Oct
19
2021

Old School Scrolling Text with Shaders, RenderTexture

An article by mgear

Tried to make scrolling text using shaders and text mesh, video below (results at 59 mins -> )

Shader Sources:
(one for text mesh, one for UI RawImage that displays camera view as rendertexture)

	// https://unitycoder.com/blog/2021/10/19/old-school-scrolling-text-with-shaders-rendertexture/
	// this is for text mesh
	Shader "Unlit/TextFx" {
	Properties {
	_MainTex ("Texture", 2D) = "white" { }
	_Col1 ("Color 1", Color) = (1, 0.0, 0.0, 1.0)
	_Col2 ("Color 2", Color) = (0, 1, 0.0, 1.0)
	_Col3 ("Color 3", Color) = (0, 0, 1, 1.0)
	_Scale ("Scale", Float) = 1

	}

	SubShader {
	Tags {
	"Queue"="Transparent"
	"IgnoreProjector"="True"
	"RenderType"="Transparent"
	"PreviewType"="Plane"
	}
	Lighting Off Cull Off ZTest Always ZWrite Off
	Blend SrcAlpha OneMinusSrcAlpha

	Pass {
	CGPROGRAM

	#pragma vertex vert
	#pragma fragment frag

	#include "UnityCG.cginc"

	struct appdata {
	float4 vertex : POSITION;
	float2 texcoord : TEXCOORD0;
	};

	struct v2f {
	float4 vertex : SV_POSITION;
	float2 texcoord : TEXCOORD0;
	float4 screenPosition : TEXCOORD1;
	};

	sampler2D _MainTex;
	float4 _MainTex_ST;
	float4 _Col1;
	float4 _Col2;
	float4 _Col3;
	float _Scale;

	v2f vert(appdata v) {
	v2f o;
	o.vertex = UnityObjectToClipPos(v.vertex);
	o.screenPosition = ComputeScreenPos(o.vertex);

	o.vertex.xy*=_Scale;

	o.texcoord = TRANSFORM_TEX(v.texcoord,_MainTex);
	return o;
	}

	float4 frag(v2f i) : SV_Target {

	float2 scroll = float2(0,sin(frac(_Time.x)20)0.5-0.5);
	float2 uv = ((i.screenPosition.xy+scroll) / i.screenPosition.w);

	float h = 0.5;
	float4 c1 = lerp(lerp(_Col1, _Col2, uv.y/h), lerp(_Col2, _Col3, (uv.y – h)/(1.0 – h)), step(h, uv.y));
	float4 c2 = lerp(lerp(_Col1, _Col2, uv.x/h), lerp(_Col2, _Col3, (uv.x – h)/(1.0 – h)), step(h, uv.x));

	float4 c = lerp(c1,c2,uv.y(cos(frac(_Time.y))0.5-0.5));

	float2 s2 = float2(frac(_Time.x),0);
	c.a *= tex2D(_MainTex, i.texcoord).a;
	return c;
	}
	ENDCG

	}
	}
	}

view raw TextFx.shader hosted with ❤ by GitHub

	// https://unitycoder.com/blog/2021/10/19/old-school-scrolling-text-with-shaders-rendertexture/
	// this is for render texture raw image

	// Unity built-in shader source. Copyright (c) 2016 Unity Technologies. MIT license (see license.txt)
	Shader "UI/Default"
	{
	Properties
	{
	[PerRendererData] _MainTex ("Sprite Texture", 2D) = "white" {}
	_Color ("Tint", Color) = (1,1,1,1)

	_StencilComp ("Stencil Comparison", Float) = 8
	_Stencil ("Stencil ID", Float) = 0
	_StencilOp ("Stencil Operation", Float) = 0
	_StencilWriteMask ("Stencil Write Mask", Float) = 255
	_StencilReadMask ("Stencil Read Mask", Float) = 255

	_ColorMask ("Color Mask", Float) = 15
	_Speed ("ScrollSpeed", Float) = 2
	_SpeedY ("ScrollSpeedY", Float) = 3

	[Toggle(UNITY_UI_ALPHACLIP)] _UseUIAlphaClip ("Use Alpha Clip", Float) = 0
	}

	SubShader
	{
	Tags
	{
	"Queue"="Transparent"
	"IgnoreProjector"="True"
	"RenderType"="Transparent"
	"PreviewType"="Plane"
	"CanUseSpriteAtlas"="True"
	}

	Stencil
	{
	Ref [_Stencil]
	Comp [_StencilComp]
	Pass [_StencilOp]
	ReadMask [_StencilReadMask]
	WriteMask [_StencilWriteMask]
	}

	Cull Off
	Lighting Off
	ZWrite Off
	ZTest [unity_GUIZTestMode]
	Blend SrcAlpha OneMinusSrcAlpha
	ColorMask [_ColorMask]

	Pass
	{
	Name "Default"
	CGPROGRAM
	#pragma vertex vert
	#pragma fragment frag
	#pragma target 2.0

	#include "UnityCG.cginc"
	#include "UnityUI.cginc"

	#pragma multi_compile __ UNITY_UI_ALPHACLIP

	struct appdata_t
	{
	float4 vertex : POSITION;
	float4 color : COLOR;
	float2 texcoord : TEXCOORD0;
	UNITY_VERTEX_INPUT_INSTANCE_ID
	};

	struct v2f
	{
	float4 vertex : SV_POSITION;
	fixed4 color : COLOR;
	float2 texcoord : TEXCOORD0;
	float4 worldPosition : TEXCOORD1;
	UNITY_VERTEX_OUTPUT_STEREO
	};

	fixed4 _Color;
	fixed4 _TextureSampleAdd;
	float4 _ClipRect;
	float _Speed;
	float _SpeedY;

	v2f vert(appdata_t IN)
	{
	v2f OUT;
	UNITY_SETUP_INSTANCE_ID(IN);
	UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(OUT);
	OUT.worldPosition = IN.vertex;
	OUT.vertex = UnityObjectToClipPos(OUT.worldPosition);
	OUT.texcoord = IN.texcoord;
	OUT.color = IN.color * _Color;
	return OUT;
	}

	sampler2D _MainTex;

	fixed4 frag(v2f IN) : SV_Target
	{
	float2 s = float2(frac(_Time.x)_Speed, cos(_Time.y+IN.texcoord.x_SpeedY)*0.3);
	float2 uv = float2(IN.texcoord.x+s.x,IN.texcoord.y+s.y);
	uv %= 1;
	half4 color = (tex2D(_MainTex, uv) + _TextureSampleAdd) * IN.color;

	color.a *= UnityGet2DClipping(IN.worldPosition.xy, _ClipRect);

	#ifdef UNITY_UI_ALPHACLIP
	clip (color.a – 0.001);
	#endif

	return color;
	}
	ENDCG
	}
	}
	}