6. Sound

In this part

You will import three sound effects and play them at the right moments: when the ship shoots, when an enemy explodes and when the ship takes damage.

Import the sounds

1. In the folder where you unzipped primeiro-jogo-recursos.zip, there are tiro.wav, explosao.wav and dano.wav.

2. Click the sounds folder, in the Recursos (Resources) panel, and drag the three files onto the panel: they go to the selected folder. If you prefer, right-click the folder and choose Importar som (WAV)… (import sound).

3. Each sound shows up with a green ▶ next to it. Click it to listen.

Select a sound to see its details in the Inspetor (Inspector):

The Copiar código (copy code) button copies the line that plays the sound, for example Audio::play("tiro");. Then just paste it into your code.

Note

Brasa plays WAV, OGG and MP3 files. For background music, see Audio::playMusic in Sound.

Sound for the shot and the damage

In Player.cpp, add two lines: one right after spawn<Bullet> and another in hurt(), after taking the life.

objects/Player.cpp

#include "Player.hpp"

#include "src/game.hpp"

#include <algorithm>

using namespace brasa;

void Player::onSpawn() {
    animSpeed = 0.2f;  // the engine flame alternates between the 2 frames
    // Touching an Enemy costs one life (and the enemy goes away too).
    onCollide<Enemy>([this](Enemy& enemy) {
        if (hurt()) enemy.destroy();
    });
}

void Player::onUpdate() {
    // The actions are in the project settings (keyboard and gamepad).
    // axis returns from -1 to 1: -1 = the first action, 1 = the second.
    float dx = axis("esquerda", "direita");
    float dy = axis("cima", "baixo");
    if (dx != 0.0f && dy != 0.0f) {  // on the diagonal, it moves at the same speed
        dx *= 0.7071f;
        dy *= 0.7071f;
    }

    // clamp keeps the ship inside the screen (the ship is 16 px, so the margin is 8).
    const float maxX = static_cast<float>(roomWidth()) - 8.0f;
    const float maxY = static_cast<float>(roomHeight()) - 8.0f;
    x = std::clamp(x + dx * velocidade, 8.0f, maxX);
    y = std::clamp(y + dy * velocidade, 8.0f, maxY);

    // held(action) is true while the key or the button is pressed.
    if (held("atirar") && canShoot_) {
        spawn<Bullet>(x, y - 8.0f, "Tiros");  // the shot is born in the Tiros layer, behind the ship
        Audio::play("tiro", {.volume = 0.4f});
        canShoot_ = false;
        after(intervaloTiro, [this] { canShoot_ = true; });  // only shoots again a few steps from now
    }
    if (invincible_ > 0) --invincible_;
}

void Player::onRender() {
    // Blinks while invincible: skips the drawing on some steps.
    if (invincible_ > 0 && (invincible_ / 4) % 2 == 0) return;
    drawSelf();
}

bool Player::hurt() {
    if (invincible_ > 0 || isDestroyed()) return false;
    --state().lives;
    Audio::play("dano");
    if (state().lives <= 0) {
        destroy();
    } else {
        invincible_ = 90;  // 1.5 s at 60 steps per second
    }
    return true;
}

BRASA_ENTITY(Player);

• Audio::play("dano") plays the sound called dano, which is the name of the file without the .wav.
• The shot plays many times per second, so it goes quieter: {.volume = 0.4f} plays at 40% of the volume.

Sound for the explosion

In Enemy.cpp, play the explosion inside kill():

objects/Enemy.cpp

#include "Enemy.hpp"

#include "src/game.hpp"

using namespace brasa;

void Enemy::onSpawn() {
    animSpeed = 0.1f;
    // random(a, b) picks a number between a and b: each enemy falls at a different speed.
    vspeed = random(0.8f, 1.6f);
    // When a Bullet touches me, the shot goes away and I die.
    // The other objects (Bullet, Player...) are already known here, with no #include.
    onCollide<Bullet>([this](Bullet& bullet) {
        bullet.destroy();
        kill();
    });
}

void Enemy::onUpdate() {
    // roomHeight() is the height of the screen; past it (with some slack), the enemy got away.
    if (y > static_cast<float>(roomHeight()) + 16.0f) destroy();
}

void Enemy::kill() {
    if (isDestroyed()) return;  // avoids scoring twice on the same step
    state().score += pontos;
    Audio::play("explosao", {.volume = 0.5f});
    destroy();
}

BRASA_ENTITY(Enemy);

Test it now

Press Play and play: the shot goes pew, the enemies explode and the ship complains when it takes damage.

What you learned

• To import sounds, just drag WAV files onto the Recursos panel, and the ▶ lets you listen right away.
• Audio::play("name") plays a sound, and {.volume = ...} adjusts the volume. See Play sounds.
• The Copiar código button in the Inspector already copies the finished line.

Next part: 7. Game over →