1 Shader "Tut/Project/Billboard_1" {
2 Properties {
3 _MainTex ("Base (RGB)", 2D) = "white" {}
4 }
5 SubShader {
6 Tags { "Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent" }
7 pass{
8 Cull Off
9 ZTest Always
10 Blend SrcAlpha OneMinusSrcAlpha
11 CGPROGRAM
12 #pragma vertex vert
13 #pragma fragment frag
14 #include "UnityCG.cginc"
15 sampler2D _MainTex;
16 struct v2f {
17 float4 pos:SV_POSITION;
18 float2 texc:TEXCOORD0;
19 };
20 v2f vert(appdata_base v)
21 {
22 v2f o;
23 float4 ori=mul(UNITY_MATRIX_MV,float4(0,0,0,1));
24 float4 vt=v.vertex;
25 vt.y=vt.z;//这个平面是沿xz平面 展开的
26 vt.z=0;//所以只关心其平面上的信息
27
28 //通过加上Object Space的原点在ViewSpace的信息，保持其透视大小
29 vt.xyz+=ori.xyz;//result is vt.z==ori.z ,so the distance to camera keeped ,and screen size keeped
30 o.pos=mul(UNITY_MATRIX_P,vt);
31
32 o.texc=v.texcoord;
33 return o;
34 }
35 float4 frag(v2f i):COLOR
36 {
37 return tex2D(_MainTex,i.texc);
38 }
39 ENDCG
40 }//endpass
41 }
42 }
