Unbreakable glass decals fix

src/game/explosion.c

@@ -2133,6 +2133,21 @@ void explosionCreateBulletImpact(struct coord3d *pos, struct coord3d *arg1, s16
         impact_type = 0x10;
     }
 
+#ifdef PORT
+    /* Glass objects: the bulletproof/unbreakable ones take the texture-based
+     * hole, a decal drawn in the opaque pass. Transparent glass writes no
+     * depth there, so the decal depth test (RDP ZMODE_DEC, emulated exactly)
+     * rejects every pixel. Use the window crack the breakable glass gets: it
+     * is drawn after the glass in the translucent pass, without the decal
+     * test. */
+    if ((prop != NULL) && (impact_type != 0x10)
+        && ((prop->obj->type == PROPDEF_GLASS) || (prop->obj->type == PROPDEF_TINTED_GLASS))
+        && ((g_ImpactTypes[impact_type].unk2 >= 2) || (g_ImpactTypes[impact_type].unk1 != 2)))
+    {
+        impact_type = (randomGetNext() % 3) + 0x11;
+    }
+#endif
+
     spA0.f[0] = pos->f[0];
     spA0.f[1] = pos->f[1];
     spA0.f[2] = pos->f[2];