Apply UV to procedural mesh

Question

I have created a mesh procedurally and then I am trying to create a terrain on top of it. I am new to Unity so from what I understand I need to start by applying some texture to do so. In order to do that though I first need to apply the UV to my mesh. What I had in mind is, simply place the texture on top of the mesh but from what I understood I can't do that and I need to generate per triangle the uv. Doing the above with this code:

  Vector2[] uvs_temp = Unwrapping.GeneratePerTriangleUV(mesh);
  Vector2[] uvs= new Vector2[vertices.Length];

  for(int i=0; i<uvs_temp.Length; i++) {
         // Removing duplicates 
         if(i == 0 || uvs_temp[i] != uvs_temp[i-1]) {
             uvs[i] = new Vector2(uvs_temp[i].x, uvs_temp[i].y);
         }
   }

   mesh.uv = uvs;

Results in the result above which if I understand correctly since I applied to each trianglethe uv, it re-applies the same grass per triangle, but I can't understand how to fix it.

How can I apply a texture on top of my whole mesh?

alt text

Answer 1

I am also quite new to Unity and I don't know if this will help, but I know that you can use a shader to apply the texture to your mesh. For example, you could write a standard surface shader that will apply a texture using world coordinates instead. Here is a sample code I wrote for this:

 Shader "Custom/TerrainShader"
 {
     Properties
     {
         _Color ("Color", Color) = (1,1,1,1)
         _MainTex ("Albedo (RGB)", 2D) = "white" {}
         _Glossiness ("Smoothness", Range(0,1)) = 0.5
         _Metallic ("Metallic", Range(0,1)) = 0.0
     }
     SubShader
     {
         Tags { "RenderType"="Opaque" }
         LOD 200
 
         CGPROGRAM
         // Physically based Standard lighting model, and enable shadows on all light types
         #pragma surface surf Standard fullforwardshadows
 
         // Use shader model 3.0 target, to get nicer looking lighting
         #pragma target 3.0
 
         sampler2D _MainTex;
         float4 _MainTex_ST;
 
         struct Input 
         {
             float3 worldPos;
         };
 
         half _Glossiness;
         half _Metallic;
         fixed4 _Color;
 
         // Add instancing support for this shader. You need to check 'Enable Instancing' on materials that use the shader.
         // See https://docs.unity3d.com/Manual/GPUInstancing.html for more information about instancing.
         // #pragma instancing_options assumeuniformscaling
         UNITY_INSTANCING_BUFFER_START(Props)
             // put more per-instance properties here
         UNITY_INSTANCING_BUFFER_END(Props)
 
         void surf (Input IN, inout SurfaceOutputStandard o)
         {
             // Albedo comes from a texture tinted by color
             fixed4 c =  tex2D (_MainTex, float2(_MainTex_ST.z + _MainTex_ST.x * IN.worldPos.x, _MainTex_ST.w + _MainTex_ST.y * IN.worldPos.z)) * _Color;
             o.Albedo = c.rgb;
             // Metallic and smoothness come from slider variables
             o.Metallic = _Metallic;
             o.Smoothness = _Glossiness;
             o.Alpha = c.a;
         }
         ENDCG
     }
     FallBack "Diffuse"
 }

This Standard Surface Shader applies a repeating texture to a mesh with the x-axis and z-axis. The only issue you might encounter with this is if you move your terrain. If you do so, the texture will stretch. Hopefully this will help.

Apply UV to procedural mesh

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