Shader实现物体淡入淡出
Unity 3D教程：
1 设置淡入的起始距离和结束距离
2 在vertex阶段计算物体顶点与相机的距离
3 根据距离计算alpha
代码撸起：
// Upgrade NOTE: replaced 'mul(UNITY_MATRIX_MVP,*)' with 'UnityObjectToClipPos(*)'
Shader "Custom/Fade"
{
Properties
{
_MainTex("Texture", 2D) = "white" { }
_FadeDistanceNear("Near fadeout dist (View Space)", float) = 35
_FadeDistanceFar("Far fadeout dist (View Space)", float) = 40
}
SubShader
{
Tags{ "Queue" = "Transparent" "RenderType" = "Transparent" }
ZWrite On
Blend SrcAlpha OneMinusSrcAlpha
pass
{
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "UnityCG.cginc"
sampler2D _MainTex;
float4 _MainTex_ST;
struct v2f
{
float4 pos : SV_POSITION;
float2 uv : TEXCOORD0;
float fade : TEXCOORD1;
};
float _FadeDistanceNear;
float _FadeDistanceFar;
v2f vert(appdata_base v)
{
v2f o;
o.pos = UnityObjectToClipPos(v.vertex);
o.uv = TRANSFORM_TEX(v.texcoord,_MainTex);
//相机坐标系的物体坐标
float3 posView = mul(UNITY_MATRIX_MV,v.vertex).xyz;
//计算与相机距离
float dis = length(posView);
//计算fade
o.fade = 1 - saturate((dis - _FadeDistanceNear) / (_FadeDistanceFar - _FadeDistanceNear));
return o;
}
float4 frag(v2f i) : COLOR
{
float4 texCol = tex2D(_MainTex,i.uv);
float4 outp = texCol;
//fade作为alpha
return float4(outp.rgb,i.fade);
}
ENDCG
}
}
}