HLSL: Add gather, improve proto generator machine for upcoming 2DMS/Shadow

Test/hlsl.gather.offsetarray.dx10.frag

@@ -0,0 +1,36 @@
+SamplerState       g_sSamp : register(s0);
+
+Texture1DArray          g_tTex1df4a : register(t1);
+
+uniform Texture1DArray <float4> g_tTex1df4 : register(t0);
+Texture1DArray <int4>   g_tTex1di4;
+Texture1DArray <uint4>  g_tTex1du4;
+
+Texture2DArray <float4> g_tTex2df4;
+Texture2DArray <int4>   g_tTex2di4;
+Texture2DArray <uint4>  g_tTex2du4;
+
+struct PS_OUTPUT
+{
+    float4 Color : SV_Target0;
+    float  Depth : SV_Depth;
+};
+
+PS_OUTPUT main()
+{
+   PS_OUTPUT psout;
+
+   // No 1D gathers
+
+   float4 txval20 = g_tTex2df4 . Gather(g_sSamp, float3(0.1, 0.2, 0.3), int2(1,0));
+   int4   txval21 = g_tTex2di4 . Gather(g_sSamp, float3(0.3, 0.4, 0.4), int2(1,1));
+   uint4  txval22 = g_tTex2du4 . Gather(g_sSamp, float3(0.5, 0.6, 0.7), int2(1,-1));
+
+   // No 3D gathers
+   // No Cube offset gathers
+
+   psout.Color = 1.0;
+   psout.Depth = 1.0;
+
+   return psout;
+}