哈喽~！大家好，你们敬爱的熊猫老师有写了一篇教程，今天咱们不讲图形效果，直击算法计算。
首先我们来探讨一个问题，大家在做shader的时候，有些效果其实并不想每帧都计算，但是又不想在模型上外挂C#脚本，甚至技术大佬更不想让大伙用粒子系统，怎么办？？？有两个办法：
1：臣妾做不到，准备 跑路。。。
2：还有一个传说方案，时间 离散处理 （当然，算法需要自己去写，将时间间隔化整数倍），听起来是不是很高大上，接下来一步一步的来看我如何实现分析
首先请看效果图，左边是ASE效果，右边是手撸代码，两边效果一样，但是性能大有不同
如图所示：
ASE的链接效果图我也贴图出来：（学技术就应该最简单的效果去学习最牛逼的技术）
ASE的原型代码：（不要学，垃圾代码）
// Made with Amplify Shader Editor
// Available at the Unity Asset Store - http://u3d.as/y3X
Shader "TA_Alpha"
{
Properties
{
[HDR]_MainTex("_MainTex", 2D) = "white" {}
[HDR]_Tint("Tint", Color) = (0.9103774,1,0.9645071,0)
_Alpha("Alpha", 2D) = "white" {}
_Speed("Speed", Float) = 0.1
[HideInInspector] _texcoord( "", 2D ) = "white" {}
[HideInInspector] __dirty( "", Int ) = 1
}
SubShader
{
Tags{ "RenderType" = "Transparent" "Queue" = "Transparent+0" "IgnoreProjector" = "True" "IsEmissive" = "true" }
Cull Back
CGINCLUDE
#include "UnityShaderVariables.cginc"
#include "UnityPBSLighting.cginc"
#include "Lighting.cginc"
#pragma target 3.0
struct Input
{
float2 uv_texcoord;
};
uniform float _Speed;
uniform sampler2D _MainTex;
uniform float4 _MainTex_ST;
uniform float4 _Tint;
uniform sampler2D _Alpha;
uniform float4 _Alpha_ST;
float3 RotateAroundAxis( float3 center, float3 original, float3 u, float angle )
{
original -= center;
float C = cos( angle );
float S = sin( angle );
float t = 1 - C;
float m00 = t * u.x * u.x + C;
float m01 = t* u.x * u.y - S * u.z;
float m02 = t * u.x * u.z + S * u.y;
float m10 = t * u.x * u.y + S * u.z;
float m11 = t * u.y * u.y + C;
float m12 = t * u.y * u.z - S * u.x;
float m20 = t * u.x * u.z - S * u.y;
float m21 = t * u.y * u.z + S * u.x;
float m22 = t * u.z * u.z + C;
float3x3 finalMatrix = float3x3( m00, m01, m02, m10, m11, m12, m20, m21, m22 );
return mul( finalMatrix, original ) + center;
}
void vertexDataFunc( inout appdata_full v, out Input o )
{
UNITY_INITIALIZE_OUTPUT( Input, o );
float mulTime17 = _Time.y * _Speed;
float3 ase_vertex3Pos = v.vertex.xyz;
float3 rotatedValue13 = RotateAroundAxis( float3( 0,0,0 ), ase_vertex3Pos, float3(0,1,0), mulTime17 );
v.vertex.xyz = rotatedValue13;
v.vertex.w = 1;
}
void surf( Input i , inout SurfaceOutputStandard o )
{
float2 uv_MainTex = i.uv_texcoord * _MainTex_ST.xy + _MainTex_ST.zw;
o.Emission = ( tex2D( _MainTex, uv_MainTex ) * _Tint ).rgb;
float2 uv_Alpha = i.uv_texcoord * _Alpha_ST.xy + _Alpha_ST.zw;
o.Alpha = tex2D( _Alpha, uv_Alpha ).r;
}
ENDCG
CGPROGRAM
#pragma surface surf Standard alpha:fade keepalpha fullforwardshadows vertex:vertexDataFunc
ENDCG
Pass
{
Name "ShadowCaster"
Tags{ "LightMode" = "ShadowCaster" }
