From 0630acce442ae7a2641a602deb71af4bb8a7c3f7 Mon Sep 17 00:00:00 2001
From: Ariel A <24759293+aarant@users.noreply.github.com>
Date: Mon, 27 May 2024 18:09:12 -0400
Subject: [PATCH] fix: make `LoadSheetGraphicsInfo` load, then free, tiles

Fixes follower pokeball gfx showing garbage for 1 frame when emerging
---
 src/event_object_movement.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/src/event_object_movement.c b/src/event_object_movement.c
index b8cfb591b3..686bbdd267 100644
--- a/src/event_object_movement.c
+++ b/src/event_object_movement.c
@@ -1587,10 +1587,12 @@ u16 LoadSheetGraphicsInfo(const struct ObjectEventGraphicsInfo *info, u16 uuid,
         u32 sheetSpan = GetSpanPerImage(info->oam->shape, info->oam->size);
         u16 oldTiles = 0;
         u16 tileStart;
+        bool32 oldInvisible;
         if (tag == TAG_NONE)
             tag = COMP_OW_TILE_TAG_BASE + uuid;
         
         if (sprite) {
+            oldInvisible = sprite->invisible;
             oldTiles = sprite->sheetTileStart;
             sprite->sheetTileStart = 0; // mark unused
             // Note: If sprite was not allocated to use a sheet,
@@ -1604,9 +1606,19 @@ u16 LoadSheetGraphicsInfo(const struct ObjectEventGraphicsInfo *info, u16 uuid,
         if (tileStart == TAG_NONE) {
             struct SpriteFrameImage image = {.size = info->size, .data = info->images->data};
             struct SpriteTemplate template = {.tileTag = tag, .images = &image};
-            if (oldTiles)
-                FieldEffectFreeTilesIfUnused(oldTiles);
+            // Load, then free, in order to avoid displaying garbage data
+            // before sprite's `sheetTileStart` is repointed
             tileStart = LoadCompressedSpriteSheetByTemplate(&template, TILE_SIZE_4BPP << sheetSpan);
+            if (oldTiles) {
+                FieldEffectFreeTilesIfUnused(oldTiles);
+                // We weren't able to load the sheet;
+                // retry (after having freed), and set sprite to invisible until done
+                if (tileStart <= 0) {
+                    if (sprite)
+                        sprite->invisible = TRUE;
+                    tileStart = LoadCompressedSpriteSheetByTemplate(&template, TILE_SIZE_4BPP << sheetSpan);
+                }
+            }
         // sheet loaded; unload any *other* sheet for sprite
         } else if (oldTiles && oldTiles != tileStart) {
             FieldEffectFreeTilesIfUnused(oldTiles);
@@ -1616,6 +1628,7 @@ u16 LoadSheetGraphicsInfo(const struct ObjectEventGraphicsInfo *info, u16 uuid,
             sprite->sheetTileStart = tileStart;
             sprite->sheetSpan = sheetSpan;
             sprite->usingSheet = TRUE;
+            sprite->invisible = oldInvisible;
         }
     // Going from sheet -> !sheet, reset tile number
     // (sheet stays loaded)