module: build failure

[gucio321]

Hi, I'm having trouble building the latest code

cd examples
go run .

# github.com/AllenDang/cimgui-go
In file included from ./cimplot_wrapper.h:3,
                 from ./cimplot_structs_accessor.h:3,
                 from ../cimplot_funcs.go:4:
./cimplot/cimplot.h:7:10: fatal error: cimgui.h: No such file or directory
    7 | #include "cimgui.h"
      |          ^~~~~~~~~~
compilation terminated.

[gucio321]

I'd blame #18

[gucio321]

the reason is, that both: cimplot.* and cimgui.* should be in the same directory OR the path to cimgui.h in cimplot generator should be set manually. Otherwise, cimplot.h searches for cimgui.h in its directory (in our case /cimplot/) and there is no such a file ofc.
becore #18 the line in cimplot.h was

#include "../cimgui/cimgui.h"

and now it is

#include "cimgui.h"

thats the reason of this failure

[eliasdaler]

The inclusion of cimplot by default here rubs me in the wrong way anyway, it introduces a ton of complexity and ImPlot is not a part of Dear ImGui anyway...
So it might be better to do this:

1. Remove ImPlot temporarily
2. Add it again properly and make it work with git submodules (and ideally move it to a different package, because a lot of people won't need it)

[eliasdaler]

Well, I almost got it to work:

diff --git a/backend.cpp b/backend.cpp
index 556bda4..9913e09 100644
--- a/backend.cpp
+++ b/backend.cpp
@@ -4,8 +4,8 @@
 #define CIMGUI_USE_OPENGL3
 
 #include "backend.h"
-#include "cimgui/cimgui.h"
-#include "cimgui/cimgui_impl.h"
+#include "cimgui.h"
+#include "cimgui_impl.h"
 #include "thirdparty/glfw/include/GLFW/glfw3.h" // Will drag system OpenGL headers
 
 // [Win32] Our example includes a copy of glfw3.lib pre-compiled with VS2010 to
diff --git a/cimplot_funcs.go b/cimplot_funcs.go
index 22ad6fb..1a6e66e 100644
--- a/cimplot_funcs.go
+++ b/cimplot_funcs.go
@@ -1,5 +1,7 @@
 package cimgui
 
+// #cgo CFLAGS: -Icimgui -Icimgui/generator/output
+// #cgo CXXFLAGS: -Icimgui -Icimgui/generator/output
 // #include "extra_types.h"
 // #include "cimplot_structs_accessor.h"
 // #include "cimplot_wrapper.h"

Now, I get these errors:

# github.com/AllenDang/cimgui-go
./cimgui_funcs.go:426:145: cannot convert glyph_ranges (variable of type *ImWchar) to type *_Ctype_ushort
./cimgui_funcs.go:436:182: cannot convert glyph_ranges (variable of type *ImWchar) to type *_Ctype_ushort
./cimgui_funcs.go:443:195: cannot convert glyph_ranges (variable of type *ImWchar) to type *_Ctype_ushort
./cimgui_funcs.go:450:163: cannot convert glyph_ranges (variable of type *ImWchar) to type *_Ctype_ushort
./cimgui_funcs.go:488:20: cannot convert func() *_Ctype_ImWchar {…}() (value of type *_Ctype_ushort) to type *ImWchar
./cimgui_funcs.go:492:20: cannot convert func() *_Ctype_ImWchar {…}() (value of type *_Ctype_ushort) to type *ImWchar
./cimgui_funcs.go:496:20: cannot convert func() *_Ctype_ImWchar {…}() (value of type *_Ctype_ushort) to type *ImWchar
./cimgui_funcs.go:500:20: cannot convert func() *_Ctype_ImWchar {…}() (value of type *_Ctype_ushort) to type *ImWchar
./cimgui_funcs.go:504:20: cannot convert func() *_Ctype_ImWchar {…}() (value of type *_Ctype_ushort) to type *ImWchar
./cimgui_funcs.go:508:20: cannot convert func() *_Ctype_ImWchar {…}() (value of type *_Ctype_ushort) to type *ImWchar
./cimgui_funcs.go:508:20: too many errors

I don't know how to fix them yet, but it finds all the headers it needs at least...
I'll debug it tomorrow.

[eliasdaler]

Welp, I found a bag of worms...

See this CMakeLists.txt. It wasn't even a "real" CMakeLists.txt from cimgui. It was an amalgamation of cimgui, glfw backend and cimplot
So, by linking to "./lib/***", we were linking to it and not to real cimgui.a which you could build from scratch.

This is wrong on many levels. There shouldn't be any "prebuilt" libraries in projects using CGo. They should be compiled from source. Dependency on GLFW backend and cimplot adds another bag of problems I'm not even sure where to start.

I'll try to fix all this, but I'd rather start from removing glfw and cimplot dependency, making "cimgui" wrapper correct and then adding things back one by one.

[AllenDang]

I think we should provide prebluit binaries. We shouldnt assume everyone has proper c/cpp compiles installed.
This repo should work with only go is installed.
Thats why i use build actions to compile them.

[eliasdaler]

Yeah, I did some investigations and building libraries during "go get" is not that great in all cases.
But, I'm also working on fixing a lot of stuff here.

For now, it only builds on Linux (only 1 precompiled lib here). I've temporarily removed GLFW backend and implot to make things easier. I will add them later in the way that will not require libimgui.a to NOT contain implot functions and I want cimgui-go to not depend on GLFW in any way.

Like I previously said, I don't use GLFW. Some people might want to use SDL/raylib. Current cimgui-go forces users to embed GLFW code into their binaries. This is not great.

Also, turns out git submodules cannot be used. When I tried to import cimgui-go using "go get" for ebiten-imgui, I got errors about cimgui.h not being there because "go get" doesn't fetch submodules. (running example)

So, ideally we should ship all needed headers inside cimgui-go. But I think we should do some form of "git submodule" system where we'll have a file like:

cimgui=https://github.com/cimgui/cimgui@8e625e95fdf469e105826cc22cb7665949f3aa21

and have a GitHub action named "update cimgui" which will automatically pull the corresponding version into the repo, build all libraries and commit it. We should always know which version of cimgui was used in a specific commit/build of all libraries.

For cimplot and GLFW backend... Well, I need to think. I can deal with cimplot being a part of cimgui which I can't get rid of, but having to depend on GLFW - this I cannot accept.

[sonoro1234]

My two cents:

You need to create a new CMakeLists.txt ( as done in https://github.com/sonoro1234/LuaJIT-ImGui) which picks whatever you want to use (cimgui, cimplot and glfw backend for example). cimgui and cimplot are ok as submodules but for glfw you can use find_package or FetchContent (as done in https://github.com/cimgui/cimgui/blob/68483775b3d7594eb14d296ec002ac11683882c9/backend_test/example_glfw_opengl3/CMakeLists.txt#L65)
I guess some go machinery will need to be added to this. (with CGo include paths setted)

Then you could use github Releases (https://github.com/AllenDang/cimgui-go/releases) if you wish to provide binaries so that user doesn`t need to compile. (Althought user will be able to compile if he/she wants to do it)