【shader】全景图

来源：互联网发布：矩阵的逆编辑：程序博客网时间：2024/06/02 04:15

最终效果

思路

通过法线方向求平面坐标。x=atan(x/z),y=acos(y/r) r为半径;
通过ddx,ddy 偏导数模糊极坐标像素解决极坐标问题。
通过反射比较真实的扑捉视觉。

源代码

Shader "QQ/Sky/Latitude"{Properties{_MainTex("Texture", 2D) = "white" {}[Enum(UnityEngine.Rendering.CullMode)] _Cull("Cull Mode", float) = 2[Enum(Off, 0, On, 1)] _Inverse("inverse", float) = 0}SubShader{Tags { "RenderType" = "Opaque" }LOD 100Pass{Cull[_Cull]CGPROGRAM#pragma vertex vert#pragma fragment frag#include "UnityCG.cginc"struct a2v{float4 vertex : POSITION;float3 normal : NORMAL;};struct v2f{float4 pos : SV_POSITION;float3 normal : TEXCOORD0;float3 wPos:TEXCOORD1;};sampler2D _MainTex;float4 _MainTex_ST;float _Cull;float _Inverse;v2f vert(a2v v){v2f o;o.pos = mul(UNITY_MATRIX_MVP, v.vertex);o.normal = v.normal;o.wPos = mul(unity_ObjectToWorld, v.vertex);return o;}fixed4 frag(v2f i) : SV_Target{float3 nor = normalize(i.normal);float3 viewDir = normalize(_WorldSpaceCameraPos.xyz - i.wPos);float3 refl = (_Inverse > 0 ? 1 : -1) * reflect(viewDir,nor);float u = atan(refl.x / refl.z) / UNITY_PI;u = (u + 0.5)*0.5;if (refl.z >= 0)u += 0.5;float v = acos(refl.y) / UNITY_PI;float2 uv = float2(u, v)*_MainTex_ST.xy + _MainTex_ST.zw;fixed4 col = tex2D(_MainTex,uv,float2(0,0), float2(0,0));return col;}ENDCG}}}

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