Prop_Camera);
        EnableProp(camera_ent, Prop_ActiveCamera);
        camera_ent->camera_follow = follow->id;

        f32 width = (f32)DEFAULT_CAMERA_WIDTH;
        f32 height = (f32)DEFAULT_CAMERA_HEIGHT;
        camera_ent->camera_quad_xform = XformFromTrs(TRS(.s = VEC2(width, height)));
    }

    return camera_ent;
}

Entity *SpawnTestExplosion(Entity *parent, Vec2 pos, f32 strength, f32 radius)
{
    Entity *ent = AcquireSyncSrc(parent);
    SetXform(ent, XformFromPos(pos));

    EnableProp(ent, Prop_Explosion);
    ent->explosion_strength = strength;
    ent->explosion_radius = radius;

    EnableProp(ent, Prop_Sensor);
    ent->local_collider.count = 1;
    ent->local_collider.radius = radius;

    return ent;
}

void TeleportTest(Entity *ent, Vec2 pos)
{
    //++ent->continuity_gen;
    Xform xf = XformFromEntity(ent);
    xf.og = pos;
    SetXform(ent, xf);
}

void SpawnTestEntities1(Entity *parent, Vec2 pos)
{
    LAX pos;

    /* Enemy */
    {
        Entity *e = SpawnTestEmployee(parent);
        Xform xf = XformFromEntity(e);
        xf.og = pos;
        SetXform(e, xf);
    }
}

void SpawnTestEntities2(Entity *parent, Vec2 pos)
{
    LAX pos;

    /* Small Box */
#if 1
    {
        //Entity *e = AcquireLocal(parent);
        Entity *e = AcquireSyncSrc(parent);

        f32 rot = 0;
        Vec2 size = VEC2(0.125, 0.125);
        Xform xf = XformFromTrs(TRS(.t = pos, .r = rot, .s = size));
        SetXform(e, xf);

        e->sprite = S_TagFromPath(Lit("sprite/tile.ase"));
        e->layer = SIM_LAYER_SHOULDERS;

        //e->sprite_tint = Alpha32F(ColorBlue, 0.75);
        //e->sprite_tint = Alpha32F(ColorWhite, 1);

        EnableProp(e, Prop_Solid);
        Quad collider_quad = QuadFromRect(RectFromScalar(-0.5, -0.5, 1, 1));
        e->local_collider = CLD_ShapeFromQuad(collider_quad);

        EnableProp(e, Prop_LightTest);

        /* FIXME: Remove this */
        {
            static RandState rand = ZI;
            f32 r = RandF64FromState(&rand, 1, 5);
            f32 g = RandF64FromState(&rand, 1, 5);
            f32 b = RandF64FromState(&rand, 1, 5);
            e->sprite_emittance = VEC3(r, g, b);
            e->sprite_tint = Rgba32F(r / 5, g / 5, b / 5, 1);
        }

        EnableProp(e, Prop_Dynamic);
        e->mass_unscaled = 50;
        e->inertia_unscaled = 2;
#if 0
        e->linear_ground_friction = 100;
        e->angular_ground_friction = 50;
#endif
    }
#endif

    /* Tiny box */
#if 0
    {
        Entity *e = AcquireSyncSrc(parent);

        f32 r = Pi / 4;
        Vec2 size = VEC2(0.5, 0.25);
        Xform xf = XformFromTrs(.t = pos, .r = r, .s = size);
        SetXform(e, xf);

        e->sprite = S_TagFromPath(Lit("sprite/bullet.ase"));
        e->sprite_collider_slice = Lit("shape");
        e->layer = SIM_LAYER_SHOULDERS;

        EnableProp(e, Prop_Solid);

        EnableProp(e, Prop_Dynamic);
        e->mass_unscaled = 0.5;
        e->inertia_unscaled = 1000;
        e->linear_ground_friction = 0.001;
    }
#endif
}

void SpawnTestEntities3(Entity *parent, Vec2 pos)
{
    LAX pos;

    /* Heavy box */
    {
        //Entity *e = AcquireLocal(parent);
        Entity *e = AcquireSyncSrc(parent);

        f32 r = 0;
        Vec2 size = VEC2(1, 1);
        Xform xf = XformFromTrs(TRS(.t = pos, .r = r, .s = size));
        SetXform(e, xf);

        e->sprite = S_TagFromPath(Lit("sprite/box.ase"));
        e->layer = SIM_LAYER_SHOULDERS;

        e->sprite_tint = ColorRed;

        EnableProp(e, Prop_Solid);
        Quad collider_quad = QuadFromRect(RectFromScalar(-0.5, -0.5, 1, 1));
        e->local_collider = CLD_ShapeFromQuad(collider_quad);
    }
}

void SpawnTestEntities4(Entity *parent, Vec2 pos)
{
    LAX pos;

    /* Light box */
    Entity *e = AcquireSyncSrc(parent);

    f32 r = 0;
    Vec2 size = VEC2(2, 1);
    Xform xf = XformFromTrs(TRS(.t = pos, .r = r, .s = size));
    SetXform(e, xf);

    //e->sprite = S_TagFromPath(Lit("sprite/box.ase"));
    e->sprite = S_TagFromPath(Lit("sprite/tile.ase"));
    e->layer = SIM_LAYER_SHOULDERS;

    EnableProp(e, Prop_LightTest);
    e->sprite_emittance = VEC3(2, 2, 2);

    e->sprite_tint = Rgb32F(1, 1, 1);
}

void SpawnTestTile(Snapshot *world, Vec2 world_pos)
{
#if 0
    Entity *e = AcquireSyncSrc(parent);

    i32 sign_x = (world_pos.x >= 0) - (world_pos.x < 0);
    i32 sign_y = (world_pos.y >= 0) - (world_pos.y < 0);
    Vec2I32 tile_index = VEC2I32(world_pos.x * SIM_TILES_PER_UNIT_SQRT, world_pos.y * SIM_TILES_PER_UNIT_SQRT);
    world_pos.x -= sign_x < 0;
    world_pos.y -= sign_y < 0;

    Vec2 tile_size = VEC2(1.f / SIM_TILES_PER_UNIT_SQRT, 1.f / SIM_TILES_PER_UNIT_SQRT);

    Vec2 pos = VEC2((f32)tile_index.x / SIM_TILES_PER_UNIT_SQRT, (f32)tile_index.y / SIM_TILES_PER_UNIT_SQRT);
    pos = AddVec2(pos, MulVec2(VEC2(tile_size.x * sign_x, tile_size.y * sign_y), 0.5));

    Xform xf = XformFromTrs(.t = pos);
    SetXform(e, xf);

    e->layer = SIM_LAYER_WALLS;
    e->sprite = S_TagFromPath(Lit("sprite/tile.ase"));
    e->sprite_tint = ColorRed;

    {
        S_Scope *scope = S_BeginScope();
        S_Sheet *sheet = S_SheetFromTagAwait(scope, e->sprite);
        e->sprite_local_xform = XformFromTrs(.s = DivVec2(sheet->frame_size, PIXELS_PER_UNIT));
        S_EndScope(scope);
    }

    EnableProp(e, Prop_Solid);
    Quad collider_quad = QuadFromRect(RectFromScalar(-tile_size.x / 2, -tile_size.y / 2, tile_size.y, tile_size.y));
    e->local_collider = CLD_ShapeFromQuad(collider_quad);
#else
    Vec2I32 tile_index = sim_world_tile_index_from_pos(world_pos);
    sim_snapshot_set_tile(world, tile_index, SIM_TILE_KIND_WALL);
#endif
}

void ClearLevelTest(SimStepCtx *ctx)
{
    Snapshot *world = ctx->world;
    for (u64 j = 0; j < world->num_ents_reserved; ++j) {
        Entity *ent = &world->ents[j];
        if (ent->valid) {
            EnableProp(ent, Prop_Release);
        }
    }
}

////////////////////////////////
//~ Tile test operations

MergesortCompareFuncDef(SortTileXCmp, arg_a, arg_b, _)
{
    Entity *a = *(Entity **)arg_a;
    Entity *b = *(Entity **)arg_b;
    i32 a_x = a->tile_chunk_index.x;
    i32 b_x = b->tile_chunk_index.x;

    i32 result = 0;
    result = (a_x < b_x) - (a_x > b_x);
    return result;
}

MergesortCompareFuncDef(SortTileYCmp, arg_a, arg_b, _)
{
    Entity *a = *(Entity **)arg_a;
    Entity *b = *(Entity **)arg_b;
    i32 a_y = a->tile_chunk_index.y;
    i32 b_y = b->tile_chunk_index.y;

    i32 result = 0;
    result = (a_y < b_y) - (a_y > b_y);
    return result;
}

void GenerateTestWalls(Snapshot *world)
{
    __prof;
    TempArena scratch = BeginScratchNoConflict();
    Entity *root = EntityFromId(world, RootEntityId);

