items: fix Item_GetDistance overflows

LostArtefacts · Nov 6, 2024 · 63df6b2 · 63df6b2
1 parent 92ced59
commit 63df6b2
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Showing 2 changed files with 26 additions and 11 deletions.
diff --git a/src/tr1/game/items.c b/src/tr1/game/items.c
@@ -336,10 +336,19 @@ bool Item_IsNearItem(const ITEM *item, const XYZ_32 *pos, int32_t distance)
 
 int32_t Item_GetDistance(const ITEM *const item, const XYZ_32 *const target)
 {
-    const int32_t x = (item->pos.x - target->x);
-    const int32_t y = (item->pos.y - target->y);
-    const int32_t z = (item->pos.z - target->z);
-    return Math_Sqrt(SQUARE(x) + SQUARE(y) + SQUARE(z));
+    int32_t x = (item->pos.x - target->x);
+    int32_t y = (item->pos.y - target->y);
+    int32_t z = (item->pos.z - target->z);
+
+    int32_t scale = 0;
+    while ((int16_t)x != x || (int16_t)y != y || (int16_t)z != z) {
+        scale++;
+        x >>= 1;
+        y >>= 1;
+        z >>= 1;
+    }
+
+    return Math_Sqrt(SQUARE(x) + SQUARE(y) + SQUARE(z)) << scale;
 }
 
 bool Item_Test3DRange(int32_t x, int32_t y, int32_t z, int32_t range)

diff --git a/src/tr2/game/math.c b/src/tr2/game/math.c
@@ -506,13 +506,19 @@ int16_t Math_DirectionToAngle(DIRECTION dir)
 
 int32_t XYZ_32_GetDistance(const XYZ_32 *const pos1, const XYZ_32 *const pos2)
 {
-    // clang-format off
-    return Math_Sqrt(
-        SQUARE(pos1->x - pos2->x) +
-        SQUARE(pos1->y - pos2->y) +
-        SQUARE(pos1->z - pos2->z)
-    );
-    // clang-format on
+    int32_t x = (pos1->x - pos2->x);
+    int32_t y = (pos1->y - pos2->y);
+    int32_t z = (pos1->z - pos2->z);
+
+    int32_t scale = 0;
+    while ((int16_t)x != x || (int16_t)y != y || (int16_t)z != z) {
+        scale++;
+        x >>= 1;
+        y >>= 1;
+        z >>= 1;
+    }
+
+    return Math_Sqrt(SQUARE(x) + SQUARE(y) + SQUARE(z)) << scale;
 }
 
 int32_t XYZ_32_GetDistance0(const XYZ_32 *const pos)