From 570afe946e478a78ac2c64d2c11335ef6a03ae66 Mon Sep 17 00:00:00 2001
From: Isaac0-dev <62234577+Isaac0-dev@users.noreply.github.com>
Date: Sat, 22 Jun 2024 11:06:29 +1000
Subject: [PATCH] fix scrolling texture interp integer overflow (#72)

---
 src/game/behaviors/texscroll.inc.c | 8 ++++----
 src/game/scroll_targets.c          | 6 +++++-
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/src/game/behaviors/texscroll.inc.c b/src/game/behaviors/texscroll.inc.c
index 533b973e..fc02b225 100644
--- a/src/game/behaviors/texscroll.inc.c
+++ b/src/game/behaviors/texscroll.inc.c
@@ -154,13 +154,13 @@ void uv_update_scroll(void) {
     // Prepare for interpolation
     if (bhv < SCROLL_UV_X) {
         u8 bhvIndex = MIN(bhv, 2);
-        for (u16 k = 0; k < scroll->size; k++) {
-            scroll->prevF32[k] = verts[k]->n.ob[bhvIndex];
+        for (u16 i = 0; i < scroll->size; i++) {
+            scroll->prevF32[i] = verts[i]->n.ob[bhvIndex];
         }
     } else {
         u8 bhvIndex = MIN(bhv-SCROLL_UV_X, 1);
-        for (u16 k = 0; k < scroll->size; k++) {
-            scroll->prevS16[k] = verts[k]->n.tc[bhvIndex];
+        for (u16 i = 0; i < scroll->size; i++) {
+            scroll->prevS16[i] = verts[i]->n.tc[bhvIndex];
         }
     }
     scroll->needInterp = true;
diff --git a/src/game/scroll_targets.c b/src/game/scroll_targets.c
index f869992b..c0e564df 100644
--- a/src/game/scroll_targets.c
+++ b/src/game/scroll_targets.c
@@ -1,4 +1,5 @@
 #include "scroll_targets.h"
+#include "pc/lua/utils/smlua_math_utils.h"
 
 static struct ScrollTarget *sScrollTargets = NULL;
 
@@ -21,6 +22,7 @@ struct ScrollTarget *get_scroll_targets(u32 id, u16 size, u16 offset) {
 
         // If we need to, realloc the block of vertices
         if ((!scroll->hasOffset && offset > 0) || size < scroll->size) {
+            if (scroll->hasOffset) { return NULL; }
             if (size > scroll->size) { size = scroll->size; } // Don't use an invalid size
             scroll->hasOffset = true;
             Vtx* *newVtx = calloc(size, sizeof(Vtx*));
@@ -137,6 +139,8 @@ void patch_scroll_targets_before(void) {
     }
 }
 
+#define SHORT_RANGE 32767
+
 void patch_scroll_targets_interpolated(f32 delta) {
     f32 antiDelta = 1.0f - delta;
     struct ScrollTarget *scroll = sScrollTargets;
@@ -152,7 +156,7 @@ void patch_scroll_targets_interpolated(f32 delta) {
             } else {
                 u8 bhvIndex = MIN(scroll->bhv-SCROLL_UV_X, 1);
                 for (u16 k = 0; k < scroll->size; k++) {
-                    verts[k]->n.tc[bhvIndex] = (int) scroll->prevS16[k] * antiDelta + scroll->interpS16[k] * delta;
+                    verts[k]->n.tc[bhvIndex] = clampf(scroll->prevS16[k] * antiDelta + scroll->interpS16[k] * delta, -SHORT_RANGE, SHORT_RANGE);
                 }
             }
         }