先上效果。
制作原理：模糊的部分是用UITexture，前面是一个UISprite。用主摄像机渲染出一张纹理，把这张纹理模糊处理，把这张纹理赋值给UITexture。
脚本代码
using UnityEngine;
using System.Collections; [RequireComponent(typeof(UITexture))]
public class BlurTextureMaker : MonoBehaviour { public int iterations = 3; public float blurSpread = 0.6f; public Shader blurShader = null; static Material m_Material = null; public Camera camera; private UITexture mTexture; private RenderTexture mRT;
protected Material material
{
get
{
if (m_Material == null)
{
m_Material = new Material(blurShader);
m_Material.hideFlags = HideFlags.DontSave;
}
return m_Material;
}
} protected void Awake()
{
mTexture = GetComponent<UITexture>();
} protected void Start()
{
// Disable if we don't support image effects
if (!SystemInfo.supportsImageEffects)
{
enabled = false;
return;
}
// Disable if the shader can't run on the users graphics card
if (!blurShader || !material.shader.isSupported)
{
enabled = false;
return;
} int rtWidth = (int)(NGUITools.screenSize.x / 4);
int rtHeight = (int)(NGUITools.screenSize.y / 4); mRT = RenderTexture.GetTemporary(rtWidth, rtHeight, 0, RenderTextureFormat.Default); mTexture.mainTexture = Generate();
} protected void OnDestroy()
{
if (null != mRT)
{
RenderTexture.ReleaseTemporary(mRT);
}
} // Performs one blur iteration.
public void FourTapCone(RenderTexture source, RenderTexture dest, int iteration)
{
float off = 0.5f + iteration * blurSpread;
Graphics.BlitMultiTap(source, dest, material,
new Vector2(-off, -off),
new Vector2(-off, off),
new Vector2(off, off),
new Vector2(off, -off)
);
} // Downsamples the texture to a quarter resolution.
private void DownSample4x(RenderTexture source, RenderTexture dest)
{
float off = 1.0f;
Graphics.BlitMultiTap(source, dest, material,
new Vector2(-off, -off),
new Vector2(-off, off),
new Vector2(off, off),
new Vector2(off, -off)
);
} // Called by the camera to apply the image effect
void RenderImage(RenderTexture source, RenderTexture destination)
{
int rtW = source.width / 4;
int rtH = source.height / 4;
RenderTexture buffer = RenderTexture.GetTemporary(rtW, rtH, 0); // Copy source to the 4x4 smaller texture.
DownSample4x(source, buffer); // Blur the small texture
for (int i = 0; i < iterations; i++)
{
RenderTexture buffer2 = RenderTexture.GetTemporary(rtW, rtH, 0);
FourTapCone(buffer, buffer2, i);
RenderTexture.ReleaseTemporary(buffer);
buffer = buffer2;
}
Graphics.Blit(buffer, destination); RenderTexture.ReleaseTemporary(buffer);
} public RenderTexture Generate()
{
int rtWidth = (int) (NGUITools.screenSize.x/4);
int rtHeight = (int) (NGUITools.screenSize.y/4); var tex = RenderTexture.GetTemporary(rtWidth, rtHeight, 0, RenderTextureFormat.Default); camera.targetTexture = tex;
camera.Render();
camera.targetTexture = null; RenderImage(tex, mRT); RenderTexture.ReleaseTemporary(tex); return mRT;
} [ContextMenu("Sample")]
public void Sample()
{
var tex = GetComponent<UITexture>();
tex.mainTexture = Generate(); }
}
//Shader代码
Shader "Hidden/BlurEffectConeTap" {
Properties { _MainTex ("", any) = "" {} }
SubShader {
Pass {
ZTest Always Cull Off ZWrite Off Fog { Mode Off }
SetTexture [_MainTex] {constantColor (0,0,0,0.25) combine texture * constant alpha}
SetTexture [_MainTex] {constantColor (0,0,0,0.25) combine texture * constant + previous}
SetTexture [_MainTex] {constantColor (0,0,0,0.25) combine texture * constant + previous}
SetTexture [_MainTex] {constantColor (0,0,0,0.25) combine texture * constant + previous}
}
}
CGINCLUDE
#include "UnityCG.cginc"
struct v2f {
float4 pos : SV_POSITION;
half2 uv : TEXCOORD0;
half2 taps[4] : TEXCOORD1;
};
sampler2D _MainTex;
half4 _MainTex_TexelSize;
half4 _BlurOffsets;
v2f vert( appdata_img v ) {
v2f o;
o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
o.uv = v.texcoord - _BlurOffsets.xy * _MainTex_TexelSize.xy; // hack, see BlurEffect.cs for the reason for this. let's make a new blur effect soon
o.taps[0] = o.uv + _MainTex_TexelSize * _BlurOffsets.xy;
o.taps[1] = o.uv - _MainTex_TexelSize * _BlurOffsets.xy;
o.taps[2] = o.uv + _MainTex_TexelSize * _BlurOffsets.xy * half2(1,-1);
o.taps[3] = o.uv - _MainTex_TexelSize * _BlurOffsets.xy * half2(1,-1);
return o;
}
half4 frag(v2f i) : SV_Target {
half4 color = tex2D(_MainTex, i.taps[0]);
color += tex2D(_MainTex, i.taps[1]);
color += tex2D(_MainTex, i.taps[2]);
color += tex2D(_MainTex, i.taps[3]);
return color * 0.25;
}
ENDCG
SubShader {
Pass {
ZTest Always Cull Off ZWrite Off
Fog { Mode off }
CGPROGRAM
#pragma fragmentoption ARB_precision_hint_fastest
#pragma vertex vert
#pragma fragment frag
ENDCG
}
}
Fallback off
}