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Hologram Effect in Unity

0 Comments - Jun 21, 2019
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Hologram is a three-dimensional projection of an object or a person onto a nearby area, by employing a technique called light beam intersection.

Even though there are no true holograms in existence, the concept was largely popularized by movies and novels in a sci-fi genre.

In this tutorial, I will be showing how to make a hologram Shader with a glitch effect in Unity.

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Meanwhile, check this Horizon Bending shader

Step 1: Create Hologram Shader

The hologram effect is done with a help of a custom Shader.

To create a hologram Shader, follow the steps below:

  • Create a new Shader and name it "Hologram"
  • Remove everything inside it then paste the code below:

Hologram.shader

//sharpcoderblog.com @2019
Shader "FX/Hologram Shader"
{
	Properties
	{
		_Color("Color", Color) = (0, 1, 1, 1)
		_MainTex("Base (RGB)", 2D) = "white" {}
		_AlphaTexture ("Alpha Mask (R)", 2D) = "white" {}
		//Alpha Mask Properties
		_Scale ("Alpha Tiling", Float) = 3
		_ScrollSpeedV("Alpha scroll Speed", Range(0, 5.0)) = 1.0
		// Glow
		_GlowIntensity ("Glow Intensity", Range(0.01, 1.0)) = 0.5
		// Glitch
		_GlitchSpeed ("Glitch Speed", Range(0, 50)) = 50.0
		_GlitchIntensity ("Glitch Intensity", Range(0.0, 0.1)) = 0
	}

	SubShader
	{
		Tags{ "Queue" = "Overlay" "IgnoreProjector" = "True" "RenderType" = "Transparent" }

		Pass
		{
			Lighting Off 
			ZWrite On
			Blend SrcAlpha One
			Cull Back

			CGPROGRAM
				
				#pragma vertex vertexFunc
				#pragma fragment fragmentFunc

				#include "UnityCG.cginc"

				struct appdata{
					float4 vertex : POSITION;
					float2 uv : TEXCOORD0;
					float3 normal : NORMAL;
				};

				struct v2f{
					float4 position : SV_POSITION;
					float2 uv : TEXCOORD0;
					float3 grabPos : TEXCOORD1;
					float3 viewDir : TEXCOORD2;
					float3 worldNormal : NORMAL;
				};

				fixed4 _Color, _MainTex_ST;
				sampler2D _MainTex, _AlphaTexture;
				half _Scale, _ScrollSpeedV, _GlowIntensity, _GlitchSpeed, _GlitchIntensity;

				v2f vertexFunc(appdata IN){
					v2f OUT;

					//Glitch
					IN.vertex.z += sin(_Time.y * _GlitchSpeed * 5 * IN.vertex.y) * _GlitchIntensity;

					OUT.position = UnityObjectToClipPos(IN.vertex);
					OUT.uv = TRANSFORM_TEX(IN.uv, _MainTex);

					//Alpha mask coordinates
					OUT.grabPos = UnityObjectToViewPos(IN.vertex);

					//Scroll Alpha mask uv
					OUT.grabPos.y += _Time * _ScrollSpeedV;

					OUT.worldNormal = UnityObjectToWorldNormal(IN.normal);
					OUT.viewDir = normalize(UnityWorldSpaceViewDir(OUT.grabPos.xyz));

					return OUT;
				}

				fixed4 fragmentFunc(v2f IN) : SV_Target{
					
					half dirVertex = (dot(IN.grabPos, 1.0) + 1) / 2;
					
					fixed4 alphaColor = tex2D(_AlphaTexture,  IN.grabPos.xy * _Scale);
					fixed4 pixelColor = tex2D (_MainTex, IN.uv);
					pixelColor.w = alphaColor.w;

					// Rim Light
					half rim = 1.0-saturate(dot(IN.viewDir, IN.worldNormal));

					return pixelColor * _Color * (rim + _GlowIntensity);
				}
			ENDCG
		}
	}
}

Step 2: Assign Shader to Material

For demonstration purposes, I will be using a Space Robot Kyle from here.

Space Robot Kyle

To assign a hologram Shader to a material, follow the steps below:

  • Create a new Material and name it "hologram_material"
  • Assign a newly created Shader to it, which should be located at 'FX/Hologram Shader'

Unity 3D Material Inspector

  • For the Color I will pick Cyan (0, 1, 1, 1) but you can pick any color

  • For Base (RGB) assign a Texture that comes with the model

  • Assign the Material to your 3D model

But as you will notice, the Model does not look much like a Hologram, that's because we need to assign one last Texture which is Alpha Mask (R).

In my case, I will be using a simple texture with horizontal stripes and transparency (to add that "Holographic segmentation" effect).

  • Check the texture below:

  • Assign a Texture above to the Alpha Mask (R)

Much better, now the model looks more like a Hologram!

Step 3: Add Glitch Effect

The hologram Shader also supports a glitch effect that can be controlled from a script.

To add a glitch effect to a hologram Shader, follow the steps below:

  • Create a new script and name it "GlitchControl"
  • Copy the code below inside it:

GlitchControl.cs

using System.Collections;
using UnityEngine;

public class GlitchControl : MonoBehaviour
{
    //How often should the glitch effect happen (higher value means more frequently)
    public float glitchChance = 0.1f;

    Material hologramMaterial;
    WaitForSeconds glitchLoopWait = new WaitForSeconds(0.1f);

    void Awake()
    {
        hologramMaterial = GetComponent<Renderer>().material;
    }

    // Start is called before the first frame update
    IEnumerator Start()
    {
        while (true)
        {
            float glitchTest = Random.Range(0f, 1f);

            if (glitchTest <= glitchChance)
            {
                //Do Glitch
                float originalGlowIntensity = hologramMaterial.GetFloat("_GlowIntensity");
                hologramMaterial.SetFloat("_GlitchIntensity", Random.Range(0.07f, 0.1f));
                hologramMaterial.SetFloat("_GlowIntensity", originalGlowIntensity * Random.Range(0.14f, 0.44f));
                yield return new WaitForSeconds(Random.Range(0.05f, 0.1f));
                hologramMaterial.SetFloat("_GlitchIntensity", 0f);
                hologramMaterial.SetFloat("_GlowIntensity", originalGlowIntensity);
            }

            yield return glitchLoopWait;
        }
    }
}

  • Assign a GlitchControl script to the same GameObject as the Renderer component with a 'hologram_material' material.
  • Press Play and observe the glitch effect:

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