Unity Shader 学习 Texture Repetition
目的
为了解决三向和双向的重复问题
iquilezles
消除纹理重复感的两种方法
UE4 Shader 简单的消除纹理重复�?/a>
Coding
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Shader "Unlit/Biplanar_Texture_Repetition"
{
Properties
{
_MainTex ("Texture", 2D) = "white" {}
_NoramlTex ("Noraml Texture", 2D) = "white" {}
_shapek ("shapek", Range(0,20)) = 1
_BlendRatio ("BlendRatio",Float ) = 1
_TriplanarBlendSharpness("Blend Sharpness", float)=1
}
SubShader
{
Tags { "RenderType"="Opaque" }
Pass
{
CGPROGRAM
// make fog work
struct appdata
{
float4 vertex : POSITION;
float2 uv : TEXCOORD0;
float4 normal : NORMAL;
float4 tangent : TANGENT;
};
struct v2f
{
float4 pos : SV_POSITION;
float2 uv : TEXCOORD0;
float4 posWS : TEXCOORD1;
float3 nDirWS : TEXCOORD2;
float3 tDirWS : TEXCOORD3; // 世界空间切线方向
float3 bDirWS : TEXCOORD4;
};
Texture2D _MainTex;
SamplerState sampler_MainTex;
float4 _MainTex_ST;
Texture2D _NoramlTex;
//sampler2D _MainTex;float4 _MainTex_ST;
//sampler2D _NoramlTex;
float _shapek;
float _BlendRatio;
float _TriplanarBlendSharpness;
v2f vert (appdata v)
{
v2f o;
o.pos = UnityObjectToClipPos( v.vertex );
o.uv = TRANSFORM_TEX(v.uv, _MainTex);
o.posWS = mul(unity_ObjectToWorld, v.vertex);
o.nDirWS = UnityObjectToWorldNormal(v.normal); // 法线方向 OS>WS
o.tDirWS = normalize(mul(unity_ObjectToWorld, float4(v.tangent.xyz, 0.0)).xyz); // 切线方向 OS>WS
o.bDirWS = normalize(cross(o.nDirWS, o.tDirWS) * v.tangent.w);
return o;
}
//哈希算法
float4 hash4(float2 p)
{
float t1 = 1.0 + dot(p, float2(37.0, 17.0));
float t2 = 2.0 + dot(p, float2(11.0, 47.0));
float t3 = 3.0 + dot(p, float2(41.0, 29.0));
float t4 = 4.0 + dot(p, float2(23.0, 31.0));
return frac(sin(float4(t1, t2, t3, t4)) * 103.0);
}
// 清除纹理本体
float4 texNoTileTech(Texture2D baseTex, SamplerState baseTexSampler, float2 uv, float2 blendRatio)
{
// 获取整数部分，即哪个tile
float2 iuv = floor(uv);
// 获取小数部分，确认采样点在单个tile中的位置
float2 fuv = frac(uv);
// 产生四次不同的变�?/span>
float4 ofa = hash4(iuv + float2(0.0, 0.0));
float4 ofb = hash4(iuv + float2(1.0, 0.0));
float4 ofc = hash4(iuv + float2(0.0, 1.0));
float4 ofd = hash4(iuv + float2(1.0, 1.0));
// 计算ddx,ddy避免UV跳跃
float2 dx = ddx(uv);
float2 dy = ddy(uv);
// 镜像处理
ofa.zw = sign(ofa.zw - 0.5);
ofb.zw = sign(ofb.zw - 0.5);
ofc.zw = sign(ofc.zw - 0.5);
ofd.zw = sign(ofd.zw - 0.5);
float2 uva = uv * ofa.zw + ofa.xy, dxa = dx * ofa.zw, dya = dy * ofa.zw;
float2 uvb = uv * ofb.zw + ofb.xy, dxb = dx * ofb.zw, dyb = dy * ofb.zw;
float2 uvc = uv * ofc.zw + ofc.xy, dxc = dx * ofc.zw, dyc = dy * ofc.zw;
float2 uvd = uv * ofd.zw + ofd.xy, dxd = dx * ofd.zw, dyd = dy * ofd.zw;
// 采样和混�?/span>
float2 b = smoothstep(blendRatio, 1.0 - blendRatio, fuv);
