读了《Unity Shader入门精要》后，下了ShadowGun 的demo来学习下。

说明

标记为转载的原因是因为不知道如何去找准确的顺序去看Shadow Gun，所以学习的顺序是按照Candy Cat的学习顺序看的。https://blog.csdn.net/candycat1992

冒烟效果

之前冒烟的效果都是用粒子做的，但是消耗很大，而Shadow Gun里的冒烟使用了扭曲的mesh加shader做的，性能会好很多。

源码

Shader "CrazyShader/Fire"{Properties{_MainTex ("Base layer (RGB)", 2D) = "white" {}_DetailTex ("2nd layer (RGB)", 2D) = "white" {}_ScrollX ("Base layer Scroll speed X", Float) = -2_ScrollY ("Base layer Scroll speed Y", Float) = -0.5_Scroll2X ("2nd layer Scroll speed X", Float) = 0.0_Scroll2Y ("2nd layer Scroll speed Y", Float) = -0.3_SineAmplX ("Base layer sine amplitude X",Float) = 0.005 _SineAmplY ("Base layer sine amplitude Y",Float) = 0.005_SineFreqX ("Base layer sine freq X",Float) = 250 _SineFreqY ("Base layer sine freq Y",Float) = 250_SineAmplX2 ("2nd layer sine amplitude X",Float) = 0.005 _SineAmplY2 ("2nd layer sine amplitude Y",Float) = 0.0_SineFreqX2 ("2nd layer sine freq X",Float) = 200 _SineFreqY2 ("2nd layer sine freq Y",Float) = 10_Color("Color", Color) = (1,1,1,1)_MMultiplier ("Layer Multiplier", Float) = 2.0}SubShader{Tags { "Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent" }Blend SrcAlpha OneMinusSrcAlphaCull OffLighting OffZWrite OffLOD 100CGINCLUDE#include "UnityCG.cginc"sampler2D _MainTex;sampler2D _DetailTex;float4 _MainTex_ST;float4 _DetailTex_ST;float4 _Color;float _ScrollX;float _ScrollY;float _Scroll2X;float _Scroll2Y;float _SineAmplX;float _SineAmplY;float _SineFreqX;float _SineFreqY;float _SineAmplX2;float _SineAmplY2;float _SineFreqX2;float _SineFreqY2;float _MMultiplier;struct v2f{float4 pos : SV_POSITION;float4 uv : TEXCOORD0;fixed4 color : TEXCOORD1; };v2f vert(appdata_full v){v2f o;o.pos = UnityObjectToClipPos(v.vertex);o.uv.xy = TRANSFORM_TEX(v.texcoord.xy, _MainTex) + frac(float2(_ScrollX, _ScrollY) * _Time);o.uv.zw = TRANSFORM_TEX(v.texcoord.xy, _DetailTex) + frac(float2(_Scroll2X, _Scroll2Y) * _Time);o.uv.x += sin(_Time * _SineFreqX) * _SineAmplX;o.uv.y += sin(_Time * _SineFreqY) * _SineAmplY;o.uv.z += sin(_Time * _SineFreqX2) * _SineAmplX2;o.uv.w += sin(_Time * _SineFreqY2) * _SineAmplY2;o.color = _MMultiplier * _Color * v.color;return o;}ENDCGPass{CGPROGRAM#pragma vertex vert#pragma fragment fragfixed4 frag(v2f i) : COLOR{fixed4 o;fixed4 tex = tex2D(_MainTex, i.uv.xy);fixed4 tex2 = tex2D(_DetailTex, i.uv.zw);o = tex * tex2 * i.color;return o;}ENDCG}}}

备注

1.如果不使用两张图片叠加的话，就会显得太亮，没有浓烟的感觉

2.SG里面的参数，不知道是怎么调出来的，按照原始Shader里的参数，图像会因为正弦函数导致画面呈现往复效果

3.关于Tag，一般含有Alpha的Shader的Tag大多都是这样的

Tags { "Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent" }

问题:

这里有些问题，烦请路过的大神们给个解答

1.原代码中用了CGINCLUDE，但是不知道这个宏的意思是什么，能说明下吗？

2.效果中的火焰除去贴图是有颜色的，应该是v.color自带的，那v.color是怎么设置的呢？