How to inverse the Mesh.

Questions & Answers
1

I have a First Person Controler. I want to create a ability that when they hold down the spacebar a shiled buble apears around them. I can do the scripting, but the size I want the bubble to be is so large, that the camera is inside the sphere, and I cant see the mesh. Is there a way to invert the mesh so that when the camera is inside the sphere, you can see its texture?
Thanks!

2

Which side of a triangle is visible depends on the winding order of the vertices. If they are drawn clockwise it’s visible, if they are drawn counter-clockwise it’s not visible. To change the winding order all you have to do is to swap two of the three indices of each triangle in the mesh.

edit
Changed the code so it works in both languages C# and UnityScript. I also added a few lines to flip the vertex normals as well so the lighting is correct.

//C# or UnityScript
var indices = mesh.triangles;
var triangleCount = indices.Length / 3;
for(var i = 0; i < triangleCount; i++)
{
    var tmp = indices[i*3];
    indices[i*3] = indices[i*3 + 1];
    indices[i*3 + 1] = tmp;
}
mesh.triangles = indices;
// additionally flip the vertex normals to get the correct lighting
var normals = mesh.normals;
for(var n = 0; n < normals.Length; n++)
{
    normals[n] = -normals[n];
}
mesh.normals = normals;
3

Ok, what I ended up doing was copying the script on The page @alucardj referenced

and applied it to the object with the mesh I wanted to invert. The lighting is a little wierd, but nothing mega important. The only thing that I dont like about it is that it wont work with the built in Icosphere mesh that I like. :frowning:

4

Even easier you can turn culling off for that “sphere”, you could use this as the shader, it’s a Standard Shader with Cull shut off, it will render both sides automatically (just copy this and save it “StandardCullOFF.shader” ):

Shader "StandardCullOFF"
{
	Properties
	{
		_Color("Color", Color) = (1,1,1,1)
		_MainTex("Albedo", 2D) = "white" {}
		
		_Cutoff("Alpha Cutoff", Range(0.0, 1.0)) = 0.5

		_Glossiness("Smoothness", Range(0.0, 1.0)) = 0.5
		_GlossMapScale("Smoothness Scale", Range(0.0, 1.0)) = 1.0
		[Enum(Metallic Alpha,0,Albedo Alpha,1)] _SmoothnessTextureChannel ("Smoothness texture channel", Float) = 0

		[Gamma] _Metallic("Metallic", Range(0.0, 1.0)) = 0.0
		_MetallicGlossMap("Metallic", 2D) = "white" {}

		[ToggleOff] _SpecularHighlights("Specular Highlights", Float) = 1.0
		[ToggleOff] _GlossyReflections("Glossy Reflections", Float) = 1.0

		_BumpScale("Scale", Float) = 1.0
		_BumpMap("Normal Map", 2D) = "bump" {}

		_Parallax ("Height Scale", Range (0.005, 0.08)) = 0.02
		_ParallaxMap ("Height Map", 2D) = "black" {}

		_OcclusionStrength("Strength", Range(0.0, 1.0)) = 1.0
		_OcclusionMap("Occlusion", 2D) = "white" {}

		_EmissionColor("Color", Color) = (0,0,0)
		_EmissionMap("Emission", 2D) = "white" {}
		
		_DetailMask("Detail Mask", 2D) = "white" {}

		_DetailAlbedoMap("Detail Albedo x2", 2D) = "grey" {}
		_DetailNormalMapScale("Scale", Float) = 1.0
		_DetailNormalMap("Normal Map", 2D) = "bump" {}

		[Enum(UV0,0,UV1,1)] _UVSec ("UV Set for secondary textures", Float) = 0


		// Blending state
		 _Mode ("__mode", Float) = 0.0
		 _SrcBlend ("__src", Float) = 1.0
		 _DstBlend ("__dst", Float) = 0.0
		 _ZWrite ("__zw", Float) = 1.0
	}

	CGINCLUDE
		#define UNITY_SETUP_BRDF_INPUT MetallicSetup
	ENDCG

	SubShader
	{
		Tags { "RenderType"="Opaque" "PerformanceChecks"="False" }
		LOD 300
	

		// ------------------------------------------------------------------
		//  Base forward pass (directional light, emission, lightmaps, ...)
		Pass
		{
			
