- Set extern "C" on IMGUI_IMPL_API so that exported backend functions aren't name-mangled

- Support loading the glfw backend via shared library
- Clear the glfw backend's `g_ContextMap` allocation to avoid leak warnings
- Fixup ImTextureID -> ImTextureRef
- Fixup paddig field naming

Author: kcbanner

build.zig

@@ -107,8 +107,11 @@ pub fn build(b: *std.Build) void {
     if (options.shared) {
         if (target.result.os.tag == .windows) {
             imgui.root_module.addCMacro("IMGUI_API", "__declspec(dllexport)");
+            imgui.root_module.addCMacro("IMGUI_IMPL_API", "extern \"C\" __declspec(dllexport)");
             imgui.root_module.addCMacro("IMPLOT_API", "__declspec(dllexport)");
             imgui.root_module.addCMacro("ZGUI_API", "__declspec(dllexport)");
+        } else {
+            imgui.root_module.addCMacro("IMGUI_IMPL_API", "extern \"C\"");
         }
 
         if (target.result.os.tag == .macos) {

libs/imgui/backends/imgui_impl_glfw.cpp

@@ -807,6 +807,7 @@ void ImGui_ImplGlfw_Shutdown()
     io.BackendPlatformUserData = nullptr;
     io.BackendFlags &= ~(ImGuiBackendFlags_HasMouseCursors | ImGuiBackendFlags_HasSetMousePos | ImGuiBackendFlags_HasGamepad | ImGuiBackendFlags_PlatformHasViewports | ImGuiBackendFlags_HasMouseHoveredViewport);
     ImGui_ImplGlfw_ContextMap_Remove(bd->Window);
+    g_ContextMap.clear();
     IM_DELETE(bd);
 }
 

src/backend_glfw.zig

@@ -1,11 +1,17 @@
 const gui = @import("gui.zig");
+const options = @import("zgui_options");
 
 // This call will install GLFW callbacks to handle GUI interactions.
 // Those callbacks will chain-call user's previously installed callbacks, if any.
 // This means that custom user's callbacks need to be installed *before* calling zgpu.gui.init().
 pub fn init(
     window: *const anyopaque, // zglfw.Window
 ) void {
+    const ImGui_ImplGlfw_InitForOther = @extern(*const fn (window: *const anyopaque, install_callbacks: bool) callconv(.c) bool, .{
+        .name = "ImGui_ImplGlfw_InitForOther",
+        .is_dll_import = options.shared,
+    });
+
     if (!ImGui_ImplGlfw_InitForOther(window, true)) {
         unreachable;
     }
@@ -14,6 +20,11 @@ pub fn init(
 pub fn initOpenGL(
     window: *const anyopaque, // zglfw.Window
 ) void {
+    const ImGui_ImplGlfw_InitForOpenGL = @extern(*const fn (window: *const anyopaque, install_callbacks: bool) callconv(.c) bool, .{
+        .name = "ImGui_ImplGlfw_InitForOpenGL",
+        .is_dll_import = options.shared,
+    });
+
     if (!ImGui_ImplGlfw_InitForOpenGL(window, true)) {
         unreachable;
     }
@@ -22,23 +33,28 @@ pub fn initOpenGL(
 pub fn initVulkan(
     window: *const anyopaque, // zglfw.Window
 ) void {
+    const ImGui_ImplGlfw_InitForVulkan = @extern(*const fn (window: *const anyopaque, install_callbacks: bool) callconv(.c) bool, .{
+        .name = "ImGui_ImplGlfw_InitForVulkan",
+        .is_dll_import = options.shared,
+    });
+
     if (!ImGui_ImplGlfw_InitForVulkan(window, true)) {
         unreachable;
     }
 }
 
 pub fn deinit() void {
+    const ImGui_ImplGlfw_Shutdown = @extern(*const fn () callconv(.c) void, .{
+        .name = "ImGui_ImplGlfw_Shutdown",
+        .is_dll_import = options.shared,
+    });
     ImGui_ImplGlfw_Shutdown();
 }
 
 pub fn newFrame() void {
+    const ImGui_ImplGlfw_NewFrame = @extern(*const fn () callconv(.c) void, .{
+        .name = "ImGui_ImplGlfw_NewFrame",
+        .is_dll_import = options.shared,
+    });
     ImGui_ImplGlfw_NewFrame();
 }
-
-// Those functions are defined in `imgui_impl_glfw.cpp`
-// (they include few custom changes).
-extern fn ImGui_ImplGlfw_InitForOther(window: *const anyopaque, install_callbacks: bool) bool;
-extern fn ImGui_ImplGlfw_InitForOpenGL(window: *const anyopaque, install_callbacks: bool) bool;
-extern fn ImGui_ImplGlfw_InitForVulkan(window: *const anyopaque, install_callbacks: bool) bool;
-extern fn ImGui_ImplGlfw_NewFrame() void;
-extern fn ImGui_ImplGlfw_Shutdown() void;

