The title says it. What I want to avoid is this:
As you can see, the floor (which is a TriangleMesh, with a texture) is blurred.
Probably you need to use techniques like mip-mapping and anisotropic filtering, neither of which are controllable via the JavaFX 8 3D API as far as I know. Likely, internally the JavaFX implementation will use some degree of anisotropic filtering which is not configurable via public API. The diffuseMap used in a PhongMaterial only provides for a single texture image, not a mip-mapped image, and though there are scene aliasing hints that can be applied, that concept differs from texture filtering hints which would be more applicable to your situation. Likely, to achieve the result you wish, you either need to use a different API than JavaFX or a higher quality texture.