exception:: std::length_error at memory location 0x00000010986FEB70.

[dfutia]

I've spent my entire day trying to set up RmlUi in my SDL2 + OpenGL project, and I just can't, for the life of me, figure out what is wrong. The first problem was with RmlUi_RendererGL3.cpp trying to do something with glad, which was conflicting with my other code that already sets up glad, so I removed #include "RmlUi_Include_GL3.h" and gladLoaderUnloadGL(); in the shutdown method.

The issue I ran into after this, I think, has something to do with a call to GenerateQuad() in the RenderInterface_GL3 constructor.

RenderInterface_GL3::RenderInterface_GL3()
{
	auto mut_program_data = Rml::MakeUnique<Gfx::ProgramData>();
	if (Gfx::CreateShaders(*mut_program_data))
	{
		program_data = std::move(mut_program_data);
		Rml::Mesh mesh;
		Rml::MeshUtilities::GenerateQuad(mesh, Rml::Vector2f(-1), Rml::Vector2f(2), {});
		fullscreen_quad_geometry = RenderInterface_GL3::CompileGeometry(mesh.vertices, mesh.indices);
	}
}

Unhandled exception at 0x00007FF807B466CA in UntitledGame.exe: Microsoft C++ exception: std::length_error at memory location 0x0000001E7D9EEEB0.

Another issue I run into is this:

unresolved external symbol "bool __cdecl Backend::Initialize(char const *,int,int,bool)" (?Initialize@Backend@@YA_NPEBDHH_N@Z) referenced in function "public: void __cdecl Game::init(void)" (?init@Game@@QEAAXXZ)
unresolved external symbol "class Rml::SystemInterface * __cdecl Backend::GetSystemInterface(void)" (?GetSystemInterface@Backend@@YAPEAVSystemInterface@Rml@@XZ) referenced in function "public: void __cdecl Game::init(void)" (?init@Game@@QEAAXXZ)
unresolved external symbol "class Rml::RenderInterface * __cdecl Backend::GetRenderInterface(void)" (?GetRenderInterface@Backend@@YAPEAVRenderInterface@Rml@@XZ) referenced in function "public: void __cdecl Game::init(void)" (?init@Game@@QEAAXXZ)
3 unresolved externals

Lastly, here is my code which tries to setup rmlui

#define RMLUI_SDL_VERSION_MAJOR 2
#include <RmlUi/Core.h>
#include <RmlUi/Debugger.h>
#include <rmluiimpl/RmlUi_Backend.h>
#include <rmluiimpl/RmlUi_Platform_SDL.h>
#include <rmluiimpl/RmlUi_Renderer_GL3.h>
#include "rmluiimpl/shell/include/Shell.h"

void Game::init()
{
	//Shell::Initialize();

	//Backend::Initialize("RmlUiWindow", 1280, 720, true);

	//static CustomSystemInterface sysInterface;
	//static CustomRenderInterface rendInterface;

	//Rml::SetSystemInterface(&sysInterface);
	//Rml::SetRenderInterface(&rendInterface);
	//Rml::SetSystemInterface(Backend::GetSystemInterface());
	//Rml::SetRenderInterface(Backend::GetRenderInterface());

	//static SystemInterface_SDL sysInterface;
	//static RenderInterface_GL3 rendInterface;

	Backend::Initialize("RmlUiWindow", 1280, 720, true);

	Rml::SetSystemInterface(Backend::GetSystemInterface());
	Rml::SetRenderInterface(Backend::GetRenderInterface());

	Rml::Initialise();

	Rml::Context* context = Rml::CreateContext("main", Rml::Vector2i(1280, 720));

	//Rml::LoadFontFace("");

	//auto* doc = context->LoadDocument("");
	//if (doc) doc->Show();
}

[mikke89]

Hello there!

Alright, there's quite a bit going on here. First of all, for the unresolved symbols, it looks like you're not adding the source code for the backend code? At least not the ones containing the referenced functions. Secondly, you must have gotten this compiled somehow, but I'm not sure how you're running the code causing the memory exception.

You're mentioning modifying the glad includes, so it could be that something is conflicting here. Make sure you are initializing glad somewhere, before the GL3 renderer constructor, and that you are not mixing up different GL headers. I don't think GenerateQuad should be an issue here. When you get crashes, it would be helpful to post the full stack trace and the values of any relevant variables.

Let me know how it goes :)

[dfutia]

Hello! If you couldn't tell, I'm a bit of a newbie at this haha. Hopefully, this provides more information.

When you get crashes, it would be helpful to post the full stack trace and the values of any relevant variables.

it looks like you're not adding the source code for the backend code?

At first I thought I was missing RmlUi_Backend.cpp but that doesn't seem to be a file (unless I'm blind lol) so here is everything I have in my project:

UntitledGame/
├── out/
│   └── build/
│       └── x64-debug/
│           └── UntitledGame/
│               ├── rmlui.dll
│               └── rmlui_debugger.dll
├── UntitledGame/
│   └── rmluiimpl/
│       ├── shell/
│       │   └── ...
│       ├── RmlUi_Backend.h
│       ├── RmlUi_Include_Windows.h
│       ├── RmlUi_Platform_SDL.cpp
│       ├── RmlUi_Platform_SDL.h
│       ├── RmlUi_Renderer_GL3.cpp
│       └── RmlUi_Renderer_GL3.h
└── vendor/
    └── RmlUi/
        ├── Include/
        │   └── RmlUi/
        │       └── ...
        └── lib/
            ├── rmlui.lib
            └── rmlui_debugger.lib

Make sure you are initializing glad somewhere, before the GL3 renderer constructor

the constructor of Game creates a GLRenderer which initializes glad and this happens before the game init function which is where I am making all the rmlui calls so far.

[dfutia]

@mikke89 Sorry to be a nuisance, but I decided to start over, and after following the documentation, I was able to run the space invader sample project. So, I created a new project to test rmlui without using the samples, but once again ran into issues in the RenderInterface_GL3 constructor with the GenerateQuad method. I uploaded the project to a test repo if that's useful at all: https://github.com/dfutia/rmlui-test

[mikke89]

Hey, no worries. To be honest, that project structure is quite a mess. It's hard to say what's going wrong exactly, but you've got binaries all over the place, hah. Lib files in some places, but dll files being copied from elsewhere. It would be quite a lot of effort for me just being able to build that project.

It could be that you are mixing up binaries, i.e. you need to make sure all lib-files correspond to the dll files being copied in. And everything should be built with the same compiler flags. In particular, make sure you don't mix up debug/release binaries, and runtime libraries being used. You also need to make sure that RmlUi is built against the same FreeType version that is being linked into your project. Also make sure to check the linker and compiler for any warnings.

Did you consider using a package manager like vcpkg instead? Another approach is to put all the source code, also from dependencies, in the same project, and use CMake add_subdirectory for them. That way all the dependencies are built together with your project.

[dfutia]

Yeah, I recently started learning cmake (literally just used the template visual studio provides) so that's fair. I can check if I got things mixed up, but for now I will try using vcpkg although I've also never used that either haha, but hopefully it works!

[mikke89]

Cheers, we all had to learn the intricacies of the C++ world at some point, an we're all still learning, heh. It's not the smoothest of journeys. I'm sure it's good experience though, next time it will be a lot easier.

[dfutia]

yup vcpkg made things much easier! cant believe I haven't considered using it sooner haha. Thanks for your time and sorry for my stupidity!

[mikke89]

Nice, great to hear that's working out better for you.