    /* Release existing walls and gather tile chunks.
     * NOTE: We sort tile chunks before iterating so that chunk-edge tiles only
     * need to check for adjacent walls to merge with in one direction */
    Entity **x_sorted_tile_chunks = 0;
    Entity **y_sorted_tile_chunks = 0;
    u64 sorted_tile_chunks_count = 0;
    {
        x_sorted_tile_chunks = PushDry(scratch.arena, Entity *);
        for (u64 ent_index = 0; ent_index < world->num_ents_reserved; ++ent_index) {
            Entity *ent = &world->ents[ent_index];
            if (!ent->valid) continue;
            if (HasProp(ent, Prop_TileChunk)) {
                /* Append chunk to array */
                *PushStructNoZero(scratch.arena, Entity *) = ent;
                ++sorted_tile_chunks_count;
            } else if (HasProp(ent, Prop_Wall)) {
                /* Release existing wall */
                EnableProp(ent, Prop_Release);
            }
        }
        y_sorted_tile_chunks = PushStructsNoZero(scratch.arena, Entity *, sorted_tile_chunks_count);
        CopyBytes(y_sorted_tile_chunks, x_sorted_tile_chunks, sizeof(*x_sorted_tile_chunks) * sorted_tile_chunks_count);

        /* NOTE: We sort x & y separately because it's possible that a wall
         * should merge with another wall that was generated from a diagonal chunk. */
        Mergesort(x_sorted_tile_chunks, sorted_tile_chunks_count, sizeof(*x_sorted_tile_chunks), SortTileXCmp, 0);
        Mergesort(y_sorted_tile_chunks, sorted_tile_chunks_count, sizeof(*y_sorted_tile_chunks), SortTileYCmp, 0);
    }

    struct wall_node {
        Vec2I32 start;
        Vec2I32 end;
        i32 wall_dir;  /* = 0 up, 1 = right, 2 = down, 3 = left */
        struct wall_node *next;
    };

    /* Dicts containing walls that end on edge of tile chunk, keyed by tile end index.
     * Used to merge walls accross tile chunks. */
    Dict *horizontal_ends_dict = InitDict(scratch.arena, 1024);
    Dict *vertical_ends_dict = InitDict(scratch.arena, 1024);

    struct wall_node *first_wall = 0;

    /* Generate horizontal wall nodes */
    for (u64 sorted_index = 0; sorted_index < sorted_tile_chunks_count; ++sorted_index) {
        Entity *chunk = x_sorted_tile_chunks[sorted_index];
        Vec2I32 chunk_index = chunk->tile_chunk_index;
        Entity *top_chunk = TileChunkFromChunkIndex(world, VEC2I32(chunk_index.x, chunk_index.y - 1));
        Entity *bottom_chunk = TileChunkFromChunkIndex(world, VEC2I32(chunk_index.x, chunk_index.y + 1));
        /* If there's no chunk below this one, then do an extra iteration (since walls are created at the top of each tile) */
        i32 y_iterations = SIM_TILES_PER_CHUNK_SQRT + !bottom_chunk->valid;
        i32 x_iterations = SIM_TILES_PER_CHUNK_SQRT + 1;
        for (i32 tile_y = 0; tile_y < y_iterations; ++tile_y) {
            i32 wall_start = -1;
            i32 wall_end = -1;
            i32 wall_dir = -1;
            for (i32 tile_x = 0; tile_x < x_iterations; ++tile_x) {
                i32 desired_wall_dir = -1;
                TileKind tile = SIM_TILE_KIND_NONE;
                if (tile_x < SIM_TILES_PER_CHUNK_SQRT && tile_y < SIM_TILES_PER_CHUNK_SQRT) {
                    tile = TileKindFromChunk(chunk, VEC2I32(tile_x, tile_y));
                }
                if (tile_x < SIM_TILES_PER_CHUNK_SQRT) {
                    TileKind top_tile = SIM_TILE_KIND_NONE;
                    if (tile_y == 0) {
                        if (top_chunk->valid) {
                            Vec2I32 top_tile_local_index = VEC2I32(tile_x, SIM_TILES_PER_CHUNK_SQRT - 1);
                            top_tile = TileKindFromChunk(top_chunk, top_tile_local_index);
                        }
                    } else {
                        top_tile = TileKindFromChunk(chunk, VEC2I32(tile_x, tile_y - 1));
                    }
                    if (tile == SIM_TILE_KIND_WALL) {
                        /* Process wall tile */
                        if (top_tile != SIM_TILE_KIND_WALL) {
                            desired_wall_dir = 0;
                        }
                    } else {
                        /* Process non-wall tile */
                        if (top_tile == SIM_TILE_KIND_WALL) {
                            desired_wall_dir = 2;
                        }
                    }
                }

                /* Stop wall */
                if (wall_dir >= 0 && desired_wall_dir != wall_dir) {
                    Vec2I32 start = sim_world_tile_index_from_local_tile_index(chunk_index, VEC2I32(wall_start, tile_y));
                    Vec2I32 end = sim_world_tile_index_from_local_tile_index(chunk_index, VEC2I32(wall_end, tile_y));
                    struct wall_node *node = 0;
                    if (wall_start == 0) {
                        u64 start_hash = RandU64FromSeed(*(u64 *)&start);
                        start_hash = RandU64FromSeeds(start_hash, wall_dir);
                        DictEntry *entry = DictEntryFromHash(horizontal_ends_dict, start_hash);
                        if (entry) {
                            /* Existing wall exists accross chunk boundary */
                            node = (struct wall_node *)entry->value;
                            RemoveDictEntry(horizontal_ends_dict, entry);
                        }
                    }
                    if (!node) {
                        node = PushStruct(scratch.arena, struct wall_node);
                        node->start = start;
                        node->next = first_wall;
                        node->wall_dir = wall_dir;
                        first_wall = node;
                    }
                    node->end = end;
                    if (wall_end == SIM_TILES_PER_CHUNK_SQRT) {
                        u64 end_hash = RandU64FromSeed(*(u64 *)&end);
                        end_hash = RandU64FromSeeds(end_hash, wall_dir);
                        SetDictValue(scratch.arena, horizontal_ends_dict, end_hash, (u64)node);
                    }
                    wall_start = -1;
                    wall_end = -1;
                    wall_dir = -1;
                }

                /* Start / extend wall */
                if (desired_wall_dir >= 0) {
                    if (wall_dir != desired_wall_dir) {
                        /* Start wall */
                        wall_start = tile_x;
                    }
                    /* Extend wall */
                    wall_end = tile_x + 1;
                    wall_dir = desired_wall_dir;
                }
            }
        }
    }

    /* Generate vertical wall nodes */
    for (u64 sorted_index = 0; sorted_index < sorted_tile_chunks_count; ++sorted_index) {
        Entity *chunk = y_sorted_tile_chunks[sorted_index];
        Vec2I32 chunk_index = chunk->tile_chunk_index;
        Entity *left_chunk = TileChunkFromChunkIndex(world, VEC2I32(chunk_index.x - 1, chunk_index.y));
        Entity *right_chunk = TileChunkFromChunkIndex(world, VEC2I32(chunk_index.x + 1, chunk_index.y));
        /* If there's no chunk to the right of this one, then do an extra iteration (since walls are created on the left of each tile) */
        i32 y_iterations = SIM_TILES_PER_CHUNK_SQRT + 1;
        i32 x_iterations = SIM_TILES_PER_CHUNK_SQRT + !right_chunk->valid;
        for (i32 tile_x = 0; tile_x < x_iterations; ++tile_x) {
            i32 wall_start = -1;
            i32 wall_end = -1;
            i32 wall_dir = -1;
            for (i32 tile_y = 0; tile_y < y_iterations; ++tile_y) {
                i32 desired_wall_dir = -1;
                TileKind tile = SIM_TILE_KIND_NONE;
                if (tile_x < SIM_TILES_PER_CHUNK_SQRT && tile_y < SIM_TILES_PER_CHUNK_SQRT) {
                    tile = TileKindFromChunk(chunk, VEC2I32(tile_x, tile_y));
                }

                if (tile_y < SIM_TILES_PER_CHUNK_SQRT) {
                    TileKind left_tile = SIM_TILE_KIND_NONE;
                    if (tile_x == 0) {
                        if (left_chunk->valid) {
                            Vec2I32 left_tile_local_index = VEC2I32(SIM_TILES_PER_CHUNK_SQRT - 1, tile_y);
                            left_tile = TileKindFromChunk(left_chunk, left_tile_local_index);
                        }
                    } else {
                        left_tile = TileKindFromChunk(chunk, VEC2I32(tile_x - 1, tile_y));
                    }
                    if (tile == SIM_TILE_KIND_WALL) {
                        /* Process wall tile */
                        if (left_tile != SIM_TILE_KIND_WALL) {
                            desired_wall_dir = 3;
                        }
                    } else {
                        /* Process non-wall tile */
                        if (left_tile == SIM_TILE_KIND_WALL) {
                            desired_wall_dir = 1;
                        }
                    }
                }

