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"It's like the difference between night and day!" - Polishing the lighting

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Hi everyone!

It has been a long time (nearly a year) since i last worked on this game. My usual development routine involves having multiple games in progress at any one time. Once i start feeling burn-out coming on, or boredom setting in with one project i flip to the other, until one or the other is complete, always having more than one ready to be developed.

This is the way it has been for me for over a decade, and it works very well for me.

To this end when restarting working on this project i took a long hard look at what I could and couldn't quickly improve in the codebase. The graphics of the game were severely lacking, with no real lighting, no shadow mapping, no physically-based rendering, none of the textures had normal maps, etc.

To add these features myself and get them looking good would take quite some time. Once they were added, i would need to implement a toolset to manipulate them correctly, and then test it all. This would also take a long time.

My other project, which some of you may have been following, was written in UE4, and this gave me the features mentioned above out of the box. I decided therefore to take my existing C++ code, and adapt it to Unreal Engine 4, using UE4 to do the rendering and sound (this also gets rid of the licensing requirements of using fmod for sound and music, as these features plus 3D audio are built into UE4).

It took surprisingly little time to get something looking pretty good out of UE4 using my existing assets, scaled up using GIMP's Sinc (Lanczos 3) scaling which prevents blockiness you usually get when scaling up an image. In the end, i plan to re-create these assets myself using edge detection to turn them into line art, then scaling the line art to suit. Currently, my old 64x64 textures have been scaled successfully to 512x512.

By being very creative, and spending the better part of 6 hours tweaking light levels, placing spot and point lights, emissive materials etc, i came up with something that pleases my eyes and looks very impressive, especially compared to the old game:

[table]
[tr][td][sharedmedia=gallery:images:7291][/td][td][sharedmedia=gallery:images:6404][/td][/tr]
[tr][td]New Graphics[/td][td]Old Graphics[/td][/tr]
[/table]

The graphics in the new version are a bit of a hack. To keep performance good when lots of particle effects will be going off, i have intended to keep FPS high at this point, and consider carefully everything i do. Therefore, the lighting must be carefully planned out. A lot of the lighting must be dynamic (movable lights) rather than static, baked lighting, as most of the items inside the room can move, including the 'play table' itself. To this end i decided that even though the game's room looks like it is indoors on a sunny day, there is actually no real sky light and no real outside environment.

Outside the room is a quad, which has an image of an outdoor scene textured onto it. The material used to texture this quad has a high emissive value (texel colour * 8.0) which makes it shine with brightness like a bright sunny day when viewed from inside a dark room. This in itself is not enough to cause light shafts to stream in through the open windows however and shadows to be cast on inside items, as the emissive materials in UE4 are a bit of a hack, which to cut a long story short, technically don't really emit light (unless you're using light propogation volumes, which are a performance hit, and still experimental even in 4.10) - it is just a post-processing effect or two.

So, to emit light, i have added a single spotlight slightly above, in front of, and to the left of the textured quad, still outside the window. The intensity of this light has been ramped up to 100,000 units, which causes a really bright light to be shone in through the window with much the same intensity as the sun on a bright summer day. For all intents and purposes, the effect is the same as being inside a room with a bright day outside. To complete the effect, as all factories and offices seem to have them, a point light has been placed just below the ceiling of the room, casting a less powerful set of shadows almost straight down. This is why when you look at the image the machines etc seem to have two shadows, one darker than the other.

The complete layout of my room (as i can't just screenshot the editor, there is no "light outside" to be cast on it to show you) is sketched below:

[sharedmedia=gallery:images:7292]

I am still undecided wether or not the high bloom effect actually contributes to the scene or detracts from it, comments on this as always or anything else are welcome :)


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