shader中的广告板技术-白红宇

shader中的广告板技术

阅读量：5139 次

发布时间：2019-06-13

本文共 7758 字，大约阅读时间需要 25 分钟。

Shader "CM/Billboard1"{	Properties	{		_MainTex ("Texture", 2D) = "white" {}	}	SubShader	{		Pass		{			CGPROGRAM			#pragma vertex vert			#pragma fragment frag			#include "UnityCG.cginc"			struct appdata			{				float4 vertex : POSITION;				float2 uv : TEXCOORD0;			};			struct v2f			{				float4 pos : SV_POSITION;				float2 uv : TEXCOORD0;			};			sampler2D _MainTex;			float4 _MainTex_ST;						float4 Billboard(float4 vertex)			{				float4 ori=mul(UNITY_MATRIX_MV, float4(0,0,0,1));				float4 vt = vertex;				float2 r1=float2(_Object2World[0][0],_Object2World[0][2]);				float2 r2=float2(_Object2World[2][0],_Object2World[2][2]);				vt.xy = vt.x*r1 + vt.z*r2;				vt.z = 0;				vt.xyz += ori.xyz;				return mul(UNITY_MATRIX_P, vt);			}						v2f vert (appdata_base v) 			{				v2f o;				o.pos = Billboard(v.vertex);				return o;			}			fixed4 frag(v2f i) : COLOR 			{				return tex2D(_MainTex, i.uv);			}			ENDCG		}	}}

跟着相机转的plane:

广告板技术之二：来自wiki ----------- https://en.wikibooks.org/wiki/Cg_Programming/Unity/Billboards 不过这种技术不能缩放广告板

Shader "Cg  shader for billboards" {   Properties {      _MainTex ("Texture Image", 2D) = "white" {}   }   SubShader {      Pass {            CGPROGRAM          #pragma vertex vert           #pragma fragment frag          // User-specified uniforms                     uniform sampler2D _MainTex;                  struct vertexInput {            float4 vertex : POSITION;            float4 tex : TEXCOORD0;         };         struct vertexOutput {            float4 pos : SV_POSITION;            float4 tex : TEXCOORD0;         };          vertexOutput vert(vertexInput input)          {            vertexOutput output;            output.pos = mul(UNITY_MATRIX_P,               mul(UNITY_MATRIX_MV, float4(0.0, 0.0, 0.0, 1.0))              - float4(input.vertex.x, input.vertex.y, 0.0, 0.0));             output.tex = input.tex;            return output;         }          float4 frag(vertexOutput input) : COLOR         {            return tex2D(_MainTex, float2(input.tex.xy));            }          ENDCG      }   }}

　　广告板技术之三：来自wiki -----------https://en.wikibooks.org/wiki/Cg_Programming/Unity/Billboards 这种技术可缩放广告板

Shader "Cg  shader for billboards" {   Properties {      _MainTex ("Texture Image", 2D) = "white" {}      _ScaleX ("Scale X", Float) = 1.0      _ScaleY ("Scale Y", Float) = 1.0   }   SubShader {      Pass {            CGPROGRAM          #pragma vertex vert           #pragma fragment frag          // User-specified uniforms                     uniform sampler2D _MainTex;                 uniform float _ScaleX;         uniform float _ScaleY;         struct vertexInput {            float4 vertex : POSITION;            float4 tex : TEXCOORD0;         };         struct vertexOutput {            float4 pos : SV_POSITION;            float4 tex : TEXCOORD0;         };          vertexOutput vert(vertexInput input)          {            vertexOutput output;            output.pos = mul(UNITY_MATRIX_P,               mul(UNITY_MATRIX_MV, float4(0.0, 0.0, 0.0, 1.0))              - float4(input.vertex.x, input.vertex.y, 0.0, 0.0)              * float4(_ScaleX, _ScaleY, 1.0, 1.0));             output.tex = input.tex;            return output;         }          float4 frag(vertexOutput input) : COLOR         {            return tex2D(_MainTex, float2(input.tex.xy));            }          ENDCG      }   }}

广告板技术4：Y轴锁定的广告板 ------------------------------------------------------------------- 只能一个片使用该shader，两个片以上就会出问题（因为Unity会动态合并或静态合并）