                /* Stop wall */
                if (wall_dir >= 0 && desired_wall_dir != wall_dir) {
                    Vec2I32 start = sim_world_tile_index_from_local_tile_index(chunk_index, VEC2I32(tile_x, wall_start));
                    Vec2I32 end = sim_world_tile_index_from_local_tile_index(chunk_index, VEC2I32(tile_x, wall_end));
                    struct wall_node *node = 0;
                    if (wall_start == 0) {
                        u64 start_hash = RandU64FromSeed(*(u64 *)&start);
                        start_hash = RandU64FromSeeds(start_hash, wall_dir);
                        DictEntry *entry = DictEntryFromHash(vertical_ends_dict, start_hash);
                        if (entry) {
                            /* Existing wall exists accross chunk boundary */
                            node = (struct wall_node *)entry->value;
                            RemoveDictEntry(vertical_ends_dict, entry);
                        }
                    }
                    if (!node) {
                        node = PushStruct(scratch.arena, struct wall_node);
                        node->start = start;
                        node->next = first_wall;
                        node->wall_dir = wall_dir;
                        first_wall = node;
                    }
                    node->end = end;
                    if (wall_end == SIM_TILES_PER_CHUNK_SQRT) {
                        u64 end_hash = RandU64FromSeed(*(u64 *)&end);
                        end_hash = RandU64FromSeeds(end_hash, wall_dir);
                        SetDictValue(scratch.arena, vertical_ends_dict, end_hash, (u64)node);
                    }
                    wall_start = -1;
                    wall_end = -1;
                    wall_dir = -1;
                }

                /* Start / extend wall */
                if (desired_wall_dir >= 0) {
                    if (wall_dir != desired_wall_dir) {
                        /* Start wall */
                        wall_start = tile_y;
                    }
                    /* Extend wall */
                    wall_end = tile_y + 1;
                    wall_dir = desired_wall_dir;
                }
            }
        }
    }

    /* Create wall entities */
    for (struct wall_node *node = first_wall; node; node = node->next) {
        Entity *wall_ent = AcquireSyncSrc(root);
        EnableProp(wall_ent, Prop_Wall);

        Vec2 start = sim_pos_from_world_tile_index(node->start);
        Vec2 end = sim_pos_from_world_tile_index(node->end);

        Xform xf = XformFromPos(start);
        SetXform(wall_ent, xf);

        EnableProp(wall_ent, Prop_Solid);
        wall_ent->local_collider.count = 2;
        wall_ent->local_collider.points[1] = SubVec2(end, start);

        Vec2 dirs[4] = { VEC2(0, -1), VEC2(1, 0), VEC2(0, 1), VEC2(-1, 0) };
        Assert(node->wall_dir >= 0 && (u32)node->wall_dir < countof(dirs));
        wall_ent->collision_dir = dirs[node->wall_dir];

        Activate(wall_ent, world->tick);
    }

    EndScratch(scratch);
}

////////////////////////////////
//~ On collision

CollisionCallbackFuncDef(OnEntityCollision, data, step_ctx)
{
    Snapshot *world = step_ctx->world;
    Entity *e0 = EntityFromId(world, data->e0);
    Entity *e1 = EntityFromId(world, data->e1);
    Entity *root = EntityFromId(world, RootEntityId);
    b32 skip_solve = 0;

    if (ShouldSimulate(e0) && ShouldSimulate(e1)) {
        /* Bullet impact */
        if (HasProp(e0, Prop_Bullet)) {
            Vec2 normal = data->normal;        /* Impact normal */
            Vec2 vrel = data->vrel;    /* Impact velocity */

            Entity *bullet = e0;
            Entity *target = e1;
            Entity *src = EntityFromId(world, bullet->bullet_src);

            /* Process collision if bullet already spent or * target share same top level parent */
            if (!bullet->bullet_has_hit && !EqId(src->top, target->top) && HasProp(target, Prop_Solid)) {
                Vec2 point = data->point;

                /* Update tracer */
                Entity *tracer = EntityFromId(world, bullet->bullet_tracer);
                if (ShouldSimulate(tracer)) {
                    Xform xf = XformFromEntity(tracer);
                    xf.og = point;
                    SetXform(tracer, xf);
                    SetLinearVelocity(tracer, VEC2(0, 0));
                }

                /* Update target */
                Vec2 knockback = MulVec2(NormVec2(vrel), bullet->bullet_knockback);
                ApplyLinearImpulse(target, knockback, point);

                /* Create test blood */
                /* TODO: Remove this */
                {
                    Xform xf = XformFromTrs(TRS(.t = point, .r = RandF64FromState(&step_ctx->rand, 0, Tau)));
                    Entity *decal = AcquireSyncSrc(root);
                    decal->sprite = S_TagFromPath(Lit("sprite/blood.ase"));
                    decal->sprite_tint = Rgba32F(1, 1, 1, 0.25f);
                    decal->layer = SIM_LAYER_FLOOR_DECALS;
                    SetXform(decal, xf);

                    f32 perp_range = 0.5;
                    Vec2 linear_velocity = MulVec2(normal, 0.5);
                    linear_velocity = AddVec2(linear_velocity, MulVec2(PerpVec2(normal), RandF64FromState(&step_ctx->rand, -perp_range, perp_range)));

                    f32 angular_velocity_range = 5;
                    f32 angular_velocity = RandF64FromState(&step_ctx->rand, -angular_velocity_range, angular_velocity_range);

                    EnableProp(decal, Prop_Kinematic);
                    SetLinearVelocity(decal, linear_velocity);
                    SetAngularVelocity(decal, angular_velocity);

                    decal->linear_damping = 5.0f;
                    decal->angular_damping = 5.0f;
                }

                /* Create explosion */
                if (bullet->bullet_explosion_strength > 0) {
                    SpawnTestExplosion(root, point, bullet->bullet_explosion_strength, bullet->bullet_explosion_radius);
                }

                /* Update bullet */
                bullet->bullet_has_hit = 1;
                EnableProp(bullet, Prop_Release);
            }
        }

        /* Explosion blast collision */
        if (HasProp(e0, Prop_Explosion)) {
            Entity *exp = e0;
            Entity *victim = e1;

            Xform xf = XformFromEntity(exp);

            CLD_Shape origin_collider = ZI;
            origin_collider.count = 1;

            Xform victim_xf = XformFromEntity(victim);
            CLD_ClosestPointData closest_points = CLD_ClosestPointDataFromShapes(&origin_collider, &victim->local_collider, xf, victim_xf);
            Vec2 dir = SubVec2(closest_points.p1, closest_points.p0);
            Vec2 point = closest_points.p1;
            f32 distance = Vec2Len(dir);
#if 0
            if (closest_points.colliding) {
                dir = NegVec2(dir);
                //distance = 0;
            }
#else
            if (DotVec2(data->normal, dir) < 0) {
                dir = NegVec2(dir);
                point = xf.og;
                distance = 0;
            }
#endif

            /* TODO: Blast obstruction */
            f32 radius = exp->explosion_radius;
            f32 strength_center = exp->explosion_strength;
            if (distance < radius) {
                const f32 falloff_curve = 3;  /* Cubic falloff */
                f32 strength_factor = PowF32(1 - distance/radius, falloff_curve);
                Vec2 impulse = Vec2WithLen(dir, strength_center * strength_factor);
                ApplyLinearImpulse(victim, impulse, point);
            }
        }

        /* Chucker zone */
        if (HasProp(e0, Prop_ChuckerZone)) {
            if (!EqId(e0->top, e1->top) && HasProp(e1, Prop_Solid)) {
                e0->chucker_zone_ent = e1->id;
                e0->chucker_zone_ent_tick = world->tick;
            }
        }
    }

    return skip_solve;
}

////////////////////////////////
//~ Step

void StepSim(SimStepCtx *ctx)
{
    __prof;
    TempArena scratch = BeginScratchNoConflict();

    b32 is_master = ctx->is_master;
    Snapshot *world = ctx->world;

