title: how do I translate a vector from xyz to xy using a plane normal? (using hlsl)
body: <pre><code>float3 plane_normal = mul(mesh_Object2World, v.normal);
  o.normal = o.worldPos - _Mouse.xyz;
  </code></pre>
  <p>//next, I dont know how to translate &quot;o.normal&quot; to 2d using &quot;plane_normal&quot;</p>