src/gui.zig

@@ -184,7 +184,7 @@ pub const ConfigFlags = packed struct(c_int) {
     user_storage: u4 = 0,
     is_srgb: bool = false,
     is_touch_screen: bool = false,
-    _padding: u10 = 0,
+    _padding2: u10 = 0,
 };
 
 pub const BackendFlags = packed struct(c_int) {
@@ -193,11 +193,11 @@ pub const BackendFlags = packed struct(c_int) {
     has_set_mouse_pos: bool = false,
     renderer_has_vtx_offset: bool = false,
     renderer_has_textures: bool = false,
-    _pading0: u5 = 0,
+    _padding0: u5 = 0,
     platform_has_viewports: bool = false,
     has_mouse_hovered_viewports: bool = false,
     renderer_has_viewports: bool = false,
-    _padding: u19 = 0,
+    _padding1: u19 = 0,
 };
 
 pub const FreeTypeLoaderFlags = packed struct(c_uint) {
@@ -4030,7 +4030,7 @@ pub fn beginDragDropSource(flags: DragDropFlags) bool {
 
 /// Note: `payload_type` can be at most 32 characters long
 pub fn setDragDropPayload(payload_type: [*:0]const u8, data: []const u8, cond: Condition) bool {
-    return zguiSetDragDropPayload(payload_type, @alignCast(@ptrCast(data.ptr)), data.len, cond);
+    return zguiSetDragDropPayload(payload_type, @ptrCast(@alignCast(data.ptr)), data.len, cond);
 }
 pub fn endDragDropSource() void {
     zguiEndDragDropSource();

src/zgui.cpp

@@ -1090,21 +1090,21 @@ extern "C"
     }
 
     ZGUI_API void zguiImage(
-        ImTextureID user_texture_id,
+        ImTextureRef user_texture_ref,
         float w,
         float h,
         const float uv0[2],
         const float uv1[2])
     {
         ImGui::Image(
-            user_texture_id,
+            user_texture_ref,
             {w, h},
             {uv0[0], uv0[1]},
             {uv1[0], uv1[1]});
     }
 
     ZGUI_API void zguiImageWithBg(
-        ImTextureID user_texture_id,
+        ImTextureRef user_texture_ref,
         float w,
         float h,
         const float uv0[2],
@@ -1113,7 +1113,7 @@ extern "C"
         const float tint_col[4])
     {
         ImGui::ImageWithBg(
-            user_texture_id,
+            user_texture_ref,
             {w, h},
             {uv0[0], uv0[1]},
             {uv1[0], uv1[1]},
@@ -1123,7 +1123,7 @@ extern "C"
 
     ZGUI_API bool zguiImageButton(
         const char *str_id,
-        ImTextureID user_texture_id,
+        ImTextureRef user_texture_ref,
         float w,
         float h,
         const float uv0[2],
@@ -1133,7 +1133,7 @@ extern "C"
     {
         return ImGui::ImageButton(
             str_id,
-            user_texture_id,
+            user_texture_ref,
             {w, h},
             {uv0[0], uv0[1]},
             {uv1[0], uv1[1]},
@@ -2529,15 +2529,15 @@ extern "C"
 
     ZGUI_API void zguiDrawList_AddImage(
         ImDrawList *draw_list,
-        ImTextureID user_texture_id,
+        ImTextureRef user_texture_ref,
         const float pmin[2],
         const float pmax[2],
         const float uvmin[2],
         const float uvmax[2],
         ImU32 col)
     {
         draw_list->AddImage(
-            user_texture_id,
+            user_texture_ref,
             {pmin[0], pmin[1]},
             {pmax[0], pmax[1]},
             {uvmin[0], uvmin[1]},
@@ -2547,7 +2547,7 @@ extern "C"
 
     ZGUI_API void zguiDrawList_AddImageQuad(
         ImDrawList *draw_list,
-        ImTextureID user_texture_id,
+        ImTextureRef user_texture_ref,
         const float p1[2],
         const float p2[2],
         const float p3[2],
@@ -2559,7 +2559,7 @@ extern "C"
         ImU32 col)
     {
         draw_list->AddImageQuad(
-            user_texture_id,
+            user_texture_ref,
             {p1[0], p1[1]},
             {p2[0], p2[1]},
             {p3[0], p3[1]},
@@ -2573,7 +2573,7 @@ extern "C"
 
     ZGUI_API void zguiDrawList_AddImageRounded(
         ImDrawList *draw_list,
-        ImTextureID user_texture_id,
+        ImTextureRef user_texture_ref,
         const float pmin[2],
         const float pmax[2],
         const float uvmin[2],
@@ -2583,7 +2583,7 @@ extern "C"
         ImDrawFlags flags)
     {
         draw_list->AddImageRounded(
-            user_texture_id,
+            user_texture_ref,
             {pmin[0], pmin[1]},
             {pmax[0], pmax[1]},
             {uvmin[0], uvmin[1]},