    ClientStore *client_store = world->client->store;
    Client *world_client = world->client;
    Client *user_input_client = ctx->user_input_client;
    Client *publish_client = ctx->publish_client;
    Client *master_client = ctx->master_client;

    i64 sim_dt_ns = ctx->sim_dt_ns;

    //- Begin frame

    world->sim_dt_ns = MaxI64(0, sim_dt_ns);
    world->sim_time_ns += world->sim_dt_ns;
    f32 sim_dt = SecondsFromNs(world->sim_dt_ns);

    S_Scope *sprite_frame_scope = S_BeginScope();

    Entity *root = EntityFromId(world, RootEntityId);
    root->owner = world->client->player_id;

    //- Sync ents from cmd producing clients

    {
        /* FIXME: Ensure only cmds are synced to master player */
        for (u64 client_index = 0; client_index < client_store->num_clients_reserved; ++client_index) {
            Client *client = &client_store->clients[client_index];
            if (client->valid && client != master_client && client != world_client && client != publish_client) {
                Entity *player = EntityFromId(world, client->player_id);

                /* Create player if necessary */
                if (is_master && !player->valid) {
                    /* FIXME: Player never released upon disconnect */
                    player = AcquireSyncSrc(root);
                    player->player_client_handle = client->handle;
                    EnableProp(player, Prop_Player);
                    player->predictor = player->id;
                    Activate(player, world->tick);
                    client->player_id = player->id;
                    if (client == user_input_client) {
                        user_input_client->player_id = player->id;
                        world_client->player_id = player->id;
                        world->local_player = player->id;
                        player->owner = player->id;
                        EnableProp(player, Prop_IsMaster);
                    }
                    P_LogInfoF("Created player with id %F for sim client %F. is_master: %F", FmtUid(player->id.uid), FmtHandle(client->handle), FmtUint(HasProp(player, Prop_IsMaster)));
                }

                /* Update rtt */
                if (is_master && player->valid) {
                    player->player_last_rtt_ns = client->last_rtt_ns;
                    player->player_average_rtt_seconds -= player->player_average_rtt_seconds / 200;
                    player->player_average_rtt_seconds += SecondsFromNs(client->last_rtt_ns) / 200;
                }

                /* Sync ents from client */
                if (player->valid) {
                    Snapshot *src_ss = sim_snapshot_from_tick(client, world->tick);
                    if (src_ss->valid) {
                        sim_snapshot_sync_ents(world, src_ss, player->id, 0);
                    }
                }
            }
        }

        /* Mark all incoming ents as sync dsts */
        for (u64 i = 0; i < world->num_ents_reserved; ++i) {
            Entity *ent = &world->ents[i];
            if (ent->valid && HasProp(ent, Prop_SyncSrc) && !EqId(ent->owner, world_client->player_id)) {
                DisableProp(ent, Prop_SyncSrc);
                EnableProp(ent, Prop_SyncDst);
            }
        }

        /* Mark incoming cmds with correct client */
        for (u64 i = 0; i < world->num_ents_reserved; ++i) {
            Entity *ent = &world->ents[i];
            if (ent->valid && HasProp(ent, Prop_Cmd) && HasProp(ent, Prop_SyncDst)) {
                ent->cmd_player = ent->owner;
            }
        }

        /* Mark any locally created CMDs as sync sources */
        if (!is_master) {
            for (u64 i = 0; i < world->num_ents_reserved; ++i) {
                Entity *ent = &world->ents[i];
                if (IsValidAndActive(ent) && HasProp(ent, Prop_Cmd)) {
                    if (!IsNilId(ent->cmd_player) && EqId(ent->cmd_player, world->local_player)) {
                        EnableProp(ent, Prop_SyncSrc);
                    }
                }
            }
        }
    }


    //- Release entities at beginning of frame

    ReleaseAllWithProp(world, Prop_Release);
    ResetSimAccel(world, ctx->accel);


    //- Activate entities

    for (u64 ent_index = 0; ent_index < world->num_ents_reserved; ++ent_index) {
        Entity *ent = &world->ents[ent_index];
        if (!ent->valid) continue;
        if (HasProp(ent, Prop_SyncDst) && !IsOwner(ent) && !ShouldPredict(ent)) continue;

        if (!HasProp(ent, Prop_Active)) {
            u64 atick = ent->activation_tick;
            if (atick != 0 || world->tick >= atick) {
                Activate(ent, world->tick);
            }
        }
    }


    //- Process player cmds

    for (u64 ent_index = 0; ent_index < world->num_ents_reserved; ++ent_index) {
        Entity *cmd_ent = &world->ents[ent_index];
        if (!is_master && !ShouldSimulate(cmd_ent)) continue;

        if (HasProp(cmd_ent, Prop_Cmd)) {
            Entity *player = EntityFromId(world, cmd_ent->cmd_player);
            if (ShouldSimulate(player)) {
                b32 persist_cmd = 0;
                if (!is_master && !EqId(player->id, world->local_player)) {
                    /* We are not the master and the command is not our own, skip processing */
                    continue;
                }

                CmdKind kind = cmd_ent->cmd_kind;
                switch (kind) {
                    case SIM_CMD_KIND_CONTROL:
                    {
                        /* Player's will send control cmds a lot, so keep it around to prevent re-creating it each time */
                        persist_cmd = 1;

                        /* Process control cmd for player */
                        ControlData old_control = player->player_control;
                        ControlData *control = &player->player_control;
                        *control = cmd_ent->cmd_control;
                        {
                            ControlFlag flags = control->flags;

                            player->player_cursor_pos = control->dbg_cursor;
                            player->player_hovered_ent = cmd_ent->cmd_control_hovered_ent;
                            player->player_dbg_drag_start = 0;
                            player->player_dbg_drag_stop = 0;

                            /* Cap movement vector magnitude */
                            if (Vec2LenSq(control->move) > 1) {
                                control->move = NormVec2(control->move);
                            }

                            /* Debug cmds */
                            if (ctx->is_master) {
                                if (flags & SIM_CONTROL_FLAG_DRAG) {
                                    if (!(old_control.flags & SIM_CONTROL_FLAG_DRAG)) {
                                        player->player_dbg_drag_start = 1;
                                    }
                                } else {
                                    if (old_control.flags & SIM_CONTROL_FLAG_DRAG) {
                                        player->player_dbg_drag_stop = 1;
                                    }
                                }
                                if (flags & SIM_CONTROL_FLAG_DELETE) {
                                    Entity *ent = EntityFromId(world, player->player_hovered_ent);
                                    if (ent->valid) {
                                        EnableProp(ent, Prop_Release);
                                    }
                                }
                                if (flags & SIM_CONTROL_FLAG_CLEAR_ALL) {
                                    ClearLevelTest(ctx);
                                }
                                if (flags & SIM_CONTROL_FLAG_SPAWN1_TEST) {
                                    P_LogDebugF("Spawn test 1");
                                    u32 count = 1;
                                    f32 spread = 0;
                                    for (u32 j = 0; j < count; ++j) {
                                        Vec2 pos = player->player_cursor_pos;
                                        pos.y += (((f32)j / (f32)count) - 0.5) * spread;
                                        SpawnTestEntities1(root, pos);
                                    }
                                }
                                if (flags & SIM_CONTROL_FLAG_SPAWN2_TEST) {
                                    P_LogDebugF("Spawn test 2");
                                    u32 count = 1;
                                    f32 spread = 0;
                                    for (u32 j = 0; j < count; ++j) {
                                        Vec2 pos = player->player_cursor_pos;
                                        pos.y += (((f32)j / (f32)count) - 0.5) * spread;
                                        SpawnTestEntities2(root, pos);
                                    }
                                }
                                if (flags & SIM_CONTROL_FLAG_SPAWN3_TEST) {
                                    P_LogDebugF("Spawn test 3");
                                    u32 count = 1;
                                    f32 spread = 0;
                                    for (u32 j = 0; j < count; ++j) {
                                        Vec2 pos = player->player_cursor_pos;
                                        pos.y += (((f32)j / (f32)count) - 0.5) * spread;
                                        SpawnTestEntities3(root, pos);
                                    }
                                }
                                if (flags & SIM_CONTROL_FLAG_SPAWN4_TEST) {
                                    P_LogDebugF("Spawn test 4");
                                    u32 count = 1;
                                    f32 spread = 0;
                                    for (u32 j = 0; j < count; ++j) {
                                        Vec2 pos = player->player_cursor_pos;
                                        pos.y += (((f32)j / (f32)count) - 0.5) * spread;
                                        SpawnTestEntities4(root, pos);
                                    }
                                }
                                if (flags & SIM_CONTROL_FLAG_WALLS_TEST) {
                                    GenerateTestWalls(world);
                                }
                                if (flags & SIM_CONTROL_FLAG_EXPLODE_TEST) {
                                    P_LogDebugF("Explosion test");
                                    SpawnTestExplosion(root, player->player_cursor_pos, 100, 2);
                                }
                            }

