This tool was made during development of the landscape shader. This shader used packed textures to reduce the amount of samples needed. In order to allow the end-users to quickly create their own packed textures I created this tool. Now anyone on the team can use the tool without having other photo manipulation software installed on their machine.
Channel packing is efficient because it allows the renderer to sample up to four grayscale maps that use the same UV coordinates with a single texture fetch.
The texture is generated using the Graphics.Blit functionality with a simple shader on the GPU.