Disable *glGetProcAddress() on the web

[dsnopek]

In PR #87981, we added the Emscripten flag (supported in 3.1.51 or later) to enable glGetProcAddress() on the web.

However, we shouldn't need it (since the GL functions are "statically linked" on the web) and it's known to be inefficient.

See these references from the Emscripten docs:

• "Optimizing WebGL":
• "Compiler Settings":

This PR explicitly disables the feature (rather than just reverting PR #87981) since the docs say it's enabled by default - since that didn't seem to be the case originally, either the docs are wrong or the default may have changed?

Marking as draft because I haven't had much time to test it yet. It succeeds in compiling and seems to work, but I'd like to be more sure that everything is good. :-)

[adamscott]

Sorry, your comments on #87981 fell in one of my cracks. 😬

Seems good. I think I added the functionality because it was a breaking change otherwise. But if it works without, then everything is good.

[adamscott]

What about this file? How can we make sure that this either doesn't get run or replace it with something else for the Web?

godot/drivers/gles3/rasterizer_gles3.cpp

Lines 299 to 314 in e78dc83

	#ifdef GLES_API_ENABLED
	if (!gles_over_gl) {
	if (OS::get_singleton()->is_stdout_verbose()) {
	DebugMessageCallbackARB callback = (DebugMessageCallbackARB)eglGetProcAddress("glDebugMessageCallback");
	if (!callback) {
	callback = (DebugMessageCallbackARB)eglGetProcAddress("glDebugMessageCallbackKHR");
	}
	if (callback) {
	print_line("godot: ENABLING GL DEBUG");
	glEnable(_EXT_DEBUG_OUTPUT_SYNCHRONOUS_ARB);
	callback((DEBUGPROCARB)_gl_debug_print, nullptr);
	glEnable(_EXT_DEBUG_OUTPUT);
	}
	}
	}

Do you have an idea, @bruvzg?

[dsnopek]

What about this file? How can we make sure that this either doesn't get run or replace it with something else for the Web?

On the web, I think we should be able to just #include <GLES3/glext.h> and call glDebugMessageCallback() directly, without having to load the function pointer first, but I haven't tested it.

Assuming that works, we could use #ifdef WEB_ENABLED to do that? Or, try to bake it into platform/web/pltaform_gl.h somehow?

[dsnopek]

Or, actually, maybe we don't need to do anything to support that at all?

All that does is print messages to the console when there are OpenGL errors, but WebGL does that all on its own.

So, maybe we just need to wrap that code in #ifndef WEB_ENABLED?

Anyway, I'll do some testing later when I have a chance.

[dsnopek]

@adamscott It looks like that code is already excluded on web builds. As I also just commented here, that code is wrapped in #ifdef CAN_DEBUG, which won't be defined on the web.

In my latest push on this PR, I've added some #defines to platform/web/platform_gl.h that make it a compiler error to use glGetProcAddress() or eglGetProcAddress() on the web, and Godot still compiles just fine, so I'm pretty confident that we aren't calling those anywhere.

Given that, I'm going to take this out of draft!

[bruvzg]

What about this file? How can we make sure that this either doesn't get run or replace it with something else for the Web?

It's inside ifdef CAN_DEBUG, which is not set on iOS and web.

[adamscott]

It's great! Thanks for your hard work, @dsnopek!

[akien-mga]

Thanks!