shader入门基础-动画
shader入门基础-动画
Unity 内置时间变量
| 名称 | 类型 | 描述 |
|---|---|---|
| _Time | float4 | t 是自然该场景加载开始所经过的时间，(t/20,t,2t,3t) |
| _SinTime | float4 | t 是时间的正弦值，(t/8,t/4,t/2,t) |
| _CosTime | float4 | t 是时间的余弦值，(t/8,t/4,t/2,t) |
| unity_DeltaTime | float4 | dt 是时间增量，(dt,1/dt,smoothDt,1/smoothDt) |
纹理动画
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Shader "Practice/SequenceAnim"
{
Properties
{
_MainTex ("Texture", 2D) = "white" {}
_RowCount("行数",int)=4
_ColCount("列数",int)=4
_Speed("播放速度",Range(0,100))=1.0
}
SubShader
{
// No culling or depth
Tags {"Queue"="Transparent" "IgnoreProjector"="true" "RenderType"="Transparent"}
Pass
{
Tags {"LightModel"="ForwardBase"}
Blend SrcAlpha OneMinusSrcAlpha
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "UnityCG.cginc"
sampler2D _MainTex;
float4 _MainTex_ST;
float _Speed;
half _RowCount;
half _ColCount;
struct appdata
{
float4 vertex : POSITION;
float2 uv : TEXCOORD0;
};
struct v2f
{
float2 uv : TEXCOORD0;
float4 vertex : SV_POSITION;
};
v2f vert (appdata v)
{
v2f o;
o.vertex = UnityObjectToClipPos(v.vertex);
o.uv = TRANSFORM_TEX(v.uv,_MainTex) ;
return o;
}
fixed4 frag (v2f i) : SV_Target
{
float length = _Speed*_Time.y;
half curRow = floor(length/_ColCount);
half curCol = floor(length-curRow*_ColCount);
half2 uv =float2(i.uv.x/_ColCount,i.uv.y/_RowCount);
uv.x+= curCol/_ColCount;
uv.y-= curRow/_RowCount;
fixed4 col =tex2D(_MainTex,uv);
return col;
}
ENDCG
}
}
}
滚动的背景
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Shader "Practice/BgAnim"
{
Properties
{
_FirstBG ("FirstBG", 2D) = "white" {}
_SecondBG ("FirstBG", 2D) = "white" {}
_ScrollX("_ScrollX",float) = 1
_ScrollX2("_ScrollX2",float)=1.1
}
SubShader
{
// No culling or depth
Cull Off ZWrite Off ZTest Always
Pass
{
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "UnityCG.cginc"
sampler2D _FirstBG;
sampler2D _SecondBG;
fixed4 _FirstBG_ST;
fixed4 _SecondBG_ST;
float _ScrollX2;
float _ScrollX;
struct appdata
{
float4 vertex : POSITION;
float2 uv : TEXCOORD0;
};
struct v2f
{
float4 uv : TEXCOORD0;
float4 vertex : SV_POSITION;
};
v2f vert (appdata v)
{
v2f o;
o.vertex = UnityObjectToClipPos(v.vertex);
o.uv.xy =TRANSFORM_TEX(v.uv,_FirstBG);
o.uv.zw = TRANSFORM_TEX(v.uv,_SecondBG);
return o;
}
fixed4 frag (v2f i) : SV_Target
{
float2 uv_offset = frac(float2(_ScrollX,0.0)*_Time.y);
float2 uv_offset2 = frac(float2(_ScrollX2,0.0)*_Time.y);
fixed4 col = tex2D(_FirstBG, i.uv.xy+uv_offset);
fixed4 col2 =tex2D(_SecondBG,i.uv.zw+uv_offset2);
fixed4 final_col=lerp(col,col2,col2.a);
return final_col;
}
ENDCG
}
}
}
顶点动画
DisableBatching: 批处理会合并所有相关的模型，而这些模型各自的模型空间会丢失。我们需要在物体的模型空间下对顶点位置进行偏移，因此需要取消 批处理操作。
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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