			Name "FORWARD" 
			Tags { "LightMode" = "ForwardBase" }

			Blend [_SrcBlend] [_DstBlend]
			ZWrite [_ZWrite]
			Cull Off

			CGPROGRAM
			#pragma target 3.0

			// -------------------------------------

			#pragma shader_feature _NORMALMAP
			#pragma shader_feature _ _ALPHATEST_ON _ALPHABLEND_ON _ALPHAPREMULTIPLY_ON
			#pragma shader_feature _EMISSION
			#pragma shader_feature _METALLICGLOSSMAP
			#pragma shader_feature ___ _DETAIL_MULX2
			#pragma shader_feature _ _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A
			#pragma shader_feature _ _SPECULARHIGHLIGHTS_OFF
			#pragma shader_feature _ _GLOSSYREFLECTIONS_OFF
			#pragma shader_feature _PARALLAXMAP

			#pragma multi_compile_fwdbase
			#pragma multi_compile_fog

			#pragma vertex vertBase
			#pragma fragment fragBase
			#include "UnityStandardCoreForward.cginc"

			ENDCG
		}
		// ------------------------------------------------------------------
		//  Additive forward pass (one light per pass)
		Pass
		{
			Name "FORWARD_DELTA"
			Tags { "LightMode" = "ForwardAdd" }
			Blend [_SrcBlend] One
			Fog { Color (0,0,0,0) } // in additive pass fog should be black
			ZWrite Off
			ZTest LEqual

			CGPROGRAM
			#pragma target 3.0

			// -------------------------------------


			#pragma shader_feature _NORMALMAP
			#pragma shader_feature _ _ALPHATEST_ON _ALPHABLEND_ON _ALPHAPREMULTIPLY_ON
			#pragma shader_feature _METALLICGLOSSMAP
			#pragma shader_feature _ _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A
			#pragma shader_feature _ _SPECULARHIGHLIGHTS_OFF
			#pragma shader_feature ___ _DETAIL_MULX2
			#pragma shader_feature _PARALLAXMAP

			#pragma multi_compile_fwdadd_fullshadows
			#pragma multi_compile_fog


			#pragma vertex vertAdd
			#pragma fragment fragAdd
			#include "UnityStandardCoreForward.cginc"

			ENDCG
		}
		// ------------------------------------------------------------------
		//  Shadow rendering pass
		Pass {
			Name "ShadowCaster"
			Tags { "LightMode" = "ShadowCaster" }

			ZWrite On ZTest LEqual

			CGPROGRAM
			#pragma target 3.0

			// -------------------------------------


			#pragma shader_feature _ _ALPHATEST_ON _ALPHABLEND_ON _ALPHAPREMULTIPLY_ON
			#pragma shader_feature _METALLICGLOSSMAP
			#pragma shader_feature _PARALLAXMAP
			#pragma multi_compile_shadowcaster

			#pragma vertex vertShadowCaster
			#pragma fragment fragShadowCaster

			#include "UnityStandardShadow.cginc"

			ENDCG
		}
		// ------------------------------------------------------------------
		//  Deferred pass
		Pass
		{
			Name "DEFERRED"
			Tags { "LightMode" = "Deferred" }

			CGPROGRAM
			#pragma target 3.0
			#pragma exclude_renderers nomrt


			// -------------------------------------

			#pragma shader_feature _NORMALMAP
			#pragma shader_feature _ _ALPHATEST_ON _ALPHABLEND_ON _ALPHAPREMULTIPLY_ON
			#pragma shader_feature _EMISSION
			#pragma shader_feature _METALLICGLOSSMAP
			#pragma shader_feature _ _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A
			#pragma shader_feature _ _SPECULARHIGHLIGHTS_OFF
			#pragma shader_feature ___ _DETAIL_MULX2
			#pragma shader_feature _PARALLAXMAP

			#pragma multi_compile ___ UNITY_HDR_ON
			#pragma multi_compile ___ LIGHTMAP_ON
			#pragma multi_compile ___ DIRLIGHTMAP_COMBINED DIRLIGHTMAP_SEPARATE
			#pragma multi_compile ___ DYNAMICLIGHTMAP_ON

			#pragma vertex vertDeferred
			#pragma fragment fragDeferred

			#include "UnityStandardCore.cginc"

			ENDCG
		}

		// ------------------------------------------------------------------
		// Extracts information for lightmapping, GI (emission, albedo, ...)
		// This pass it not used during regular rendering.
		Pass
		{
			Name "META" 
			Tags { "LightMode"="Meta" }

