Cannot compile sample project with nuklear

[SimonRegistrierung]

Hi there,

ich have an annoying issue with compiling the sample project, which I canot get rid of. My project structure looks like this:

with the nuklear directory being the freshly downloaded and extracted copy of the nuklear repository.

the CMakeLists.txt is:

cmake_minimum_required(VERSION 3.20)
project(nuklearTest)

set(CMAKE_CXX_STANDARD 14)

add_executable(nuklearTest main.cpp)

target_include_directories(${PROJECT_NAME} PUBLIC ${PROJECT_SOURCE_DIR}/nuklear)

here's my main.cpp:

#include <iostream>
#include "nuklear.h"

int main()
{
	/* init gui state */
	struct nk_context ctx;
	nk_init_fixed(&ctx, calloc(1, MAX_MEMORY), MAX_MEMORY, &font);

	enum {EASY, HARD};
	static int op = EASY;
	static float value = 0.6f;
	static int i =  20;

	if (nk_begin(&ctx, "Show", nk_rect(50, 50, 220, 220),
		NK_WINDOW_BORDER|NK_WINDOW_MOVABLE|NK_WINDOW_CLOSABLE)) {
		/* fixed widget pixel width */
		nk_layout_row_static(&ctx, 30, 80, 1);
		if (nk_button_label(&ctx, "button")) {
			/* event handling */
		}

		/* fixed widget window ratio width */
		nk_layout_row_dynamic(&ctx, 30, 2);
		if (nk_option_label(&ctx, "easy", op == EASY)) op = EASY;
		if (nk_option_label(&ctx, "hard", op == HARD)) op = HARD;

		/* custom widget pixel width */
		nk_layout_row_begin(&ctx, NK_STATIC, 30, 2);
		{
			nk_layout_row_push(&ctx, 50);
			nk_label(&ctx, "Volume:", NK_TEXT_LEFT);
			nk_layout_row_push(&ctx, 110);
			nk_slider_float(&ctx, 0, &value, 1.0f, 0.1f);
		}
		nk_layout_row_end(&ctx);
	}
	nk_end(&ctx);

}

First, I am missing references to the constant MAX_MEMORY and &font. I have manually created them at the beginning of the main.cpp function like this (I don't know if that's correct, but at least the CLion IDE doesn't complain anymore):

const int MAX_MEMORY = 128;
nk_user_font font = (const nk_user_font&)"Times New Roman";

but now I encounter the error:

main.cpp.obj : error LNK2019: unresolved external symbol nk_begin referenced in function main
main.cpp.obj : error LNK2019: unresolved external symbol nk_end referenced in function main
main.cpp.obj : error LNK2019: unresolved external symbol nk_layout_row_dynamic referenced in function main
main.cpp.obj : error LNK2019: unresolved external symbol nk_layout_row_static referenced in function main
main.cpp.obj : error LNK2019: unresolved external symbol nk_layout_row_begin referenced in function main
main.cpp.obj : error LNK2019: unresolved external symbol nk_layout_row_push referenced in function main
main.cpp.obj : error LNK2019: unresolved external symbol nk_layout_row_end referenced in function main
main.cpp.obj : error LNK2019: unresolved external symbol nk_label referenced in function main
main.cpp.obj : error LNK2019: unresolved external symbol nk_button_label referenced in function main
main.cpp.obj : error LNK2019: unresolved external symbol nk_option_label referenced in function main
main.cpp.obj : error LNK2019: unresolved external symbol nk_slider_float referenced in function main
main.cpp.obj : error LNK2019: unresolved external symbol nk_rect referenced in function main
nuklearTest.exe : fatal error LNK1120: 13 unresolved externals

I am quite sure the nuklear.h is correctly linked, as I can implement other functions from within the IDE. I already played around with other CMake commands, like include_directories in order to find nuklear, but to no avail. I have also tried to include:

#define NK_IMPLEMENTATION
#include "nuklear.h"

Then, the project compiles but I get this error during execution:

There must be something I am missing. Any help is welcome. Thanks

[riri]

You need to define NK_IMPLEMENTATION before including nuklear.h (header files are never compiled). Check the demo to understand the concept of single header libraries.

[lockie]

We might want to fix the example in the README so that it does not reference undefined font and newcomers stop bumping into this.

[persinammon]

@SimonRegistrierung were you able to resolve your issue?

I am having difficulty with finding how to define nk_user_font.

I tried the same nk_user_font font = (const nk_user_font&)"Times New Roman";. I am able to compile an executable but am getting Segmentation Fault at runtime. My main function is calling another function that uses SDL though. I am not sure if the problem is the font object or not integrating with SDL. Did that font line work for you?

[riri]

@persinammon : nk_user_font isn't a string on which you define the name of a system font. Please read the demos source code and nuklear.h comments (part dealing with font baking) to understand those concepts.

Nuklear isn't a ready to use system, and from @SimonRegistrierung example I already see it's not a full program, there is no implementation backend, so nothing will happen.

I don't think the README example is a problem, it's a snippet (to me it seems clear it's not a complete program). Maybe a hint to refer to demos directory to see how the link with underlaying system is done would be useful tho.