                            if (flags & SIM_CONTROL_FLAG_TILE_TEST) {
                                SpawnTestTile(world, player->player_cursor_pos);
                            } else if (old_control.flags & SIM_CONTROL_FLAG_TILE_TEST) {
                                GenerateTestWalls(world);
                            }
                        }
                    } break;

#if 0
                    case SIM_CMD_KIND_CHAT:
                    {
                        struct sim_data_key msg_key = cmd_ent->cmd_chat_msg;
                        String msg = sim_data_from_key(sim_data_store, msg_key);
                        if (msg.len > 0) {
                            Entity *chat_ent = AcquireSyncSrc(root);
                            EnableProp(chat_ent, Prop_CHAT);
                            chat_ent->chat_player = player->id;
                            chat_ent->chat_msg = msg_key;
                        }
                    } break;
#endif

                    default:
                    {
                        /* Invalid cmd kind */
                        Assert(0);
                    } break;
                }

                /* Release cmd */
                if (!persist_cmd) {
                    EnableProp(cmd_ent, Prop_Release);
                }
            }
        }
    }


    //- Update entity control from player control

    for (u64 ent_index = 0; ent_index < world->num_ents_reserved; ++ent_index) {
        Entity *ent = &world->ents[ent_index];
        if (!ShouldSimulate(ent)) continue;

        if (HasProp(ent, Prop_Controlled)) {
            Entity *player = EntityFromId(world, ent->controlling_player);
            if (player->valid) {
                ent->control = player->player_control;
            }
        }
    }


    //- Create employees

    if (is_master) {
        for (u64 i = 0; i < world->num_ents_reserved; ++i) {
            Entity *ent = &world->ents[i];
            if (!ShouldSimulate(ent)) continue;
            if (HasProp(ent, Prop_Player)) {
                /* FIXME: Ents never released when client disconnects */
                Entity *control_ent = EntityFromId(world, ent->player_control_ent);
                if (!control_ent->valid) {
                    control_ent = SpawnTestEmployee(root);
                    control_ent->predictor = ent->id;
                    EnableProp(control_ent, Prop_Controlled);
                    ent->player_control_ent = control_ent->id;
                    control_ent->controlling_player = ent->id;
                }
                Entity *camera_ent = EntityFromId(world, ent->player_camera_ent);
                if (!camera_ent->valid) {
                    camera_ent = SpawnTestCamera(root, control_ent);
                    camera_ent->predictor = ent->id;
                    ent->player_camera_ent = camera_ent->id;
                }
                Entity *camera_follow = EntityFromId(world, camera_ent->camera_follow);
                if (!camera_follow->valid) {
                    camera_ent->camera_follow = control_ent->id;
                }
            }
        }
    }


    //- Update entities from sprite

    for (u64 ent_index = 0; ent_index < world->num_ents_reserved; ++ent_index) {
        Entity *ent = &world->ents[ent_index];
        if (!ShouldSimulate(ent)) continue;
        if (S_IsTagNil(ent->sprite)) continue;

        S_Sheet *sheet = S_SheetFromTagAwait(sprite_frame_scope, ent->sprite);

        /* Update animation */
        {
            S_Span span = S_SpanFromName(sheet, ent->sprite_span_name);
            if (ent->animation_last_frame_change_time_ns == 0) {
                ent->animation_last_frame_change_time_ns = SecondsFromNs(world->sim_time_ns);
            }

            f64 time_in_frame = SecondsFromNs(world->sim_time_ns - ent->animation_last_frame_change_time_ns);
            u64 frame_index = ent->animation_frame;
            if (frame_index < span.start || frame_index > span.end) {
                frame_index = span.start;
            }

            if (span.end > span.start) {
                S_Frame frame = S_FrameFromIndex(sheet, frame_index);
                while (time_in_frame > frame.duration) {
                    time_in_frame -= frame.duration;
                    ++frame_index;
                    if (frame_index > span.end) {
                        /* Loop animation */
                        frame_index = span.start;
                    }
                    frame = S_FrameFromIndex(sheet, frame_index);
                    ent->animation_last_frame_change_time_ns = world->sim_time_ns;
                }
            }

            ent->animation_frame = frame_index;
        }

#if 0
        /* Update sprite local xform */
        {
            S_Slice slice = S_SliceFromNameIndex(sheet, Lit("pivot"), ent->animation_frame);
            Vec2 sprite_size = DivVec2(sheet->frame_size, (f32)PIXELS_PER_UNIT);

            Vec2 dir = MulVec2Vec2(sprite_size, slice.dir);
            f32 rot = AngleFromVec2(dir) + Pi / 2;

            Xform xf = XformIdentity;
            xf = RotateXform(xf, -rot);
            xf = ScaleXform(xf, sprite_size);
            xf = TranslateXform(xf, NegVec2(slice.center));
            ent->sprite_local_xform = xf;
        }
#endif

        /* Update collider from sprite */
        if (ent->sprite_collider_slice.len > 0) {
            Xform cxf = ent->sprite_local_xform;

            S_Slice slice = S_SliceFromNameIndex(sheet, ent->sprite_collider_slice, ent->animation_frame);
            ent->local_collider = CLD_ShapeFromQuad(MulXformQuad(cxf, QuadFromRect(slice.rect)));
        }

        /* Test collider */
#if 0
        if (HasProp(ent, Prop_Test)) {
            //if ((1)) {
#if 0
            ent->local_collider.points[0] = VEC2(0, 0);
            ent->local_collider.count = 1;
            ent->local_collider.radius = 0.5;
#elif 0
            ent->local_collider.points[0] = Vec2WithLen(VEC2(0.08f, 0.17f), 0.15f);
            ent->local_collider.points[1] = Vec2WithLen(VEC2(-0.07f, -0.2f), 0.15f);
            ent->local_collider.count = 2;
            ent->local_collider.radius = 0.075f;
#elif 1
#if 0
                /* "Bad" winding order */
            ent->local_collider.points[0] = VEC2(-0.15, 0.15);
            ent->local_collider.points[1] = VEC2(0.15, 0.15);
            ent->local_collider.points[2] = VEC2(0, -0.15);
#else
            ent->local_collider.points[0] = VEC2(0, -0.15);
            ent->local_collider.points[1] = VEC2(0.15, 0.15);
            ent->local_collider.points[2] = VEC2(-0.15, 0.15);
#endif
            ent->local_collider.count = 3;
            ent->local_collider.radius = 0.25;
            //ent->local_collider.radius = AbsF32(SinF32(ctx->tick.time) / 3);
#else
                //ent->local_collider.radius = 0.5;
            ent->local_collider.radius = 0.25;
            //ent->local_collider.radius = 0.;
#endif
        }
#endif
    }


    //- Update attachments

    for (u64 ent_index = 0; ent_index < world->num_ents_reserved; ++ent_index) {
        Entity *ent = &world->ents[ent_index];
        if (!ShouldSimulate(ent)) continue;
        if (!HasProp(ent, Prop_Attached)) continue;

        Entity *parent = EntityFromId(world, ent->parent);
        S_Tag parent_sprite = parent->sprite;
        S_Sheet *parent_sheet = S_SheetFromTagAwait(sprite_frame_scope, parent_sprite);

        Xform parent_sprite_xf = parent->sprite_local_xform;

        S_Slice attach_slice = S_SliceFromNameIndex(parent_sheet, ent->attach_slice, parent->animation_frame);
        Vec2 attach_pos = MulXformV2(parent_sprite_xf, attach_slice.center);
        Vec2 attach_dir = MulXformBasisV2(parent_sprite_xf, attach_slice.dir);

        Xform xf = LocalXformFromEntity(ent);
        xf.og = attach_pos;
        xf = XformWIthWorldRotation(xf, AngleFromVec2(attach_dir) + Pi / 2);
        SetLocalXform(ent, xf);
    }


