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Author Topic: Triggering custom text after a certain action  (Read 1303 times)


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Triggering custom text after a certain action
« on: February 14, 2016, 12:54:49 pm »
I have been hacking nfl blitz lately and have gotten a decent handle on assembly. I want to take it to the next level and add functions into the rom that are completely custom. Here is a summary of what I would like to try and do. Please let me know if you think it's possible and methods for how to do it.

Idea: when the ball holding player is tackled, I want text to appear saying which tackle was executed. There are about 12 different animations that can occur, with each having a specific hex value associated with it. I want text to appear like how "first down" or "touchdown" text appears.

I think I would need to read the value of the tackle animation and jump to either 1. A new function that writes the text, or 2. Jump to the function that writes the text that's already there and try and shove it in somewhere (possibly adding jumps if there's not enough room).

I have seen Tareks tutorial using cajeASM where he shows a simple example of having custom text appear, so I know it's possible.

Anyone have any experience with this sort of thing?


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Re: Triggering custom text after a certain action
« Reply #1 on: February 14, 2016, 02:58:58 pm »
It does vary with the thing you want doing and if there might already be a provision in the game for what you want, or at least something you can piggyback on. If you just want a text screen to pop up in the middle of an RPG world map and there is no hidden trap thing you might abuse then that is harder, if there is a hidden trap function then you might even be able to do it within game logic as a basic map edit, if you instead have an animation function already being called for something else...
I mention this mainly as you seem to be more concerned the jumping and the doing. Now don't get me wrong as they can provide any number of frustrations and obstacles but the finding the function you want to attach to, adding an interrupt should there be nothing suitable or subverting something else, all three falling under the umbrella of what would be know as hooking in cheating/hacking/debugging/functionality expanding circles, is the fun part.

In this case there will be something saying call someanimation and it should not be too bad to attach something to also do something else. Indeed I imagine the bigger problem might be space in and generally handling video memory, as it often is in these situations, or if you prefer there is a reason that 90% of such cheats/hacks you might have seen in the past will look like debug text rather than something fancy. That said I saw a video and touchdown and first down appear to be the same font (give or take animation for touchdown) so you might get lucky and have a font already in memory to build something better from. If you will accept the ?? yard down text instead that might be something more doable still.