bloom效果

bloom是模拟真实相机，较亮的部分扩散到周围，造成一种朦胧的感觉。

• 先用第一个pass筛选出原图中较亮的部分
• 然后在第二和第三个pass中把较亮的图像进行高斯模糊
• 最后在第四个pass中把模糊后的亮部和原图进行混合得到bloom效果

  
void OnRenderImage(RenderTexture src, RenderTexture dest)
{
    if (material != null)
    {
        material.SetFloat("_LuminanceThreshold", luminanceThreshold);
        int rtW = src.width / downSample;
        int rtH = src.height / downSample;
        RenderTexture buffer0 = RenderTexture.GetTemporary(rtW, rtH, 0);
        buffer0.filterMode = FilterMode.Bilinear;
        Graphics.Blit(src, buffer0, material, 0);
        for (int i = 0; i < iterations; i++)
        {
            material.SetFloat("_BlurSize", 1.0f + i * blurSpread);
            RenderTexture buffer1 = RenderTexture.GetTemporary(rtW, rtH, 0);
            Graphics.Blit(buffer0, buffer1, material, 1);
            RenderTexture.ReleaseTemporary(buffer0);
            buffer0 = buffer1;
        }
        material.SetTexture("_Bloom", buffer0);
        Graphics.Blit(src, dest, material, 3);
        RenderTexture.ReleaseTemporary(buffer0);
    }
    else
    {
        Graphics.Blit(src, dest);
    }
}

  
Shader "UnityShaderLearning/Bloom"
{
	Properties
	{
		_MainTex ("Base (RGB)", 2D) = "white" {}
		_Bloom ("Bloom (RGB)", 2D) = "black" {}
		_LuminanceThreshold("Luminance Threshold", Float) = 0.5
		_BlurSize("Blur Size", Float) = 1.0
	}
	SubShader
	{
		CGINCLUDE
		#include "UnityCG.cginc"
		sampler2D _MainTex;
		half4 _MainTex_TexelSize;
		sampler2D _Bloom;
		float _LuminanceThreshold;
		float _BlurSize;

		struct v2f
		{
			float4 pos : SV_POSITION;
			half2 uv : TEXCOORD0;
		};

		v2f vertExtractBright(appdata_img v)
		{
			v2f o;
			o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
			o.uv = v.texcoord;
			return o;
		}

		fixed luminance(fixed4 color)
		{
			return 0.2125 * color.r + 0.7154 * color.g + 0.0721 * color.b;
		}

		fixed4 fragExtractBright(v2f i) : SV_Target
		{
			fixed4 c = tex2D(_MainTex, i.uv);
			fixed val = clamp(luminance(c) - _LuminanceThreshold, 0.0, 1.0);
			return c * val;
		}

		struct v2fBloom
		{
			float4 pos : SV_POSITION;
			half4 uv : TEXCOORD0;
		};

		v2fBloom vertBloom(appdata_img v)
		{
			v2fBloom o;
			o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
			o.uv.xy = v.texcoord;
			o.uv.zw = v.texcoord;
			#if UNITY_UV_STARTS_AT_TOP
			if (_MainTex_TexelSize.y < 0.0)
				o.uv.w = 1.0 - o.uv.w;
			#endif
			return o;
		}

		fixed4 fragBloom(v2fBloom i) : SV_Target
		{
			return tex2D(_MainTex, i.uv.xy) * tex2D(_Bloom, i.uv.zw);
		}
		ENDCG
		ZTest Always Cull Off ZWrite Off
		Pass
		{
			CGPROGRAM
			#pragma vertex vertBloom
			#pragma fragment fragBloom
			ENDCG
		}

		UsePass "UnityShaderLearning/GaussianBlurShader/GAUSSIAN_BLUR_VERTICAL"

		UsePass "UnityShaderLearning/GaussianBlurShader/GAUSSIAN_BLUR_HORIZONTAL"

		Pass
		{
			CGPROGRAM
			#pragma vertex vertBloom
			#pragma fragment fragBloom
			ENDCG
		}
	}
	Fallback Off
}

赏

谢谢你请我吃糖果