I'm trying to reproduce the (now common famous) blur effect on the background of a UI window for my game in Unity3D.
One of the best examples I can think of right now is Heroes Of The Storm, notice how the background of the Level Up panel blurs what's behind it :
Is there any way to reproduce the same effect with the recently-added Canvas in Unity3D?
I know there is a way to do so by using a camera, but I'm not really familiar with the whole thing, especially when it comes to making it work with the new UI system.
Thanks.
Here's a shader script that works nicely for me.
Source: https://forum.unity3d.com/threads/solved-dynamic-blurred-background-on-ui.345083/#post-2853442
// Upgrade NOTE: replaced 'mul(UNITY_MATRIX_MVP,*)' with 'UnityObjectToClipPos(*)'
Shader "Unlit/FrostedGlass"
{
Properties
{
_Radius("Radius", Range(1, 255)) = 1
}
Category
{
Tags{ "Queue" = "Transparent" "IgnoreProjector" = "True" "RenderType" = "Opaque" }
SubShader
{
GrabPass
{
Tags{ "LightMode" = "Always" }
}
Pass
{
Tags{ "LightMode" = "Always" }
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#pragma fragmentoption ARB_precision_hint_fastest
#include "UnityCG.cginc"
struct appdata_t
{
float4 vertex : POSITION;
float2 texcoord: TEXCOORD0;
};
struct v2f
{
float4 vertex : POSITION;
float4 uvgrab : TEXCOORD0;
};
v2f vert(appdata_t v)
{
v2f o;
o.vertex = UnityObjectToClipPos(v.vertex);
#if UNITY_UV_STARTS_AT_TOP
float scale = -1.0;
#else
float scale = 1.0;
#endif
o.uvgrab.xy = (float2(o.vertex.x, o.vertex.y*scale) + o.vertex.w) * 0.5;
o.uvgrab.zw = o.vertex.zw;
return o;
}
sampler2D _GrabTexture;
float4 _GrabTexture_TexelSize;
float _Radius;
half4 frag(v2f i) : COLOR
{
half4 sum = half4(0,0,0,0);
#define GRABXYPIXEL(kernelx, kernely) tex2Dproj( _GrabTexture, UNITY_PROJ_COORD(float4(i.uvgrab.x + _GrabTexture_TexelSize.x * kernelx, i.uvgrab.y + _GrabTexture_TexelSize.y * kernely, i.uvgrab.z, i.uvgrab.w)))
sum += GRABXYPIXEL(0.0, 0.0);
int measurments = 1;
for (float range = 0.1f; range <= _Radius; range += 0.1f)
{
sum += GRABXYPIXEL(range, range);
sum += GRABXYPIXEL(range, -range);
sum += GRABXYPIXEL(-range, range);
sum += GRABXYPIXEL(-range, -range);
measurments += 4;
}
return sum / measurments;
}
ENDCG
}
GrabPass
{
Tags{ "LightMode" = "Always" }
}
Pass
{
Tags{ "LightMode" = "Always" }
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#pragma fragmentoption ARB_precision_hint_fastest
#include "UnityCG.cginc"
struct appdata_t
{
float4 vertex : POSITION;
float2 texcoord: TEXCOORD0;
};
struct v2f
{
float4 vertex : POSITION;
float4 uvgrab : TEXCOORD0;
};
v2f vert(appdata_t v)
{
v2f o;
o.vertex = UnityObjectToClipPos(v.vertex);
#if UNITY_UV_STARTS_AT_TOP
float scale = -1.0;
#else
float scale = 1.0;
#endif
o.uvgrab.xy = (float2(o.vertex.x, o.vertex.y*scale) + o.vertex.w) * 0.5;
o.uvgrab.zw = o.vertex.zw;
return o;
}
sampler2D _GrabTexture;
float4 _GrabTexture_TexelSize;
float _Radius;
half4 frag(v2f i) : COLOR
{
half4 sum = half4(0,0,0,0);
float radius = 1.41421356237 * _Radius;
#define GRABXYPIXEL(kernelx, kernely) tex2Dproj( _GrabTexture, UNITY_PROJ_COORD(float4(i.uvgrab.x + _GrabTexture_TexelSize.x * kernelx, i.uvgrab.y + _GrabTexture_TexelSize.y * kernely, i.uvgrab.z, i.uvgrab.w)))
sum += GRABXYPIXEL(0.0, 0.0);
int measurments = 1;
for (float range = 1.41421356237f; range <= radius * 1.41; range += 1.41421356237f)
{
sum += GRABXYPIXEL(range, 0);
sum += GRABXYPIXEL(-range, 0);
sum += GRABXYPIXEL(0, range);
sum += GRABXYPIXEL(0, -range);
measurments += 4;
}
return sum / measurments;
}
ENDCG
}
}
}
}
I modified this one a little. Added tint color and UI compatibility. Although while using on UI is possible, makes UI before it invisible.
// Based on cician's shader from https://forum.unity3d.com/threads/simple-optimized-blur-shader.185327/#post-1267642
Shader "Custom/MaskedUIBlur" {
Properties {
_Size ("Blur", Range(0, 30)) = 1
[HideInInspector] _MainTex ("Masking Texture", 2D) = "white" {}
_AdditiveColor ("Additive Tint color", Color) = (0, 0, 0, 0)
_MultiplyColor ("Multiply Tint color", Color) = (1, 1, 1, 1)
}
Category {
// We must be transparent, so other objects are drawn before this one.
