You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and dots ('.'), can be up to 35 characters long. Letters must be lowercase.
37 lines
2.6 KiB
37 lines
2.6 KiB
// What does this file solves? |
|
// - Since Dear ImGui 1.00 we took pride that most of our examples applications had their entire |
|
// main-loop inside the main() function. That's because: |
|
// - It makes the examples easier to read, keeping the code sequential. |
|
// - It permit the use of local variables, making it easier to try things and perform quick |
|
// changes when someone needs to quickly test something (vs having to structure the example |
|
// in order to pass data around). This is very important because people use those examples |
|
// to craft easy-to-past repro when they want to discuss features or report issues. |
|
// - It conveys at a glance that this is a no-BS framework, it won't take your main loop away from you. |
|
// - It is generally nice and elegant. |
|
// - However, comes Emscripten... it is a wonderful and magical tech but it requires a "main loop" function. |
|
// - Only some of our examples would run on Emscripten. Typically the ones rendering with GL or WGPU ones. |
|
// - I tried to refactor those examples but felt it was problematic that other examples didn't follow the |
|
// same layout. Why would the SDL+GL example be structured one way and the SGL+DX11 be structured differently? |
|
// Especially as we are trying hard to convey that using a Dear ImGui backend in an *existing application* |
|
// should requires only a few dozens lines of code, and this should be consistent and symmetrical for all backends. |
|
// - So the next logical step was to refactor all examples to follow that layout of using a "main loop" function. |
|
// This worked, but it made us lose all the nice things we had... |
|
|
|
// Since only about 3 examples really need to run with Emscripten, here's our solution: |
|
// - Use some weird macros and capturing lambda to turn a loop in main() into a function. |
|
// - Hide all that crap in this file so it doesn't make our examples unusually ugly. |
|
// As a stance and principle of Dear ImGui development we don't use C++ headers and we don't |
|
// want to suggest to the newcomer that we would ever use C++ headers as this would affect |
|
// the initial judgment of many of our target audience. |
|
// - Technique is based on this idea: https://github.com/ocornut/imgui/pull/2492/ |
|
#ifdef __EMSCRIPTEN__ |
|
#include <emscripten.h> |
|
#include <functional> |
|
static std::function<void()> MainLoopForEmscriptenP; |
|
static void MainLoopForEmscripten() { MainLoopForEmscriptenP(); } |
|
#define EMSCRIPTEN_MAINLOOP_BEGIN MainLoopForEmscriptenP = [&]() |
|
#define EMSCRIPTEN_MAINLOOP_END ; emscripten_set_main_loop(MainLoopForEmscripten, 0, true) |
|
#else |
|
#define EMSCRIPTEN_MAINLOOP_BEGIN |
|
#define EMSCRIPTEN_MAINLOOP_END |
|
#endif
|
|
|