unity3d:shader: Clip裁剪显示

深藏阁楼爱情的钟 2023-06-06 12:30 14阅读 0赞

表面

Shader "Custom/Clip" { 
    	Properties{ 
    		_MainTex("Texture", 2D) = "white" { }
    	_BumpMap("Bumpmap", 2D) = "bump" { }
    	[Space(10)]_ClipObjPos("遮罩位置",	Vector) = (0, 0, 0, 1)
    		_ClipObjNormal("遮罩法线向量",	Vector) = (0, 1, 0, 1)
    	}
    		SubShader{ 
    		Tags{  "RenderType" = "Opaque" }             Cull Off
    		CGPROGRAM
    #pragma surface surf Lambert
    		struct Input { 
    		float2 uv_MainTex;
    		float2 uv_BumpMap;               float3 worldPos;
    	};
    	sampler2D _MainTex;
    	sampler2D _BumpMap;
    	fixed4 _ClipObjPos;
    	fixed4 _ClipObjNormal;
    	float distanceToPlane(float3 pos, float3 objNormal, float3 pointInWorld)
    	{ 
    		float3 w = -(pos - pointInWorld);
    		//根据数学公式，用平面的法向量计算距离
    		float res = (objNormal.x * w.x + objNormal.y * w.y + objNormal.z * w.z)
    			/ sqrt(objNormal.x * objNormal.x + objNormal.y * objNormal.y + objNormal.z * objNormal.z);
    		return res;
    	}
    
    	void surf(Input IN, inout SurfaceOutput o) { 
    
    		clip(distanceToPlane(_ClipObjPos.xyz, _ClipObjNormal.xyz, IN.worldPos));
          
    		o.Albedo = tex2D(_MainTex, IN.uv_MainTex).rgb;
    		o.Normal = UnpackNormal(tex2D(_BumpMap, IN.uv_BumpMap));
    	}
    	ENDCG
    	}
    		Fallback "Diffuse"
    }

顶点片段

Shader "luoyikun/Clip"
    { 
    	Properties
    	{ 
    	_MainTex("Texture", 2D) = "white" { }
    	[Space(10)]_ClipObjPos("遮罩位置",	Vector) = (0, 0, 0, 1)
    	_ClipObjNormal("遮罩法线向量",	Vector) = (0, 1, 0, 1)
    
    	}
    SubShader
    	{ 
    	Tags {  "RenderType" = "Opaque" }
    	//不关闭背面剔除的话看不到物体内侧
    	Cull off
    	Pass
    	{ 
    	CGPROGRAM
    	#pragma vertex vert
    	#pragma fragment frag 
    	#include "UnityCG.cginc"
    	struct v2f
    	{ 
    	float2 uv : TEXCOORD0;
    	float4 vertex : SV_POSITION;
    	float3 worldPos:TEXCOORD1;
    	};
    
    	sampler2D _MainTex;
    	fixed4 _ClipObjPos;
    	fixed4 _ClipObjNormal;
    	v2f vert(appdata_base v)
    	{ 
    	v2f o;
    	o.vertex = UnityObjectToClipPos(v.vertex);
    	o.worldPos = mul(unity_ObjectToWorld, v.vertex).xyz;
    	o.uv = v.texcoord;
    	return o;
    	}
    
    	float distanceToPlane(float3 pos, float3 objNormal, float3 pointInWorld)
    	{ 
    		float3 w = -(pos - pointInWorld);
    		//根据数学公式，用平面的法向量计算距离
    		float res = (objNormal.x * w.x + objNormal.y * w.y + objNormal.z * w.z);//两个向量的点乘，<0不同方向
    		return res;
    	}
    
    	fixed4 frag(v2f i) : SV_Target
    	{ 
    	clip(distanceToPlane(_ClipObjPos.xyz, _ClipObjNormal.xyz, i.worldPos));//<0不显示
    
    	float4 color = tex2D(_MainTex, i.uv);
    
    	return color;
    		}
    	ENDCG
    	}
    	}
    }

需要裁剪的物体，换上此shader，可增加实时判断需要裁剪的位置

using System.Collections;
    using System.Collections.Generic;
    using UnityEngine;
    
    public class ClipTest : MonoBehaviour { 
        Material m_mat;
        public GameObject m_clipPlane;
    	// Use this for initialization
    	void Start () { 
            m_mat = GetMat(gameObject.GetComponent<Renderer>());
            SetMaterialValue(m_clipPlane.transform.position, m_clipPlane.transform.rotation * -Vector3.up);
        }
    	
    	// Update is called once per frame
    	void Update () { 
            SetMaterialValue(m_clipPlane.transform.position, m_clipPlane.transform.rotation * -Vector3.up);
        }
    
        void SetMaterialValue(Vector3 pos, Vector3 normal)
        { 
            m_mat.SetVector("_ClipObjPos", pos);
            m_mat.SetVector("_ClipObjNormal", normal);
        }
    
        public static Material GetMat(Renderer render)
        { 
    #if UNITY_EDITOR
            return render.material;
    #else
    		return render.sharedMaterial;
    #endif
        }
    
    }

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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2x1b3lpa3Vu_size_16_color_FFFFFF_t_70 1]: /images/20230601/bb0bf14218f94e71aa939cee7499e65f.png