CMake: Add external UI support

Squashed commit of the following:

commit d1a6823458
Author: AnClark <clarklaw4701@qq.com>
Date:   Thu Dec 15 09:03:18 2022 +0800

    Refactor CMake var _dgl_library -> _dgl_has_ui in plugin build functions

    Plugin build functions (dpf__build_<PLUGIN_TYPE>) invokes
    dpf__add_ui_main() which has a parameter HAS_UI. This parameter acts
    like a switch, controlling if DistrhoPluginMain.cpp shall be compiled.

    Before this patch, value of _dgl_library is passed into HAS_UI. However,
    this will make it ambiguous. Variable _dgl_library should only be served
    as a flag of DGL UI type, and should not be a switch of whether to build
    DistrhoPluginMain.cpp or not.

    What's more, since DPF's CMake build system starts to support external
    UI, which is not limited to DGL, simply checking _dgl_library for
    dgl__add_ui_main() is no longer relevant.

    So, instead, I use variable _dgl_has_ui which keeps to the point. It
    will be set to ON if _dgl_library is non-empty or _dgl_external is ON.

commit 2d162a16b6
Author: AnClark Liu <anclarkliu@outlook.com>
Date:   Tue Dec 13 23:13:49 2022 +0800

    Build ExternalUI and EmbedExternalUI example plugins with cmake

    Note: Build CLAP versions as well.

commit 2cf060910e
Author: AnClark Liu <anclarkliu@outlook.com>
Date:   Tue Dec 13 23:07:40 2022 +0800

    Add external UI support for cmake

Signed-off-by: falkTX <falktx@falktx.com>

CMakeLists.txt

@@ -47,7 +47,8 @@ if(DPF_EXAMPLES)
       add_subdirectory("examples/CairoUI")
     endif()
   endif()
-  #add_subdirectory("examples/ExternalUI")
+  add_subdirectory("examples/ExternalUI")
+  add_subdirectory("examples/EmbedExternalUI")
   add_subdirectory("examples/FileHandling")
   add_subdirectory("examples/Info")
   add_subdirectory("examples/Latency")

cmake/DPF-plugin.cmake

@@ -75,7 +75,7 @@ include(CMakeParseArguments)
 #       `jack`, `ladspa`, `dssi`, `lv2`, `vst2`, `vst3`, `clap`
 #
 #   `UI_TYPE` <type>
-#       the user interface type: `opengl` (default), `cairo`
+#       the user interface type: `opengl` (default), `cairo`, `external`
 #
 #   `MONOLITHIC`
 #       build LV2 as a single binary for UI and DSP
@@ -101,6 +101,7 @@ function(dpf_add_plugin NAME)
   endif()
 
   set(_dgl_library)
+  set(_dgl_external OFF)
   if(_dpf_plugin_FILES_UI)
     if(_dpf_plugin_UI_TYPE STREQUAL "cairo")
       dpf__add_dgl_cairo("${_dpf_plugin_NO_SHARED_RESOURCES}")
@@ -108,11 +109,18 @@ function(dpf_add_plugin NAME)
     elseif(_dpf_plugin_UI_TYPE STREQUAL "opengl")
       dpf__add_dgl_opengl("${_dpf_plugin_NO_SHARED_RESOURCES}")
       set(_dgl_library dgl-opengl)
+    elseif(_dpf_plugin_UI_TYPE STREQUAL "external")
+      set(_dgl_external ON)
     else()
       message(FATAL_ERROR "Unrecognized UI type for plugin: ${_dpf_plugin_UI_TYPE}")
     endif()
   endif()
 
+  set(_dgl_has_ui OFF)
+  if(_dgl_library OR _dgl_external)
+    set(_dgl_has_ui ON)
+  endif()
+
   ###
   dpf__ensure_sources_non_empty(_dpf_plugin_FILES_COMMON)
   dpf__ensure_sources_non_empty(_dpf_plugin_FILES_DSP)
@@ -127,17 +135,20 @@ function(dpf_add_plugin NAME)
     target_link_libraries("${NAME}" PRIVATE "dl")
   endif()
 
