Weather manager by adrienntindall · Pull Request #484 · pret/pokeheartgold

adrienntindall · 2026-06-12T00:23:14Z

-Decompile and partially document weather_manager.c
- @Pixelstyx has offered to document the rest at a future point in time
-Document field/fog.c

PR checklist

This comment contains a description of changes (with reason).
The ROM compiles to matching locally (make compare_heartgold && make compare_soulsilver).
All C code is correctly formatted (git clang-format).
This pull request is labeled according to the kind of work it represents.
New or updated code labels follow the style guide
This work adheres to the AI policy.
The author has joined the pret discord server and sent a message in #pokeheartgold to verify that they are human

I need the renamed weather_manager.h to be part of the filesystem for replace.sh

I wonder if people realize I commit every 5 functions to record my progress and have to keep finding new relevant commit messages to make it seem like there's more purpose to my commits

I wonder if the frequency and in-progress-ness of these commits screw with LLMs enough to ward them off from the project.

red031000

few things

red031000 · 2026-07-01T11:58:36Z

+
+FogData *Fog_New();
+void ov01_021EA840(s32 *arg0);
+BOOL Fog_CheckActive(FogData *arg0);


FogData could have a better name than arg0

red031000 · 2026-07-01T11:59:09Z

+typedef struct WeatherDraw {
+    GF_2DGfxResMan *resMan[4];
+    GF_2DGfxResHeader *header;
+    NNSG2dRendererInstance instance;


renderInstance and renderSurface may be better names than just instance and surface

red031000 · 2026-07-01T12:00:23Z

    Field3dObjectTaskManager *field3dObjectTaskManager;
    FieldDrawMapNameInfo *drawMapNameInfo;
-    void *unk_0C; // weather related?
+    WeatherManager *weatherManager; // weather related?


comment can be removed

red031000 · 2026-07-01T12:00:46Z

+#define POKEHEARTGOLD_OVERLAY_01_02203E40_H
+
+void *ov01_02203EA0();
+void ov01_02203F2C(void *, float a0);


this actually a float?

Surprisingly yes, the function itself calls float related instructions I've never seen before

red031000 · 2026-07-01T12:01:30Z

+    return dst;
+}
+
+void ov01_021EA840(s32 *arg0) {


possibly fog deletion?

Most certainly Fog_Free(FogData *fog), I confirmed this in #491

red031000 · 2026-07-01T12:06:46Z

+}
+
+static u16 ov01_021EB804(WeatherSystem *weatherSystem, int weather) {
+    if (weather >= 14) {


weather constant

red031000 · 2026-07-01T12:07:31Z

+    }
+
+    if (v0->unk2 != 0xFFFF) {
+        GfGfx_EngineATogglePlanes(4, 0);


plane constant

red031000 · 2026-07-01T12:09:08Z

+    WeatherSystem_Sub0 *v0 = &weatherSystem->unk0[weather];
+
+    if (v0->unk2 != 0xFFFF) {
+        GfGfx_EngineATogglePlanes(4, 0);


this should be GfGfx_EngineATogglePlanes(GX_PLANEMASK_BG2, GF_PLANE_TOGGLE_OFF);

red031000 · 2026-07-01T12:10:32Z

+
+    Sprite *temp = a0->unk4;
+    memset(a0, 0, sizeof(WeatherObject));
+    a0->unk4 = temp;


can unk4 be documented

red031000 · 2026-07-01T12:12:25Z

    LocalFieldData *localFieldData = Save_LocalFieldData_Get(ctx->fieldSystem->saveData);
    LocalFieldData_SetWeatherType(localFieldData, 12);
-    FieldWeatherUpdate_UsedFlash(ctx->fieldSystem->unk4->unk_0C, LocalFieldData_GetWeatherType(localFieldData)); // CallFieldTask_Flash?
+    WeatherManager_ChangeWeather(ctx->fieldSystem->unk4->weatherManager, LocalFieldData_GetWeatherType(localFieldData)); // CallFieldTask_Flash?


comment can be removed

Pixelstyx · 2026-07-27T02:40:29Z

+typedef struct WeatherObject WeatherObject;
+struct WeatherObject {
+    WeatherSystem *weatherSystem;
+    Sprite *unk4;


Could just be named sprite?