    //- Process ent control

    for (u64 ent_index = 0; ent_index < world->num_ents_reserved; ++ent_index) {
        Entity *ent = &world->ents[ent_index];
        if (!ShouldSimulate(ent)) continue;

        if (HasProp(ent, Prop_Controlled)) {
            ControlData *control = &ent->control;
            ControlFlag flags = control->flags;
            if (flags & SIM_CONTROL_FLAG_FIRE) {
                Entity *equipped = EntityFromId(world, ent->equipped);
                if (equipped->valid) {
                    ++equipped->num_primary_triggers;
                }
            }
            if (flags & SIM_CONTROL_FLAG_FIRE_ALT) {
                Entity *equipped = EntityFromId(world, ent->equipped);
                if (equipped->valid) {
                    ++equipped->num_secondary_triggers;
                }
            }
            if (flags & SIM_CONTROL_FLAG_TELEPORT_TEST) {
                TeleportTest(ent, control->dbg_cursor);
            }
        }
    }


    //- Process triggered entities

    for (u64 ent_index = 0; ent_index < world->num_ents_reserved; ++ent_index) {
        Entity *ent = &world->ents[ent_index];
        if (!ShouldSimulate(ent)) continue;

        b32 primary_triggered = ent->num_primary_triggers > 0;
        b32 secondary_triggered = ent->num_secondary_triggers > 0;
        ent->num_primary_triggers = 0;
        ent->num_secondary_triggers = 0;

        if (primary_triggered) {
            i64 world_time_ns = world->sim_time_ns;
            if ((world_time_ns - ent->last_primary_fire_ns >= NsFromSeconds(ent->primary_fire_delay)) || ent->last_primary_fire_ns == 0) {
                ent->last_primary_fire_ns = world_time_ns;
            } else {
                primary_triggered = 0;
            }
        }
        if (secondary_triggered) {
            i64 world_time_ns = world->sim_time_ns;
            if ((world_time_ns - ent->last_secondary_fire_ns >= NsFromSeconds(ent->secondary_fire_delay)) || ent->last_secondary_fire_ns == 0) {
                ent->last_secondary_fire_ns = world_time_ns;
            } else {
                secondary_triggered = 0;
            }
        }

        /* Fire smg */
        if (HasProp(ent, Prop_Smg)) {
            if (primary_triggered) {
                S_Tag sprite = ent->sprite;
                u32 animation_frame = ent->animation_frame;
                S_Sheet *sheet = S_SheetFromTagAwait(sprite_frame_scope, sprite);
                Xform sprite_local_xform = ent->sprite_local_xform;
                S_Slice out_slice = S_SliceFromNameIndex(sheet, Lit("out"), animation_frame);
                Vec2 rel_pos = MulXformV2(sprite_local_xform, out_slice.center);
                Vec2 rel_dir = MulXformBasisV2(sprite_local_xform, out_slice.dir);

                /* Spawn bullet */
                Entity *bullet;
                {
                    bullet = AcquireSyncSrc(root);

                    EnableProp(bullet, Prop_Bullet);
                    bullet->bullet_src = ent->id;
                    bullet->bullet_src_pos = rel_pos;
                    bullet->bullet_src_dir = rel_dir;
                    //bullet->bullet_launch_velocity = 0.75f;
                    bullet->bullet_launch_velocity = 50.0f;
                    bullet->bullet_knockback = 10;
                    bullet->layer = SIM_LAYER_BULLETS;

    #if 1
                    /* Point collider */
                    bullet->local_collider.points[0] = VEC2(0, 0);
                    bullet->local_collider.count = 1;
    #else
                    bullet->sprite = S_TagFromPath(Lit("sprite/bullet.ase"));
                    bullet->sprite_collider_slice = Lit("shape");
    #endif
                }

                /* Spawn tracer */
                {
                    Entity *tracer = AcquireSyncSrc(root);
                    tracer->tracer_fade_duration = 0.025f;
                    tracer->layer = SIM_LAYER_TRACERS;
                    EnableProp(tracer, Prop_Tracer);

                    bullet->bullet_tracer = tracer->id;
                }
            }
        }

        /* Fire launcher */
        if (HasProp(ent, Prop_Launcher)) {
            if (primary_triggered) {
                S_Tag sprite = ent->sprite;
                u32 animation_frame = ent->animation_frame;
                S_Sheet *sheet = S_SheetFromTagAwait(sprite_frame_scope, sprite);
                Xform sprite_local_xform = ent->sprite_local_xform;
                S_Slice out_slice = S_SliceFromNameIndex(sheet, Lit("out"), animation_frame);
                Vec2 rel_pos = MulXformV2(sprite_local_xform, out_slice.center);
                Vec2 rel_dir = MulXformBasisV2(sprite_local_xform, out_slice.dir);

                /* Spawn bullet */
                Entity *bullet;
                {
                    bullet = AcquireSyncSrc(root);

                    EnableProp(bullet, Prop_Bullet);
                    bullet->bullet_src = ent->id;
                    bullet->bullet_src_pos = rel_pos;
                    bullet->bullet_src_dir = rel_dir;
                    //bullet->bullet_launch_velocity = 0.75f;
                    bullet->bullet_launch_velocity = 15;
                    bullet->bullet_knockback = 50;
                    bullet->bullet_explosion_strength = 100;
                    bullet->bullet_explosion_radius = 4;
                    bullet->layer = SIM_LAYER_BULLETS;

                    /* Point collider */
                    bullet->local_collider.points[0] = VEC2(0, 0);
                    bullet->local_collider.count = 1;
                    bullet->local_collider.radius = 0.05f;

                }

                /* Spawn tracer */
                {
                    Entity *tracer = AcquireSyncSrc(root);
                    tracer->tracer_fade_duration = 0.025f;
                    tracer->layer = SIM_LAYER_TRACERS;
                    EnableProp(tracer, Prop_Tracer);

                    bullet->bullet_tracer = tracer->id;
                }
            }
        }

        /* Fire chucker */
        if (HasProp(ent, Prop_Chucker)) {
            if (primary_triggered) {
            }
            if (secondary_triggered) {
                Entity *zone = EntityFromId(world, ent->chucker_zone);
                Entity *target = EntityFromId(world, zone->chucker_zone_ent);
                Entity *old_joint_ent = EntityFromId(world, ent->chucker_joint);
                if (IsValidAndActive(target) && zone->chucker_zone_ent_tick == world->tick - 1) {
                    if (!EqId(old_joint_ent->weld_joint_data.e1, target->id)) {
                        Entity *joint_ent = AcquireSyncSrc(root);
                        EnableProp(joint_ent, Prop_Active);

                        Xform xf0 = XformFromEntity(ent);
                        Xform xf1 = XformFromEntity(target);
                        Xform xf0_to_xf1 = MulXform(InvertXform(xf0), xf1);

                        EnableProp(joint_ent, Prop_WeldJoint);
                        WeldJointDesc def = CreateWeldJointDef();
                        def.e0 = ent->id;
                        def.e1 = target->id;
                        def.xf = xf0_to_xf1;
                        def.linear_spring_hz = 10;
                        def.linear_spring_damp = 0.3f;
                        def.angular_spring_hz = 10;
                        def.angular_spring_damp = 0.3f;
                        joint_ent->weld_joint_data = WeldJointFromDef(def);
                        ent->chucker_joint = joint_ent->id;
                    }
                }
                if (old_joint_ent->valid) {
                    EnableProp(old_joint_ent, Prop_Release);
                    DisableProp(old_joint_ent, Prop_Active);
                }
            }
        }
    }


    //- Create & update motor joints from control move

    for (u64 ent_index = 0; ent_index < world->num_ents_reserved; ++ent_index) {
        Entity *ent = &world->ents[ent_index];
        if (!ShouldSimulate(ent)) continue;

        if (HasProp(ent, Prop_Controlled)) {
            Entity *joint_ent = EntityFromId(world, ent->move_joint);
            if (is_master && !IsValidAndActive(joint_ent)) {
                joint_ent = AcquireSyncSrc(root);
                joint_ent->predictor = ent->predictor;
                joint_ent->mass_unscaled = F32Infinity;
                joint_ent->inertia_unscaled = F32Infinity;
                EnableProp(joint_ent, Prop_Active);
                EnableProp(joint_ent, Prop_Kinematic);
                ent->move_joint = joint_ent->id;

                EnableProp(joint_ent, Prop_MotorJoint);
                MotorJointDesc def = CreateMotorJointDef();
                def.e0 = joint_ent->id;  /* Re-using joint entity as e0 */
                def.e1 = ent->id;
                def.correction_rate = 0;
                def.max_force = ent->control_force;
                def.max_torque = 0;
                joint_ent->motor_joint_data = MotorJointFromDef(def);
            }

            if (ShouldSimulate(joint_ent)) {
                SetXform(joint_ent, XformIdentity);  /* Reset joint ent position */
                SetLinearVelocity(joint_ent, MulVec2(ClampVec2Len(ent->control.move, 1), ent->control_force_max_speed));
            }
        }
    }


