Your C++ application sets the color of the ambient lighting by invoking the IDirect3DDevice7::SetRenderState method and passing the enumerated value D3DRENDERSTATE_AMBIENT as the first parameter. The second parameter is a color in RGBA format. The default is zero.

// This code fragment assumes that lpD3DDevice is a valid pointer to
// an IDirect3DDevice7 interface.
 
// Set the ambient light.
D3DCOLOR d3dclrAmbientLightColor = D3DRGBA(1.0f,1.0f,1.0f,1.0f);
lpD3DDevice->SetRenderState(D3DRENDERSTATE_AMBIENT, 
                            d3dclrAmbientLightColor);

A Visual Basic application sets the color of the ambient lighting by invoking the Direct3DDevice7.SetRenderState method and passing the enumerated value D3DRENDERSTATE_AMBIENT as the first parameter. The second parameter is a color in RGBA format. The default is zero.

' This code fragment assumes that D3DDevice contains a valid
' reference to a Direct3DDevice7 object, and dx contains a 
' valid reference to a DirectX7 object.
Dim AmbientLightColor As Long

' Set the ambient light.
AmbientLightColor = dx.CreateColorRGBA(1#, 1#, 1#, 1#)
Call D3DDevice.SetRenderState(D3DRENDERSTATE_AMBIENT, _
                              AmbientLightColor)