Reveal dragon cost cards from DTK

by **demeitri1** » 02 May 2015, 01:53

what are the issues you guys are having? is it coding related?

by **saturnine** » 03 May 2015, 18:49

It's new-mechanic-that-hasn't-existed-prior-to-DTK-and-needs-coding-from-scratch related, I'd think. Nowhere in this game have we seen this kind of mechanic--LRW had it as an additional cost, but not as an if-not-then-this one.

by **Marek14** » 04 May 2015, 05:38

Specifically, Lorwyn had it as a straight-up additional cost. The DTK implementation is a bit different, with some problematic rules interpretations:

1. Clone problem - a Clone copying Scaleguard Sentinels should get a +1/+1 counter if you controlled a Dragon as you cast Clone. But at the time you cast Clone, you don't yet know that you need to check for that! So either there must be a way to look back in time or all spells need to check what creature types you control when you cast them (not just Clone-type cards because there's also a possibility of suddenly getting Infinite Reflection on the battlefield etc.). Clone has similar problems with sunburst cards, but I think that colors used for casting are stored standardly.

2. Fork problem - a copy of dragon presence spell should never have the dragon presence active, as it was never cast, and so the condition can't be true. Spells cast from a copy of a card (for example Draconic Roar cast from Isochron Scepter) can still have the condition fulfilled. Spells that somehow resolve under control of different player (thanks to things like Perplexing Chimera or Gather Specimens) won't have dragon presence active as their current controller never cast them.

3. Artificial Evolution problem - Artificial Evolution can hit Dragon Presence spells while on stack and change "Dragon" to something else. When the spell resolves, it then has to check whether you revealed or controlled the new type determined by Artificial Evolution. This is similar to the Clone problem in that you might need to check something from the past you didn't know you will have to check. Also, it means that the full set of creature types of the revealed card must be stored for this case.