add a comment describing PC specific shield handling

src/game/chr.c

@@ -4545,6 +4545,13 @@ void chrTestHit(struct prop *prop, struct shotdata *shotdata, bool isshooting, b
 			if (hitpart) {
 				if (chrGetShield(chr) > 0.0f) {
 #ifndef PLATFORM_N64
+					/**
+					 * var8005efc0 > 0.0f adds a padding to bbox hit detection
+					 * in modelTestBboxNodeForHit() that accounts for a character's
+					 * surrounding shield. We skip this step on PC when checking
+					 * line-of-sight hits to light artifacts because lights should
+					 * be visible through the transparent shield.
+					 */
 					if (g_BgHitXluDisabled == false)
 #endif
 						var8005efc0 = 10.0f / model->scale;