Shader "Custom/OutLine" {Properties {
_Color ("Main Color", Color) = (.5,.5,.5,1)
_OutlineColor ("Outline Color", Color) = (0,0,0,1)
//_Outline ("Outline width", Range (0.0, 0.03)) = .005
_Outline ("Outline width", Range (0.0, 0.5)) = .005
_MainTex ("Base (RGB)", 2D) = "white" { }
}
CGINCLUDE
#include "UnityCG.cginc"
struct appdata {
float4 vertex : POSITION;
float3 normal : NORMAL;
};
struct v2f {
float4 pos : POSITION;
float4 color : COLOR;
};
uniform float _Outline;
uniform float4 _OutlineColor;
v2f vert(appdata v) {
v2f o;
// 方法1
//o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
//float3 norm = mul ((float3x3)UNITY_MATRIX_IT_MV, v.normal);
// 应该是要用UNITY_MATRIX_P的逆转置矩阵去变换，这样为什么不用呢？
// 如果一个矩阵是正交矩阵，那么转置与逆相等，所以逆转置就等于原来的矩阵，UNITY_MATRIX_P == 正交矩阵？
// 在C#上打印了，Camera.main.projectionMatrix.inverse, Camera.main.projectionMatrix.transpose,不是相同的
// 目前理解：
// 不利用UNITY_MATRIX_P的逆转置变换法线，得到的法线可能会偏了，但是，现在法线偏了并不影响轮廓向外扩展
// 所以，并不在乎法线的方向是否正确。
//float2 offset = TransformViewToProjection(norm.xy); //float2 offset = mul((float2x2)UNITY_MATRIX_P, norm.xy);
//o.pos.xy += offset * o.pos.z * _Outline;
// 方法2
float4 viewPos = mul(UNITY_MATRIX_MV, v.vertex);
float3 viewNorm = mul ((float3x3)UNITY_MATRIX_IT_MV, v.normal);
float3 offset = normalize(viewNorm) * _Outline;
viewPos.xyz += offset;
o.pos = mul(UNITY_MATRIX_P, viewPos);
o.color = _OutlineColor;
return o;
}
ENDCG
SubShader {
Tags{ "RenderType"="Transparent" "Queue"="Transparent" }
/*
Pass {
ZWrite Off
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
half4 frag(v2f i) :COLOR {
return i.color;
}
ENDCG
}
*/
Pass {
//Blend SrcFactor DstFactor, SrcFactorA DstFactorA:
//BlendOp OpColor, OpAlpha
Blend SrcAlpha OneMinusSrcAlpha, Zero Zero
BlendOp Add, Add
//ZWrite On
CGPROGRAM
#pragma vertex vert2
#pragma fragment frag2
#include "UnityCG.cginc"
struct appdata_t {
float4 vertex : POSITION;
float2 texcoord : TEXCOORD0;
};
struct v2f2 {
float4 vertex : SV_POSITION;
half2 texcoord : TEXCOORD0;
};
sampler2D _MainTex;
float4 _MainTex_ST;
v2f2 vert2 (appdata_t v)
{
v2f2 o;
o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
o.texcoord = TRANSFORM_TEX(v.texcoord, _MainTex);
return o;
}
fixed4 frag2 (v2f2 i) : COLOR
{
fixed4 col = tex2D(_MainTex, i.texcoord);
return col;
//return fixed4(col.rgb, 0.1);
}
ENDCG
}
Pass {
Blend DstAlpha OneMinusDstAlpha
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
half4 frag(v2f i) :COLOR {
return i.color;
}
ENDCG
}
}
Fallback "Diffuse"
}
