# Flipped Normals On Back Faces

I'm trying to create grass quads and have therefore disabled backface culling when rendering these quads. With each vertex normal set upwards ( 0.f, 1.f, 0.f ), all front faces are lit correctly, but backfaces are black. If I change the the Y normal to -1.f the backfaces light up and the front faces go black.

D3D11_RASTERIZER_DESC desc {};

desc.AntialiasedLineEnable  = false;
desc.CullMode               = D3D11_CULL_NONE;
desc.DepthBias              = 0;
desc.DepthBiasClamp         = 0.f;
desc.DepthClipEnable        = true;
desc.FillMode               = D3D11_FILL_SOLID;
desc.FrontCounterClockwise  = false;
desc.MultisampleEnable      = false;
desc.ScissorEnable          = false;
desc.SlopeScaledDepthBias   = 0.f;


I'm not so sure there's a problem here. Any ideas?

• Are you only applying duffuse lighting? Ambient would need to be applied also – ErnieDingo Feb 22 '18 at 8:55
• to add also, no, there is no problem here. I am assuming your lighting model is responding correctly due to the normal just being flipped. Could you post your pixel shader to assist in elaborating what your code is doing. – ErnieDingo Feb 22 '18 at 21:55