V2 working

apps/RenderCadenceCompositor/platform/HiddenGlWindow.cpp

@@ -0,0 +1,120 @@
+#include "HiddenGlWindow.h"
+
+namespace
+{
+constexpr const char* kWindowClassName = "RenderCadenceCompositorHiddenGlWindow";
+}
+
+HiddenGlWindow::~HiddenGlWindow()
+{
+	Destroy();
+}
+
+bool HiddenGlWindow::Create(unsigned width, unsigned height, std::string& error)
+{
+	Destroy();
+
+	mInstance = GetModuleHandle(nullptr);
+
+	WNDCLASSA wc = {};
+	wc.style = CS_OWNDC;
+	wc.lpfnWndProc = HiddenGlWindow::WindowProc;
+	wc.hInstance = mInstance;
+	wc.lpszClassName = kWindowClassName;
+
+	mClassAtom = RegisterClassA(&wc);
+	if (mClassAtom == 0 && GetLastError() != ERROR_CLASS_ALREADY_EXISTS)
+	{
+		error = "RegisterClassA failed for hidden OpenGL window.";
+		return false;
+	}
+
+	mWindow = CreateWindowA(
+		kWindowClassName,
+		"Render Cadence Compositor Hidden GL",
+		WS_OVERLAPPEDWINDOW,
+		CW_USEDEFAULT,
+		CW_USEDEFAULT,
+		static_cast<int>(width),
+		static_cast<int>(height),
+		nullptr,
+		nullptr,
+		mInstance,
+		nullptr);
+	if (!mWindow)
+	{
+		error = "CreateWindowA failed for hidden OpenGL window.";
+		return false;
+	}
+
+	mDc = GetDC(mWindow);
+	if (!mDc)
+	{
+		error = "GetDC failed for hidden OpenGL window.";
+		return false;
+	}
+
+	PIXELFORMATDESCRIPTOR pfd = {};
+	pfd.nSize = sizeof(pfd);
+	pfd.nVersion = 1;
+	pfd.dwFlags = PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER;
+	pfd.iPixelType = PFD_TYPE_RGBA;
+	pfd.cColorBits = 32;
+	pfd.cDepthBits = 0;
+	pfd.iLayerType = PFD_MAIN_PLANE;
+
+	const int pixelFormat = ChoosePixelFormat(mDc, &pfd);
+	if (pixelFormat == 0 || !SetPixelFormat(mDc, pixelFormat, &pfd))
+	{
+		error = "Could not choose/set pixel format for hidden OpenGL window.";
+		return false;
+	}
+
+	mGlrc = wglCreateContext(mDc);
+	if (!mGlrc)
+	{
+		error = "wglCreateContext failed for hidden OpenGL window.";
+		return false;
+	}
+
+	return true;
+}
+
+bool HiddenGlWindow::MakeCurrent() const
+{
+	return mDc != nullptr && mGlrc != nullptr && wglMakeCurrent(mDc, mGlrc) == TRUE;
+}
+
+void HiddenGlWindow::ClearCurrent() const
+{
+	wglMakeCurrent(nullptr, nullptr);
+}
+
+void HiddenGlWindow::Destroy()
+{
+	ClearCurrent();
+
+	if (mGlrc)
+	{
+		wglDeleteContext(mGlrc);
+		mGlrc = nullptr;
+	}
+	if (mWindow && mDc)
+	{
+		ReleaseDC(mWindow, mDc);
+		mDc = nullptr;
+	}
+	if (mWindow)
+	{
+		DestroyWindow(mWindow);
+		mWindow = nullptr;
+	}
+
+	mInstance = nullptr;
+	mClassAtom = 0;
+}
+
+LRESULT CALLBACK HiddenGlWindow::WindowProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
+{
+	return DefWindowProc(hwnd, message, wParam, lParam);
+}