DAY 29
0

• Bloom效果

from wiki

## 開始撰寫吧!

``````Shader "Learning/Bloom" {
Properties {
_MainTex ("Base (RGB)", 2D) = "white" {}
_Bloom ("Bloom (RGB)", 2D) = "black" {}
_LuminanceThreshold ("Luminance Threshold", Float) = 0.5
_BlurSize ("Blur Size", Float) = 1.0
}
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 = UnityObjectToClipPos(v.vertex);

o.uv = v.texcoord;

return o;
}

// 降至灰階，分析明亮度
// wiki: https://en.wikipedia.org/wiki/Grayscale#Converting_color_to_grayscale
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 = UnityObjectToClipPos (v.vertex);
// 第一組紋理座標為原圖，第二組為Bloom
o.uv.xy = v.texcoord;
o.uv.zw = v.texcoord;

// 紋理座標是否顛倒
#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
// 各4個Pass處理這個效果
Pass {
CGPROGRAM
#pragma vertex vertExtractBright
#pragma fragment fragExtractBright

ENDCG
}

UsePass "Learning/Blur/GAUSSIAN_BLUR_VERTICAL"

UsePass "Learning/Blur/GAUSSIAN_BLUR_HORIZONTAL"

Pass {
CGPROGRAM
#pragma vertex vertBloom
#pragma fragment fragBloom

ENDCG
}
}
}
``````

1. Script
``````[RequireComponent(typeof(Camera))]
public class BloomCopy : MonoBehaviour
{

private Material material;

[Range(0, 4)]
public int iterations = 3;

[Range(0.2f, 3.0f)]

[Range(0.0f, 4.0f)]
public float luminanceThreshold = 0.6f;

void Start()
{
{
return;
}
else{
material.hideFlags = HideFlags.DontSave;
}
}

private void OnRenderImage(RenderTexture src, RenderTexture dest) {
if (material != null) {
material.SetFloat("_LuminanceThreshold", luminanceThreshold);

RenderTexture buffer0 = RenderTexture.GetTemporary(src.width, src.height, 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(src.width, src.height, 0);

// Render the vertical pass
Graphics.Blit(buffer0, buffer1, material, 1);

RenderTexture.ReleaseTemporary(buffer0);
buffer0 = buffer1;
buffer1 = RenderTexture.GetTemporary(src.width, src.height, 0);

// Render the horizontal pass
Graphics.Blit(buffer0, buffer1, material, 2);

RenderTexture.ReleaseTemporary(buffer0);
buffer0 = buffer1;
}

material.SetTexture ("_Bloom", buffer0);
Graphics.Blit (src, dest, material, 3);

RenderTexture.ReleaseTemporary(buffer0);
} else {
Graphics.Blit(src, dest);
}
}
}
``````