ZWrite On
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#pragma target 3.0
#pragma multi_compile_shadowcaster
#pragma multi_compile UNITY_PASS_SHADOWCASTER
#pragma skip_variants FOG_LINEAR FOG_EXP FOG_EXP2
#include "HLSLSupport.cginc"
#if ( SHADER_API_D3D11 || SHADER_API_GLCORE || SHADER_API_GLES || SHADER_API_GLES3 || SHADER_API_METAL || SHADER_API_VULKAN )
#define CAN_SKIP_VPOS
#endif
#include "UnityCG.cginc"
#include "Lighting.cginc"
#include "UnityPBSLighting.cginc"
sampler3D _DitherMaskLOD;
struct v2f
{
V2F_SHADOW_CASTER;
float2 customPack1 : TEXCOORD1;
float3 worldPos : TEXCOORD2;
UNITY_VERTEX_INPUT_INSTANCE_ID
UNITY_VERTEX_OUTPUT_STEREO
};
v2f vert( appdata_full v )
{
v2f o;
UNITY_SETUP_INSTANCE_ID( v );
UNITY_INITIALIZE_OUTPUT( v2f, o );
UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO( o );
UNITY_TRANSFER_INSTANCE_ID( v, o );
Input customInputData;
vertexDataFunc( v, customInputData );
float3 worldPos = mul( unity_ObjectToWorld, v.vertex ).xyz;
half3 worldNormal = UnityObjectToWorldNormal( v.normal );
o.customPack1.xy = customInputData.uv_texcoord;
o.customPack1.xy = v.texcoord;
o.worldPos = worldPos;
TRANSFER_SHADOW_CASTER_NORMALOFFSET( o )
return o;
}
half4 frag( v2f IN
#if !defined( CAN_SKIP_VPOS )
, UNITY_VPOS_TYPE vpos : VPOS
#endif
) : SV_Target
{
UNITY_SETUP_INSTANCE_ID( IN );
Input surfIN;
UNITY_INITIALIZE_OUTPUT( Input, surfIN );
surfIN.uv_texcoord = IN.customPack1.xy;
float3 worldPos = IN.worldPos;
half3 worldViewDir = normalize( UnityWorldSpaceViewDir( worldPos ) );
SurfaceOutputStandard o;
UNITY_INITIALIZE_OUTPUT( SurfaceOutputStandard, o )
surf( surfIN, o );
#if defined( CAN_SKIP_VPOS )
float2 vpos = IN.pos;
#endif
half alphaRef = tex3D( _DitherMaskLOD, float3( vpos.xy * 0.25, o.Alpha * 0.9375 ) ).a;
clip( alphaRef - 0.01 );
SHADOW_CASTER_FRAGMENT( IN )
}
ENDCG
}
}
Fallback "Diffuse"
CustomEditor "ASEMaterialInspector"
}
/*ASEBEGIN
Version=18800
406;129;1920;977;1457.315;529.5779;1.3;True;True
Node;AmplifyShaderEditor.CommentaryNode;19;-959.0353,121.038;Inherit;False;890;506;整体顶点动画 ;5;17;14;13;12;18;;1,1,1,1;0;0
Node;AmplifyShaderEditor.RangedFloatNode;14;-909.0353,304.9381;Inherit;False;Property;_Speed;Speed;3;0;Create;True;0;0;0;False;0;False;0.1;0.1;0;0;0;1;FLOAT;0
Node;AmplifyShaderEditor.SimpleTimeNode;17;-734.8353,347.8381;Inherit;False;1;0;FLOAT;1;False;1;FLOAT;0
Node;AmplifyShaderEditor.Vector3Node;12;-738.7358,193.138;Inherit;False;Constant;_RotationDirection;RotationDirection;2;0;Create;True;0;0;0;False;0;False;0,1,0;0,0,0;0;4;FLOAT3;0;FLOAT;1;FLOAT;2;FLOAT;3
