Fix Water decals

src/game/bg.c

@@ -3358,6 +3358,38 @@ bool bgTestRayIntersectsBbox(coord3d *origin, coord3d *dir, s32 *bbox_min, s32 *
 }
 
 
+#ifdef PORT
+#include "image.h"
+
+/* The image id of a room triangle's texture, read like the N64 does: texLoad
+ * stores the id in the 8 bytes before the texture data, and the room's
+ * G_SETTIMG points at that data (a full host pointer in w1 on PC). Room GDLs
+ * load into the default pool, so anything outside it is not a texture.
+ * The id selects the impact decal, sound and dust puff (HIT_WATER: no decal,
+ * no puff, splash sound). */
+static s32 bgTexnumFromSetTimg(Gfx *settimg)
+{
+    struct texpool *pool = &ptr_texture_alloc_start;
+    u8 *data = (u8 *)settimg->words.w1;
+    s32 texnum;
+
+    if (data < pool->start + 8 || data >= (u8 *)pool->end)
+    {
+        return -1;
+    }
+
+    texnum = *(s16 *)(data - 8);
+
+    if (texnum < 0 || texnum >= MAX_TEXTURES)
+    {
+        return -1;
+    }
+
+    return texnum;
+}
+#endif
+
+
 bool bgTestRayIntersectionInRoom(coord3d *from, coord3d *to, coord3d *dir, RoomVtxBatchBounds *point, s32 roomnum, struct HitThing *hitthing)
 {
     Vertex *vtxbase;
@@ -3555,6 +3587,11 @@ bool bgTestRayIntersectionInRoom(coord3d *from, coord3d *to, coord3d *dir, RoomV
                             #ifdef PORT
                             /* D154: KSEG0 texnum deref invalid for converted GDLs (cf. D135). D431 (#119): light fixtures are the one texture class the game acts on, so recover their image id from the fixture table. */
                             texnum = lightFixtureTexnumForGfx(gdl, roomnum);
+
+                            if (texnum < 0)
+                            {
+                                texnum = bgTexnumFromSetTimg(tcmd);
+                            }
 #else
                             temp.word = ((u32 *) tcmd)[1] - 8;
                             texnum = *((u16 *) (temp.word | 0x80000000));
@@ -3737,6 +3774,11 @@ bool bgTestRayIntersectionInRoom(coord3d *from, coord3d *to, coord3d *dir, RoomV
                                     #ifdef PORT
                                     /* D154: KSEG0 texnum deref invalid for converted GDLs (cf. D135). D431 (#119): light fixtures are the one texture class the game acts on, so recover their image id from the fixture table. */
                                     texnum = lightFixtureTexnumForGfx(gdl, roomnum);
+
+                                    if (texnum < 0)
+                                    {
+                                        texnum = bgTexnumFromSetTimg(tcmd);
+                                    }
 #else
                                     temp.word = ((u32 *) tcmd)[1] - 8;
                                     texnum = *((u16 *) (temp.word | 0x80000000));