Repository: staffantan/unity-vhsglitch
Branch: master
Commit: 01f8eeccd9c2
Files: 4
Total size: 3.5 KB

Directory structure:
gitextract_bsseorug/

├── README.md
├── Scripts/
│   └── VHSPostProcessEffect.cs
├── Shaders/
│   └── VHSPostProcessEffect.shader
└── VHSGlitch.unitypackage

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FILE CONTENTS
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FILE: README.md
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# unity-vhsglitch
glitched VHS post-processing shader for Unity3D

This work is licensed under a Creative Commons Attribution 3.0 Unported License.
http://creativecommons.org/licenses/by/3.0/deed.en_GB

You are free:

to copy, distribute, display, and perform the work
to make derivative works
to make commercial use of the work


This post-processing effect requires Unity Pro

USAGE:
Add VHSPostProcessEffect script to camera.

VHS Glitched Video footage by Christopher Huppertz:
https://www.youtube.com/watch?v=9eFVeErnUzg

Licensed under: Creative Commons Attribution licence (reuse allowed)


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FILE: Scripts/VHSPostProcessEffect.cs
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using UnityEngine;
using UnityEngine.Video;

[ExecuteInEditMode]
[AddComponentMenu("Image Effects/GlitchEffect")]
[RequireComponent(typeof(Camera))]
[RequireComponent(typeof(VideoPlayer))]
public class VHSPostProcessEffect : MonoBehaviour
{
	public Shader shader;
	public VideoClip VHSClip;

	private float _yScanline;
	private float _xScanline;
	private Material _material = null;
	private VideoPlayer _player;

	void OnEnable()
	{
		_material = new Material(shader);
		_player = GetComponent<VideoPlayer>();
		_player.isLooping = true;
		_player.renderMode = VideoRenderMode.APIOnly;
		_player.audioOutputMode = VideoAudioOutputMode.None;
		_player.clip = VHSClip;
		_player.Play();
	}

	void OnRenderImage(RenderTexture source, RenderTexture destination)
	{
		_material.SetTexture("_VHSTex", _player.texture);

		_yScanline += Time.deltaTime * 0.01f;
		_xScanline -= Time.deltaTime * 0.1f;

		if (_yScanline >= 1)
		{
			_yScanline = Random.value;
		}
		if (_xScanline <= 0 || Random.value < 0.05)
		{
			_xScanline = Random.value;
		}
		_material.SetFloat("_yScanline", _yScanline);
		_material.SetFloat("_xScanline", _xScanline);
		Graphics.Blit(source, destination, _material);
	}

	protected void OnDisable()
	{
		if (_material)
		{
			DestroyImmediate(_material);
		}
	}
}

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FILE: Shaders/VHSPostProcessEffect.shader
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Shader "Hidden/VHSPostProcessEffect" {
	Properties {
		_MainTex ("Base (RGB)", 2D) = "white" {}
		_VHSTex ("Base (RGB)", 2D) = "white" {}
	}

	SubShader {
		Pass {
			ZTest Always Cull Off ZWrite Off
			Fog { Mode off }
					
			CGPROGRAM
			#pragma vertex vert_img
			#pragma fragment frag
			#pragma fragmentoption ARB_precision_hint_fastest 
			#include "UnityCG.cginc"

			uniform sampler2D _MainTex;
			uniform sampler2D _VHSTex;
			
			float _yScanline;
			float _xScanline;
			float rand(float3 co){
			     return frac(sin( dot(co.xyz ,float3(12.9898,78.233,45.5432) )) * 43758.5453);
			}
 
			fixed4 frag (v2f_img i) : COLOR{
				fixed4 vhs = tex2D (_VHSTex, i.uv);
				
				float dx = 1-abs(distance(i.uv.y, _xScanline));
				float dy = 1-abs(distance(i.uv.y, _yScanline));
				
				//float x = ((int)(i.uv.x*320))/320.0;
				dy = ((int)(dy*15))/15.0;
				dy = dy;
				i.uv.x += dy * 0.025 + rand(float3(dy,dy,dy)).r/500;//0.025;
				
				float white = (vhs.r+vhs.g+vhs.b)/3;
				
				if(dx > 0.99)
					i.uv.y = _xScanline;
				//i.uv.y = step(0.99, dy) * (_yScanline) + step(dy, 0.99) * i.uv.y;
				
				i.uv.x = i.uv.x % 1;
				i.uv.y = i.uv.y % 1;
				
				fixed4 c = tex2D (_MainTex, i.uv);
				
				float bleed = tex2D(_MainTex, i.uv + float2(0.01, 0)).r;
				bleed += tex2D(_MainTex, i.uv + float2(0.02, 0)).r;
				bleed += tex2D(_MainTex, i.uv + float2(0.01, 0.01)).r;
				bleed += tex2D(_MainTex, i.uv + float2(0.02, 0.02)).r;
				bleed /= 6;
				
				if(bleed > 0.1){
					vhs += fixed4(bleed * _xScanline, 0, 0, 0);
				}
				
				float x = ((int)(i.uv.x*320))/320.0;
				float y = ((int)(i.uv.y*240))/240.0;
				
				c -= rand(float3(x, y, _xScanline)) * _xScanline / 5;
				return c + vhs;
			}
			ENDCG
		}
	}
Fallback off
}