Question by Skaltum · Nov 01, 2013 at 03:16 PM · shader material uv worldspace

How do I create a dynamicly spaced and UVed brick wall without having multiple material instances?

Hello, I'm trying to get world space uvs working to create a seamless facade without having to creating a seperate instance for each objects material. Here is an example of what I have achieved.

alt text

The red lines indicate seperate gameobjects that share a parent gameobject.

Windows can be added and removed from the facade. This causes seams between the objects if regular uvs are used.

The problem is that I have to pass in the worldToLocal matrix of parent that these objects share. This causes the material to turn into instances of the material.

I need a way to obtain the same effect without having to pass in the shared parents transformation matrix.

 Shader "Tri-Planar World" {
 
   Properties {
 
         _Side("Side", 2D) = "white" {}
 
         _SideScale("SideScale", Float) = 2
         
     }
     
     SubShader {
         Tags {
             "Queue"="Geometry"
             "IgnoreProjector"="False"
             "RenderType"="Opaque"
         }
 
         Cull Back
         ZWrite On
         
         CGPROGRAM
         #pragma surface surf Lambert
         #pragma exclude_renderers flash
 
         sampler2D _Side, _SecondTone;
         float _SideScale;
         float4x4 _SharedParent;
 
 
         struct Input {
             float3 worldPos;
         };
             
         void surf (Input IN, inout SurfaceOutput o) {
             float3 vertexPos = mul(_SharedParent, float4(IN.worldPos, 1)).xyz;
         
             float2 texCoord = frac(vertexPos.xy * _SideScale);
 
 
             o.Albedo =  tex2D(_Side, texCoord);
             
 
         } 
         ENDCG
 
     }
     Fallback "Diffuse"
 }

I'm setting the _SharedParent variable through this bit of script.

 /// <summary>
     /// Set all the shared parent matrix variables in the dynamic uv materials that are child of the component.transform.
     /// </summary>
     /// <param name="component">Start of material search and set as the shared parent.</param>
     protected static void SetWorldUvShaderMatrixInChildren(Component component)
     {
         Renderer[] renderers = component.GetComponentsInChildren<Renderer>();
         foreach (var renderer in renderers)
         {
             foreach (var mat in renderer.materials)
             {
                 //mat.HasProperty("_SharedParent") does not return true. probably because matrix4x4 is not supported in a property block.
                 if (mat.name.ToLower().Contains("triuv"))
                 {
                     mat.SetMatrix("_SharedParent", component.transform.worldToLocalMatrix);
                 }
             }
 
         }
     }

The solution also has to work for rotated surfaces:

alt text