-  if(_dgl_library)
+  if(_dgl_library AND NOT _dgl_external)
     # make sure that all code will see DGL_* definitions
     target_link_libraries("${NAME}" PUBLIC
       "${_dgl_library}-definitions"
       dgl-system-libs-definitions)
+  elseif(_dgl_external)
+    target_link_libraries("${NAME}" PUBLIC
+      dgl-system-libs-definitions)
   endif()
 
   dpf__add_static_library("${NAME}-dsp" ${_dpf_plugin_FILES_DSP})
   target_link_libraries("${NAME}-dsp" PUBLIC "${NAME}")
 
-  if(_dgl_library)
+  if(_dgl_library AND NOT _dgl_external)
     dpf__add_static_library("${NAME}-ui" ${_dpf_plugin_FILES_UI})
     target_link_libraries("${NAME}-ui" PUBLIC "${NAME}" ${_dgl_library})
     if((NOT WIN32) AND (NOT APPLE) AND (NOT HAIKU))
@@ -145,6 +156,14 @@ function(dpf_add_plugin NAME)
     endif()
     # add the files containing Objective-C classes
     dpf__add_plugin_specific_ui_sources("${NAME}-ui")
+  elseif(_dgl_external)
+    dpf__add_static_library("${NAME}-ui" ${_dpf_plugin_FILES_UI})
+    target_link_libraries("${NAME}-ui" PUBLIC "${NAME}")
+    if((NOT WIN32) AND (NOT APPLE) AND (NOT HAIKU))
+      target_link_libraries("${NAME}-ui" PRIVATE "dl")
+    endif()
+    # add the files containing Objective-C classes
+    dpf__add_plugin_specific_ui_sources("${NAME}-ui")
   else()
     add_library("${NAME}-ui" INTERFACE)
   endif()
@@ -152,19 +171,19 @@ function(dpf_add_plugin NAME)
   ###
   foreach(_target ${_dpf_plugin_TARGETS})
     if(_target STREQUAL "jack")
-      dpf__build_jack("${NAME}" "${_dgl_library}")
+      dpf__build_jack("${NAME}" "${_dgl_has_ui}")
     elseif(_target STREQUAL "ladspa")
       dpf__build_ladspa("${NAME}")
     elseif(_target STREQUAL "dssi")
-      dpf__build_dssi("${NAME}" "${_dgl_library}")
+      dpf__build_dssi("${NAME}" "${_dgl_has_ui}")
     elseif(_target STREQUAL "lv2")
-      dpf__build_lv2("${NAME}" "${_dgl_library}" "${_dpf_plugin_MONOLITHIC}")
+      dpf__build_lv2("${NAME}" "${_dgl_has_ui}" "${_dpf_plugin_MONOLITHIC}")
     elseif(_target STREQUAL "vst2")
-      dpf__build_vst2("${NAME}" "${_dgl_library}")
+      dpf__build_vst2("${NAME}" "${_dgl_has_ui}")
     elseif(_target STREQUAL "vst3")
-      dpf__build_vst3("${NAME}" "${_dgl_library}")
+      dpf__build_vst3("${NAME}" "${_dgl_has_ui}")
     elseif(_target STREQUAL "clap")
-      dpf__build_clap("${NAME}" "${_dgl_library}")
+      dpf__build_clap("${NAME}" "${_dgl_has_ui}")
     else()
       message(FATAL_ERROR "Unrecognized target type for plugin: ${_target}")
     endif()
@@ -184,12 +203,12 @@ endfunction()
 #
 # Add build rules for a JACK/Standalone program.
 #
-function(dpf__build_jack NAME DGL_LIBRARY)
+function(dpf__build_jack NAME HAS_UI)
   dpf__create_dummy_source_list(_no_srcs)
 
   dpf__add_executable("${NAME}-jack" ${_no_srcs})
   dpf__add_plugin_main("${NAME}-jack" "jack")
-  dpf__add_ui_main("${NAME}-jack" "jack" "${DGL_LIBRARY}")
+  dpf__add_ui_main("${NAME}-jack" "jack" "${HAS_UI}")
   target_link_libraries("${NAME}-jack" PRIVATE "${NAME}-dsp" "${NAME}-ui")
   set_target_properties("${NAME}-jack" PROPERTIES
     RUNTIME_OUTPUT_DIRECTORY "${PROJECT_BINARY_DIR}/bin/$<0:>"
@@ -267,7 +286,7 @@ endfunction()
 #
 # Add build rules for a DSSI plugin.
 #
-function(dpf__build_dssi NAME DGL_LIBRARY)
+function(dpf__build_dssi NAME HAS_UI)
   find_package(PkgConfig)
   pkg_check_modules(LIBLO "liblo")
   if(NOT LIBLO_FOUND)
@@ -288,9 +307,9 @@ function(dpf__build_dssi NAME DGL_LIBRARY)
     OUTPUT_NAME "${NAME}-dssi"
     PREFIX "")
 
