fix to dx9_normalize macro

-possible error fix to 0 length situation
-related to #52

bin/d912pxy/shaders/common.hlsli

@@ -307,10 +307,13 @@ float4 dx9_fix_halfpixel_offset(float4 inPos)
 #define dx9_expp(a) exp2(a)
 #define dx9_exp(a) exp2(a)
 #define dx9_lerp(a,b,c) lerp(a,b,c)
-#define dx9_rcp(a) (a != 0 ? rcp(a) : 1e9)
+//megai2: looks like it works fine, but just in case left a note here
+//#define dx9_rcp(a) (a != 0 ? rcp(a) : 1e9)
+#define dx9_rcp(a) rcp(a)
 #define dx9_max(a,b) max(a,b) 
 #define dx9_min(a,b) min(a,b)
 #define dx9_rsqrt(a) rsqrt(abs(a))
 #define dx9_frac(a) frac(a)
 #define dx9_pow(a,b) pow(abs(a), b)
-#define dx9_normalize(a) normalize(a)
+//megai2: TODO optimize it thru HLSL generation cause normalize(a) says indefinete results on length(a) == 0
+#define dx9_normalize(a) (length(a) != 0 ? (a/length(a)) : a)