rooms: use calculated max abyss height

Rather than hardcoding the maximum abyss height to 16384, we calculate
it based on the OG difference between this and Floating Islands abyss
height. This avoids potential collision issues near the top of the
level.

src/libtrx/game/rooms/common.c

@@ -33,7 +33,8 @@ static bool m_FlipStatus = false;
 static int32_t m_FlipEffect = -1;
 static int32_t m_FlipTimer = 0;
 static int32_t m_FlipSlotFlags[MAX_FLIP_MAPS] = {};
-static int16_t m_AbyssHeight = 0;
+static int16_t m_AbyssMinHeight = 0;
+static int32_t m_AbyssMaxHeight = 0;
 static HEIGHT_TYPE m_HeightType = HT_WALL;
 
 static const int16_t *M_ReadTrigger(
@@ -511,12 +512,17 @@ SECTOR *Room_GetSkySector(
 
 void Room_SetAbyssHeight(const int16_t height)
 {
-    m_AbyssHeight = height;
+    // Once Lara reaches the min abyss height, she will be killed; she will
+    // continue to fall however, so the max height is needed until the inventory
+    // is shown, otherwise Lara will hit the floor.
+    m_AbyssMinHeight = height;
+    m_AbyssMaxHeight = height == 0 ? 0 : m_AbyssMinHeight + 26 * STEP_L;
+    CLAMPG(m_AbyssMaxHeight, MAX_HEIGHT - STEP_L);
 }
 
 bool Room_IsAbyssHeight(const int16_t height)
 {
-    return m_AbyssHeight != 0 && height >= m_AbyssHeight;
+    return m_AbyssMinHeight != 0 && height >= m_AbyssMinHeight;
 }
 
 HEIGHT_TYPE Room_GetHeightType(void)
@@ -533,7 +539,7 @@ int16_t Room_GetHeight(
     int32_t height = pit_sector->floor.height;
 
     if (Room_IsAbyssHeight(height)) {
-        height = 0x4000;
+        height = m_AbyssMaxHeight;
     } else {
         height = M_GetFloorTiltHeight(pit_sector, x, z);
     }