I want to reset FOV when player is applied speed modifier.

The Game doesn't call onFOVChange method...

  @SubscribeEvent
  public static void setSpeedPlayer(TickEvent.PlayerTickEvent event) {
      player_movement_speed = event.player.getAttribute(SharedMonsterAttributes.MOVEMENT_SPEED);
      player_movement_speed.removeModifier(/*UUID*/);
      player_movement_speed.applyModifier(new AttributeModifier(/*UUID*/, /*Name*/, speed - 1.0f, AttributeModifier.Operation.MULTIPLY_TOTAL));
    }
  }

  @SubscribeEvent
  @OnlyIn(Dist.CLIENT)
  public void onFOVChange(FOVUpdateEvent event) {
    LOGGER.debug("ChangeFOV!");
    if (event.getEntity() instanceof PlayerEntity) {
      PlayerEntity player = event.getEntity();
      EffectInstance speed = player.getActivePotionEffect(Effects.SPEED);
      float fov = 0.9f, sprint_fov = 1.02f;
      if (player.isSprinting())
        event.setNewfov(speed != null ? sprint_fov + ((0.104f * (speed.getAmplifier() + 1))) : sprint_fov);
      else
        event.setNewfov(speed != null ? fov + (0.08f * (speed.getAmplifier() + 1)) : fov);
    }
  }

Edited January 30, 20205 yr by kyazuki

I wrote @Mod.EventBusSubscriber and @SubscribeEvent.

Isn't it enough to register?

I'm such an idiot...

Thank you very much!