Texture Atlas Shader

Hello, it's me again..

i thought that today i can solve my uv atlas problem, but it seems that im not the best coder in the GLSL/HLSL languages... so my question.. can somebody help/show me or give me an example for texture altases.

A full shader example would be nice.. as i said im not the best shader coder...

Here are my greedy voxel chunks:


As u can see the uvs r correct.. but i can only display one texture and i don't want to use submeshes because of performance issues...

I've found a solution for texture atlases with greedy meshing:
https://0fps.net/2013/07/09/texture-atlases-wrapping-and-mip-mapping/

Thanks to everyone who can help me solving this problem

MR Michael

 

ok i found a solution.. but i works not perfectly..

here is the uv error:


can somebody explain why the textures r stretched?

this is my shader:

Code (CSharp):

1. Shader "BioGen/Block" {
2.     Properties{
3.         _MainTex("Atlas", 2D) = "gray" {}
4.     }
5.         SubShader{
6.         Tags{ "RenderType" = "Opaque" }
7.         LOD 200
8.  
9.         CGPROGRAM
10. #pragma surface surf Standard fullforwardshadows
11. #pragma target 3.0
12.  
13.         sampler2D _MainTex;
14.  
15.     struct Input {
16.         float4 color : COLOR;
17.         float3 worldNormal;
18.         float3 worldPos;
19.     };
20.  
21.     void surf(Input i, inout SurfaceOutputStandard o)
22.     {
23.         const float gridSize = 8;
24.         const float margin = (1 / gridSize) / 4; //For 16x16 textures, margin of 1px, 32x32 => 2px etc.
25.         const float cellSize = (1 / gridSize) - (margin * 2);
26.         float blockId = int(i.color.a * gridSize * gridSize) / gridSize;
27.  
28.         float2 uv = float2(
29.             i.worldPos.x * (1 - i.worldNormal.x) + i.worldPos.z * i.worldNormal.x,
30.             i.worldPos.y * (1 - i.worldNormal.y) + i.worldPos.z * i.worldNormal.y);
31.  
32.         fixed4 c = tex2Dgrad(_MainTex, frac(uv) * cellSize + float2(blockId + margin, floor(blockId) / gridSize + margin), ddx(uv * cellSize), ddy(uv * cellSize));
33.         o.Albedo = c.rgb;
34.     }
35.     ENDCG
36.     }
37.         FallBack "Diffuse"
38. }

and here is my texture atlas, it is 32x32px and i supports 8 textures for now...