WIP - Demons of Dex

[phvic]

Hi!

I'm writing a roguelike game in assembly for the unexpended VIC-20. The game is about 60% complete.

Status:
- level generation DONE
- doors DONE
- enemy and item placement DONE
- gradual reveal of map DONE
- status bar and message area DONE
- enemy AI DONE
- player damage and dying DONE
- usable items (not done)
- monster special abilities (not done)
- xp and level ups (not done)
- special levels (not done)
- end game (not done)
- sounds (not done)

How to play:
- move using W,S,A,D
- items are picked up when you walk over them
- attack by walking on monsters

Source code and PRG file here:
https://github.com/petrihakkinen/demons

[phvic]

Basic player movement, collision detection and random enemy placement done. Now at 344 bytes.

Now I understand why Kernal's PLOT routine is weird and takes X=row, Y=column and not the other way around... because there is no addressing mode "LDA ($D1),X" only "LDA ($D1),Y"! ($D1 = address of current line in screen RAM).

[phvic]

Descending to next level works now. Also implemented basics of player attacking monsters. 494 bytes used.

There seems to be a weird problem with keyboard input. For some reason when I hold left cursor while pressing cursor up, the player moves northeast (should be nw!). Can't see anything wrong with the code. Maybe limitation of Kernal's GETIN or bug in vice? Anybody care to test if this manifests on a real vic?

I'm done for tonight, if somebody is interested to check this out, comments are welcome!

[joshuadenmark]

Fast progress will test tomorrow on real Vic.

[phvic]

Thanks, looking forward to your feedback!

[ravenxau]

good work - I am also a fan of roguelikes (my program serpent caves) - will you be implementing the fog-of-war to progressively reveal the levels???

[phvic]

good work - I am also a fan of roguelikes (my program serpent caves) - will you be implementing the fog-of-war to progressively reveal the levels???

Thanks! Yes, hopefully I will have some time this weekend to work on it.

btw. Serpent Caves is one of the reasons why I'm doing this

[ravenxau]

good work - I am also a fan of roguelikes (my program serpent caves) - will you be implementing the fog-of-war to progressively reveal the levels???

Thanks! Yes, hopefully I will have some time this weekend to work on it.

btw. Serpent Caves is one of the reasons why I'm doing this

glad you like Serpent Caves.....have you tried the 'alternate' version with the green on white color scheme and 9 levels?

[phvic]

have you tried the 'alternate' version with the green on white color scheme and 9 levels?

Not yet, when I get this done I'll check it out

[phvic]

New version with doors, preliminary colors and bugs fixed. Movement changed to W,A,S,D keys.

Getting closer to first playable version... 729 bytes used.

[ravenxau]

just curious, can you give a brief description of how the maze/dungeon is generated??? - I always find it interesting to see how people develop solutions when creating games

[phvic]

just curious, can you give a brief description of how the maze/dungeon is generated??? - I always find it interesting to see how people develop solutions when creating games

Sure! The level generation algorithm is actually really simple (I needed it to be really tiny, about 100 bytes). I start with an empty level and place a random walker on the map. The walker carves tunnels and turns at map boundaries. There is also 30% chance of making a random turn.

Door placement is a little bit more complicated and adds about 200 more bytes (I'm not totally happy about this bloat). I scan the entire level and for each floor tile encountered I compute a bitmask encoding the walls of the 8 neighbor cells. I have a list of predetermined values, and if this bitmask matches with any of them in the list, a door is placed in the empty cell.

Stairs and monsters are placed on randomly selected empty spaces. I need to work on stairs placement, currently it's possible for the player to start next to the stairs making for a really short level

[phvic]

Does anyone know if it's possible to call BASIC's random number generation routine from assembly to create (preferably uniformly distributed) random numbers in range 0-255? I know BASIC operates on floats, but maybe it's still possible...

[ravenxau]

Does anyone know if it's possible to call BASIC's random number generation routine from assembly to create (preferably uniformly distributed) random numbers in range 0-255? I know BASIC operates on floats, but maybe it's still possible...

Scan the jiffy clock might be an option

[ravenxau]

just curious, can you give a brief description of how the maze/dungeon is generated??? - I always find it interesting to see how people develop solutions when creating games

Sure! The level generation algorithm is actually really simple (I needed it to be really tiny, about 100 bytes). I start with an empty level and place a random walker on the map. The walker carves tunnels and turns at map boundaries. There is also 30% chance of making a random turn.

Door placement is a little bit more complicated and adds about 200 more bytes (I'm not totally happy about this bloat). I scan the entire level and for each floor tile encountered I compute a bitmask encoding the walls of the 8 neighbor cells. I have a list of predetermined values, and if this bitmask matches with any of them in the list, a door is placed in the empty cell.

Stairs and monsters are placed on randomly selected empty spaces. I need to work on stairs placement, currently it's possible for the player to start next to the stairs making for a really short level

Do you just pick a random new direction for the drill head, or rotate it 90 degrees each change?