Merge pull request #363 from Unity-Technologies/fix-checkerboard

Fixing AA of procedural checkerboard node

com.unity.shadergraph/Editor/Data/Nodes/Procedural/CheckerboardNode.cs

@@ -32,15 +32,15 @@ namespace UnityEditor.ShaderGraph
             return
                 @"
 {
-    UV = UV + 0.25 / Frequency;
+    UV = (UV.xy + 0.5) * Frequency;
     {precision}4 derivatives = {precision}4(ddx(UV), ddy(UV));
     {precision}2 duv_length = sqrt({precision}2(dot(derivatives.xz, derivatives.xz), dot(derivatives.yw, derivatives.yw)));
-    {precision} width = 0.5;
-    {precision}2 distance3 = 2.0 * abs(frac((UV.xy + 0.5) * Frequency) - 0.5) - width;
-    {precision}2 scale = 0.5 / duv_length.xy;
-    {precision}2 blend_out = saturate(scale / 3);
-    {precision}2 vector_alpha = clamp(distance3 * scale.xy * blend_out.xy, -1.0, 1.0);
-    {precision} alpha = saturate(vector_alpha.x * vector_alpha.y);
+    {precision} width = 1.0;
+    {precision}2 distance3 = 4.0 * abs(frac(UV + 0.25) - 0.5) - width;
+    {precision}2 scale = 0.35 / duv_length.xy;
+    {precision} freqLimiter = sqrt(clamp(1.1f - max(duv_length.x, duv_length.y), 0.0, 1.0));
+    {precision}2 vector_alpha = clamp(distance3 * scale.xy, -1.0, 1.0);
+    {precision} alpha = saturate(0.5f + 0.5f * vector_alpha.x * vector_alpha.y * freqLimiter);
     Out = lerp(ColorA, ColorB, alpha.xxx);
 }";
         }