Dungeons of Doom is a hack of the TRS-80 Color Computer classic Dungeons of Daggorath. I added in some characters from Doom and enabled joystick-based controls, among other things.
Dungeons of Daggorath was a very popular first-person RPG in the early 1980s. It was compatible with the Tandy TRS-80 Color Computer 1/2/3.
It was a very early three-dimensional game that allowed the player to explore a dungeons and battle monsters via a text based interface. That interface is used to move around, fight, pick up or use items, and much more. However, the vast majority of the time, the commands entered revolve around moving and attacking.
For these common actions, the text-based interface can be a bit slow and clunky, so I modified the source code to enable the right joystick (I always wished this was possible as a child). Moving the joystick moves the player around the dungeon, just as would be expected. The button triggers the command ATTACK RIGHT.
Being a first-person game, I could not resist the temptation to insert a few Doom characters in place of some of the originals. The CoCo may not be able to play Doom, but it kinda-sorta can do something like it.
I also gave the player unlimited power and health, which is great for exploring and testing, but that boost can be left out for those that want the challenge.
After assembly, the binary can be burned to a ROM chip mapped into the cartridge port, or should also work with any decent emulator. I assembled the source code with LWASM.
Speaking of source code, the former CEO of DynaMicro, Inc. very graciously released the source code for public distribution, but only in its original form. Since I have modified it, I cannot distribute my work. However, one can still recreate Dungeons of Doom without too much trouble by:
- Downloading the original 6809 source code.
- Making the modifications I have listed below.
- Assembling the code.
Screencaps of modified enemies:
For comparison:
Playing on my CoCo 2:
- In
CD.ASM:
After line 623, insert the following:
TEMP1 RMB 1 ; NAB
BAGP RMB 2 ; NAB- In
HUMAN.ASM:
Replace line 13 with:
LBNE PLAY20 ; yes ; NAB: BNE to LBNEOn line 17, insert the follwing code after the PLAY10 label:
; NAB - check for joystick input.
; Joystick button.
LDA 65280
ANDA #1
CMPA #0
BNE NOBUTTONPRESS
; Attack right.
LDU #PRHAND
JSR ATTACKRIGHT
JMP NOMOVE
NOBUTTONPRESS
JSR [$A00A] ; BASIC joystick reading routine.
LDA $015B ; Right joystick y-axis
CMPA #10
BHI NOMOVEFORWARD
; Move forward
JSR PMOVEFORWARD
JMP NOMOVE
NOMOVEFORWARD
CMPA #50
BLO NOMOVEBACKWARD
; Move backward
JSR PMOVEBACKWARD
JMP NOMOVE
NOMOVEBACKWARD
LDA $015A ; Right joystick x-axis
CMPA #10
BHI NOMOVELEFT
; Move left
LDB PDIR
JSR PMOVELEFT
JMP NOMOVE
NOMOVELEFT
CMPA #50
BLO NOMOVE
; Move right
LDB PDIR
JSR PMOVERIGHT
NOMOVE
; NAB - END check for joystick input.Replace line 47 with:
LBRA PLAY10 ;loop ; NAB - BRA to LBRA- In
HUPDAT.ASM:
This is optional, if you want infinte health. After line 40, add:
CLRA ; NAB - IDDQD
CLRB
STD PDAM- In
ONCE.ASM:
After line 284, add:
CLR TEMP1This is optional, if you want infinite power. After line 288, add:
LDA #$7F ; NAB - Max power.
