Terrain, Tile, UV, Splat

Hi Unity Family!
I have 1028x1028 mapdata
-Heightmap (size 257x257)
-Alphamap (size 257x257)
-Per tile have 2 Texture (128x128, DXT), 2 UV (need blend)

My problem is texture resolution and uv. How can i rotate tile with using uv and fix tile resolution ? I can fix this with plane * mapsize^2, but render time is too long. I want to use terrain object.

// SplatPrototypes

SplatPrototype[] tex = new SplatPrototype[tileRes.Length];

for (int i = 0; i < tileRes.Length; i++)

{

    tex[i] = new SplatPrototype();

    tex[i].texture = tileRes[i];

    tex[i].tileSize = new Vector2(128,128);

}

t.terrainData.splatPrototypes = tex;



// HeightMap

float[,] heightmap = t.terrainData.GetHeights(0, 0, mapData.mapSize, mapData.mapSize);

for (var y = 0; y < t.terrainData.heightmapHeight; y++)

    for (var x = 0; x < t.terrainData.heightmapWidth; x++)

        heightmap[y, x] = mapData.mData[x][y].Height/1.5f;

t.terrainData.SetHeights(0, 0,heightmap);



// AlphaMaps

float[,,] map = new float[t.terrainData.alphamapWidth, t.terrainData.alphamapHeight, tileRes.Length];

for (var y = 0; y < t.terrainData.alphamapHeight; y++)

{

    for (var x = 0; x < t.terrainData.alphamapWidth; x++)

    {

        for (int i = 0; i < tileRes.Length; i++)

            map[y, x, i] = 0f;



        if (mapData.mData[x][y].Tex1Idx <= tileRes.Length - 1) map[y, x, mapData.mData[x][y].Tex1Idx] = 0.5f;

        if (mapData.mData[x][y].Tex2Idx <= tileRes.Length - 1) map[y, x, mapData.mData[x][y].Tex2Idx] = 0.5f;

    }

}

t.terrainData.SetAlphamaps(0, 0, map);

 

My other project, its good but render time too long.

 

I have same issue pls help.