Tags { "Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Opaque" }
SubShader
{
// Horizontal blur
GrabPass
{
"_HBlur"
}
/*
ZTest Off
Blend SrcAlpha OneMinusSrcAlpha
*/
Cull Off
Lighting Off
ZWrite Off
ZTest [unity_GUIZTestMode]
Blend SrcAlpha OneMinusSrcAlpha
Pass
{
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#pragma fragmentoption ARB_precision_hint_fastest
#include "UnityCG.cginc"
struct appdata_t {
float4 vertex : POSITION;
float2 texcoord : TEXCOORD0;
};
struct v2f {
float4 vertex : POSITION;
float4 uvgrab : TEXCOORD0;
float2 uvmain : TEXCOORD1;
};
sampler2D _MainTex;
float4 _MainTex_ST;
v2f vert (appdata_t v)
{
v2f o;
o.vertex = UnityObjectToClipPos(v.vertex);
#if UNITY_UV_STARTS_AT_TOP
float scale = -1.0;
#else
float scale = 1.0;
#endif
o.uvgrab.xy = (float2(o.vertex.x, o.vertex.y * scale) + o.vertex.w) * 0.5;
o.uvgrab.zw = o.vertex.zw;
o.uvmain = TRANSFORM_TEX(v.texcoord, _MainTex);
return o;
}
sampler2D _HBlur;
float4 _HBlur_TexelSize;
float _Size;
float4 _AdditiveColor;
float4 _MultiplyColor;
half4 frag( v2f i ) : COLOR
{
half4 sum = half4(0,0,0,0);
#define GRABPIXEL(weight,kernelx) tex2Dproj( _HBlur, UNITY_PROJ_COORD(float4(i.uvgrab.x + _HBlur_TexelSize.x * kernelx * _Size, i.uvgrab.y, i.uvgrab.z, i.uvgrab.w))) * weight
sum += GRABPIXEL(0.05, -4.0);
sum += GRABPIXEL(0.09, -3.0);
sum += GRABPIXEL(0.12, -2.0);
sum += GRABPIXEL(0.15, -1.0);
sum += GRABPIXEL(0.18, 0.0);
sum += GRABPIXEL(0.15, +1.0);
sum += GRABPIXEL(0.12, +2.0);
sum += GRABPIXEL(0.09, +3.0);
sum += GRABPIXEL(0.05, +4.0);
half4 result = half4(sum.r * _MultiplyColor.r + _AdditiveColor.r,
sum.g * _MultiplyColor.g + _AdditiveColor.g,
sum.b * _MultiplyColor.b + _AdditiveColor.b,
tex2D(_MainTex, i.uvmain).a);
return result;
}
ENDCG
}
// Vertical blur
GrabPass
{
"_VBlur"
}
Pass
{
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#pragma fragmentoption ARB_precision_hint_fastest
#include "UnityCG.cginc"
struct appdata_t {
float4 vertex : POSITION;
float2 texcoord: TEXCOORD0;
};
struct v2f {
float4 vertex : POSITION;
float4 uvgrab : TEXCOORD0;
float2 uvmain : TEXCOORD1;
};
sampler2D _MainTex;
float4 _MainTex_ST;
v2f vert (appdata_t v) {
v2f o;
o.vertex = UnityObjectToClipPos(v.vertex);
#if UNITY_UV_STARTS_AT_TOP
float scale = -1.0;
#else
float scale = 1.0;
#endif
o.uvgrab.xy = (float2(o.vertex.x, o.vertex.y * scale) + o.vertex.w) * 0.5;
o.uvgrab.zw = o.vertex.zw;
o.uvmain = TRANSFORM_TEX(v.texcoord, _MainTex);
return o;
}
sampler2D _VBlur;
float4 _VBlur_TexelSize;
float _Size;
float4 _AdditiveColor;
float4 _MultiplyColor;
half4 frag( v2f i ) : COLOR
{
half4 sum = half4(0,0,0,0);
#define GRABPIXEL(weight,kernely) tex2Dproj( _VBlur, UNITY_PROJ_COORD(float4(i.uvgrab.x, i.uvgrab.y + _VBlur_TexelSize.y * kernely * _Size, i.uvgrab.z, i.uvgrab.w))) * weight
sum += GRABPIXEL(0.05, -4.0);
sum += GRABPIXEL(0.09, -3.0);
sum += GRABPIXEL(0.12, -2.0);
sum += GRABPIXEL(0.15, -1.0);
sum += GRABPIXEL(0.18, 0.0);
sum += GRABPIXEL(0.15, +1.0);
sum += GRABPIXEL(0.12, +2.0);
sum += GRABPIXEL(0.09, +3.0);
sum += GRABPIXEL(0.05, +4.0);
half4 result = half4(sum.r * _MultiplyColor.r + _AdditiveColor.r,
sum.g * _MultiplyColor.g + _AdditiveColor.g,
sum.b * _MultiplyColor.b + _AdditiveColor.b,
tex2D(_MainTex, i.uvmain).a);
return result;
}
ENDCG
}
}
}
}