Mechanic · movement · rail shooter

Barrel roll

A quick spin of the player's craft along its length, which in some games turns enemy shots away while it lasts.

stubAlso: do a barrel roll, aileron roll, roll, deflect rollUpdated 2026-10-22
On this page
  1. Related
  2. Games
  3. References
  4. Sources

A barrel roll spins the player’s craft along its length. In Star Fox 64 two presses of Z or R start the roll, and while a value tied to the spin is above 0, enemy shots that reach the Arwing are turned away and do no damage1.

  • DeflectStar Fox 64 (1997). A second press of Z or R while the first press's 10-update count runs rolls the Arwing; while the roll's deflect value is above 0, enemy shots turn away and do no damage.1

See also

Games

GameYearHowNote
Star Fox 641997Deflecta second press of Z or R while the first press's 10-update count runs rolls the Arwing; while the roll's deflect value is above 0, enemy shots turn away and do no damage
Every claim about this mechanic, by game (1)
Star Fox 64 1997In the US 1.1 version of Star Fox 64, the Arwing rolls when Z or R is pressed twice. The first press sets that button's counter to 10, which Player_UpdateArwingRoll counts down once per player update, and a second press while it is above 0 starts the roll, turning the ship 30 degrees an update for 10 updates and then slowing by 5 degrees an update until it stops. barrelRollAlpha falls by 30 every update while it is above 0, and in each update the roll's count is still above 0 after counting down (9 of its 10) it then gains 100, capped at 180, a net rise of 70 an update. While that value is above 0, the enemy-shot update (Effect_EnemyShot_Update) widens the shot's box around the player by 100 units on each axis, sends a shot inside it off in a new direction, and applies no damage.Code

References

  1. ^ abIn the US 1.1 version of Star Fox 64, the Arwing rolls when Z or R is pressed twice. The first press sets that button's counter to 10, which Player_UpdateArwingRoll counts down once per player update, and a second press while it is above 0 starts the roll, turning the ship 30 degrees an update for 10 updates and then slowing by 5 degrees an update until it stops. barrelRollAlpha falls by 30 every update while it is above 0, and in each update the roll's count is still above 0 after counting down (9 of its 10) it then gains 100, capped at 180, a net rise of 70 an update. While that value is above 0, the enemy-shot update (Effect_EnemyShot_Update) widens the shot's box around the player by 100 units on each axis, sends a shot inside it off in a new direction, and applies no damage.Codesonicdcer/sf64revised
    How we know
    3397    if (gInputPress->button & Z_TRIG) {
3398        player->sfx.bank = 1;
3399        if (player->rollInputTimerL != 0) {
3400            player->rollState = 1;
3401            player->rollTimer = 10;
3402            player->rollRate = player->baseRollRate = 30;
⋮
3405            player->rollInputTimerL = 10;
⋮
3409    if (gInputPress->button & R_TRIG) {
3410        player->sfx.bank = 1;
3411        if (player->rollInputTimerR != 0) {
3412            player->rollState = 1;
3413            player->rollTimer = 10;
⋮
    src/engine/fox_play.c lines 3397–3419 at 4235c59 · upstream ↗
    4823    if (player->barrelRollAlpha > 0) {
4824        player->barrelRollAlpha -= 30;
4825        if (player->barrelRollAlpha <= 0) {
4826            player->barrelRollAlpha = 0;
⋮
4834        if (player->rollInputTimerL != 0) {
4835            player->rollInputTimerL--;
⋮
4837        if (player->rollInputTimerR != 0) {
4838            player->rollInputTimerR--;
    src/engine/fox_play.c lines 4823–4839 at 4235c59 · upstream ↗
    4846        if (player->rollTimer != 0) {
4847            player->rollTimer--;
⋮
4850        if (player->rollState != 0) {
4851            player->rollInputTimerR = 0;
4852            player->rollInputTimerL = 0;
⋮
4854            player->zRotBarrelRoll += player->rollRate;
4855            if (player->rollTimer == 0) {
4856                if (player->rollRate > 0) {
4857                    player->rollRate -= 5;
⋮
4859                if (player->rollRate < 0) {
4860                    player->rollRate += 5;
⋮
4862                if (player->rollRate == 0) {
⋮
    src/engine/fox_play.c lines 4846–4870 at 4235c59 · upstream ↗
    5534void Player_UpdateOnRails(Player* player) {
⋮
5545            Player_ArwingBank(player);
5546            Player_ArwingBoost(player);
5547            Player_ArwingBrake(player);
5548            Play_dummy_800B41E0(player);
5549            Player_UpdateArwingRoll(player);
    src/engine/fox_play.c lines 5534–5549 at 4235c59 · upstream ↗
    2902    if (gPlayer[0].barrelRollAlpha != 0) {
2903        var_fa0 = 100.0f;
⋮
2906    if (fabsf(gPlayer[0].trueZpos - this->obj.pos.z) < (50.0f + var_fa0)) {
2907        if ((fabsf(gPlayer[0].pos.x - this->obj.pos.x) < (30.0f + var_fa0)) &&
2908            (fabsf(gPlayer[0].pos.y - this->obj.pos.y) < (30.0f + var_fa0))) {
2909            if ((gPlayer[0].barrelRollAlpha != 0) || (gPlayer[0].meteoWarpTimer != 0)) {
2910                this->obj.rot.y = 90.0f;
2911                this->obj.rot.x = RAND_FLOAT(360.0f);
⋮
2921                gPlayer[0].deflectCount++;
2922                AUDIO_PLAY_SFX(NA_SE_ROLLING_REFLECT, this->sfxSource, 0);
⋮
2925            if ((gPlayer[0].barrelRollAlpha == 0) && (gPlayer[0].mercyTimer == 0)) {
2926                Player_ApplyDamage(&gPlayer[0], 0, this->info.damage);
    src/engine/fox_effect.c lines 2902–2926 at 4235c59 · upstream ↗

    Checked against the evidence by its author, an AI model, 2026-10-22.

    Revised after a check by a second AI model, 2026-10-22.

    In the claim ledger

Sources

Code