Changing shape of playfield rocks in Dig Dug

[NostAlgae37]

Hi, I am working on updating some of the sprite graphics for the 2600 hack Dig Dug Arcade. One of the more significant changes that I have made is to the shape of the rocks that Dig Dug can drop on the enemies. The new rocks look more natural and have a shape closer to the arcade once Dig Dug loosens them and they fall, but they are still perfect squares when stationary because they are playfield graphics instead of sprites. Is there a way to alter the shape of the playfield rocks to match the first frame of the new sprite rock that I made? My thanks in advance to anyone who can help.

 

[Nukey Shay]

They are drawn using the ball sprite, not PF pixels. You'd need to update CTRLPF and/or HMBL on the lines it is displayed to alter its shape to be something other than a square pixel. Doesn't seem to be enough time to do this and still hit all the other registers at the appropriate times.

[NostAlgae37]

Thanks for answering, Nukey. What a bummer, it would really help to sell the whole effect because currently it starts out with that unsightly square then changes into something that looks far more convincing (if I do say so myself ). I'll post the updated rom after I've had a look at the (mostly vegetable) bonus items to see if they can be massaged any further in terms of visual appeal. I must compliment the original hacker on the amazing job that he did updating the enemy monster sprites, but I wasn't entirely sold on his edits to the Dig Dug sprite or the way that he left the rock graphics unaltered (although after your reply I can understand why).

 

Speaking of the playfield in this game, is there any chance that the terrain strata can be updated to look more like dirt (dotted/speckled instead of horizontally lined)? I imagine that wavy/uneven strata divisions would be a pipe dream given the inherent hardware constraints. Maybe a flower on the surface above ground is not out of the question?

 

[Arenafoot]

Hi, I am working on updating some of the sprite graphics for the 2600 hack Dig Dug Arcade. One of the more significant changes that I have made is to the shape of the rocks that Dig Dug can drop on the enemies. The new rocks look more natural and have a shape closer to the arcade once Dig Dug loosens them and they fall, but they are still perfect squares when stationary because they are playfield graphics instead of sprites.

 

This would be sweet if its possible! Can't wait!!

[NostAlgae37]

Thanks, Arenafoot. Well, here is the first frame of the new rock graphic in case anyone wants to have a go at inserting it into the playfield:

 

 

It does indeed make for a nice effect on the actual game screen when it wobbles and falls (it truly has to be seen to be appreciated).

Edited April 20, 2017 by NostAlgae37

[CDS Games]

The ball is a bit odd--its width can only be set to 1, 2, 4, or 8 pixels. So you can't have any line at 3 or 5-7 pixels wide, or any lines with gaps between pixels (like 1F42 in your sprite). In other words, you wouldn't be able to recreate your first animation sprite with the ball. The closest you could get is something like this…all the lines are either 1, 2, or 4 pixels:



But like Nukey said, you'd definitely have to change CTRLPF on the fly and also HMBL (f you are using this design) to reposition the ball a couple pixels per line. If the kernel cycles are tight, it will be quite a challenge getting it to work.

 

Wavy borders on the strata divisions might be possible. You can get a subtle wave effect by inserting a background-color border between the strata. Like so:

 

Haven't really looked at the code to see if it's feasible though.

[NostAlgae37]

The ball is a bit odd--its width can only be set to 1, 2, 4, or 8 pixels. So you can't have any line at 3 or 5-7 pixels wide, or any lines with gaps between pixels (like 1F42 in your sprite). In other words, you wouldn't be able to recreate your first animation sprite with the ball. The closest you could get is something like this…all the lines are either 1, 2, or 4 pixels:

 

BallRock.png

 

But like Nukey said, you'd definitely have to change CTRLPF on the fly and also HMBL (f you are using this design) to reposition the ball a couple pixels per line. If the kernel cycles are tight, it will be quite a challenge getting it to work.

 

Wavy borders on the strata divisions might be possible. You can get a subtle wave effect by inserting a background-color border between the strata. Like so:

 

WavyBorder.png

 

Haven't really looked at the code to see if it's feasible though.

 

Very interesting, thanks for the info. Is there any possibility of replacing the ball with plain playfield pixels or just the sprite frame itself? I imagine not because the original programmer probably would have done it, but it merits asking because I think it would really up the ante on the visual appeal of each stage.

 

Wow, I really doubted that wavy strata divisions would be possible at all, maybe there is hope after all. Now if only we could replace those pesky horizontal lines with something that looks more like the texture of dirt, the 2600 port of Dig Dug would be an impressive recreation of the original arcade experience.

[Nukey Shay]

The horizontal lines are there to hide PF during sprite repositioning (i.e. "intelligent flicker"). Best that could be done without a major kernel rewrite would probably be a Cosmic Ark starfield effect to dot the playfield using one or both of the missiles. But not very convincing since neither of the player sprites could be set to an unchanging color.

[CDS Games]

 

Is there any possibility of replacing the ball with plain playfield pixels or just the sprite frame itself? I imagine not because the original programmer probably would have done it, but it merits asking because I think it would really up the ante on the visual appeal of each stage.

 

Playfield pixels are too low resolution for that job unfortunately. If you see that blank space the rocks are in...that's only two playfield pixels wide.

 

Putting a dedicated rock sprite there would really be the best way to get the effect you want--but I'm not sure if that's feasible and there will likely be tradeoffs. It'll make the flicker worse, for sure.

[NostAlgae37]

OK guys, one more question before I post the (semi-final) version of the rom. For the bonus items, is there any way that I can assign a different color to just a section of them? I added leaves/stems to the tops of some of the vegetables and would like to change the color of those lines to something different than the main body. From my understanding, on the VCS there can't be more than one color to a line but each line of a sprite can be a different color? Or does that not apply in this case? Admittedly, my coding/programming knowledge is nil, I am just an artistically-oriented person who enjoys fiddling with Hack-O-Matic.

 

[Nukey Shay]

Once again, the problem is time. To add multicolor to a sprite, an additional pointer must be set up to fetch the color value for the current line and then passed to the color register for the sprite. Because either sprite is used in Dig Dug's flicker kernel, you would also need to determine which sprite is currently being used for the veggie.

[NostAlgae37]

I have been working on my Dig Dug hack again (looking to improve it), but I need some help from the community. Is there a part of the code that defines the address range that the program looks to fetch the graphics for each individual fruit/vegetable prize from? In other words, does it specify the locations of each of the bonus prizes?