/*************************************************************************/
/*  context_gl_win.cpp                                                   */
/*************************************************************************/
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/*                           GODOT ENGINE                                */
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/* Copyright (c) 2007-2018 Juan Linietsky, Ariel Manzur.                 */
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#if defined(OPENGL_ENABLED) || defined(GLES_ENABLED)

// Author: Juan Linietsky <reduzio@gmail.com>, (C) 2008

#include "context_gl_win.h"

#define WGL_CONTEXT_MAJOR_VERSION_ARB 0x2091
#define WGL_CONTEXT_MINOR_VERSION_ARB 0x2092
#define WGL_CONTEXT_FLAGS_ARB 0x2094
#define WGL_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB 0x00000002
#define WGL_CONTEXT_PROFILE_MASK_ARB 0x9126
#define WGL_CONTEXT_CORE_PROFILE_BIT_ARB 0x00000001

typedef HGLRC(APIENTRY *PFNWGLCREATECONTEXTATTRIBSARBPROC)(HDC, HGLRC, const int *);

void ContextGL_Win::release_current() {

	wglMakeCurrent(hDC, NULL);
}

void ContextGL_Win::make_current() {

	wglMakeCurrent(hDC, hRC);
}

int ContextGL_Win::get_window_width() {

	return OS::get_singleton()->get_video_mode().width;
}

int ContextGL_Win::get_window_height() {

	return OS::get_singleton()->get_video_mode().height;
}

void ContextGL_Win::swap_buffers() {

	SwapBuffers(hDC);
}

void ContextGL_Win::set_use_vsync(bool p_use) {

	if (wglSwapIntervalEXT) {
		wglSwapIntervalEXT(p_use ? 1 : 0);
	}
	use_vsync = p_use;
}

bool ContextGL_Win::is_using_vsync() const {

	return use_vsync;
}

#define _WGL_CONTEXT_DEBUG_BIT_ARB 0x0001

Error ContextGL_Win::initialize() {

	static PIXELFORMATDESCRIPTOR pfd = {
		sizeof(PIXELFORMATDESCRIPTOR), // Size Of This Pixel Format Descriptor
		1,
		PFD_DRAW_TO_WINDOW | // Format Must Support Window
				PFD_SUPPORT_OPENGL | // Format Must Support OpenGL
				PFD_DOUBLEBUFFER,
		PFD_TYPE_RGBA,
		OS::get_singleton()->is_layered_allowed() ? 32 : 24,
		0, 0, 0, 0, 0, 0, // Color Bits Ignored
		OS::get_singleton()->is_layered_allowed() ? 8 : 0, // Alpha Buffer
		0, // Shift Bit Ignored
		0, // No Accumulation Buffer
		0, 0, 0, 0, // Accumulation Bits Ignored
		24, // 24Bit Z-Buffer (Depth Buffer)
		0, // No Stencil Buffer
		0, // No Auxiliary Buffer
		PFD_MAIN_PLANE, // Main Drawing Layer
		0, // Reserved
		0, 0, 0 // Layer Masks Ignored
	};

	hDC = GetDC(hWnd);
	if (!hDC) {
		MessageBox(NULL, "Can't Create A GL Device Context.", "ERROR", MB_OK | MB_ICONEXCLAMATION);
		return ERR_CANT_CREATE; // Return FALSE
	}

	pixel_format = ChoosePixelFormat(hDC, &pfd);
	if (!pixel_format) // Did Windows Find A Matching Pixel Format?
	{
		MessageBox(NULL, "Can't Find A Suitable pixel_format.", "ERROR", MB_OK | MB_ICONEXCLAMATION);
		return ERR_CANT_CREATE; // Return FALSE
	}

	BOOL ret = SetPixelFormat(hDC, pixel_format, &pfd);
	if (!ret) // Are We Able To Set The Pixel Format?
	{
		MessageBox(NULL, "Can't Set The pixel_format.", "ERROR", MB_OK | MB_ICONEXCLAMATION);
		return ERR_CANT_CREATE; // Return FALSE
	}

	hRC = wglCreateContext(hDC);
	if (!hRC) // Are We Able To Get A Rendering Context?
	{
		MessageBox(NULL, "Can't Create A Temporary GL Rendering Context.", "ERROR", MB_OK | MB_ICONEXCLAMATION);
		return ERR_CANT_CREATE; // Return FALSE
	}

	wglMakeCurrent(hDC, hRC);

	if (opengl_3_context) {

		int attribs[] = {
			WGL_CONTEXT_MAJOR_VERSION_ARB, 3, //we want a 3.3 context
			WGL_CONTEXT_MINOR_VERSION_ARB, 3,
			//and it shall be forward compatible so that we can only use up to date functionality
			WGL_CONTEXT_PROFILE_MASK_ARB, WGL_CONTEXT_CORE_PROFILE_BIT_ARB,
			WGL_CONTEXT_FLAGS_ARB, WGL_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB /*| _WGL_CONTEXT_DEBUG_BIT_ARB*/,
			0
		}; //zero indicates the end of the array

		PFNWGLCREATECONTEXTATTRIBSARBPROC wglCreateContextAttribsARB = NULL; //pointer to the method
		wglCreateContextAttribsARB = (PFNWGLCREATECONTEXTATTRIBSARBPROC)wglGetProcAddress("wglCreateContextAttribsARB");

		if (wglCreateContextAttribsARB == NULL) //OpenGL 3.0 is not supported
		{
			MessageBox(NULL, "Cannot get Proc Address for CreateContextAttribs", "ERROR", MB_OK | MB_ICONEXCLAMATION);
			wglDeleteContext(hRC);
			return ERR_CANT_CREATE;
		}

		HGLRC new_hRC = wglCreateContextAttribsARB(hDC, 0, attribs);
		if (!new_hRC) {
			wglDeleteContext(hRC);
			MessageBox(NULL, "Can't Create An OpenGL 3.3 Rendering Context.", "ERROR", MB_OK | MB_ICONEXCLAMATION);
			return ERR_CANT_CREATE; // Return false
		}
		wglMakeCurrent(hDC, NULL);
		wglDeleteContext(hRC);
		hRC = new_hRC;

		if (!wglMakeCurrent(hDC, hRC)) // Try To Activate The Rendering Context
		{
			MessageBox(NULL, "Can't Activate The GL 3.3 Rendering Context.", "ERROR", MB_OK | MB_ICONEXCLAMATION);
			return ERR_CANT_CREATE; // Return FALSE
		}
	}

	wglSwapIntervalEXT = (PFNWGLSWAPINTERVALEXTPROC)wglGetProcAddress("wglSwapIntervalEXT");
	//glWrapperInit(wrapper_get_proc_address);

	return OK;
}

ContextGL_Win::ContextGL_Win(HWND hwnd, bool p_opengl_3_context) {

	opengl_3_context = p_opengl_3_context;
	hWnd = hwnd;
	use_vsync = false;
}

ContextGL_Win::~ContextGL_Win() {
}

#endif