Chasm: The Rift

   Poor man's Quake.

   Chasm: The Rift is a 1997 FPS [1]game, developed basically by a few
   Ukrainian basement nerds to be a cheaper version of [2]Quake, which was of
   course completely overshadowed by this giant and therefore isn't much
   known but which is nevertheless quite technically impressive upon closer
   inspection.

   { TODO: do more research about the engine, attempt to translate the
   Russian YT video, reach the devs. ~drummyfish }

   The game requirements were a [3]486 [4]CPU (which reached 100 MHz at
   most), 16 MB [5]RAM and 75 MB storage space.

   The engine is possibly the most [6]interesting part of the game as it used
   [7]software rendering that combined a [8]"2.5D" level rendering and "true
   3D" polygonal models for things like level decorations, enemies and weapon
   view model. Not much is known about the internals as the whole code is
   proprietary and "closed source", we may only inspect it visually and
   through [9]reverse engineering. To us it is not known if environment
   rendering uses [10]BSP rendering, [11]portal rendering, [12]raycasting,
   something similar or whether it just utilizes its 3D model renderer for
   levels too, however there are some 2.5D simplifications going on as levels
   are defined as 2D (no room-above-room) and looking up/down is faked (even
   for the environment inserted "true 3D" models, the up/down look is limited
   to just a small offset probably to mask the "2.5D" nature of the engine).
   In fact it isn't even possible to have different height levels of floor,
   all levels just have the same floor height (ceiling height can be set
   though)! This is masked a bit by using 3D models onto which it is indeed
   possible to jump. The game's level editor shows levels use a square grid
   on which however it is possible to place even non-90 degree walls. There
   is also a [13]lightmap lighting system present allowing [14]dynamic lights
   -- a pretty advanced feature, though the lightmap only seems to be 2D,
   just as the level itself. Destructible environment is also faked in some
   levels by having a 3D model behaving like part of a wall, then
   disappearing when destroyed.

   Apart from the engine the game was also nice for being quite [15]KISS,
   taking similar approach to e.g. [16]Anarch by using very minimal menu and
   controls: for example there is no door opening or "use" button, items just
   activate by proximity, weapon switching is also performed by single
   button. This is actually quite nice as setting up controls and learning
   them is many times something that just puts you off.

See Also

     * [17]Gloom

Links:
1. game.md
2. quake.md
3. 486.md
4. cpu.md
5. ram.md
6. interesting.md
7. sw_rendering.md
8. pseudo3d.md
9. reverse_engineering.md
10. bsp.md
11. portal_rendering.md
12. raycasting.md
13. lightmap.md
14. dynamic.md
15. kiss.md
16. anarch.md
17. gloom.md