Not just that, you’ll also have the ability to create your own resource packs that let you change metallic properties, light emissions, and the roughness of materials. With features like direct lighting, emissive surfaces (such as glowstone and lava), realistic shadows, per-pixel emissive lighting, reflections, and transparent materials, you’ll have a whole new way to bring your beautiful worlds to life.
Before you go racing off to join the beta and get in on the fun (by following this very tempting link), please be aware that this beta, like every beta, is a work in progress. Things may go wrong, be a bit unstable, not available in all parts of the game (such as the Nether or the End), or may not match gameplay rules – but that’s part of the process. With that in mind, we’d love your help! Join the beta and let us know your suggestions on feedback.minecraft.net and of course please report all bugs on bugs.mojang.com. We have several known issues for this beta already and you can find the complete list at http://Aka.ms/rtxbeta.
[Source : xbox news]