Try forcing highp precision everywhere in the fragment shader, disabling mipmaps, using nearest-neighbor filtering, and verifying UV alignment. Compare encoded/decoded values in compute vs fragment shaders. Also check for texel padding and interpolation errors at probe boundaries.

“IBL” just means you're getting lighting from an image. Any method for sampling lighting from an image is IBL, what the OP is doing here definitely qualifies. There are of course many other options for implementing IBL, such as pre-filtered cubemaps and other related techniques.

If your image has sm…

Hi,

I'm building Mystalia Online which is a 2d online action RPG. You can play it here: https://mystalia.herokuapp.com/​ (may take a moment to load). It's made using a custom engine built from the ground up.

There are some basics that have been decided what the world should be like but we need to go …