}
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 = UnityObjectToClipPos(v.vertex + offset);
o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);
o.uv += float2(0.0, _Time.y * _Speed);
return o;
}
fixed4 frag(v2f i) : SV_Target {
fixed4 c = tex2D(_MainTex, i.uv);
c.rgb *= _Color.rgb;
return c;
}
ENDCG
}
}
FallBack "Transparent/VertexLit"
广告牌技术
根据视角方向来旋转一个被纹理着色的多边形，使得多边形看起来好像总是面对摄像机。广告牌技术的本质是构建旋转矩阵。 
为了避免使用模型空间的中心作为锚点，我们可以利用顶点颜色存储每个顶点到锚点的距离值。
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Shader "Practice/BillBoard"
{
Properties {
_MainTex ("Main Tex", 2D) = "white" {}
_Color ("Color Tint", Color) = (1, 1, 1, 1)
_VerticalBillboarding ("Vertical Restraints", Range(0, 1)) = 1
}
SubShader {
// 关闭批处理，批处理会导致模型各自的模型空间丢失
Tags {"Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent" "DisableBatching"="True"}
Pass {
Tags { "LightMode"="ForwardBase" }
ZWrite Off
Blend SrcAlpha OneMinusSrcAlpha
//关闭剔除让广告牌每个面都能显示
Cull Off
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "Lighting.cginc"
sampler2D _MainTex;
float4 _MainTex_ST;
fixed4 _Color;
fixed _VerticalBillboarding;
struct a2v {
float4 vertex : POSITION;
float4 texcoord : TEXCOORD0;
};
struct v2f {
float4 pos : SV_POSITION;
float2 uv : TEXCOORD0;
};
v2f vert (a2v v) {
v2f o;
//模型空间位置原点
float3 center = float3(0, 0, 0);
//将摄像机位置转换到模型空间坐标
float3 viewer = mul(unity_WorldToObject,float4(_WorldSpaceCameraPos, 1));
// 摄像机指向原点的方向作为法线方向
float3 normalDir = viewer - center;
//_VerticalBillboarding == 1 我们使用摄像机指向原点的方向作为法线方向
//_VerticalBillboarding == 0 则固定方向作为法线方向
normalDir.y =normalDir.y * _VerticalBillboarding;
normalDir = normalize(normalDir);
// 获取up方向
float3 upDir = abs(normalDir.y) > 0.999 ? float3(0, 0, 1) : float3(0, 1, 0);
//叉积后获取指向右方的向量
float3 rightDir = normalize(cross(upDir, normalDir));
upDir = normalize(cross(normalDir, rightDir));
// 使用3个正焦急矢量做相对于锚点旋转
float3 centerOffs = v.vertex.xyz - center;
float3 localPos = center + rightDir * centerOffs.x + upDir * centerOffs.y + normalDir * centerOffs.z;
o.pos = UnityObjectToClipPos(float4(localPos, 1));
o.uv = TRANSFORM_TEX(v.texcoord,_MainTex);
return o;
}
fixed4 frag (v2f i) : SV_Target {
fixed4 c = tex2D (_MainTex, i.uv);
c.rgb *= _Color.rgb;
return c;
}
ENDCG
}
}
FallBack "Transparent/VertexLit"
}
对包含顶点动画的物体添加阴影
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Pass {
//阴影投射pass
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);
offset.x = sin(_Frequency * _Time.y + v.vertex.x * _InvWaveLength + v.vertex.y * _InvWaveLength + v.vertex.z * _InvWaveLength) * _Magnitude;
v.vertex = v.vertex + offset;
TRANSFER_SHADOW_CASTER_NORMALOFFSET(o)
return o;
}
fixed4 frag(v2f i) : SV_Target {
SHADOW_CASTER_FRAGMENT(i)
}
ENDCG
}
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