-  if(DGL_LIBRARY)
+  if(HAS_UI)
     dpf__add_executable("${NAME}-dssi-ui" ${_no_srcs})
-    dpf__add_ui_main("${NAME}-dssi-ui" "dssi" "${DGL_LIBRARY}")
+    dpf__add_ui_main("${NAME}-dssi-ui" "dssi" "${HAS_UI}")
     target_link_libraries("${NAME}-dssi-ui" PRIVATE "${NAME}-ui")
     set_target_properties("${NAME}-dssi-ui" PROPERTIES
       RUNTIME_OUTPUT_DIRECTORY "${PROJECT_BINARY_DIR}/bin/${NAME}-dssi/$<0:>"
@@ -308,12 +327,12 @@ endfunction()
 #
 # Add build rules for an LV2 plugin.
 #
-function(dpf__build_lv2 NAME DGL_LIBRARY MONOLITHIC)
+function(dpf__build_lv2 NAME HAS_UI MONOLITHIC)
   dpf__create_dummy_source_list(_no_srcs)
 
   dpf__add_module("${NAME}-lv2" ${_no_srcs})
   dpf__add_plugin_main("${NAME}-lv2" "lv2")
-  if(DGL_LIBRARY AND MONOLITHIC)
+  if(HAS_UI AND MONOLITHIC)
     dpf__set_module_export_list("${NAME}-lv2" "lv2")
   else()
     dpf__set_module_export_list("${NAME}-lv2" "lv2-dsp")
@@ -325,15 +344,15 @@ function(dpf__build_lv2 NAME DGL_LIBRARY MONOLITHIC)
     OUTPUT_NAME "${NAME}_dsp"
     PREFIX "")
 
-  if(DGL_LIBRARY)
+  if(HAS_UI)
     if(MONOLITHIC)
-      dpf__add_ui_main("${NAME}-lv2" "lv2" "${DGL_LIBRARY}")
+      dpf__add_ui_main("${NAME}-lv2" "lv2" "${HAS_UI}")
       target_link_libraries("${NAME}-lv2" PRIVATE "${NAME}-ui")
       set_target_properties("${NAME}-lv2" PROPERTIES
         OUTPUT_NAME "${NAME}")
     else()
       dpf__add_module("${NAME}-lv2-ui" ${_no_srcs})
-      dpf__add_ui_main("${NAME}-lv2-ui" "lv2" "${DGL_LIBRARY}")
+      dpf__add_ui_main("${NAME}-lv2-ui" "lv2" "${HAS_UI}")
       dpf__set_module_export_list("${NAME}-lv2-ui" "lv2-ui")
       target_link_libraries("${NAME}-lv2-ui" PRIVATE "${NAME}-ui")
       set_target_properties("${NAME}-lv2-ui" PROPERTIES
@@ -361,12 +380,12 @@ endfunction()
 #
 # Add build rules for a VST2 plugin.
 #
-function(dpf__build_vst2 NAME DGL_LIBRARY)
+function(dpf__build_vst2 NAME HAS_UI)
   dpf__create_dummy_source_list(_no_srcs)
 
   dpf__add_module("${NAME}-vst2" ${_no_srcs})
   dpf__add_plugin_main("${NAME}-vst2" "vst2")
-  dpf__add_ui_main("${NAME}-vst2" "vst2" "${DGL_LIBRARY}")
+  dpf__add_ui_main("${NAME}-vst2" "vst2" "${HAS_UI}")
   dpf__set_module_export_list("${NAME}-vst2" "vst2")
   target_link_libraries("${NAME}-vst2" PRIVATE "${NAME}-dsp" "${NAME}-ui")
   set_target_properties("${NAME}-vst2" PROPERTIES
@@ -439,14 +458,14 @@ endfunction()
 #
 # Add build rules for a VST3 plugin.
 #
-function(dpf__build_vst3 NAME DGL_LIBRARY)
+function(dpf__build_vst3 NAME HAS_UI)
   dpf__determine_vst3_package_architecture(vst3_arch)
 
