Shaders

Shaders are Mods that can add things such as different lighting, waving water, clouds, reflections and much more. Now-a-days the shader mod is bundled inside of Optifine, but they used to require a mod called "GLSL Shader Mod", thats why you may see that name around when you are searching for shaderpacks.

Most shader packs add sunlight lighting and shadows, as that is one of the most immediately noticeable things you'll like to see in the game, but there are other packs that only add basic stuff like wavy leaves and water, these packs are usually called "lite" or lightweight shaderpacks that are suitable for people who have computers that cannot handle the significant additions of a full pack.

The shaderpack I've been mentioning here and there in this tutroial page is called SEUS PTGI, made by Sonic Ether, for our following topics we'll be using that one.

Yes, SEUS does look a lot like RTX on Bedrock version the only difference is that the RTX version is considered "True" Raytracing, where as SEUS is called path tracing.

True Raytracing utilizes special "cores" called Cuda cores, found on NVIDIA 20 & 30 Series Graphics cards, the RTX version was made in collaboration with NVIDIA in order to provide RTX ray tracing properly to the bedrock version of the game, it is however not currently possible for JAVA edition, this is why we use path tracing which uses the standard graphics processor.

Path tracing is a much more expensive process due to the fact that your GPU is not only trying to perform the calculations for path tracing, but you're also trying to run your game on it, and the desktop of your computer, and possibly YouTube in your browser... basically everything you are seeing on screen is being run off that graphics processor, so to add path tracing to that is very stressful for your poor old computer. This is why shaders with path tracing support dont run at very high frame rates, some developers like Sonic Ether have tried methods to relive this burden, his latest shaderpack SEUS PTGI HHR 2.1 basically renders the game at a smaller resolution then upscales it to the resolution of your computer monitor, this works great but leaves issues with the sharpness of the image.

The best part about both path tracing & RTX is that they can create coloured light illumination blocks, because they are sending out light rays rather than faking it like a non-path-tracing shader would be to achieve lighting. SEUS is currently the only one I know of for Java Edition that can allow you to make coloured illumination blocks, they are specificly set to redstone_block lapis_block emerald_block and sea_lanturn, with a few extras like torches and glowstone.