Wait the hard one is me. Wii U homebrew development is EASY!

all you have to do is...

initialize ProcUI. make all the callback functions.
at the least, you will need a callback for

• exiting the game
• going into "foreground operation" (ran when the app first starts, and returning from background)
• going into "background operation" (when the user presses the home button on any controller)

initialize GX2, the graphics API.

be mindful of what you store in the 40MB region MEM1 (color, depth buffer...). it will have to be cleared when putting the app in the background, and restored when returning to foreground

• ProcUI has functions that basically make a savestate of MEM1 when going into BG, but they seem to make process switching slower. I haven't tested them out yet though

make sure to define every user-defined value in the color buffer during initialization or else it will not clear correctly

make a basic pass-thru vertex/pixel shader and compile it (ideally with the PC version of CafeGLSL)

load the shader from content folder into MEM2 and initialize it

bind the shader

uhh do nothing? i haven't gotten past this yet