/*************************************************************************/
/*  gl_manager_osx.mm                                                    */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
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/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md).   */
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/*************************************************************************/

#include "gl_manager_osx.h"

#ifdef OSX_ENABLED
#ifdef GLES3_ENABLED

#include <stdio.h>
#include <stdlib.h>

Error GLManager_OSX::_create_context(GLWindow &win) {
	NSOpenGLPixelFormatAttribute attributes[] = {
		NSOpenGLPFADoubleBuffer,
		NSOpenGLPFAClosestPolicy,
		NSOpenGLPFAOpenGLProfile, NSOpenGLProfileVersion3_2Core,
		NSOpenGLPFAColorSize, 32,
		NSOpenGLPFADepthSize, 24,
		NSOpenGLPFAStencilSize, 8,
		0
	};

	NSOpenGLPixelFormat *pixel_format = [[NSOpenGLPixelFormat alloc] initWithAttributes:attributes];
	ERR_FAIL_COND_V(pixel_format == nil, ERR_CANT_CREATE);

	win.context = [[NSOpenGLContext alloc] initWithFormat:pixel_format shareContext:_shared_context];
	ERR_FAIL_COND_V(win.context == nil, ERR_CANT_CREATE);
	if (_shared_context == nullptr) {
		_shared_context = win.context;
	}

	[win.context setView:win.window_view];
	[win.context makeCurrentContext];

	return OK;
}

Error GLManager_OSX::window_create(DisplayServer::WindowID p_window_id, id p_view, int p_width, int p_height) {
	if (p_window_id >= (int)_windows.size()) {
		_windows.resize(p_window_id + 1);
	}

	GLWindow &win = _windows[p_window_id];
	win.in_use = true;
	win.window_id = p_window_id;
	win.width = p_width;
	win.height = p_height;
	win.window_view = p_view;

	if (_create_context(win) != OK) {
		_windows.remove(_windows.size() - 1);
		return FAILED;
	}

	window_make_current(_windows.size() - 1);

	return OK;
}

void GLManager_OSX::_internal_set_current_window(GLWindow *p_win) {
	_current_window = p_win;
}

void GLManager_OSX::window_resize(DisplayServer::WindowID p_window_id, int p_width, int p_height) {
	if (p_window_id == -1) {
		return;
	}

	GLWindow &win = _windows[p_window_id];
	if (!win.in_use) {
		return;
	}

	win.width = p_width;
	win.height = p_height;

	GLint dim[2];
	dim[0] = p_width;
	dim[1] = p_height;
	CGLSetParameter((CGLContextObj)[win.context CGLContextObj], kCGLCPSurfaceBackingSize, &dim[0]);
	CGLEnable((CGLContextObj)[win.context CGLContextObj], kCGLCESurfaceBackingSize);
	if (OS::get_singleton()->is_hidpi_allowed()) {
		[win.window_view setWantsBestResolutionOpenGLSurface:YES];
	} else {
		[win.window_view setWantsBestResolutionOpenGLSurface:NO];
	}

	[win.context update];
}

int GLManager_OSX::window_get_width(DisplayServer::WindowID p_window_id) {
	return get_window(p_window_id).width;
}

int GLManager_OSX::window_get_height(DisplayServer::WindowID p_window_id) {
	return get_window(p_window_id).height;
}

void GLManager_OSX::window_destroy(DisplayServer::WindowID p_window_id) {
	GLWindow &win = get_window(p_window_id);
	win.in_use = false;

	if (_current_window == &win) {
		_current_window = nullptr;
	}
}

void GLManager_OSX::release_current() {
	if (!_current_window) {
		return;
	}

	[NSOpenGLContext clearCurrentContext];
}

void GLManager_OSX::window_make_current(DisplayServer::WindowID p_window_id) {
	if (p_window_id == -1) {
		return;
	}

	GLWindow &win = _windows[p_window_id];
	if (!win.in_use) {
		return;
	}

	if (&win == _current_window) {
		return;
	}

	[win.context makeCurrentContext];

	_internal_set_current_window(&win);
}

void GLManager_OSX::make_current() {
	if (!_current_window) {
		return;
	}
	if (!_current_window->in_use) {
		WARN_PRINT("current window not in use!");
		return;
	}
	[_current_window->context makeCurrentContext];
}

void GLManager_OSX::swap_buffers() {
	// NO NEED TO CALL SWAP BUFFERS for each window...
	// see https://www.khronos.org/registry/OpenGL-Refpages/gl2.1/xhtml/glXSwapBuffers.xml

	if (!_current_window) {
		return;
	}
	if (!_current_window->in_use) {
		WARN_PRINT("current window not in use!");
		return;
	}
	[_current_window->context flushBuffer];
}

void GLManager_OSX::window_update(DisplayServer::WindowID p_window_id) {
	if (p_window_id == -1) {
		return;
	}

	GLWindow &win = _windows[p_window_id];
	if (!win.in_use) {
		return;
	}

	if (&win == _current_window) {
		return;
	}

	[win.context update];
}

Error GLManager_OSX::initialize() {
	return OK;
}

void GLManager_OSX::set_use_vsync(bool p_use) {
	use_vsync = p_use;
	CGLContextObj ctx = CGLGetCurrentContext();
	if (ctx) {
		GLint swapInterval = p_use ? 1 : 0;
		CGLSetParameter(ctx, kCGLCPSwapInterval, &swapInterval);
		use_vsync = p_use;
	}
}

bool GLManager_OSX::is_using_vsync() const {
	return use_vsync;
}

GLManager_OSX::GLManager_OSX(ContextType p_context_type) {
	context_type = p_context_type;
	use_vsync = false;
	_current_window = nullptr;
}

GLManager_OSX::~GLManager_OSX() {
	release_current();
}

#endif // GLES3_ENABLED
#endif // OSX