Terrain shader questions

[tkuehnl]

Greetings,

  Am I correct that the terrain vertex data does not include tangents and binormals? I would like to add normal mapping to my shader, is my only option to calculate tangents and binormals in the shader? I have my concerns about performance with that method.

Anyone care to discuss? Anyone already have it working?

Much appreciated.

-Todd

[SylvainTV]

Yes for now you must compute Tangent & Binormal in shader.

It's not that hard in the case of land shader though. You can compute it in the vertex shader using the vertex normal as a base. It can be done with 2 or 3 cross products so the performance loss won't be big.

Tangent info will be soon available in minimesh & terrain.

[tkuehnl]

Thanks for the info Sylvain, I will compute them within the shader.

take care,

-Todd

[AriusEso]

I actually did this a couple months back. With the help of Sylvain and Waterman on IRC we got the following solution working. So, for anybody searching:

Code:

float3 Tangent   = cross(IN.Normal, float3(1, 0, 0));
float3 BiTangent = cross(Tangent, IN.Normal);
         Tangent          = cross(IN.Normal, BiTangent);