Scrolling Background Pixelated

i tried to make the game with background scrolling. where i moving the background offset. At first it works. then after a 10 minutes of playing. the background become pixelated. Any idea how to fixed it. here is the code i moving the background.

void Update () 
	{
		renderer.material.mainTextureOffset += scrollSpeed * Time.deltaTime;
	}

Here i attach the pixelated background.

UV values should stay as close to the 0…1 range as possible. Instead of continuously adding to mainTextureOffset, make the .x and .y elements wrap around after going above 1.0.

–Eric

Thanks…

Something like:

if (renderer.material.mainTextureOffset > 1)
  renderer.material.mainTextureOffset -= 1;