mrbgem.rake

MRuby::Gem::Specification.new('mruby-gpu-narray') do |spec|
  spec.license = 'MIT'
  spec.authors = 'Yuji Teshima'
  spec.version = '0.1.0'
  spec.summary = 'GPU N-dimensional array (Numo-like) for mruby via Vulkan Compute'

  # Only dependency is the Vulkan loader. No ncnn / SDL2 / glslang lib / OpenMP.
  spec.linker.libraries << 'vulkan'

  gem_dir    = File.dirname(File.expand_path(__FILE__))
  shader_dir = File.join(gem_dir, 'shader')

  # Embed the absolute shader directory into a generated header so that
  # GPU.init is optional (the first GPU op can lazily initialize). We write a
  # header instead of a -D define to avoid shell quote-escaping fragility.
  File.write(File.join(gem_dir, 'src', 'shader_dir.h'),
             "/* auto-generated by mrbgem.rake -- do not edit, do not commit */\n" \
             "#define GPU_NARRAY_SHADER_DIR \"#{shader_dir}\"\n")

  # Compile the GLSL compute shaders to SPIR-V at build time, so that adding
  # this gem "just works" with no manual `make -C shader` step. Requires
  # glslangValidator on PATH (override with the GLSLANG env var). If it is
  # missing we warn but keep building; the shaders can be compiled later with
  # `make -C shader`.
  glslang = ENV['GLSLANG'] || 'glslangValidator'
  if system(glslang, '--version', out: File::NULL, err: File::NULL).nil?
    warn "mruby-gpu-narray: '#{glslang}' not found on PATH; SPIR-V shaders were " \
         "not compiled. Install glslang or run `make -C #{shader_dir}` before use."
  else
    Dir.glob(File.join(shader_dir, '*.comp')).sort.each do |comp|
      spv = comp.sub(/\.comp\z/, '.spv')
      next if File.exist?(spv) && File.mtime(spv) >= File.mtime(comp)
      puts "GLSLANG   #{File.basename(comp)} -> #{File.basename(spv)}"
      unless system(glslang, '-V', comp, '-o', spv)
        warn "mruby-gpu-narray: failed to compile #{comp} to SPIR-V"
      end
    end
  end
end