Shader教程：顶点动画
发表于2018-03-29
顶点动画是Shader实现动画的方式之一，而顶点动画的实现原理就是在顶点着色器中对模型的顶点进行偏移，再将偏移后的顶点位置输出到片元着色器中。下面就给大家分享一个顶点动画的代码实现。
代码如下：
Shader "Water" ｛
Properties ｛
_MainTex ("Main Tex", 2D) = "white" ｛｝
_Color ("Color Tint", Color) = (1, 1, 1, 1)
_Magnitude ("Distortion Magnitude", Float) = 1
_Frequency ("Distortion Frequency", Float) = 1
_InvWaveLength ("Distortion Inverse Wave Length", Float) = 10
_Speed ("Speed", Float) = 0.5
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SubShader ｛
// Need to disable batching because of the vertex animation
Tags ｛"Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent" "DisableBatching"="True"｝
Pass ｛
Tags ｛ "LightMode"="ForwardBase" ｝
ZWrite Off
Blend SrcAlpha OneMinusSrcAlpha
Cull Off
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "UnityCG.cginc"
sampler2D _MainTex;
float4 _MainTex_ST;
fixed4 _Color;
float _Magnitude;
float _Frequency;
float _InvWaveLength;
float _Speed;
struct a2v ｛
float4 vertex : POSITION;
float4 texcoord : TEXCOORD0;
｝;
struct v2f ｛
float4 pos : SV_POSITION;
float2 uv : TEXCOORD0;
｝;
v2f vert(a2v v) ｛
v2f o;
float4 offset;
offset.yzw = float3(0.0, 0.0, 0.0);
offset.x = sin(
_Frequency * _Time.y +
v.vertex.x * _InvWaveLength +
v.vertex.y * _InvWaveLength +
v.vertex.z * _InvWaveLength)
* _Magnitude;
o.pos = mul(UNITY_MATRIX_MVP, v.vertex + offset);
o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);
o.uv += float2(0.0, _Time.y * _Speed);
return o;
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fixed4 frag(v2f i) : SV_Target ｛
fixed4 c = tex2D(_MainTex, i.uv);
c.rgb *= _Color.rgb;
return c;
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ENDCG
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FallBack "Transparent/VertexLit"
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顶点动画的阴影
Pass ｛
// 如果之前的pass中有顶点动画,此时如果还是使用系统内置的ShadowCaster
// 仍然可以产生阴影,但是,它不会改变顶点的位置,也就是阴影不会随着之前顶点动画的改变而改变
// 所以如果希望阴影和顶点动画的阴影匹配,那就需要自定义阴影并且顶点的改变应该和之前的pass相同
Tags ｛ "LightMode" = "ShadowCaster" ｝
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#pragma multi_compile_shadowcaster
#include "UnityCG.cginc"
float _Magnitude;
float _Frequency;
float _InvWaveLength;
float _Speed;
struct v2f ｛
V2F_SHADOW_CASTER;
｝;
v2f vert(appdata_base v) ｛
v2f o;
float4 offset;
offset.yzw = float3(0.0, 0.0, 0.0);
// 需要与上一个pass中顶点动画的改变一样
offset.x = sin(_Frequency * _Time.y + v.vertex.x * _InvWaveLength + v.vertex.y * _InvWaveLength + v.vertex.z * _InvWaveLength) * _Magnitude;
v.vertex = v.vertex + offset;
// 需要名字是v.vertex v.normal这两个参数
TRANSFER_SHADOW_CASTER_NORMALOFFSET(o)
return o;
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fixed4 frag(v2f i) : SV_Target ｛
SHADOW_CASTER_FRAGMENT(i)
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ENDCG
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