Shader "CM/Billboard"{	Properties 	{		_MainTex ("Base texture", 2D) = "white" {}		_VerticalBillboarding("Vertical Restraints", Range(0,1)) = 1	}	SubShader 	{		Tags { "Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent" }		Blend one one		cull off		zwrite off						Pass 		{			CGPROGRAM				#pragma vertex vert			#pragma fragment frag			#pragma fragmentoption ARB_precision_hint_fastest					#include "UnityCG.cginc"			sampler2D _MainTex;			float4 _MainTex_ST;			float _VerticalBillboarding;						struct v2f 			{				float4	pos	: SV_POSITION;				float2	uv	: TEXCOORD0;			};			void CalcOrthonormalBasis(float3 dir,out float3 right,out float3 up)			{				up    = abs(dir.y) > 0.999f ? float3(0,0,1) : float3(0,1,0);						right = normalize(cross(up,dir));						up    = cross(dir,right);				}									v2f vert (appdata_full v)			{				v2f o;				o.uv    = TRANSFORM_TEX(v.texcoord.xy, _MainTex);								float3	centerLocal = 0;				float3	centerOffs  = v.vertex;				float3	viewerLocal = mul(_World2Object,float4(_WorldSpaceCameraPos,1));							float3	localDir    = viewerLocal - centerLocal;										localDir.y =localDir.y * _VerticalBillboarding;								float3	rightLocal;				float3	upLocal;								CalcOrthonormalBasis(normalize(localDir) ,rightLocal,upLocal);				float3	BBNormal   = rightLocal * v.normal.x + upLocal * v.normal.y;				float3	BBLocalPos = centerLocal - (rightLocal * centerOffs.x + upLocal * centerOffs.y);															o.pos = mul(UNITY_MATRIX_MVP, float4(BBLocalPos, 1));								return o;			}						fixed4 frag (v2f i) : COLOR			{				fixed4 col = tex2D(_MainTex, i.uv);				return col;			}			ENDCG		}	}}

广告板技术5：与4表现一样，计算方式不一样

Shader "CM/Billboard"{	Properties	{		_MainTex ("Texture", 2D) = "white" {}	}	SubShader	{		Tags { "Queue" = "Transparent" "RenderType"="Transparent" }		Blend srcalpha one		cull off		zwrite off		LOD 100		Pass		{			CGPROGRAM			#pragma vertex vert			#pragma fragment frag			#include "UnityCG.cginc"			struct appdata			{				float4 vertex : POSITION;				float3 normal : NORMAL;				float2 uv : TEXCOORD0;			};			struct v2f			{				float4 vertex : SV_POSITION;				float2 uv : TEXCOORD0;				float randAlpha: TEXCOORD1;			};			sampler2D _MainTex;			float4 _MainTex_ST;						inline float4 Billboard(float4 localVertex)			{				float2 billboardDirection_local_xy = normalize (					_WorldSpaceCameraPos.xz					 -float2(_World2Object[1].w, _World2Object[2].w)				);			   				float2x2 billboardRotation = float2x2(					billboardDirection_local_xy.y,					billboardDirection_local_xy.x,					-billboardDirection_local_xy.x,					billboardDirection_local_xy.y				); 			   				float4 billboardLocalVertex;				billboardLocalVertex.xz = mul(billboardRotation, localVertex.xz);				billboardLocalVertex.yw = localVertex.yw;				return billboardLocalVertex;			}						float4x4 inverse(float4x4 input)			{				#define minor(a,b,c) determinant(float3x3(input.a, input.b, input.c))				//determinant(float3x3(input._22_23_23, input._32_33_34, input._42_43_44))				float4x4 cofactors = float4x4(					minor(_22_23_24, _32_33_34, _42_43_44), 					-minor(_21_23_24, _31_33_34, _41_43_44),					minor(_21_22_24, _31_32_34, _41_42_44),					-minor(_21_22_23, _31_32_33, _41_42_43),					-minor(_12_13_14, _32_33_34, _42_43_44),					minor(_11_13_14, _31_33_34, _41_43_44),					-minor(_11_12_14, _31_32_34, _41_42_44),					minor(_11_12_13, _31_32_33, _41_42_43),					minor(_12_13_14, _22_23_24, _42_43_44),					-minor(_11_13_14, _21_23_24, _41_43_44),					minor(_11_12_14, _21_22_24, _41_42_44),					-minor(_11_12_13, _21_22_23, _41_42_43),					-minor(_12_13_14, _22_23_24, _32_33_34),					minor(_11_13_14, _21_23_24, _31_33_34),					-minor(_11_12_14, _21_22_24, _31_32_34),					minor(_11_12_13, _21_22_23, _31_32_33)				);				#undef minor				return transpose(cofactors) / determinant(input);			} 			v2f vert (appdata v)			{				v2f o;				float4 bbLocalVertx = Billboard(v.vertex);				o.vertex = mul(UNITY_MATRIX_MVP,  bbLocalVertx);				o.uv = TRANSFORM_TEX(v.uv, _MainTex);				return o;			}						fixed4 frag (v2f i) : SV_Target			{				fixed4 col = tex2D(_MainTex, i.uv);				return col;			}			ENDCG		}	}}

广告板技术6：草 ---------------------- 类似4、5，不过要提防unity的动静态合并，可以先选择在3dsmax中做一个草坪的4边形集合，这样就可以确定各四边形的localCenter.

转载于:https://www.cnblogs.com/skylinee/p/5811545.html

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