The image on the left is called a "normal map". The weird colors are used to tell a game engine how lighting is meant to interact with a flat texture. It can create shadow and highlights on flat surfaces to mimic a 3D look without needing to use a higher detail model.
By combining the cobblestone texture in the caption with the normal map on the left, the game engine can create the realistically lit cobblestone street on the right out of just a flat plane.
To be pedantic, they don't create shadows, they merely indicate which texels reflect light in which direction.
Shadows (ambient diffusion? idk) are more of a bump map thing, which normal maps are sometimes conflated with and they seem to be too much of a headache for me to look into.
What
The image on the left is called a "normal map". The weird colors are used to tell a game engine how lighting is meant to interact with a flat texture. It can create shadow and highlights on flat surfaces to mimic a 3D look without needing to use a higher detail model.
By combining the cobblestone texture in the caption with the normal map on the left, the game engine can create the realistically lit cobblestone street on the right out of just a flat plane.
To be pedantic, they don't create shadows, they merely indicate which texels reflect light in which direction.
Shadows (ambient diffusion? idk) are more of a bump map thing, which normal maps are sometimes conflated with and they seem to be too much of a headache for me to look into.
True, no real shadows are being cast! Normal maps are bump maps though, could you be thinking of height maps?
I thought the two were the same, talk about conflating huh?