Smooth field of view (FOV) change in Source Engine games.

smooth_fov.py

# ../smooth_fov/smooth_fov.py

# Source.Python
from players.entity import Player
from engines.server import global_vars
from commands.say import SayCommand


def change_fov(index, target_fov, rate=0.3):
    """Changes a player's field of view (FOV) smoothly.

    Args:
        index (int): A valid player index.
        target_fov (int): The new FOV value.
        rate (float): Duration of the FOV transition (in seconds).

    Raises:
        OverflowError: If 'target_fov' is less than 0 or greater than 255.
    """
    player = Player(index)
    # Get the player's current FOV.
    old_fov = player.fov

    if old_fov == 0:
        # When changing a player's FOV for the first time, the value of 'fov'
        # will be zero. So we get the 'default_fov' instead.
        old_fov = player.default_fov

    # Time when the FOV starts changing.
    player.fov_time = global_vars.current_time
    # Duration of the transition (in seconds).
    player.fov_rate = rate

    # The FOV will transition from 'fov_start' to 'fov'.
    player.fov_start = old_fov
    player.fov = target_fov


@SayCommand('fov')
def change_fov_command(command, index, team_only=False):
    """Chat command for changing your own FOV.

    Example:
        >>> fov 120 2
        This will change your FOV to 120 over the next 2 seconds.

        >>> fov 0 0
        This will instantly change your FOV to the default value (90).
    """
    # Was the new FOV value not specified? (required)
    if len(command) <= 1:
        return

    try:
        target_fov = clamp(abs(int(command[1])), 0, 255)
    except ValueError:
        return

    rate = 0.3
    # Was the rate specified? (optional)
    if len(command) >= 3:
        try:
            rate = abs(float(command[2]))
        except ValueError:
            pass

    change_fov(index, target_fov, rate)


def clamp(value, min_value, max_value):
    """Restricts 'value' to the specified range."""
    return max(min_value, min(value, max_value))