void update() {

    // Physics
    survivor.y += world.gravity;

    // Platform collision
    if (survivor.y + survivor.h > platform.y &&
        survivor.x + 48 >= platform.x &&
        survivor.x + survivor.w - 48 <= platform.x + platform.w &&
        survivor.y + (survivor.h/2) < platform.y) {
        survivor.y = platform.y - survivor.h;
    }

    // Input processing
    const Uint8* keys = SDL_GetKeyboardState(NULL);
    if (survivor.state != "state_shoot") {
        if (keys[SDL_SCANCODE_D]) {
            survivor.x += survivor.speed;
            survivor.scaleX = 1;
            survivor.frameY = 1;
            survivor.state = "state_walk";
        } else if (keys[SDL_SCANCODE_A]) {
            survivor.x -= survivor.speed;
            survivor.scaleX = -1;
            survivor.frameY = 1;
            survivor.state = "state_walk";
        } else if (keys[SDL_SCANCODE_J]) {
            survivor.frameX = 0;
            survivor.frameY = 2;
            survivor.animCompleted = false;
            survivor.shot = false;
            survivor.state = "state_shoot";
        } else {
            survivor.frameX = 0;
            survivor.frameY = 0;
            survivor.state = "state_idle";
        }
    }

    // Player states
    if (survivor.state == "state_shoot") {

        if (survivor.frameX / survivor.animSpeed == 2 && !survivor.shot) {
            survivor.shot = true;
            shootBullet();
        }

        if (survivor.animCompleted) {
            survivor.frameY = 0;
            survivor.state = "state_idle";
        }
    }
}