    //- Create & update motor joints from control focus (aim)

#if SIM_PLAYER_AIM
    for (u64 ent_index = 0; ent_index < world->num_ents_reserved; ++ent_index) {
        Entity *ent = &world->ents[ent_index];
        if (!ShouldSimulate(ent)) continue;

        if (HasProp(ent, Prop_Controlled)) {
            Xform xf = XformFromEntity(ent);
            Xform sprite_xf = MulXform(xf, ent->sprite_local_xform);

            /* Retrieve / create aim joint */
            Entity *joint_ent = EntityFromId(world, ent->aim_joint);
            if (is_master && !IsValidAndActive(joint_ent)) {
                joint_ent = AcquireSyncSrc(root);
                joint_ent->predictor = ent->predictor;
                joint_ent->mass_unscaled = F32Infinity;
                joint_ent->inertia_unscaled = F32Infinity;
                EnableProp(joint_ent, Prop_Kinematic);  /* Since we'll be setting velocity manually */
                EnableProp(joint_ent, Prop_MotorJoint);
                EnableProp(joint_ent, Prop_Active);
                ent->aim_joint = joint_ent->id;

                MotorJointDesc def = CreateMotorJointDef();
                def.e0 = joint_ent->id;  /* Re-using joint entity as e0 */
                def.e1 = ent->id;
                def.max_force = 0;
                def.max_torque = ent->control_torque;
                joint_ent->motor_joint_data = MotorJointFromDef(def);
            }

            if (ShouldSimulate(joint_ent)) {
                /* Set correction rate dynamically since motor velocity is only set for one frame */
                joint_ent->motor_joint_data.correction_rate = 10 * sim_dt;


                /* Solve for final angle using law of sines */
                f32 new_angle;
                {
                    Vec2 ent_pos = xf.og;
                    Vec2 focus_pos = AddVec2(ent_pos, ent->control.focus);

                    Vec2 sprite_hold_pos;
                    Vec2 sprite_hold_dir;
                    {
                        S_Sheet *sheet = S_SheetFromTagAwait(sprite_frame_scope, ent->sprite);
                        S_Slice slice = S_SliceFromNameIndex(sheet, Lit("attach.wep"), ent->animation_frame);
                        sprite_hold_pos = slice.center;
                        sprite_hold_dir = slice.dir;
                    }

                    Vec2 hold_dir = MulXformBasisV2(sprite_xf, sprite_hold_dir);
                    Vec2 hold_pos = MulXformV2(sprite_xf, sprite_hold_pos);
                    if (EqVec2(hold_pos, ent_pos)) {
                        /* If hold pos is same as origin (E.G if pivot is being used as hold pos), then move hold pos forward a tad to avoid issue */
                        sprite_hold_pos = AddVec2(sprite_hold_pos, VEC2(0, -1));
                        hold_pos = MulXformV2(sprite_xf, sprite_hold_pos);
                    }

                    f32 forward_hold_angle_offset;
                    {
                        Xform xf_unrotated = XformWIthWorldRotation(xf, 0);
                        Vec2 hold_pos_unrotated = MulXformV2(xf_unrotated, MulXformV2(ent->sprite_local_xform, sprite_hold_pos));
                        forward_hold_angle_offset = AngleFromVec2Dirs(VEC2(0, -1), SubVec2(hold_pos_unrotated, xf_unrotated.og));
                    }

                    Vec2 hold_ent_dir = SubVec2(ent_pos, hold_pos);
                    Vec2 focus_ent_dir = SubVec2(ent_pos, focus_pos);

                    f32 hold_ent_len = Vec2Len(hold_ent_dir);
                    f32 focus_ent_len = Vec2Len(focus_ent_dir);

                    f32 final_hold_angle_btw_ent_and_focus = AngleFromVec2Dirs(hold_ent_dir, hold_dir);
                    f32 final_focus_angle_btw_ent_and_hold = ArcSinF32((SinF32(final_hold_angle_btw_ent_and_focus) * hold_ent_len) / focus_ent_len);
                    f32 final_ent_angle_btw_focus_and_hold = Pi - (final_focus_angle_btw_ent_and_hold + final_hold_angle_btw_ent_and_focus);

                    new_angle = UnwindAngleF32(AngleFromVec2Dirs(VEC2(0, -1), SubVec2(focus_pos, ent_pos)) + final_ent_angle_btw_focus_and_hold - forward_hold_angle_offset);
                }

                f32 new_vel = 0;
                if (!IsF32Nan(new_angle)) {
                    const f32 angle_error_allowed = 0.001f;
                    Xform joint_xf = XformFromEntity(joint_ent);
                    f32 diff = UnwindAngleF32(new_angle - RotationFromXform(joint_xf));
                    if (AbsF32(diff) > angle_error_allowed) {
                        /* Instantly snap joint ent to new angle */
                        new_vel = diff / sim_dt;
                    }
                }
                SetAngularVelocity(joint_ent, new_vel);
            }

        }
    }
#endif


    //- Create motor joints from ground friction (gravity)

#if 1
    for (u64 ent_index = 0; ent_index < world->num_ents_reserved; ++ent_index) {
        Entity *ent = &world->ents[ent_index];
        if (!ShouldSimulate(ent)) continue;
        if (!HasProp(ent, Prop_Dynamic)) continue;

        Entity *joint_ent = EntityFromId(world, ent->ground_friction_joint);

        MotorJointDesc def = CreateMotorJointDef();
        def.e0 = root->id;
        def.e1 = ent->id;
        def.correction_rate = 0;
        def.max_force = ent->linear_ground_friction;
        def.max_torque = ent->angular_ground_friction;
        if (joint_ent->motor_joint_data.max_force != def.max_force || joint_ent->motor_joint_data.max_torque != def.max_torque) {
            if (is_master && !IsValidAndActive(joint_ent)) {
                joint_ent = AcquireSyncSrc(root);
                joint_ent->predictor = ent->predictor;
                EnableProp(joint_ent, Prop_MotorJoint);
                EnableProp(joint_ent, Prop_Active);
                joint_ent->motor_joint_data = MotorJointFromDef(def);
                ent->ground_friction_joint = joint_ent->id;
            }
        }
    }
#endif


    //- Create mouse joints from client debug drag

    if (is_master) {
        for (u64 i = 0; i < world->num_ents_reserved; ++i) {
            Entity *player = &world->ents[i];
            if (!ShouldSimulate(player)) continue;
            if (!HasProp(player, Prop_Player)) continue;

            Vec2 cursor = player->player_cursor_pos;
            b32 start_dragging = player->player_dbg_drag_start;
            b32 stop_dragging = player->player_dbg_drag_stop;

            Entity *joint_ent = EntityFromId(world, player->player_dbg_drag_joint_ent);
            Entity *target_ent = EntityFromId(world, joint_ent->mouse_joint_data.target);

            if (stop_dragging) {
                target_ent = NilEntity();
            } else if (start_dragging) {
                target_ent = EntityFromId(world, player->player_hovered_ent);
            }

            if (ShouldSimulate(target_ent)) {
                if (!IsValidAndActive(joint_ent)) {
                    /* FIXME: Joint ent may never release */
                    joint_ent = AcquireLocal(root);
                    joint_ent->mass_unscaled = F32Infinity;
                    joint_ent->inertia_unscaled = F32Infinity;
                    player->player_dbg_drag_joint_ent = joint_ent->id;
                    EnableProp(joint_ent, Prop_MouseJoint);
                    EnableProp(joint_ent, Prop_Active);
                }
                Xform xf = XformFromEntity(target_ent);

                MouseJointDesc def = CreateMouseJointDef();
                def.target = target_ent->id;
                if (EqId(joint_ent->mouse_joint_data.target, target_ent->id)) {
                    def.point_local_start = joint_ent->mouse_joint_data.point_local_start;
                } else {
                    def.point_local_start = InvertXformMulV2(xf, cursor);
                }
                def.point_end = cursor;
                def.max_force = F32Infinity;
                def.linear_spring_hz = 5;
                def.linear_spring_damp = 0.7f;
                def.angular_spring_hz = 1;
                def.angular_spring_damp = 0.1f;
                joint_ent->mouse_joint_data = MouseJointFromDef(def);
            } else if (IsValidAndActive(joint_ent)) {
                joint_ent->mouse_joint_data.target = target_ent->id;
            }
        }
    }