STA PPOW- In
PATTK.ASM:
After line 11, add this label:
ATTACKRIGHT- In
PTURN.ASM:
After line 20, add the label:
PMOVELEFTAfter line 29, add the label:
PMOVERIGHTAfter line 153, add the label:
PMOVEFORWARDAfter line 166, add the label:
PMOVEBACKWARD- In
SOUNDS.ASM:
On line 16, insert the following after the SOUNDI label:
; NAB - sound back on (reading joystick turns it off)
STA TEMP1
LDA $FF23
ORA #8
STA $FF23
LDA TEMP1Replace line 198 with:
SNRAT1 LBSR SNOISE ;get a random noise value ; NAB - LReplace line 279 with:
SNWSH2 LBSR SNZNVA ;get some noise ; NAB - LReplace line 285 with:
SNWSH1 LBSR SNENVN ;decompression subroutine ; NAB - LOn line 309, after the SNOUT label, insert:
; NAB - sound back on (reading joystick turns it off)
STA TEMP1
LDA $FF23
ORA #8
STA $FF23
LDA TEMP1On line 320, insert after the SNOISE label:
; NAB - sound back on (reading joystick turns it off)
STA TEMP1
LDA $FF23
ORA #8
STA $FF23
LDA TEMP1Replace lines 411-412 with:
LBLS SNCLK4 ; ; NAB - L
LBRA SNOUT ; ; NAB - L- In
D3.ASM:
Replace the spider vector list with:
; Body
SPIDER SVORG 40,100
SVECT 40,105
SVECT 42,115
SVECT 52,125
SVECT 60,128
SVECT 68,125
SVECT 78,115
SVECT 80,105
SVECT 80,95
SVECT 78,90
SVECT 68,80
SVECT 60,77
SVECT 52,80
SVECT 42,90
SVECT 40,100
SVNEW
; Eye
SVORG 50,101
SVECT 52,106
SVECT 56,106
SVECT 58,101
SVECT 56,96
SVECT 52,96
SVECT 50,101
SVNEW
; Pupil
SVORG 53,99
SVECT 53,103
SVECT 55,103
SVECT 55,99
SVECT 53,99
SVNEW
; Mouth
SVORG 64,90
SVECT 64,95
SVECT 64,101
SVECT 64,105
SVECT 64,112
SVECT 69,114
SVECT 73,110
SVECT 74,101
SVECT 73,92
SVECT 69,88
SVECT 64,90
SVNEW
; Teeth
SVORG 65,95
SVECT 70,97
SVECT 65,99
SVNEW
SVORG 65,103
SVECT 70,105
SVECT 65,107
SVNEW
SVORG 71,99
SVECT 66,101
SVECT 71,103
SVNEW
; Horns
SVORG 44,118
SVECT 40,124
SVECT 35,127
SVECT 45,127
SVECT 50,123
SVNEW
SVORG 44,87
SVECT 40,81
SVECT 35,78
SVECT 45,78
SVECT 50,82
SVNEW
SVORG 40,108
SVECT 35,111
SVECT 41,114
SVNEW
SVORG 40,97
SVECT 35,94
SVECT 41,91
SVEND
; End of Spider vector list- In
D4.ASM:
Replace the viper vector list with:
VIPER
; Head
SVORG 55,120
SVECT 55,130
SVECT 55,140
SVECT 62,147
SVECT 69,140
SVECT 75,140
SVECT 83,140
SVECT 83,130
SVECT 83,120
SVECT 75,120
SVECT 69,120
SVECT 62,113
SVECT 55,120
SVNEW
; Eyes
SVORG 62,118
SVECT 66,124
SVECT 66,129
SVECT 62,123
SVECT 62,118
SVNEW
SVORG 62,142
SVECT 66,136
SVECT 66,131
SVECT 62,137
SVECT 62,142
SVNEW
; Mouth
SVORG 70,122
SVECT 70,130
SVECT 70,138
SVECT 78,138
SVECT 78,130
SVECT 78,122
SVECT 70,122
SVNEW
SVORG 70,124
SVECT 72,124
SVECT 72,130
SVECT 72,136
SVECT 70,136
SVNEW
SVORG 78,124
SVECT 76,124
SVECT 76,130
SVECT 76,136
SVECT 78,136
SVNEW
; R
SVORG 68,140
SVECT 73,145
SVECT 78,150
SVECT 85,152
SVECT 88,153
SVECT 98,155
SVECT 98,150
SVECT 88,145
SVECT 88,140
SVECT 98,139
SVECT 108,138
SVECT 118,136
SVECT 124,135
SVNEW
; L
SVORG 68,120
SVECT 73,115
SVECT 78,110
SVECT 85,108
SVECT 88,107
SVECT 98,105
SVECT 98,110
SVECT 88,115
SVECT 88,120
SVECT 98,121
SVECT 108,122
SVECT 118,124
SVECT 124,125
SVNEW
; Legs
SVORG 120,128
SVECT 114,129
SVECT 104,129
SVECT 94,128
SVECT 94,131
SVECT 104,132
SVECT 114,132
SVECT 120,133
SVNEW
; Horns
SVORG 74,146
SVECT 68,148
SVECT 77,149
SVNEW
SVORG 74,114
SVECT 68,112
SVECT 77,111
SVEND
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