float4 sampler1 = baseTex.SampleGrad(baseTexSampler, uva, dxa, dya);
float4 sampler2 = baseTex.SampleGrad(baseTexSampler, uvb, dxb, dyb);
float4 sampler3 = baseTex.SampleGrad(baseTexSampler, uvc, dxc, dyc);
float4 sampler4 = baseTex.SampleGrad(baseTexSampler, uvd, dxd, dyd);
return lerp(lerp(sampler1, sampler2, b.x), lerp(sampler3, sampler4, b.x), b.y);
//return float4(uva,0,0);
}
fixed4 frag (v2f i) : SV_Target
{
//数据构建
float3 p = i.posWS;
float3 dpdx = ddx(p);
float3 dpdy = ddy(p);
float3 n = abs(i.nDirWS);
uint3 ma = (n.x>n.y&&n.x>n.z) ? uint3(0,1,2):
(n.y>n.z) ? uint3(1,2,0):
uint3(2,0,1);
uint3 mi = (n.x<n.y&&n.x<n.z) ? uint3(0,1,2):
(n.y<n.z) ? uint3(1,2,0):
uint3(2,0,1);
uint3 me = uint3(3,3,3)-mi-ma;
float2 w = float2(n[ma.x],n[me.x]);
w = saturate((w-0.5)/(1-0.5));
float k = _shapek/8.0;
w = pow(w,_TriplanarBlendSharpness);
w=pow(w,float2(k,k));
// sample the texture
float4 x = _MainTex.SampleGrad(sampler_MainTex,float2(p[ma.y],p[ma.z]),float2(dpdx[ma.y],dpdx[ma.z]),float2(dpdy[ma.y],dpdy[ma.z]));
float4 y = _MainTex.SampleGrad(sampler_MainTex,float2(p[me.y],p[me.z]),float2(dpdx[me.y],dpdx[me.z]),float2(dpdy[me.y],dpdy[me.z]));
//fixed4 col = tex2D(_MainTex, i.uv);
//_MainTex.Sample(sampler_MainTex, i.uv);
// apply fog
fixed4 cx = texNoTileTech(_MainTex,sampler_MainTex,float2(p[ma.y],p[ma.z]),_BlendRatio);
fixed4 cy = texNoTileTech(_MainTex,sampler_MainTex,float2(p[me.y],p[me.z]),_BlendRatio);
float4 col = (cx*w.x+cy*w.y)/(w.x+w.y);
//float4 col = (x*w.x+y*w.y)/(w.x+w.y);
//ramp world y
//NORMAL
fixed4 Nx = texNoTileTech(_NoramlTex,sampler_MainTex,float2(p[ma.y],p[ma.z]),_BlendRatio);
fixed4 Ny = texNoTileTech(_NoramlTex,sampler_MainTex,float2(p[me.y],p[me.z]),_BlendRatio);
//float4 Nx = tex2Dgrad(_NoramlTex,float2(p[ma.y],p[ma.z]),float2(dpdx[ma.y],dpdx[ma.z]),float2(dpdy[ma.y],dpdy[ma.z]));
//float4 Ny = tex2Dgrad(_NoramlTex,float2(p[me.y],p[me.z]),float2(dpdx[me.y],dpdx[me.z]),float2(dpdy[me.y],dpdy[me.z]));
float3 n1 = UnpackNormal(Nx);
float3 n2 = UnpackNormal(Ny);
float3 nW;
float3 n1W = float3(n1.y+i.nDirWS[ma.z],n1.x+i.nDirWS[ma.y],abs(n1.z)*i.nDirWS[ma.x]);
float3 n2W = float3(n2.y+i.nDirWS[me.z],n2.x+i.nDirWS[me.y],abs(n2.z)*i.nDirWS[me.x]);
n1W = float3(n1W[ma.z],n1W[ma.y],n1W[ma.x]);
n2W = float3(n2W[me.z],n2W[me.y],n2W[me.x]);
//nW = normalize(n1*w.x+n2*w.y);
nW = normalize(n1W*w.x+n2W*w.y);
float3 normalT = mul(nW,float3x3(i.tDirWS,i.bDirWS,i.nDirWS));
half3 lDirWS = _WorldSpaceLightPos0.xyz;
half ndotl = dot(nW, lDirWS);
return fixed4(col.rgb*ndotl,1);
}
ENDCG
}
}
}
1 | Shader "Unlit/Biplanar_Texture_Repetition" |
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本文作�?Master Gong Sheng, 许可�?CC BY-NC 4.0.