Baked lighting versus real-time lighting
Some light is painted into the scene ahead of time. Some is calculated while you play. The picture and the frame rate both care.
Lighting is half of what a screenshot is selling, and it is also a bill the frame rate pays. Some of that light is calculated while you move. Some was calculated earlier and stored in the scene like paint. Baked lighting and real-time lighting are not rival religions. They are two ways to spend a limited budget, and most games quietly use both.
What baking stores
Baking means the tool computes light for a static scene ahead of time and saves the result, often in textures or probes the game can sample cheaply. A beautiful bounce of warm light into a hallway can be almost free at runtime because the work already happened on someone's computer overnight. The limit is motion. A baked shadow does not know about a door you opened or a character who walked in, unless the team fakes that part another way. Move a baked lamp in play and the paint is now a lie. A Calm Guide to the Graphics Settings That Matter Most is the player-side stack. Baking is why some of that stack looks rich on modest hardware.
What real-time light spends
A real-time light asks the GPU to consider that lamp for the surfaces it touches, this frame. Move the lamp and the picture updates. Characters cast shadows that belong to this instant. The cost climbs with the number of lights, the shadow resolution, and the screen area. A scene that was calm with one sun becomes a different performance problem with a dozen torches all casting shadows. This is why games cheat: a few lights are real, many are unshadowed or baked, and the hero light is the one that had to move.
The hybrid you are usually seeing
A common picture is a baked world, a real-time sun or flashlight, and blob or capsule shadows under characters that would be too expensive to light truthfully. You accept it because the floor's color feels right and the moving shadow tells you where the danger is. When the hybrid fails, you see a character with two shadows, or a dark room that ignores your torch, or a seam where a baked corner meets a dynamic object. Those are production seams, not proof that one method is fake and the other is pure. What Does a Game Engine Actually Do Every Frame? includes this work in the frame. Something had to be precomputed or the frame would not end.
Time of day and destructible rooms
If the sun must crawl across the sky, baking one beautiful hour is not enough. Teams bake several hours, blend them, or pay for a more dynamic sky and accept a simpler bounce. Destructible games have the same trouble. A wall that can vanish cannot own a shadow painted forever. The more the world changes, the more the lighting has to be willing to forget its homework. That willingness costs frame rate or artist time. Sometimes both.
How to look at a screenshot honestly
Ask what can move. If nothing in the promo moves except the character, you may be admiring a bake. If every neon sign flickers and casts a unique shadow, someone is paying at runtime, or the shot is a trailer captured with settings the game will not hold. Game Engines Explained for Curious Players is a map of these tradeoffs without the keynote. Pretty is a budget. It is always a budget.
Frequently asked questions
Is baked light outdated? No. It is still how many interiors look warm without setting the GPU on fire. Outdated is using it and then moving the furniture in play without a plan.
Why do my shadows look blocky? Shadow maps have a resolution. A larger or closer map looks sharper and costs more. Blocky can be a setting, a distance, or a real-time shadow asked to cover too much ground.
Can a game be fully real-time and still run? Yes, with fewer lights, simpler bounces, or a machine that can pay. Fully real-time is a choice about what you refuse to precompute, not a quality ranking.