Node;AmplifyShaderEditor.PosVertexDataNode;18;-740.0353,444.038;Inherit;False;0;0;5;FLOAT3;0;FLOAT;1;FLOAT;2;FLOAT;3;FLOAT;4
Node;AmplifyShaderEditor.SamplerNode;2;-678.0999,-402.3;Inherit;True;Property;_MainTex;_MainTex;0;1;[HDR];Create;True;0;0;0;False;0;False;-1;None;None;True;0;False;white;Auto;False;Object;-1;Auto;Texture2D;8;0;SAMPLER2D;;False;1;FLOAT2;0,0;False;2;FLOAT;0;False;3;FLOAT2;0,0;False;4;FLOAT2;0,0;False;5;FLOAT;1;False;6;FLOAT;0;False;7;SAMPLERSTATE;;False;5;COLOR;0;FLOAT;1;FLOAT;2;FLOAT;3;FLOAT;4
Node;AmplifyShaderEditor.ColorNode;8;-687.8998,-206.6;Inherit;False;Property;_Tint;Tint;1;1;[HDR];Create;True;0;0;0;False;0;False;0.9103774,1,0.9645071,0;0,0,0,0;True;0;5;COLOR;0;FLOAT;1;FLOAT;2;FLOAT;3;FLOAT;4
Node;AmplifyShaderEditor.SimpleMultiplyOpNode;4;-322.1,-254.5001;Inherit;False;2;2;0;COLOR;0,0,0,0;False;1;COLOR;0,0,0,0;False;1;COLOR;0
Node;AmplifyShaderEditor.SamplerNode;20;-465.7349,-133.162;Inherit;True;Property;_Alpha;Alpha;2;0;Create;True;0;0;0;False;0;False;-1;None;None;True;0;False;white;Auto;False;Object;-1;Auto;Texture2D;8;0;SAMPLER2D;;False;1;FLOAT2;0,0;False;2;FLOAT;0;False;3;FLOAT2;0,0;False;4;FLOAT2;0,0;False;5;FLOAT;1;False;6;FLOAT;0;False;7;SAMPLERSTATE;;False;5;COLOR;0;FLOAT;1;FLOAT;2;FLOAT;3;FLOAT;4
Node;AmplifyShaderEditor.RotateAboutAxisNode;13;-389.0353,169.738;Inherit;False;False;4;0;FLOAT3;0,0,0;False;1;FLOAT;0;False;2;FLOAT3;0,0,0;False;3;FLOAT3;0,0,0;False;1;FLOAT3;0
Node;AmplifyShaderEditor.StandardSurfaceOutputNode;9;365,-218;Float;False;True;-1;2;ASEMaterialInspector;0;0;Standard;TA_Alpha;False;False;False;False;False;False;False;False;False;False;False;False;False;False;True;False;False;False;False;False;False;Back;0;False;-1;0;False;-1;False;0;False;-1;0;False;-1;False;0;Transparent;0.5;True;True;0;False;Transparent;;Transparent;All;14;all;True;True;True;True;0;False;-1;False;0;False;-1;255;False;-1;255;False;-1;0;False;-1;0;False;-1;0;False;-1;0;False;-1;0;False;-1;0;False;-1;0;False;-1;0;False;-1;False;2;15;10;25;False;0.5;True;2;5;False;-1;10;False;-1;0;0;False;-1;0;False;-1;0;False;-1;0;False;-1;0;False;0;0,0,0,0;VertexOffset;True;False;Cylindrical;False;Absolute;0;;-1;-1;-1;-1;0;False;0;0;False;-1;-1;0;False;-1;0;0;0;False;0.1;False;-1;0;False;-1;False;16;0;FLOAT3;0,0,0;False;1;FLOAT3;0,0,0;False;2;FLOAT3;0,0,0;False;3;FLOAT;0;False;4;FLOAT;0;False;5;FLOAT;0;False;6;FLOAT3;0,0,0;False;7;FLOAT3;0,0,0;False;8;FLOAT;0;False;9;FLOAT;0;False;10;FLOAT;0;False;13;FLOAT3;0,0,0;False;11;FLOAT3;0,0,0;False;12;FLOAT3;0,0,0;False;14;FLOAT4;0,0,0,0;False;15;FLOAT3;0,0,0;False;0
