1 チャンネルあたり 8 ビットで構成されたアルファチャンネルを持つカラーのテクスチャ形式
Each of RGBA color channels is stored as an 8-bit value in [0..1] range. In memory, the channel data is ordered this way: A, R, G, B bytes one after another.
Note that RGBA32 format might be slightly more efficient on most platforms, as the data layout in memory more
closely matches what the graphics APIs expect.
関連項目: Texture2D, texture assets.