Unity Shader Example 2 (流光与模拟光照)

Shader "Example2"

{

Properties {

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

_Color ("Color", Color) = (1, 1, 1, 1)

_MatCap ("Mat (RGB)", 2D) = "white" {}

_Strongth ("Strongth", Range(0, 2)) = 1

_Rotate ("Rotate", float) = 0

_LightTex ("Light Texture(A)", 2D) = "black" {}

_MaskTex ("Mask Texture(A)", 2D) = "black" {}

_Brightness ("Brightness", Range(0, 5)) = 1

_uSpeed ("U Speed", float) = 0

_vSpeed ("V Speed", float) = 0

}

SubShader {

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

LOD 200

Pass {

CGPROGRAM

#pragma vertex vert

#pragma fragment frag

#include "UnityCG.cginc"

sampler2D _MainTex;

sampler2D _MatCap;

float _Strongth;

float _Rotate;

float4 _Color;

float4 _MainTex_ST;

uniform float4 _TimeEditor;

sampler2D _LightTex;

sampler2D _MaskTex;

float4 _LightTex_ST;

float _uSpeed;

float _vSpeed;

float _Brightness;

struct v2f {

float4 pos : SV_POSITION;

float2 uv : TEXCOORD0;

float2 cap : TEXCOORD1;

float2 light : TEXCOORD2;

};

float2 rotate2d (in float2 v, in float a) {

float sinA = sin(a);

float cosA = cos(a);

// 就是旋转矩阵

return float2(v.x * cosA - v.y * sinA, v.y * cosA + v.x * sinA);

}

float2x2 rotmatrix (in float a) {

float sinA = sin(a);

float cosA = cos(a);

return float4(cosA, sinA, -sinA, cosA);

}

v2f vert (appdata_base v)

{

v2f o;

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

o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);

half2 capCoord;

/ Matrices in unity are column major

// 这里就是把v.normal变换到view空间

//capCoord.x = dot(UNITY_MATRIX_IT_MV[0].xyz, v.normal);

//capCoord.y = dot(UNITY_MATRIX_IT_MV[1].xyz, v.normal);

// 这样是同上面的一样的结果

capCoord = mul(UNITY_MATRIX_IT_MV, v.normal).xy;

// 这个是的做法就相当于把v.normal 乘上了一个_Object2World的逆转置矩阵

//capCoord = mul(v.normal, _World2Object).xy;

// 如果是v.normal是单位向量，那么，dot的结果的区间就是[-1, 1]

// 这里就是把[-1, 1] 变换到[0, 1]

o.cap = capCoord * 0.5 + 0.5;

//o.cap = mul(capCoord - float2(0.5, 0.5), rotmatrix(_Rotate)) + float2(0.5, 0.5);

//o.cap = mul( rotmatrix(_Rotate), o.cap).xy;

// 先把UV变换到[-0.5, 0.5], 再旋转，旋转完之后，再变换到[0, 1]

// 这样做的效果才是正确的，画图就知道了

o.cap = (o.cap + 0.5) - 1;

o.cap = rotate2d(o.cap, _Rotate);

o.cap = o.cap + 0.5;

o.light = TRANSFORM_TEX(v.texcoord, _LightTex);// * uvSpeed(_uSpeed, _vSpeed);

float4 moveUv = _Time + _TimeEditor;

o.light = (o.light + moveUv.g * float2(_uSpeed, _vSpeed));

return o;

}

fixed4 frag (v2f i) : COLOR

{

fixed4 tex = tex2D(_MainTex, i.uv);

fixed4 mc = tex2D(_MatCap, i.cap);

fixed4 lightC = tex2D(_LightTex, i.light) * _Brightness;

fixed4 mask = tex2D(_MaskTex, i.uv);

// ((mc * 2.0) - 1.0)的意思就是把mc从区间[0, 1]变换到[-1, 1]

fixed4 c = (tex + (((mc * 2.0) - 1.0) * _Color) * _Strongth);

c.rgb += lightC.rgb * mask.rgb;

return c;

}

ENDCG

}

}

}