    //- Physics step

    {
        PhysStepCtx phys = ZI;
        phys.sim_step_ctx = ctx;
        phys.collision_callback = OnEntityCollision;
        StepPhys(&phys, sim_dt);
    }


    //- Update explosions

    for (u64 ent_index = 0; ent_index < world->num_ents_reserved; ++ent_index) {
        Entity *ent = &world->ents[ent_index];
        if (!ShouldSimulate(ent)) continue;
        if (!HasProp(ent, Prop_Explosion)) continue;

        /* Explosion doesn't need to generate any more collisions after initial physics step */
        DisableProp(ent, Prop_Sensor);
    }


    //- Update tracers

    for (u64 ent_index = 0; ent_index < world->num_ents_reserved; ++ent_index) {
        Entity *ent = &world->ents[ent_index];
        if (!ShouldSimulate(ent)) continue;
        if (!HasProp(ent, Prop_Tracer)) continue;

        Vec2 end = XformFromEntity(ent).og;

        Vec2 tick_velocity = MulVec2(ent->tracer_start_velocity, sim_dt);
        Vec2 gradient_start = AddVec2(ent->tracer_gradient_start, tick_velocity);
        Vec2 gradient_end = AddVec2(ent->tracer_gradient_end, tick_velocity);

        if (DotVec2(tick_velocity, SubVec2(gradient_start, end)) > 0) {
            /* Tracer has disappeared */
            EnableProp(ent, Prop_Release);
        }

        ent->tracer_gradient_start = gradient_start;
        ent->tracer_gradient_end = gradient_end;
    }


    //- Initialize bullet kinematics from sources

    for (u64 ent_index = 0; ent_index < world->num_ents_reserved; ++ent_index) {
        Entity *ent = &world->ents[ent_index];
        if (!ShouldSimulate(ent)) continue;
        if (!HasProp(ent, Prop_Bullet)) continue;

        if (ent->activation_tick == world->tick) {
            Entity *src = EntityFromId(world, ent->bullet_src);
            Xform src_xf = XformFromEntity(src);

            /* Activate collision */
            EnableProp(ent, Prop_Sensor);
            EnableProp(ent, Prop_Toi);

            Vec2 pos = MulXformV2(src_xf, ent->bullet_src_pos);
            Vec2 vel = MulXformBasisV2(src_xf, ent->bullet_src_dir);
            vel = Vec2WithLen(vel, ent->bullet_launch_velocity);

#if 0
            /* Add shooter velocity to bullet */
            {
                /* TODO: Add angular velocity as well? */
                Entity *top = EntityFromId(ss_blended, src->top);
                impulse = AddVec2(impulse, MulVec2(top->linear_velocity, dt));
            }
#endif

            Xform xf = XformFromTrs(TRS(.t = pos, .r = AngleFromVec2(vel) + Pi / 2));
            SetXform(ent, xf);

            EnableProp(ent, Prop_Kinematic);
            SetLinearVelocity(ent, vel);

            /* Initialize tracer */
            Entity *tracer = EntityFromId(world, ent->bullet_tracer);
            if (ShouldSimulate(tracer)) {
                SetXform(tracer, xf);
                EnableProp(tracer, Prop_Kinematic);
                SetLinearVelocity(tracer, ent->linear_velocity);
                tracer->tracer_start = pos;
                tracer->tracer_start_velocity = ent->linear_velocity;
                tracer->tracer_gradient_end = pos;
                tracer->tracer_gradient_start = SubVec2(pos, MulVec2(ent->linear_velocity, tracer->tracer_fade_duration));
            }

            /* Spawn quake */
            {
                Entity *quake = AcquireSyncSrc(root);
                SetXform(quake, XformFromPos(pos));
                quake->quake_intensity = 0.2f;
                quake->quake_fade = quake->quake_intensity / 0.1f;
                EnableProp(quake, Prop_Quake);
            }
        }
    }


    //- Update cameras

    for (u64 ent_index = 0; ent_index < world->num_ents_reserved; ++ent_index) {
        Entity *ent = &world->ents[ent_index];
        if (!ShouldSimulate(ent)) continue;
        if (!HasProp(ent, Prop_Camera)) continue;

        Xform xf = XformFromEntity(ent);

        /* Camera follow */
        {
            Entity *follow = EntityFromId(world, ent->camera_follow);

            f32 aspect_ratio = 1.0;
            {
                Xform quad_xf = MulXform(XformFromEntity(ent), ent->camera_quad_xform);
                Vec2 camera_size = ScaleFromXform(quad_xf);
                if (!IsVec2Zero(camera_size)) {
                    aspect_ratio = camera_size.x / camera_size.y;
                }
            }
            f32 ratio_y = 0.33f;
            f32 ratio_x = ratio_y / aspect_ratio;
            Vec2 camera_focus_dir = MulVec2Vec2(follow->control.focus, VEC2(ratio_x, ratio_y));
            Vec2 camera_focus_pos = AddVec2(XformFromEntity(follow).og, camera_focus_dir);
            ent->camera_xform_target = xf;
            ent->camera_xform_target.og = camera_focus_pos;

            /* Lerp camera */
            if (ent->camera_applied_lerp_continuity_gen_plus_one == ent->camera_lerp_continuity_gen + 1) {
                f32 t = 1 - PowF32(2.f, -20.f * (f32)sim_dt);
                xf = LerpXform(xf, ent->camera_xform_target, t);
            } else {
                /* Skip lerp */
                xf = ent->camera_xform_target;
            }
            ent->camera_applied_lerp_continuity_gen_plus_one = ent->camera_lerp_continuity_gen + 1;
        }

        /* Camera shake */
        {
            /* TODO: Update based on distance to quake */
            ent->shake = 0;
            for (u64 quake_ent_index = 0; quake_ent_index < world->num_ents_reserved; ++quake_ent_index) {
                Entity *quake = &world->ents[quake_ent_index];
                if (!ShouldSimulate(quake)) continue;
                if (!HasProp(quake, Prop_Quake)) continue;
                ent->shake += quake->quake_intensity;
            }
        }

        SetXform(ent, xf);
    }


    //- Update quakes

    for (u64 ent_index = 0; ent_index < world->num_ents_reserved; ++ent_index) {
        Entity *ent = &world->ents[ent_index];
        if (!ShouldSimulate(ent)) continue;
        if (!HasProp(ent, Prop_Quake)) continue;

        ent->quake_intensity = MaxF32(0, ent->quake_intensity - (ent->quake_fade * sim_dt));
        if (ent->quake_intensity <= 0) {
            EnableProp(ent, Prop_Release);
        }
    }


    //- Update relative layers

    {
        TempArena temp = BeginTempArena(scratch.arena);

        Entity **stack = PushStructNoZero(temp.arena, Entity *);
        u64 stack_count = 1;
        *stack = root;

        while (stack_count > 0) {
            Entity *parent;
            PopStruct(temp.arena, Entity *, &parent);
            --stack_count;

            i32 parent_layer = parent->final_layer;
            for (Entity *child = EntityFromId(world, parent->first); child->valid; child = EntityFromId(world, child->next)) {
                if (ShouldSimulate(child)) {
                    child->final_layer = parent_layer + child->layer;
                    *PushStructNoZero(temp.arena, Entity *) = child;
                    ++stack_count;
                }
            }
        }

        EndTempArena(temp);
    }


    //- Release entities at end of frame

    ReleaseAllWithProp(world, Prop_Release);


    //- Sync to publish client

    if (publish_client->valid && world->tick > publish_client->last_tick) {
        Snapshot *prev_pub_world = sim_snapshot_from_tick(publish_client, publish_client->last_tick);
        Snapshot *pub_world = sim_snapshot_acquire(publish_client, prev_pub_world, world->tick);

        /* Sync */
        sim_snapshot_sync_ents(pub_world, world, world_client->player_id, 0);

        /* Mark all synced ents as both sync dsts & sync srcs */
        for (u64 ent_index = 2; ent_index < pub_world->num_ents_reserved; ++ent_index) {
            Entity *ent = &pub_world->ents[ent_index];
            if (ent->valid) {
                EnableProp(ent, Prop_SyncDst);
                EnableProp(ent, Prop_SyncSrc);
            }
        }

        pub_world->sim_dt_ns = world->sim_dt_ns;
        pub_world->sim_time_ns = world->sim_time_ns;
        pub_world->continuity_gen = world->continuity_gen;
        pub_world->phys_iteration = world->phys_iteration;
        pub_world->local_player = world->local_player;
    }


    //- End frame

    S_EndScope(sprite_frame_scope);

    EndScratch(scratch);
}