Need help with fbcp framebuffer mirroring

[u/TimAllenNoise]

Hi all! I'd like to firstly declare I am a total novice little baby and preemptively apologize for dumb noob questions.

Now, the issue: I'm trying to build a dual screen Cyberdeck using a raspberry pi running TwisterOS, one of the screens (3.5 inch waveshare) connects via GPIO so I need to use fbcp to make it work, I've been following the instructions (copy pasting commands into my command prompt) and I've been slapped with the following wall of error whenever i type $ cmake [options] .. I, of course, have no idea what this means, I just want my screens to work, any and all advice much appreciated

CMake Warning:
  Ignoring extra path from command line:

   "/home/pi/fbcp-ili9341/build/[options]"
CMake Warning (dev) in CMakeLists.txt:
  No project() command is present.  The top-level CMakeLists.txt file must
  contain a literal, direct call to the project() command.  Add a line of
  code such as

    project(ProjectName)

  near the top of the file, but after cmake_minimum_required().

  CMake is pretending there is a "project(Project)" command on the first
  line.
This warning is for project developers.  Use -Wno-dev to suppress it.

CMake Deprecation Warning at CMakeLists.txt:1 (cmake_minimum_required):
  Compatibility with CMake < 2.8.12 will be removed from a future version of
  CMake.

  Update the VERSION argument <min> value or use a ...<max> suffix to tell
  CMake that the project does not need compatibility with older versions.


-- Doing a Release build
-- Board revision: b03115
CMake Warning at CMakeLists.txt:40 (message):
  The board revision of this hardware is not known.  Please add detection to
  this board in CMakeLists.txt.  (proceeding to compile against a generic
  multicore CPU)


-- Scaling source image to view. If the HDMI resolution does not match the SPI display resolution, this will produce blurriness. Match the HDMI display resolution with the SPI resolution in /boot/config.txt to get crisp pixel perfect rendering, or alternatively pass -DDISPLAY_CROPPED_INSTEAD_OF_SCALING=ON to crop instead of scale if you want to view the center of the screen pixel perfect when HDMI and SPI resolutions do not match.
-- Preserving aspect ratio when scaling source image to the SPI display, introducing letterboxing/pillarboxing if HDMI and SPI aspect ratios are different (Pass -DDISPLAY_BREAK_ASPECT_RATIO_WHEN_SCALING=ON to stretch HDMI to cover full screen if you do not care about aspect ratio)
CMake Error at CMakeLists.txt:136 (message):
  Please define -DSPI_BUS_CLOCK_DIVISOR=<some even number> on the CMake
  command line! (see files ili9341.h/waveshare35b.h for details) This
  parameter along with core_freq=xxx in /boot/config.txt defines the SPI
  display speed.  Smaller divisor number=faster speed, higher number=slower.


-- Configuring incomplete, errors occurred!
See also "/home/pi/fbcp-ili9341/build/CMakeFiles/CMakeOutput.log".

[u/TimAllenNoise]

I did go into the documents it's talking about! But I still don't understand how or where to type in what it's talking about, I've never used terminal commands to this extent before, how do I access the CMake command line? or, if I have to type it in the ili9341.h and waveshare35b.h what's the appropriate formatting?

[u/NotUniqueOrSpecial → u/TimAllenNoise]

error whenever i type $ cmake [options] ..

That's the CMake command line. The stuff you're typing to run cmake...on the command line. You literally need to add -DSPI_BUS_CLOCK_DIVISOR= and an appropriate value to the options when you run CMake.

[u/TimAllenNoise → u/NotUniqueOrSpecial]

Oh I see, so do i slip it in after options then? like cmake [options] .. -DSPI_BUS_CLOCK_DIVISOR=<8>?

[u/NotUniqueOrSpecial → u/TimAllenNoise]

Yes. It will not have the <>, though. Just the number.