Texture Streaming
Load only the mip you need
Also known as: Mip streaming · Virtual texturing
Definition
Texture streaming keeps high-resolution mips of a texture on disk and only loads the level of detail the camera currently needs into VRAM. It is what lets open-world games fit on a console: instead of holding every 4K texture resident, the engine streams smaller mips for distant or off-screen surfaces and promotes them when the camera gets close. The visible artifact is a brief blur when you turn a corner — usually a sign of bandwidth pressure or mis-tagged priorities.
In production
Unreal Engine's virtual texturing and standard texture streaming pool both rely on mip-map generation at import — if an artist disables mips on a texture (common for UI sprites) it becomes streaming-ineligible and stays fully resident, a frequent cause of memory budget overruns on console certification. The pop-in blur players notice when whipping the camera around in an open-world game is the streamer failing to hit its target mip in time, usually because the Texture Streaming Pool Size in Unreal's project settings is set too low for the target platform's VRAM. Unity's mipmap streaming uses a similar priority system, and artists can flag specific textures as "non-streaming" for things like hero character faces where any softness is unacceptable in cutscenes. On PS5/Xbox Series X, the fast SSD lets both engines load higher-priority mips within a frame or two, which is why current-gen texture pop-in is far less visible than on HDD-based last-gen hardware.
