The programs that are the most fun to write are games. Graphic games (like Super Mario Brothers) are complex programs requiring bitmapped graphics, which is covered in the guide "BitMap.doc". Other graphic games (like tic-tac-toe) are possible, but text-based games are a good starting point.
B2C is well suited to writing all-text role-playing games (RPGs). A role-playing game is one where you act as a character in a world created by the computer. You can interact with objects in that world and move from place to place. I will present a simple role-playing game using a generic approach. There are many ways to write RPGs, so you should experiment and find the one that makes most sense to you.
The first step in creating a RPG is deciding what your universe will be like. Is your setting in outer space? Or the deep sea? What is your experience level? Are you an expert spy? Or a novice cowboy? What is your goal in the adventure? Are you trying to get to the end of a maze? Or are you attempting to collect all the Dragon Balls? Regardless of the subject matter, a good RPG tells a story, and the more detailed your descriptions of the adventure, the more interested your user will be and the more exciting your game will be.
Once you have decided on a universe, make a map of the universe. Make a box for each room and a line with an arrow showing how to go from one room to the next. Keep it down to 5-10. Make a description for each room. Make a list of objects and decide where in universe these objects reside. Make a description for each object. Make a list of commands, like "north" to go north and "eat" to eat food.
The next step is a technical one. How do you get your inputs from the user? Will you list their options and have them input a number selecting what to do? Or will you have them input text strings and discover what commands work best.
This RPG is located in the TARDIS. It stands for Time and Relative Dimensions in Space. The RPG is based on the British TV Series "Dr. Who". The TARDIS is "dimensionally transcendental" which simply means that it is larger on the inside than on the outside. While the TARDIS is about the size of a telephone booth, it has many chambers inside. The goal of our game will be to enter the TARDIS, find the sonic screwdriver, and exit.
In this game each room is a separate Function. When you enter the function a description of the room is printed. When the function exits, it returns the number of the next room to go to. This offers our program modularity. Rather than a linear adventure that runs from the top of the program to the bottom, the user can wander from room to room and even get caught in a trap between rooms.
There are several tricks in this program. One trick is that the return value from each room is an integer describing the next room to visit. Using this method you can rewrite the adventure by changing descriptions and the return rooms. Another trick is "parsing". I create a variable with the value of the lettername of that variable. (eg: a=97). When I parse I check each letter in the "verb" against the variable. So, for "eat" I check verb[0]=e and verb[1]=a and verb[2]=t as well as verb[3]=0 (null terminator).
I allow you to carry 2 objects (one in each hand). And you can drop only 1 object in each room. The only commands are :
Command |
Meaning |
Description |
| n | go north | |
| e | go east | |
| s | go south | |
| w | go west | |
| I | Inventory | Lists all the objects you are carrying |
| eat | eat something | increase your energy |
| take | take something | move an object from right hand to left hand and pick up something in your right hand. do nothing if hands full |
| drop | drop something | drop something from your left hand move other object from right hand to left hand. cannot drop if room is full |
DO THIS |
Execute
the command "build tardis.bld". Download the tardis.app file to the
cybiko.
print "Welcome to Tardis" print "Press any key" print "To Continue" dim xxx[1] as char input xxx font "mini_normal_font" dim zz as int dim sd as int dim ky as int dim sc as int dim jb as int dim st as int sd=1 ky=2 sc=3 jb=4 st=5 dim iv[2] as int dim ir as int dim drp[10] as int dim vb[10] as char dim nrg as int dim cmd as int dim dr as int dim eat as int dim tk as int dim nh as int dim sh as int dim et as int dim wt as int dim inventory as int dr=1 eat=2 tk=3 nh=5 sh=6 et=7 wt=8 inventory=9 dim ou as int dim co as int dim ad as int dim va as int dim cl as int dim e1 as int dim e2 as int dim so as int ou=0 co=1 ad=2 va=3 cl=4 e1=5 e2=6 so=7 function parse ( zz as int) as int parse=0 if vb[0]=101 and vb[1]=97 and vb[2]=116 and vb[3]=0 then parse=eat elseif vb[0]=116 and vb[1]=97 and vb[2]=107 and vb[3]=101 and vb[4]=0 then parse=tk elseif vb[0]=100 and vb[1]=114 and vb[2]=111 and vb[3]=112 and vb[4]=0 then parse=dr elseif vb[0]=105 then parse=inventory elseif vb[0]=104 then parse=0'help elseif vb[0]=110 then parse=nh elseif vb[0]=115 then parse=sh elseif vb[0]=101 then parse=et elseif vb[0]=119 then parse=wt end if