Animating Pixel Art Fabric with Unity Shader

Sara — Sat, 30 Aug 2025 22:23:55 +0000

This blog explores how I implemented a simple shader that shows the illusion of a rug affected by the wind.

Lots of tutorials explaining how to do a waving flag shader but it’s always a 3D approach, so let’s just turn this into something that looks appropriate for a pixel art sprite.

My goal:

Shader Components

Time Based Wave:

1st step is our typical time based wave that is going to be applied on the sprite.

Control how fast it animates → Time * WaveSpeed
Set how many waves appear → UV.x * WaveFrequency
Use Sine wave to oscillate each pixel up&down

(Time * WaveSpeed) + (UV.X * WaveFrequency) → Sine Wave

To better understand it, I imagine if we paused time, we get too see each pixel at a different position on the sine curve and if we continue, all pixels shift position simulating the wave effect.

Secondary Wave for natural variation:

It is exactly the same as the first wave, except we could change the values of WaveSpeed(1.7) & WaveFrequency(2.2) a bit to add some natural variation to the wave and avoid a repetitive sine wave. Another thing added is the amplitude ratio, in my case (0.6) looked fairly good to avoid overpowering our main time based wave.

Wave Displacement:

Now we have got two waves and we need to combine them together

(Wave1+Wave2) * DampeningPower(0.004)

Pixel Snapping:

This is crucial step for my case since I want to keep the pixelated aesthetic to the sprite, without it the sprite will have very smooth wave effect which I don’t need in my case.

Floor(Wave Displacement * Pixel Density) / PixelDensity

we round down using Floor to whole units to eliminate sub pixel positioning (which causes smoothing to the sprite)
Divide by PixelDensity to convert back to UV space for texture sampling

First one uses pixel density of value 90, as we can see it’s way crispier than the other two, last one is very smooth which I don’t want in my current game so I’ve decided to go with a value of 300 which adds a little bit of pixelated aesthetic to it.

Combine all values to assign to our texture UV

Fake Light Effect

For adding a shadow effect I Just decided to add fake light and shadow wave on the fabric

we use the WaveDisplacement value for creating such effect.

Apply absolute to the WaveDisplacement value to remove -ve values and just focus on the peaks and valleys of the wave
Use Power to soften the values a little bit since it’s a shadow & light effect
Multiply just to control the intensity
Add to set minimum brightness
Lastly we multiply it with the SampleTextrue2D RGBA

1st rug fake light values are set to zero which disables this part of the shader, 2nd simulates a little bit of dim light and shadow using low values for the wave, 3rd uses a higher LightMultiplay value.

This concludes my simple approach to animating rug sprites using a shader.
Thanks for reading! Tips and feedback are always welcome.

Check out Alchemy Tunes

Pixel art by https://kenmi-art.itch.io/ & https://franuka.itch.io/

Quick Guide: Voice Manipulation Using Dissonance & FMOD In Unity

Sara — Wed, 21 May 2025 23:38:55 +0000

I have been going back to Lethal Company every once in a while and I’ve been fascinated by a lot of features in this game as a player and a developer. For this blog, I wanted to focus on one of my favourite features and it’s how voice chat manipulation is implemented technically. So I thought recreating it myself will be a fun challenge.

Tools:

Main tools I loved working with and investing in for this technical implementation:

Dissonances VOIP: Lethal Company uses this asset so It’s pretty reliable and seems to integrate to any project just fine. It supports lots of network solutions too so it gives you flexibilty in your choices.
FMOD For Unity: It has a really nice learning curve and any developer can set it up easily. It was my first time using FMOD but I didn’t have any problems checking documentation and adding audio myself.
Dissonance For FMOD: Luckily, there is an integration already made for FMOD playback
Fishnet SDK: There are multiple networking solutions out there but I have experience with fishnet and it integerates well with Dissonance. In addition, It’s an open source solution & supported by an active community which makes it reliable for me.

Approach:

FMOD voice playback integration routes players voice through an audio bus in FMOD, so we can add any effect to that audio bus. My initial thought process was to create a specific Voice bus for players and then manipulate audio through adding effects to the bus, however it didn’t seem as dynamic as I wanted.

To Create a voice bus on FMOD:

Window→Mixer
Create VoiceChat bus
Add VoiceChat path to FMOD Bus playback as bus:/VoiceChat

Second approach is going a step backward in the voice emitting route and checking the channel before it reaches the bus. Since FMOD playback instantiates a unique instance for each player, that means we can use each channel (per player) and apply effects on it before routing to the VoiceChat bus. Then it gives us the flexiblity we need.

Implementation Steps:

Instantiating a player-specific channel made everything easier, so firstly I stored the FMOD voice playback channel for each player

  private void SetVoicePlaybackDictionary()
  {
    fmodVoicePlaybacks.Clear();
    fmodVoicePlaybacks = dissonanceSetup.GetComponentsInChildren<FMODVoicePlayback>().ToList();

    FMODVoicePlayBackDictionary.Clear();

    foreach (var voicePlayBack in fmodVoicePlaybacks)
      FMODVoicePlayBackDictionary.TryAdd(voicePlayBack.PlayerName, voicePlayBack.Channel);
  }

Once channels are mapped to players, we can dynamically add or remove effects according to the game mechanics

This leaves us with the last step, modifying the channel based on the player state (e.g., adding reverb in specific zones).

To add an effect to a channel we need to create DSP effect and use addDSP() method to the player’s channel

    public void AddChannelEffect(Channel channel)
    {
    var dsp = GetEchoEffect();
        channel.addDSP(FMOD.CHANNELCONTROL_DSP_INDEX.HEAD, dsp);
    }

    private List<DSP> GetEchoEffect()
    {
     var dspEffectList = new List<DSP>();
     CreateDspEffect(DSP_TYPE.SFXREVERB, out var dspEffect);

     dspEffectList.Add(dspEffect);
     SetEchoEffectParams(dspEffect);

     return dspEffectList;
    }

    private void SetEchoEffectParams(DSP dspEffect)
    {
        dspEffect.setParameterFloat((int)FMOD.DSP_SFXREVERB.DECAYTIME, 2.0f);
    }

Removing the Effect would require the DSP type to remove from the channel (e.g., DSP_TYPE.SFXREVERB

    public void GetDspEffects(SfxEffectType sfxEffectType, out List<DSP_TYPE> dsp_types)
    {
        dsp_types = new List<DSP_TYPE>();
        switch (sfxEffectType)
        {
            case SfxEffectType.Echo:
                dsp_types.Add(DSP_TYPE.SFXREVERB);
                break;
        }
    }


    public void RemoveChannelEffect(Channel channel, SFXEffectsManager.SfxEffectType effectType)
    {
        GetDspEffects(effectType, out List<DSP_TYPE> dsp_types);
        foreach (var dspType in dsp_types)
        {
            channel.getNumDSPs(out var numDSPs);
            for (int i = 0; i < numDSPs; i++)
            {
                channel.getDSP(i, out var dsp);
                dsp.getType(out var type);

                if (type != dspType) continue;

                channel.removeDSP(dsp);
                dsp.release();
            }
        }
    }

This concludes how all these tools were very easy to integrate together and made me reach my goal in the quickest way possible.

A demo if anyone wants to try adding dsp through channels without dissonance.
https://github.com/SaraAkmal/Unity-FMOD-DSPEffects-Demo

Check out Alchemy Tunes

Thanks for reading! Tips and feedback are super welcome.

DEV Community: Sara

Animating Pixel Art Fabric with Unity Shader

Quick Guide: Voice Manipulation Using Dissonance & FMOD In Unity