Output rotation matrix along with seamless UV

Terrain_SampleSeamlessUV now additionally returns a 2x2 rotation matrix which can be used to transform vectors and other data if necessary.

This also adds a function overload `Terrain_SampleSeamlessUV( float2 uv )` for cases when you don't need a rotation matrix. This will avoid breaking any shaders that rely on old implementation of this function

game/addons/base/Assets/shaders/terrain/TerrainCommon.hlsl

@@ -73,7 +73,7 @@ class Terrain
 
 // Get UV with per-tile UV offset to reduce visible tiling
 // Works by offsetting UVs within each tile using a hash of the tile coordinate
-float2 Terrain_SampleSeamlessUV( float2 uv )
+float2 Terrain_SampleSeamlessUV( float2 uv, out float2x2 uvAngle )
 {
     float2 tileCoord = floor( uv );
     float2 localUV = frac( uv );
@@ -89,6 +89,9 @@ float2 Terrain_SampleSeamlessUV( float2 uv )
     float sinA = sin(angle);
     float2x2 rot = float2x2(cosA, -sinA, sinA, cosA);
 
+    // Output rotation matrix 
+    uvAngle = rot;
+
     // Rotate around center
     localUV = mul(rot, localUV - 0.5) + 0.5;
 
@@ -96,6 +99,12 @@ float2 Terrain_SampleSeamlessUV( float2 uv )
     return tileCoord + frac(localUV + hash);
 }
 
+float2 Terrain_SampleSeamlessUV( float2 uv ) 
+{
+    float2x2 dummy;
+    return Terrain_SampleSeamlessUV( uv, dummy ); 
+}
+
 // Move to another file:
 
 //