FRLG Map Previews

I implemented FireRed's map preview screen feature in pokeemerald and pokeemerald-expansion. This will allow you to use these map preview screens for whatever maps you want. Incidentally, I made this branch entirely from scratch before I found out that ghoulslash had already done it years ago! Our code is very similar, mostly because the majority of it is just directly ported from pokefirered. Full credit to ghoulslash for beating me to the punch! However, I did make some tweaks to the code to make it generally easier for most people to use.

Basic merge instructions:

The repo can be found here: https://github.com/Bivurnum/pokeemerald/tree/map-previews

Enter the following commands into the console:
git remote add Bivurnum https://github.com/Bivurnum/pokeemerald
git pull Bivurnum map-previews

Or, if you want to apply the changes manually, you can find the comparison with all of my changes here:
https://github.com/Bivurnum/pokeemerald/compare/master...map-previews

Merge instructions for expansion 1.9 and 1.10:

The repo can be found here: https://github.com/Bivurnum/pokeemerald-expansion/tree/map-previews

Enter the following commands into the console:
git remote add Biv-expansion https://github.com/Bivurnum/pokeemerald-expansion
git pull Biv-expansion map-previews

Or, if you want to apply the changes manually, you can find the comparison with all of my changes here:
https://github.com/rh-hideout/pokeemerald-expansion/compare/expansion/1.9.0...Bivurnum:pokeemerald-expansion:map-previews

Click here for a guide on how to create your own map previews.

Using the Map Previews

I'll be using an example of adding a map preview to Petalburg Woods for this section.

You will need to define a new map preview screen in include/map_preview_screen.h. Just add your new entry near the bottom of the list in MapPreviewScreenId, leaving MPS_COUNT at the very end. Like so:

Then, you will go to src/map_preview_screen.c and add a new section in the sMapPreviewScreenData list for the map preview you just defined. Keep in mind that this list has to be in the same order as the list in include/map_preview_screen.h.

• mapsec is just the name of the map section your map is in. This map preview will apply to all maps within this map section (but not when traveling between maps within the same map section, similarly to the map name popups). If it doesn't have one alredy, the mapsec will need an entry in src/data/region_map/region_map_sections.json for the map name to show up in the map preview.
• type will be either MPS_TYPE_BASIC, MPS_TYPE_FADE_IN or MPS_TYPE_CAVE.
  • MPS_TYPE_BASIC will show the map preview, then fade to black before loading into the new map.
  • MPS_TYPE_FADE_IN will fade the map preview into the new map (see the gif at the top of this page for example).
  • MPS_TYPE_CAVE will perform the warp animation for entering a cave at the end of the map preview, before the map is loaded in.

MPS_BASIC example

MPS_FADE_IN example

MPS_CAVE example

• flagId is just the name of the flag you want to set when visiting this map for the first time. The flag state determines how long the map preview will last on screen; it gets a shorter duration if the player has been to that map before. A lot of Emerald maps already have associated flags, but Petalburg Woods does not have one by default, so I repurposed one of the unused flags for use in this example. If you don't want to use a flag, you can enter MPS_FLAG_NULL here and the duration will have its own custom value (this can be adjusted in the configs in include/map_preview_screen.h).
• image is the image you'd like to use for the preview screen. The full list of options can be found in include/map_preview_screen.h under PreviewImageId.

That's all there is to it!

Scripting

Two new scripting macros have been added:

• mappreview fades the screen to black, runs a map preview for the current map, then fades back from black before continuing the script. This uses the behavior of MPS_TYPE_BASIC, regardless of the designated type of the map.
• mappopup initiates the vanilla map name popup for the current map.

Configs

In the include/map_preview_screen.h file, there are a few configs you can customize for the map previews.

• MPS_DURATION_LONG determines how many frames the map preview lasts on screen the first time the player enters that map.
• MPS_DURATION_SHORT determines how many frames the map preview lasts on screen after the map's flag has been set.
• MPS_DURATION_NO_FLAG determines how many frames the map preview lasts if the flag has been set to MPS_FLAG_NULL.
• MPS_DURATION_ALWAYS overrides all other duration values if it is set to anything but 0.
• MPS_DURATION_SCRIPT determines how many frames the map preview lasts when triggered by mappreview. It is not affected by MPS_DURATION_ALWAYS.
• MPS_BASIC_FADE_SPEED determines how quickly the fade to black animation plays at the end of MPS_TYPE_BASIC. A larger value makes it fade out slower. A smaller value (even a negative number) makes it fade out faster.

Notes

• Keep in mind that ON_FRAME mapscripts may not play nice with the MPS_TYPE_FADE_IN map previews due to the mapscript running before the map preview screen has fully faded out. You could use MPS_TYPE_BASIC or the mappreview script macro to get around this.
• MPS_TYPE_FADE_IN does not work properly if the map has any of the following weather types. (You can use MPS_TYPE_BASIC for the map preview instead.)
  • WEATHER_SUNNY_CLOUDS
  • WEATHER_FOG_HORIZONTAL
  • WEATHER_FOG_DIAGONAL
  • WEATHER_UNDERWATER
  • WEATHER_UNDERWATER_BUBBLES