   dpf__create_dummy_source_list(_no_srcs)
 
   dpf__add_module("${NAME}-vst3" ${_no_srcs})
   dpf__add_plugin_main("${NAME}-vst3" "vst3")
-  dpf__add_ui_main("${NAME}-vst3" "vst3" "${DGL_LIBRARY}")
+  dpf__add_ui_main("${NAME}-vst3" "vst3" "${HAS_UI}")
   dpf__set_module_export_list("${NAME}-vst3" "vst3")
   target_link_libraries("${NAME}-vst3" PRIVATE "${NAME}-dsp" "${NAME}-ui")
   set_target_properties("${NAME}-vst3" PROPERTIES
@@ -481,12 +500,12 @@ endfunction()
 #
 # Add build rules for a VST2 plugin.
 #
-function(dpf__build_clap NAME DGL_LIBRARY)
+function(dpf__build_clap NAME HAS_UI)
   dpf__create_dummy_source_list(_no_srcs)
 
   dpf__add_module("${NAME}-clap" ${_no_srcs})
   dpf__add_plugin_main("${NAME}-clap" "clap")
-  dpf__add_ui_main("${NAME}-clap" "clap" "${DGL_LIBRARY}")
+  dpf__add_ui_main("${NAME}-clap" "clap" "${HAS_UI}")
   dpf__set_module_export_list("${NAME}-clap" "clap")
   target_link_libraries("${NAME}-clap" PRIVATE "${NAME}-dsp" "${NAME}-ui")
   set_target_properties("${NAME}-clap" PROPERTIES

examples/EmbedExternalUI/CMakeLists.txt

@@ -0,0 +1,13 @@
+# CMake file for DISTRHO Plugins #
+# ------------------------------ #
+
+dpf_add_plugin(d_embed_external_ui
+  TARGETS lv2 vst2 vst3 clap
+  UI_TYPE external
+  FILES_DSP
+    EmbedExternalExamplePlugin.cpp
+  FILES_UI
+    EmbedExternalExampleUI.cpp)
+
+target_include_directories(
+    d_embed_external_ui PUBLIC ".")

examples/EmbedExternalUI/DistrhoPluginInfo.h

@@ -20,6 +20,7 @@
 #define DISTRHO_PLUGIN_BRAND "DISTRHO"
 #define DISTRHO_PLUGIN_NAME  "EmbedExternalUI"
 #define DISTRHO_PLUGIN_URI   "http://distrho.sf.net/examples/EmbedExternalUI"
+#define DISTRHO_PLUGIN_CLAP_ID "studio.kx.distrho.examples.embed-external-ui"
 
 #define DISTRHO_PLUGIN_HAS_UI          1
 #define DISTRHO_PLUGIN_HAS_EMBED_UI    1

examples/ExternalUI/CMakeLists.txt

@@ -0,0 +1,13 @@
+# CMake file for DISTRHO Plugins #
+# ------------------------------ #
+
+dpf_add_plugin(d_external_ui
+  TARGETS lv2 vst2 vst3 clap
+  UI_TYPE external
+  FILES_DSP
+    ExternalExamplePlugin.cpp
+  FILES_UI
+    ExternalExampleUI.cpp)
+
+target_include_directories(
+    d_external_ui PUBLIC ".")

examples/ExternalUI/DistrhoPluginInfo.h

@@ -20,6 +20,7 @@
 #define DISTRHO_PLUGIN_BRAND "DISTRHO"
 #define DISTRHO_PLUGIN_NAME  "ExternalUI"
 #define DISTRHO_PLUGIN_URI   "http://distrho.sf.net/examples/ExternalUI"
+#define DISTRHO_PLUGIN_CLAP_ID "studio.kx.distrho.examples.external-ui"
 
 #define DISTRHO_PLUGIN_HAS_UI          1
 #define DISTRHO_PLUGIN_HAS_EMBED_UI    1