WireConnection;17;0;14;0
WireConnection;4;0;2;0
WireConnection;4;1;8;0
WireConnection;13;0;12;0
WireConnection;13;1;17;0
WireConnection;13;3;18;0
WireConnection;9;2;4;0
WireConnection;9;9;20;1
WireConnection;9;11;13;0
ASEEND*/
//CHKSM=2F22B8227D330DA8D379CA30A1A6A8B71E58CAD2我自己针对ASE脚本重写（ASE我是用的surface shader）
我自己手撸一个代码如下：
Shader "Optimized/ObjectRotation"
{
Properties
{
[HDR] _Color("Color", Color) = (1,1,1,0)
_MainTex ("Texture", 2D) = "white" {}
_Alpha ("Alpha", 2D) = "white" {}
_RotationSpeed ("Rotation Speed", Float) = 1.0
// 保留时间离散化功能，这是降低计算频率的核心
_FrameInterval ("Frame Interval", Float) = 0.05
}
SubShader
{
Tags {
"RenderType"="Transparent"
"Queue" = "Transparent"
"IgnoreProjector" = "True"
}
LOD 100
// 重要：保持单Pass，这是合批的前提
Blend SrcAlpha OneMinusSrcAlpha
ZWrite Off
Cull Back // 明确指定剔除，避免不必要的片元计算
Pass
{
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
// 添加此指令以支持动态合批（如果条件满足）
#pragma multi_compile_fog
#include "UnityCG.cginc"
struct appdata
{
float4 vertex : POSITION;
float2 uv : TEXCOORD0;
};
struct v2f
{
float2 uv : TEXCOORD0;
float4 vertex : SV_POSITION;
UNITY_FOG_COORDS(1) // 雾效坐标
};
// 精度优化：纹理和颜色通常使用 half 或 fixed 即可
sampler2D _MainTex;
half4 _MainTex_ST; // ST变换使用half精度
sampler2D _Alpha;
half4 _Alpha_ST;
half4 _Color;
half _RotationSpeed;
half _FrameInterval;
// 优化函数：获取离散化时间
half GetDiscreteTime(half currentTime, half interval)
{
return floor(currentTime / interval) * interval;
}
v2f vert (appdata v)
{
v2f o;
// 1. 时间离散化计算
half discreteTime = GetDiscreteTime(_Time.y, _FrameInterval);
half angle = discreteTime * _RotationSpeed;
// 2. 优化旋转计算：假设绕Y轴旋转，直接计算旋转后的坐标，避免完整矩阵
half s, c;
sincos(angle, s, c); // 使用sincos指令同时计算正弦和余弦，比分别调用sin/cos更高效
float3 rotatedVertex = v.vertex.xyz;
// 简化后的绕Y轴旋转公式
rotatedVertex.xz = half2(
c * rotatedVertex.x + s * rotatedVertex.z,
c * rotatedVertex.z - s * rotatedVertex.x
);
o.vertex = UnityObjectToClipPos(rotatedVertex);
o.uv = TRANSFORM_TEX(v.uv, _MainTex);
UNITY_TRANSFER_FOG(o, o.vertex);
return o;
}
fixed4 frag (v2f i) : SV_Target
{
// 片元着色器保持简单：纹理采样和混合
half4 col = tex2D(_MainTex, i.uv) * _Color;
half alpha = tex2D(_Alpha, i.uv).r;
col.a = alpha;
UNITY_APPLY_FOG(i.fogCoord, col); // 应用雾效
return col;
}
ENDCG
}
}
// 可添加Fallback
Fallback "Transparent/VertexLit"
}时间离散算法：
// 优化函数：获取离散化时间
half GetDiscreteTime(half currentTime, half interval)
{
return floor(currentTime / interval) * interval;
}我们在做运动速度计算的时候，把time替换成算法即可
如下：
// 1. 时间离散化计算
half discreteTime = GetDiscreteTime(_Time.y, _FrameInterval);
half angle = discreteTime * _RotationSpeed;接下来我们来看看性能上的区别：
在移动端做shader的时候，一定要注意性能这块