Fading Values
You can help by
adding links to this article from other relevant articles. This article describes an advanced effect in the Source engine, used to fade fog between different values, but it can be used for any entity that has a color value to change over time. You might also use that article to shift the Z-plane on a map to reduce the visibility, etc.
This trick is quite powerful, as it allows you to alter values that we usually leave static on a map: it would add game immersion.
Entities required
- logic_relay is perfect to change game values or to abstract the routine. It also makes it much easier to duplicate the effect in other maps.
- logic_timer is the basis of the effect, this entities is designed for measuring the time ticks.
- math_counter keeps track of the evolution of the values uppon time for our effect.
- math_colorblend or math_remap do essentially the same thing: they remap a value based on the input value.
Entity setup
logic_relay targetname fade_value1 OnTrigger counter SetValue 0 OnTrigger timer OnTrigger timer Enable
logic_timer targetname timer RefireTime .2 StartDisabled 1 OnTimer counter Add .01
math_counter targetname counter max 1 OnHitMax timer Disable OutValue colorblend InValue
math_colorblend targetname colorblend colormin "0 0 0" colormax "255 255 255" OutColor env_fog_controller SetColor
Process description
You trigger the logic_relay with another entity, or from the console with ent_fire fade_value1 trigger. This will start the sequence. The logic_relay starts the logic_timer and resets the math_counter. The logic_timer re-fires every .2 seconds, firing its output OnTimer, which adds .01 to the math_counter's stored value. The math_counter outputs its OutValue whenever its value is changed, which is in turn put into the math_colorblend. The math_colorblend takes the input value, which is a range from 0-1, and changes the colors based on that.
This range allows for 100 steps. The values that are setup are a compromise between making the blend really smooth and performance. It's slightly "steppy" because it happens only 5 times a second. It would be a lot smoother if you increased it to happen more often, with less of a step. You could do that by only adding .005 or a smaller value than the default .01.
Once the math_counter hits its maximum value (1) it will fire an output telling the logic_timer to disable. This effectively stops the sequence until the logic_relay is fired again.
OutColor and OutValue outputs both accept a parameter in Hammer, but make sure you do not specify one. The parameter they pass will be dynamically generated by the entity itself.
You can change OutColor on the math_colorblend to target any entity that will accept a color value, and it should work just the same. This entity rig can be further adapted to work with a math_remap, and used to fade between any two values, allowing you to affect the values of pretty much any entity in the game, and change them over time.
