UV动画
UV动画,顾名思义,就是针对UV做的动画。在游戏中,一些动态水面,飞流直下的瀑布,流动的岩浆,跳动的火焰等等,很多都是通过操作UV做的动画。在unity中我可以实用挂载脚本或者直接针对UV key动画帧做动画操作,而在本文中将通过shader编写实现三个比较常见的UV动画方式:
1.UV位移动画
2.UV序列帧动画
3.UV旋转动画
先从UV位移动画开始
我们将做一个流动岩浆的效果,在开始前,我们需要介绍下Unity内置变量_Time
float4 _Time : Time (t/20, t, t*2, t*3)
这是个随时间变化的增量,从函数的定义我们可以知道这个变量的4个分量速率比 _Time=20*_Time.x=_Time.y=_Time.z/2=_Time.w/3.
为了方便控制位移动画的速率和方向我们定义一个变量
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- _ScrollingSpeed("Scrolling speed", Vector) = (0,0,0,0)
在顶点函数中将uv坐标乘以_Time变量和_ScrollingSpeed,下面为关键代码
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- o.uvScroll = TRANSFORM_TEX((v.texcoord.xy+_Time.x*_ScrollingSpeed.xy), _Tex);// 这里只使用了xy上的两个分量对应uv
VF版本代码01:
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- Shader "PengLu/Self-Illumin/IlluminDiffuseScrollVF"
- {
- Properties
- {
- _Color ("Main Color", Color) = (1,1,1,1)
- _MainTex ("Base (RGB)", 2D) = "white" {}
- _Illum ("Illumin (A)", 2D) = "white" {}
- _Tex("Scroll Tex (RGB)", 2D)= "white" {}
- _ScrollingSpeed("Scrolling speed", Vector) = (0,0,0,0)
- }
-
- SubShader
- {
-
- Tags { "RenderType"="Opaque" }
- LOD 200
-
- pass
- {
- CGPROGRAM
- #pragma vertex vert
- #pragma fragment frag
- #include "UnityCG.cginc"
- sampler2D _MainTex,_Illum,_Tex;
- float4 _MainTex_ST,_Illum_ST,_Tex_ST,_Color,_ScrollingSpeed;
-
- struct appdata {
- float4 vertex : POSITION;
- float2 texcoord : TEXCOORD0;
- float2 texcoord1 : TEXCOORD1;
- };
-
- struct v2f {
- float4 pos : POSITION;
- float2 uv_MainTex : TEXCOORD0;
- float2 uv_Illum : TEXCOORD1;
- float2 uvLM : TEXCOORD2;
- float2 uvScroll : TEXCOORD3;
- };
-
- v2f vert (appdata v)
- {
- v2f o;
- o.pos = mul(UNITY_MATRIX_MVP,v.vertex)*_Color;
- o.uv_MainTex = TRANSFORM_TEX(v.texcoord, _MainTex);
- o.uv_Illum = TRANSFORM_TEX(v.texcoord, _Illum);
- o.uvScroll = TRANSFORM_TEX((v.texcoord.xy+_Time.x*_ScrollingSpeed.xy), _Tex);
- o.uvLM = v.texcoord1.xy * unity_LightmapST.xy + unity_LightmapST.zw;
- return o;
- }
-
- float4 frag (v2f i) : COLOR
- {
- float4 texCol = tex2D(_MainTex, i.uv_MainTex);
- float4 IllumTex = tex2D(_Illum,i.uv_Illum);
- float3 lm = DecodeLightmap (UNITY_SAMPLE_TEX2D(unity_Lightmap, i.uvLM.xy));
- IllumTex.rgb+=tex2D(_Tex,i.uvScroll).rgb;
- IllumTex*=IllumTex.a;
- texCol+=IllumTex;
- texCol.rgb*=lm;
- return texCol;
- }
- ENDCG
- }
- }
- FallBack "Diffuse"
- }
VF版本代码01效果:
UV序列帧动画
序列帧动画是游戏比较常用的一种动画形式,在unity自带的粒子系统中就可以设置序列帧动画(下图),但是这个只能用于粒子系统的粒子效果,如果是自己做的模型就要使用序列帧动画就得自己写脚本或shader,下面我们将用shader实现序列帧动画效果。
首先得准备一张序列帧的贴图,如下图这样的:
然后我们需要声明三个变量:
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- _SizeX ("SizeX", Float) = 4//列数
- _SizeY ("SizeY", Float) = 4//行数
- _Speed ("Speed", Float) = 200//动画的播放速度
在frag函数里面处理动画
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- int indexX=fmod (_Time.x*_Speed,_SizeX);//获得列数的循环
- int indexY=fmod ((_Time.x*_Speed)/_SizeX,_SizeY);//获得行数的循环
fmod函数是取余函数,int用来强制取整,当然也可以用floor函数来取整
为了直观解释,将用下面的列表列出上面变量的值的对应关系,假设_SizeX=_SizeY=4
参考网络上的例子我还有写了另外一种获得循环动画的代码(我是孔乙己啦),和上面两句功能是一样的,貌似消耗稍微少一点