Pixelstyx · 2026-07-27T02:51:18Z

+struct WeatherSystem_Sub0_Sub8 {
+    WeatherSystem *weatherSystem;
+    WeatherSystem_Sub0 *unk4;
+    WeatherSpriteResources *unk8;


weatherSpriteResources

Pixelstyx · 2026-07-27T02:52:45Z

+
+struct WeatherSystem {
+    WeatherSystem_Sub0 *unk0;
+    const WeatherGfxNarcData *unk4;


narcData?

Pixelstyx · 2026-07-27T03:01:44Z

+    u32 weather;
+    u32 nextWeather;
+    u32 state;
+    u32 unk10;


unkWeather? We know it is definitely weather, just not what purpose it serves.

Pixelstyx · 2026-07-27T03:04:33Z

+    weatherSystem->unk0 = ov01_022098B0;
+    weatherSystem->unk4 = ov01_0220675C;
+
+    weatherSystem->narc = NARC_New(NARC_a_0_6_3, HEAP_ID_FIELD1);


Can we confirm the contents of this NARC and rename the constant accordingly?

Having looked at it in tinke, everything other than the bin files is individual weather particles. there's also an enormous rainbow that i assume is unused.

the bin files could also be weather, i dunno.

Pixelstyx · 2026-07-27T03:31:49Z

+    WeatherSystem_Sub0 *unk4;
+    WeatherSpriteResources *unk8;
+    WeatherObject linkedListDummy;
+    WeatherObject linkedList[64];


I suspect the data attached to this linked list is used to cyclically spawn and free individual weather particles (e.g. raindrops)

Pixelstyx · 2026-07-27T04:11:29Z

+static void ov01_021EC028(WeatherSystem_Sub0_Sub8 *a0) {
+    for (int i = 0; i < 64; i++) {
+        a0->linkedList[i].unk4 = Sprite_CreateAffine(&a0->unk8->spriteTemplate);
+        Sprite_SetDrawFlag(a0->linkedList[i].unk4, 0);


SetDrawFlag's second param is a BOOL

Pixelstyx · 2026-07-27T04:17:12Z

+static void ov01_021EC300(void *data) {
+}
+
+static VecFx32 ov01_021EC304(WeatherObject *a0) {


WeatherObject_GetSpriteMatrixPtr?

Pixelstyx · 2026-07-27T04:30:13Z

+static void ov01_021EC6A4(WeatherFogChange *fogChange, FogData *fog, s32 arg2, s32 arg3, GXRgb rgb, s32 arg5) {
+    int slope = Fog_GetSlope(fog);
+    int offset = Fog_GetOffset(fog);
+    GXRgb rgb2 = ov01_021EA860(fog);


Surely this can just be Fog_GetColor?

adrienntindall and others added 24 commits May 31, 2026 03:59

WeatherManager base struct

12dafef

Locate weatherManager in FieldSystem substruct

5898325

I need the renamed weather_manager.h to be part of the filesystem for replace.sh

Document WeatherDraw struct

f061703

struct UnkWeatherStruct_021EB64C

2e35014

Identify WeatherSystem struct from UnkWeatherStruct_021EB64C

d86d40e

I wonder if people realize I commit every 5 functions to record my progress and have to keep finding new relevant commit messages to make it seem like there's more purpose to my commits

To ov01_021EB9A8

f6031fc

Rework WeatherSystem_Sub0 substructs

38dbf5d

To ov01_021EBE4C

0bfe14b

To ov01_021EBF94

ff8ebc8

To ov01_021EC0C0

c933e55

To ov01_021EC240

b5ffa87

I wonder if the frequency and in-progress-ness of these commits screw with LLMs enough to ward them off from the project.

To ov01_021EC304

c678e10

To ov01_021EC52C

9397031

To ov01_021EC6A4

c22881d

To ov01_021EC7C8

f382f65

To ov01_021EC8F8

0d05fc9

To ov01_021ECF4C

d447c3e

To ov01_021ED584

34682fd

Identify field/fog.c

ae1386e

Merge branch 'master' of https://github.com/pret/pokeheartgold

5da12ed

Finish decomping functions

2ab12f4

Decompile weather manager data

091c931

Make functions static and run formater

a9bf3b2

Merge branch 'master' into weather-manager

390f081

red031000 requested changes Jul 1, 2026

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Pixelstyx reviewed Jul 27, 2026

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adrienntindall commented Jun 12, 2026

PR checklist

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Pixelstyx Jul 27, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Pixelstyx Jul 27, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Pixelstyx Jul 27, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Pixelstyx Jul 27, 2026 •

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