[Graphics] [pokeemerald] Problem with World Map (512 tiles)

Doctor Juanjo · Feb 20, 2021

Hi guys.

I was trying to insert a World Map composed by more than 256 tiles.
In order to do that, I decided to separate the map in two maps: One for the background, and the second one for the front layout:

[pokeemerald] Problem with World Map (512 tiles)

Spoiler:

My original ideas was use the bg3 to be the background and the bg2 to be the layout.

To do that I added a new element of sFieldRegionMapBgTemplates in field_region_map.c

Code:

    {
        .bg = 3,
        .charBaseIndex = 1,
        .mapBaseIndex = 26,
        .screenSize = 2,
        .paletteMode = 1,
        .priority = 2,
        .baseTile = 0
    }

This new map will use the charBaseIndex 1 and the mapBaseIndex 26

Then in the function FieldUpdateRegionMap() I just had to add this line: ShowBg(3);

Code:

        case 2:
            SetGpuRegBits(REG_OFFSET_DISPCNT, DISPCNT_OBJ_1D_MAP | DISPCNT_OBJ_ON);
            ShowBg(0);
            ShowBg(2);
+++++ ShowBg(3);
            sFieldRegionMapHandler->state++;
            break;

Aditionally in region_map.c I uploaded the new background as sRegionMapBg_GfxLZ2 and the raw map as sRegionMapBg_TilemapLZ2

Then I modified the function LoadRegionMapGfx() in order to force the use of this new tileset and map in the char- and mapBaseIndex (1 and 26):

Code:

bool8 LoadRegionMapGfx(void)
{
    switch (gRegionMap->initStep)
    {
    case 0:
        if (gRegionMap->bgManaged){
            DecompressAndCopyTileDataToVram(gRegionMap->bgNum, sRegionMapBg_GfxLZ, 0, 0, 0);
+++++ DecompressAndCopyTileDataToVram(3, sRegionMapBg_GfxLZ2, 0, 0, 0);
            }
        else{
            LZ77UnCompVram(sRegionMapBg_GfxLZ, (u16 *)BG_CHAR_ADDR(2));
+++++ LZ77UnCompVram(sRegionMapBg_GfxLZ2, (u16 *)BG_CHAR_ADDR(1));}
        break;
    case 1:
        if (gRegionMap->bgManaged)
        {
            if (!FreeTempTileDataBuffersIfPossible()){
                DecompressAndCopyTileDataToVram(gRegionMap->bgNum, sRegionMapBg_TilemapLZ, 0, 0, 1);
+++++++ DecompressAndCopyTileDataToVram(3, sRegionMapBg_TilemapLZ2, 0, 0, 1);                
                }
        }
        else
        {
            LZ77UnCompVram(sRegionMapBg_TilemapLZ, (u16 *)BG_SCREEN_ADDR(28));
+++++ LZ77UnCompVram(sRegionMapBg_TilemapLZ2, (u16 *)BG_SCREEN_ADDR(26));
        }
        break;

I compiled the project and I got this map:

Spoiler:

Apparently, Bg3 was mapped effectively but it appears invisible :( (But appears in the MapViewer), also the tileset seems to be well inserted and not overlapped (the bug tiles between the two tilesets are just bc the background tileset is smaller than 128x128)

Then I realized that perhaps the problem could be in field_region_map.c when the Bgs are initialized:

Code:

InitBgsFromTemplates(1, sFieldRegionMapBgTemplates, ARRAY_COUNT(sFieldRegionMapBgTemplates));

I don't understand how this bg-thingys work (black magic??). But when I changed that 1 to a 2 I got a beauty map composed by 512 tiles... The only problem... I destroyed the Bg0 including the name of the region and route:

Spoiler:

But now is the Bg0 which don't want to be shown...

I know I am playing with fire and go beyond the specifications of the GBA... but, any idea???

Thanks a lot!

Anon822 · Feb 20, 2021

The first argument of InitBgsFromTemplates seems to be the graphics mode number.
In mode 1 backgrounds 0, 1 & 2 are available while in mode 2 only bgs 2 & 3 are usable.

Loading your new background as BG1 in mode 1 might work, but you wouldn't be able to apply affine transformations to it (since only BG2 is transformable in mode 1).

Doctor Juanjo · Feb 20, 2021

Anon822 said:
The first argument of InitBgsFromTemplates seems to be the graphics mode number.
In mode 1 backgrounds 0, 1 & 2 are available while in mode 2 only bgs 2 & 3 are usable.

Loading your new background as BG1 in mode 1 might work, but you wouldn't be able to apply affine transformations to it (since only BG2 is transformable in mode 1).

Thanks a lot for your answer.

Indeed now the three bg appears. But the problem now is that the Bg1 appears to have a different dimension and is broken (use a random tileset composed for both tilesets)

Is there an additional step to do this?

Anon822 · Feb 20, 2021

Since it's a non-affine background, the tilemap format is different and so is the meaning of the .screenSize value
EDIT: If you're planning on making the region map non-affine, do you even need 2 backgrounds? The 256 tile limit only applies to affine backgrounds.

Doctor Juanjo · Feb 20, 2021

Anon822 said:
Since it's a non-affine background, the tilemap format is different and so is the meaning of the .screenSize value
EDIT: If you're planning on making the region map non-affine, do you even need 2 backgrounds? The 256 tile limit only applies to affine backgrounds.

Thanks a lot, now it works!!!

Is sad that now I can't do affine functions (for example, the zoom in Pokenav) but it is something

[Graphics] [pokeemerald] Problem with World Map (512 tiles)

Doctor Juanjo

Anon822

Doctor Juanjo

Anon822

Doctor Juanjo