15-493 Game Programming
Chobits - Postmortem

Game: Chobits
Team: David and Luisa

Overview:

Chobits is an adventure game based on anime series of the same title. Each level is an episode or scene from the anime. We try to follow the story as mush as possible, sequence of events that according in the story, and the map of the town story took place in. The first level we designed is based on episode 4, where Chii goes to buy panties for Hideki. You walk around in town, your mini persocon friend guid you toward your goal, you can also talk to NPCs and try to find your way to the panty store. There is also a battle mode (2 players), where Chii fights her sister, the Black Chii.

Features include single and multiplayer mode (battle mode), data driven design (level, event, cut scene, map, npc, input), 3D world (based on the original story), animated walking 3D characters, location based event trigger, collision detection, minimap, dialog boxs.

You control the main character with keyboard, default mapping for single player is

forward - 8
backward - 5
turn left - 4
turn right - 6
look up - -
look down - +
camera control : w, s, a, d, r, f, t, g
camera toggle - b
action - n
attack - m

Development summary:

Code:
ours
main
intro - display intro screens
game - main game loop

world - keep track of all component of the scene

camera - calculate camera stats
input - take input, update camera, player stats
course - render map, collison detection
events - keep track of in game events (cut scene and sumomo msg)
npc - npc AI, render 3DS models
minimap - render minimap
conversation - render npc dialog box and sumomo dialog box

library
lib3ds - from sourceforge


/afs/andrew.cmu.edu/course/15/493/www/projects/chobits/library
config.h


vector - from Jim Bruce


vector.h, util.h


Content:
3DS model - most models were created in poser and edited in 3ds max (a few i found on the web) some animation generated in poser some in max
texture - all building texture were taken from screen cap of the anime
data - all original

game.txt - list all the levels
level.txt - resources for the level
course.txt - map, generated based on the anime
also textures for buildings, player starting position
npc.txt - model resources, npc scripts
input.txt - key mapping (see doc/input-readme.txt about format)

Key technical challenges:

Animating 3DS models


it turned out 3DS format does not support the biped system from 3DSMax charactor studio. Since I alread spent fair amount of time learning and generating biped model, I decided to stick with biped instead of bone system. So I made the model animate by exporting every single frame in the loop into 3DS model and load each of them. It turns out not too bad, after the first loop, animation is cached into display list.

Combining the 2D and 3D graphics


The game makes heavy use of 2D graphics for cut scenes, the minimap, conversations, and other features. Rendering functions had to be ordered to keep the right things in front. A lot of tweaking was necessary to get the 2D graphics aligned properly, especially the text.

...


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Postmortem:

Problems:
3DS Model


I spent way too much time search for appropriate sample models on the web, and trying to learn 3DS and poser. Even after learning to use them, generating NPC takes way too long. But the animtion turned out very nice, esp the way players dress animates.

Content in general


This was the big bottleneck. Collecting textures and designing levels is an extremely time consuming process, and the nature of the game puts a heavy emphasis on getting the content right. The game is mostly content driven, and we didn't have much time for content. It was necessary to take numerous shortcuts and drop a variety of planned features to get level 1 in a playable state.

Culling and LOD


We didnt think the final map would be this big, so we didnt bother implementing fustrum culling. Actully occlusion culling would be the most appropriate since we have so many buildings, but we didnt think it would be worth the effort. Though LOD would probabbly help too. In the end we just added culling by radial distance, it's pretty effective just by itself.

Sucess:
Control


Input, player control and camera control turned out very nicely. You can remap the keys or disable them how ever you like. You can pick between 3 differernt camera mode, attched mode, detached mode and tailing mode (usually called detached). You can reposition your camera relative to the player. ie put it in the front to make it into FPS mode.

Conversations/Events


The systems for conversations with NPC's and messages from your mobile persocon worked well. Event triggering is a nice addition to the game content and interactivness. Sumomo messaging helps alot in replicating the feel of the original story where she help guid Chii to her final destination. Though it would be even nicer if we can fully combine NPC and events, and if we have better AI for NPCs. Then we can perhaps replaces the cut scene with the real thin

another one


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-the end-