			Cull Off

			CGPROGRAM
			#pragma vertex vert_meta
			#pragma fragment frag_meta

			#pragma shader_feature _EMISSION
			#pragma shader_feature _METALLICGLOSSMAP
			#pragma shader_feature _ _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A
			#pragma shader_feature ___ _DETAIL_MULX2

			#include "UnityStandardMeta.cginc"
			ENDCG
		}
	}

	SubShader
	{
		Tags { "RenderType"="Opaque" "PerformanceChecks"="False" }
		LOD 150

		// ------------------------------------------------------------------
		//  Base forward pass (directional light, emission, lightmaps, ...)
		Pass
		{
			Name "FORWARD" 
			Tags { "LightMode" = "ForwardBase" }

			Blend [_SrcBlend] [_DstBlend]
			ZWrite [_ZWrite]

			CGPROGRAM
			#pragma target 2.0
			
			#pragma shader_feature _NORMALMAP
			#pragma shader_feature _ _ALPHATEST_ON _ALPHABLEND_ON _ALPHAPREMULTIPLY_ON
			#pragma shader_feature _EMISSION 
			#pragma shader_feature _METALLICGLOSSMAP 
			#pragma shader_feature _ _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A
			#pragma shader_feature _ _SPECULARHIGHLIGHTS_OFF
			#pragma shader_feature _ _GLOSSYREFLECTIONS_OFF
			// SM2.0: NOT SUPPORTED shader_feature ___ _DETAIL_MULX2
			// SM2.0: NOT SUPPORTED shader_feature _PARALLAXMAP

			#pragma skip_variants SHADOWS_SOFT DIRLIGHTMAP_COMBINED DIRLIGHTMAP_SEPARATE

			#pragma multi_compile_fwdbase
			#pragma multi_compile_fog

			#pragma vertex vertBase
			#pragma fragment fragBase
			#include "UnityStandardCoreForward.cginc"

			ENDCG
		}
		// ------------------------------------------------------------------
		//  Additive forward pass (one light per pass)
		Pass
		{
			Name "FORWARD_DELTA"
			Tags { "LightMode" = "ForwardAdd" }
			Blend [_SrcBlend] One
			Fog { Color (0,0,0,0) } // in additive pass fog should be black
			ZWrite Off
			ZTest LEqual
			
			CGPROGRAM
			#pragma target 2.0

			#pragma shader_feature _NORMALMAP
			#pragma shader_feature _ _ALPHATEST_ON _ALPHABLEND_ON _ALPHAPREMULTIPLY_ON
			#pragma shader_feature _METALLICGLOSSMAP
			#pragma shader_feature _ _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A
			#pragma shader_feature _ _SPECULARHIGHLIGHTS_OFF
			#pragma shader_feature ___ _DETAIL_MULX2
			// SM2.0: NOT SUPPORTED shader_feature _PARALLAXMAP
			#pragma skip_variants SHADOWS_SOFT
			
			#pragma multi_compile_fwdadd_fullshadows
			#pragma multi_compile_fog
			
			#pragma vertex vertAdd
			#pragma fragment fragAdd
			#include "UnityStandardCoreForward.cginc"

			ENDCG
		}
		// ------------------------------------------------------------------
		//  Shadow rendering pass
		Pass {
			Name "ShadowCaster"
			Tags { "LightMode" = "ShadowCaster" }
			
			ZWrite On ZTest LEqual

			CGPROGRAM
			#pragma target 2.0

			#pragma shader_feature _ _ALPHATEST_ON _ALPHABLEND_ON _ALPHAPREMULTIPLY_ON
			#pragma shader_feature _METALLICGLOSSMAP
			#pragma skip_variants SHADOWS_SOFT
			#pragma multi_compile_shadowcaster

			#pragma vertex vertShadowCaster
			#pragma fragment fragShadowCaster

			#include "UnityStandardShadow.cginc"

			ENDCG
		}

		// ------------------------------------------------------------------
		// Extracts information for lightmapping, GI (emission, albedo, ...)
		// This pass it not used during regular rendering.
		Pass
		{
			Name "META" 
			Tags { "LightMode"="Meta" }

			Cull Off

			CGPROGRAM
			#pragma vertex vert_meta
			#pragma fragment frag_meta

			#pragma shader_feature _EMISSION
			#pragma shader_feature _METALLICGLOSSMAP
			#pragma shader_feature _ _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A
			#pragma shader_feature ___ _DETAIL_MULX2

			#include "UnityStandardMeta.cginc"
			ENDCG
		}
	}


	FallBack "VertexLit"
	CustomEditor "StandardShaderGUI"
}