UnityShader 学习笔记 24 屏幕后期之运动模糊

• Shader:

Shader "_MyShader/9_PostScreenEffect/4_MyMotionBlur"{

    Properties {

        _MainTex ("Base (RGB)", 2D) = "white" {}

            _BlurAmount ("Blur Amount", Float) = 1.0

    }

    SubShader {

        CGINCLUDE



        #include "UnityCG.cginc"



        sampler2D _MainTex;

        fixed _BlurAmount;



        struct v2f {

            float4 pos : SV_POSITION;

            half2 uv : TEXCOORD0;

        };



        v2f vert(appdata_img v) {

            v2f o;



            o.pos = mul(UNITY_MATRIX_MVP, v.vertex);



            o.uv = v.texcoord;



            return o;

        }



        fixed4 fragRGB (v2f i) : SV_Target {

            return fixed4(tex2D(_MainTex, i.uv).rgb, _BlurAmount);

        }



        half4 fragA (v2f i) : SV_Target {

            return tex2D(_MainTex, i.uv);

        }



        ENDCG



        ZTest Always Cull Off ZWrite Off



        Pass {

            Blend SrcAlpha OneMinusSrcAlpha

            ColorMask RGB



            CGPROGRAM



            #pragma vertex vert  

            #pragma fragment fragRGB  



            ENDCG

        }



        Pass {   

            Blend One Zero

            ColorMask A



            CGPROGRAM  



            #pragma vertex vert  

            #pragma fragment fragA



            ENDCG

        }

    }

    FallBack Off

}

• C#:

using UnityEngine;

using System.Collections;



public class MyMotionBlur : ScreenEffectBase {

    public Shader motionBlurShader;

    private Material motionBlurMaterial = null;



    public Material material {  

        get {

            motionBlurMaterial = CheckShaderAndCreateMaterial(motionBlurShader, motionBlurMaterial);

            return motionBlurMaterial;

        }  

    }



    [Range(0.0f, 0.9f)]

    public float blurAmount = 0.5f;



    private RenderTexture accumulationTexture;



    void OnDisable() {

        DestroyImmediate(accumulationTexture);

    }



    void OnRenderImage (RenderTexture src, RenderTexture dest) {

        if (material != null) {

            // Create the accumulation texture

            if (accumulationTexture == null || accumulationTexture.width != src.width || accumulationTexture.height != src.height) {

                DestroyImmediate(accumulationTexture);

                accumulationTexture = new RenderTexture(src.width, src.height, 0);

                accumulationTexture.hideFlags = HideFlags.HideAndDontSave;

                Graphics.Blit(src, accumulationTexture);

            }



            // We are accumulating motion over frames without clear/discard

            // by design, so silence any performance warnings from Unity

            accumulationTexture.MarkRestoreExpected();



            material.SetFloat("_BlurAmount", 1.0f - blurAmount);



            Graphics.Blit (src, accumulationTexture, material);

            Graphics.Blit (accumulationTexture, dest);

        } else {

            Graphics.Blit(src, dest);

        }

    }

}