end function sub descObject(obj as int) if (obj = 1) then print "sonic screwdriver" elseif (obj = 2) then print "golden key" elseif (obj = 3) then print "very long scarf" elseif (obj = 4) then print "delicious jelly babies" elseif (obj = 5) then print "shining star" else print "nothing" end if end sub sub showinventory(zz as int) print "In your left hand" descObject(iv[0]) print "In your right hand" descObject(iv[1]) end sub sub drItem(zz as int) if drp[ir]=0 then drp[ir]=iv[0] iv[0]=iv[1] iv[1]=0 print "You dropped" descObject(drp[ir]) else print "Cant drop object here" end if end sub sub tkItem(zz as int) if drp[ir]<>0 then if iv[1]=0 then if iv[0]=0 then iv[0]=drp[ir] drp[ir]=0 print "Took . . ." descObject(iv[0]) elseif iv[1]=0 then iv[1]=drp[ir] drp[ir]=0 print "Took . . ." descObject(iv[1]) else print "Your hands are full" end if end if else print "There is nothing to take" end if end sub sub die(zz as int) print "you faint on the spot" print "The light on" print "top of the police box" print "flashes and the TARDIS" print "disappears from view" print "The End." beep 4 while 1 wend end sub sub eatFood(zz as int) if iv[0]=jb then iv[0] = iv[1] iv[1] = 0 nrg = nrg + 100 elseif iv[1]=jb then iv[1]=0 nrg = nrg + 100 else print "You have no food" end if end sub function command(zz as int) as int dim x as int x=0 while x=0 nrg = nrg - 1 if nrg <= 0 then die(zz) end if print "Energy ", nrg input "command ", vb x=parse(zz) if x=0 then print "huh?" elseif x=dr then drItem(zz) elseif x=tk then tkItem(zz) elseif x=inventory then showinventory(zz) elseif x=eat then eatFood(zz) end if wend command = x end function function our(zz as int) as int print "outside the TARDIS," print "a big blue police box" print "doors e" print "I see" descObject(drp[ir]) while cmd=0 cmd = command(zz) if cmd=et then our=co exit function else print "nope" cmd=0 end if wend end function function cor(zz as int) as int print "inside the TARDIS " print "control room - larger" print "inside than outside" print "doors e & w" print "I see" descObject(drp[ir]) while cmd=0 cmd = command(zz) if cmd=wt then if drp[ir]=ky then cor = -1 ' game's over exit function else print "The door is locked" cmd=0 end if elseif cmd=et then cor = ad else cmd=0 end if wend end function function adr(zz as int) as int print "inside Adric's room." print "Adric is the doctor's" print "companion" print "doors n, e, s, & w" print "I see" descObject(drp[ir]) while cmd=0 cmd = command(zz) if cmd=nh then adr=cl elseif cmd=et then adr=e1 elseif cmd=sh then adr=va elseif cmd=wt then adr=co elseif drp[ir]=st then drp[ir]=ky print "POOF" adr=ad else cmd=0 end if wend end function function var(zz as int) as int print "a large room with" print "vaulted ceilings. There" print "is a peg on the wall." print "doors n, e, s" print "I see" descObject(drp[ir]) while cmd=0 cmd = command(zz) if cmd=nh then var=ad elseif cmd=et then var=e2 elseif cmd=sh then var=so elseif drp[ir]=sc then print "PING" drp[ir]=st var=va else cmd=0 end if wend end function function clr(zz as int) as int print "a huge cloister bell" print "is here in this room" print "doors s" print "I see" descObject(drp[ir]) while cmd=0 cmd = command(zz) if cmd=sh then clr=ad else print "BONG" cmd=0 end if wend end function function e1r(zz as int) as int print "there's an echo in here" print "there's an echo in here" print "doors n, e, s, & w" print "I see" descObject(drp[ir]) while cmd=0 cmd = command(zz) if cmd=nh or cmd=wt then e1r=e1 elseif cmd=sh or cmd=et then e1r=e2 else print vb print vb cmd=0 end if wend end function function e2r(zz as int) as int print "there's an echo in here" print "there's an echo in here" print "doors n, e, s, & w" print "I see" descObject(drp[ir]) while cmd=0 cmd = command(zz) if cmd=sh or cmd=wt or cmd=et then e2r=e2 elseif cmd=nh then e2r=ad else print vb print vb cmd=0 end if wend end function function sdr(zz as int) as int print "this is an empty room." print "doors n" print "I see" descObject(drp[ir]) while cmd=0 cmd = command(zz) if cmd=nh then sdr=e1 elseif cmd=et then sdr=ad else print "hmm..." cmd=0 end if wend end function sub top(zz as int) ir=0 while ir <> -1 cmd=0 if ir=ou then ir=our(zz) elseif ir=co then ir=cor(zz) elseif ir=ad then ir=adr(zz) elseif ir=va then ir=var(zz) elseif ir=cl then ir=clr(zz) elseif ir=e1 then ir=e1r(zz) elseif ir=e2 then ir=e2r(zz) elseif ir=so then ir=sdr(zz) end if wend cls if iv[0]=sd or iv[1]=sd then cls beep 7 print "Congratulations" print "The Doctor is here to" print "shake your hand. He" print "thanks you for his" print "Sonic Screwdriver" wait 50 print "He pokes his head" print "out. With a gleam in " print "his eye he asks . . ." print "Care to go for a ride?" print "The End." beep 6 else cls beep 4 print "The Doctor is very " print "disappointed in you." print "You forgot the Sonic" print "Screwdriver." wait 50 print "The Doctor sulks into" print "the TARDIS and it" print "disappears" print "The End." beep 4 end if while 1 wend end sub nrg=26 drp[cl]=sc drp[e1]=jb drp[so]=sd top(zz) |