From 068e2fb2e40b6fdfba030469ecc8cc7c246b5596 Mon Sep 17 00:00:00 2001
From: numzero <numzer0@yandex.ru>
Date: Sat, 22 Aug 2026 01:38:43 +0300
Subject: [PATCH] use cbindgen for FFI

---
 CMakeLists.txt   |  2 ++
 cbindgen.cmake   | 13 +++++++++++++
 ui/cbindgen.toml | 14 ++++++++++++++
 ui/impl.cmake    | 21 +++++++++++++++++++++
 ui/src/api.cxx   |  7 -------
 ui/src/api.hxx   | 17 ++---------------
 ui/src/types.hxx | 12 ++++++++++++
 7 files changed, 64 insertions(+), 22 deletions(-)
 create mode 100644 cbindgen.cmake
 create mode 100644 ui/cbindgen.toml
 create mode 100644 ui/src/types.hxx

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 61bc0df..e4e9092 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -9,6 +9,8 @@ find_package(Qt6 REQUIRED COMPONENTS Gui Widgets)
 find_program(CARGO cargo REQUIRED)
 set(CARGO_TARGET_DIR "${CMAKE_BINARY_DIR}/cargo")
 
+include(cbindgen.cmake)
+
 qt_standard_project_setup()
 
 add_subdirectory(ui)
diff --git a/cbindgen.cmake b/cbindgen.cmake
new file mode 100644
index 0000000..f0d4a7c
--- /dev/null
+++ b/cbindgen.cmake
@@ -0,0 +1,13 @@
+option(LOCAL_CBINDGEN "Download and build `cbindgen` even if one can be found on the system")
+
+if(NOT LOCAL_CBINDGEN)
+	find_program(CBINDGEN cbindgen)
+endif()
+
+if(NOT CBINDGEN)
+	message(CONFIGURE_LOG "cbindgen not found, downloading...")
+	set(crates "${CMAKE_BINARY_DIR}/crates")
+	file(MAKE_DIRECTORY ${crates})
+	execute_process(COMMAND ${CARGO} install --root ${crates} cbindgen@0.29.4)
+	set(CACHE{CBINDGEN} TYPE FILEPATH FORCE VALUE "${crates}/bin/cbindgen")
+endif()
diff --git a/ui/cbindgen.toml b/ui/cbindgen.toml
new file mode 100644
index 0000000..3321c4d
--- /dev/null
+++ b/ui/cbindgen.toml
@@ -0,0 +1,14 @@
+includes = ["types.hxx"]
+sys_includes = ["cstdint"]
+pragma_once = true
+no_includes = true
+namespace = "ffi"
+tab_width = 4
+language = "C++"
+
+[parse]
+parse_deps = true
+include = ["PROJECT-NAME"]
+
+[export]
+exclude = ["Box"]
diff --git a/ui/impl.cmake b/ui/impl.cmake
index ff00ffc..b2b758b 100644
--- a/ui/impl.cmake
+++ b/ui/impl.cmake
@@ -22,3 +22,24 @@ add_library(PROJECT_NAME_impl STATIC IMPORTED)
 set_target_properties(PROJECT_NAME_impl PROPERTIES
 	IMPORTED_LOCATION ${impl_basename}.a
 )
+
+# generate the bindings
+file(MAKE_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/include")
+set(bindings_basename "${CMAKE_CURRENT_BINARY_DIR}/include/bindings")
+
+add_custom_command(
+	OUTPUT ${bindings_basename}.hxx
+	COMMAND ${CBINDGEN} --only-target-dependencies --output "${bindings_basename}.hxx" --depfile "${bindings_basename}.d"
+	WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
+	DEPFILE ${bindings_basename}.d
+	VERBATIM
+	CODEGEN
+	DEPENDS_EXPLICIT_ONLY
+)
+
+target_sources(PROJECT_NAME_impl INTERFACE
+	${bindings_basename}.hxx
+)
+target_include_directories(PROJECT_NAME_impl INTERFACE
+	"${CMAKE_CURRENT_BINARY_DIR}/include"
+)
diff --git a/ui/src/api.cxx b/ui/src/api.cxx
index aaa2b64..5b8e689 100644
--- a/ui/src/api.cxx
+++ b/ui/src/api.cxx
@@ -3,13 +3,6 @@
 #include <stdexcept>
 #include <utility>
 
-namespace ffi {
-extern "C" Core* rt4_viewport_create(xcb_connection_t* connection, std::uint32_t window, std::uint32_t width, std::uint32_t height);
-extern "C" void rt4_viewport_destroy(Core* viewport);
-extern "C" void rt4_viewport_configure(Core* viewport, std::uint32_t width, std::uint32_t height);
-extern "C" void rt4_viewport_redraw(Core* viewport, const RedrawArgs* args);
-} // namespace ffi
-
 BoxCore::BoxCore(BoxCore&& b)
 	: ptr(std::exchange(b.ptr, {})) {
 }
diff --git a/ui/src/api.hxx b/ui/src/api.hxx
index 82d9880..4847123 100644
--- a/ui/src/api.hxx
+++ b/ui/src/api.hxx
@@ -2,23 +2,10 @@
 
 #include <cstdint>
 
+#include "bindings.hxx"
+
 struct xcb_connection_t;
 
-struct alignas(16) Vec4 {
-	float x, y, z, w;
-};
-
-namespace ffi {
-struct Core;
-
-struct RedrawArgs {
-	float cam_yaw;
-	float cam_pitch;
-	float cam_distance;
-	float cam_fovy;
-};
-} // namespace ffi
-
 using ffi::RedrawArgs;
 
 class MutCore {
diff --git a/ui/src/types.hxx b/ui/src/types.hxx
new file mode 100644
index 0000000..b8b5b73
--- /dev/null
+++ b/ui/src/types.hxx
@@ -0,0 +1,12 @@
+#pragma once
+
+struct alignas(16) Vec4 {
+	float x, y, z, w;
+};
+
+namespace ffi {
+
+template <typename T>
+using Box = T*;
+
+} // namespace ffi