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- int index = floor(_Time .x * _Speed);
- int indexY = index/_SizeX;
- int indexX = index - indexY*_SizeX;
通过列表对应,可以看出获取循环数的差别
接下来将获得的循环数与uv贴图的UV进行操作
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- fixed2 seqUV = float2((i.texcoord.x) /_SizeX, (i.texcoord.y)/_SizeY);//将uv切分
- seqUV.x += indexX/_SizeX;//U方向上循环
- seqUV.y -= indexY/_SizeY;//V方向上循环
VF版本代码02:
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- Shader "PengLu/Particle/SequenceAdd" {
- Properties {
- _TintColor ("Tint Color", Color) = (0.5,0.5,0.5,0.5)
- _MainTex ("Particle Texture", 2D) = "white" {}
- _InvFade ("Soft Particles Factor", Range(0.01,3.0)) = 1.0
- _SizeX ("SizeX", Float) = 4
- _SizeY ("SizeY", Float) = 4
- _Speed ("Speed", Float) = 200
- }
-
- Category {
- Tags { "Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent" }
- Blend SrcAlpha One
- AlphaTest Greater .01
- ColorMask RGB
- Cull Off Lighting Off ZWrite Off Fog { Color (0,0,0,0) }
-
- SubShader {
- Pass {
-
- CGPROGRAM
- #pragma vertex vert
- #pragma fragment frag
- #pragma multi_compile_particles
-
- #include "UnityCG.cginc"
-
- sampler2D _MainTex;
- fixed4 _TintColor;
- fixed _SizeX;
- fixed _SizeY;
- fixed _Speed;
-
- struct appdata_t {
- float4 vertex : POSITION;
- fixed4 color : COLOR;
- float2 texcoord : TEXCOORD0;
- };
-
- struct v2f {
- float4 vertex : POSITION;
- fixed4 color : COLOR;
- float2 texcoord : TEXCOORD0;
- #ifdef SOFTPARTICLES_ON
- float4 projPos : TEXCOORD1;
- #endif
- };
-
- float4 _MainTex_ST;
-
- v2f vert (appdata_t v)
- {
- v2f o;
- o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
- #ifdef SOFTPARTICLES_ON
- o.projPos = ComputeScreenPos (o.vertex);
- COMPUTE_EYEDEPTH(o.projPos.z);
- #endif
- o.color = v.color;
- o.texcoord = TRANSFORM_TEX(v.texcoord,_MainTex);
- return o;
- }
-
- sampler2D _CameraDepthTexture;
- float _InvFade;
-
- fixed4 frag (v2f i) : COLOR
- {
- #ifdef SOFTPARTICLES_ON
- float sceneZ = LinearEyeDepth (UNITY_SAMPLE_DEPTH(tex2Dproj(_CameraDepthTexture, UNITY_PROJ_COORD(i.projPos))));
- float partZ = i.projPos.z;
- float fade = saturate (_InvFade * (sceneZ-partZ));
- i.color.a *= fade;
- #endif
- int indexX=fmod (_Time.x*_Speed,_SizeX);
- int indexY=fmod ((_Time.x*_Speed)/_SizeX,_SizeY);
-
- // 以下三行代码和之前两行代码功能一样
- // int index = floor(_Time .x * _Speed);
- // int indexY = index/_SizeX;
- // int indexX = index-indexY*_SizeX;
-
- fixed2 seqUV = float2((i.texcoord.x) /_SizeX, (i.texcoord.y)/_SizeY);
- seqUV.x += indexX/_SizeX;
- seqUV.y -= indexY/_SizeY;
- return 2.0f * i.color * _TintColor * tex2D(_MainTex, seqUV);
- }
- ENDCG
- }
- }
- }
- }
VF版本代码02效果:
UV旋转动画
UV旋转动画在游戏开发中用得相对比较少,特效师一般会采用其他方式代替,这里将用shader实现一个UV旋转的动画。UV旋转实际上一个2D旋转,有关2D旋转的理论在这里。这边文章里讲得比较透彻,在这里我只需要拿到最终结果公式:
x' = r*cosα*cosθ - r*sinα*sinθ = x * cos θ – y * sin θ
y' = r*sinα*cosθ +r*cosα*sinθ = y * cos θ + x * sin θ
那么开始,同意需要声明一个变量来控制旋转方向和速度;
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- _Speed ("Speed", Float) = 200
接下来就要在frag函数里面操作UV,关键代码如下:
