Commander X16

My first steps will be careful ones.... I've never done sprite programming using CC65.

 

Updated with some more vision statementy things.

 

I. A PRETTY MAP

• 
  Rounded coastlines, no overlapping sprites.
  

II. AN ECOLOGY

• 
  (1602) Terrain squares have their own characteristics, which define what can be grown on them.
  


• 
  (1602, 7 Cities of Gold) Settlements produce people, supplies, ships, trade goods.  Some are better at self-defense.  They can be owned, and can rebel.
  

• 
  (7 Cities of Gold) A "soft empire" model, based on relationships between settlements.
  


• 
  (1602, 7 Cities of Gold) Establish and dismantle settlements.
  


• 
  (Pirates, 7 Cities of Gold) Barter with or plunder settlements.
  


• 
  (7 Cities of Gold) Explore.
  

 

OK, replaced the BASIC version with the C version.  It's more responsive, but the scrolling is terrible.  Also I don't like the way I did the map.  I have to rethink things and use fewer sprites if possible.

 

For example, I use sprites to tile the ocean.  I shouldn't have to do that -- surely I can just use characters to represent the ocean.  Like a reverse period, or something. 

Then, the land sprites themselves are memory hungry.  Each one is 64 x 64 and 8 bit pixels -- 4K!  Oink!  

I think I need to go back to using "coastline" sprites for the edges.  8 x 64 and 64 x 8 sprites.  We'll see.

 

And even after all that, there does appear to be an obvious redraw going on when the ship moves: the sprites appear to stagger.  In other words, C is not fast enough.

Mainly, you need to make sure you are doing the scrolling during VBLANK by putting it at the beginning of your VSYNC interrupt routine. That should clean it up a lot.

On 1/26/2022 at 9:36 AM, SlithyMatt said:

Mainly, you need to make sure you are doing the scrolling during VBLANK by putting it at the beginning of your VSYNC interrupt routine. That should clean it up a lot.

You can do that in C?

On 1/26/2022 at 2:08 PM, rje said:

You can do that in C?

I should hope so! You may just need some inline assembly to overwrite the IRQ vector with a function address, but you may be able to do that in pure C. 

You could also develop this in the direction of the Flying Spaghetti Monster game - fsmgame.com

I forget exactly every step I did in Flappy Bird, but it does IRQ handling in C.

Basically, I made a #define that makes the IRQ vector in RAM ($030-something)  so it looks like a variable, and then I did an inline assembly to SEI, then IRQ_VECTOR = &irq_handler;

Something akin to that.

Very nice demo. Curious how you created the dynamic tile algorithm.

On 1/29/2022 at 4:09 AM, svenvandevelde said:

Very nice demo. Curious how you created the dynamic tile algorithm.

I overlapped the sprites significantly -- 8 pixels on every edge I think.  

The result was absolutely horrible refresh.

 

Today I got rid of the overlap and reverted to plain square sprites instead of ones with contoured shorelines.  It looks uglier but moves MUCH MUCH smoother.

The current view is only a bit more than 5 x 6 "squares".  I also added a regional map view -- typing 'm' draws a 50 x 50 PETSCII map.  That helps get my bearings, so to speak.  I might instead just have a 20 x 20 mini-map on a corner of the normal view.