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- //将uv偏移0.5,使旋转中心到贴图中心
- float2 uv=i.texcoord-0.5;
- //定义一个二元变量,存储时间变量的正弦和余弦值
- float2 rotate = float2(cos(_Speed*_Time.x),sin(_Speed*_Time.x));
- //获得旋转后的uv坐标值
- uv=float2((uv.x*rotate.x-uv.y*rotate.y),(uv.x*rotate.y+uv.y*rotate.x));
- //将偏移的uv偏移回来
- uv+=0.5;
VF版本代码03
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- Shader "PengLu/Particle/RotationAdd" {
- Properties {
- _TintColor ("Tint Color", Color) = (0.5,0.5,0.5,0.5)
- _MainTex ("Particle Texture", 2D) = "white" {}
- _InvFade ("Soft Particles Factor", Range(0.01,3.0)) = 1.0
- _Speed ("Speed", Float) = 200
- }
-
- Category {
- Tags { "Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent" }
- Blend SrcAlpha One
- AlphaTest Greater .01
- ColorMask RGB
- Cull Off Lighting Off ZWrite Off Fog { Color (0,0,0,0) }
-
- SubShader {
- Pass {
-
- CGPROGRAM
- #pragma vertex vert
- #pragma fragment frag
- #pragma multi_compile_particles
-
- #include "UnityCG.cginc"
-
- sampler2D _MainTex;
- fixed4 _TintColor;
- fixed _Speed;
-
- struct appdata_t {
- float4 vertex : POSITION;
- fixed4 color : COLOR;
- float2 texcoord : TEXCOORD0;
- };
-
- struct v2f {
- float4 vertex : POSITION;
- fixed4 color : COLOR;
- float2 texcoord : TEXCOORD0;
- #ifdef SOFTPARTICLES_ON
- float4 projPos : TEXCOORD1;
- #endif
- };
-
- float4 _MainTex_ST;
-
- v2f vert (appdata_t v)
- {
- v2f o;
- o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
- #ifdef SOFTPARTICLES_ON
- o.projPos = ComputeScreenPos (o.vertex);
- COMPUTE_EYEDEPTH(o.projPos.z);
- #endif
- o.color = v.color;
- o.texcoord = TRANSFORM_TEX(v.texcoord,_MainTex);
- return o;
- }
-
- sampler2D _CameraDepthTexture;
- float _InvFade;
-
- fixed4 frag (v2f i) : COLOR
- {
- #ifdef SOFTPARTICLES_ON
- float sceneZ = LinearEyeDepth (UNITY_SAMPLE_DEPTH(tex2Dproj(_CameraDepthTexture, UNITY_PROJ_COORD(i.projPos))));
- float partZ = i.projPos.z;
- float fade = saturate (_InvFade * (sceneZ-partZ));
- i.color.a *= fade;
- #endif
- float2 uv=i.texcoord-0.5;
- float2 rotate = float2(cos(_Speed*_Time.x),sin(_Speed*_Time.x));
- uv=float2((uv.x*rotate.x-uv.y*rotate.y),(uv.x*rotate.y+uv.y*rotate.x));
- uv+=0.5;
- return 2.0f * i.color * _TintColor * tex2D(_MainTex, uv);
- }
- ENDCG
- }
- }
- }
- }
VF版本代码03效果:
PS:贴图的Wrap Mode要设置成Clamp,原因你懂的 ^_^
原文链接:http://blog.csdn.net/u011047171/article/details/46776713
添加一个浮动的Shader实现:
Shader "Custom/WaveShader" {
Properties{
_WaveSpeed("WaveSpeed",float)=4
_MaxHight("MaxHeight(峰值)",float)=3
_Frenquncy("WaveF(频率)",float)=3
}
SubShader{
Tags{ "Queue" = "Transparent" }
Pass{
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "UnityCG.cginc"
float _WaveSpeed;
float _MaxHight;
float _Frenquncy;
struct a2v {
fixed4 vertex : POSITION;
};
struct v2f {
fixed4 pos : SV_POSITION;
};
v2f vert(a2v v)
{
v2f o;
v.vertex.y += _MaxHight*sin(v.vertex.x*_Frenquncy + _Time.y*_WaveSpeed);
o.pos = mul(UNITY_MATRIX_MVP,v.vertex);
return o;
}
fixed4 frag(v2f v) :SV_Target
{
return fixed4(1,1,1,1);
}
ENDCG
}
}
}