re organisation

apps/LoopThroughWithOpenGLCompositing/gl/pipeline/PngScreenshotWriter.cpp

@@ -0,0 +1,137 @@
+#include "PngScreenshotWriter.h"
+
+#include <windows.h>
+#include <wincodec.h>
+#include <atlbase.h>
+
+#include <sstream>
+#include <thread>
+
+namespace
+{
+std::string HResultToString(HRESULT hr)
+{
+	std::ostringstream stream;
+	stream << "HRESULT 0x" << std::hex << static_cast<unsigned long>(hr);
+	return stream.str();
+}
+
+bool WritePngFile(
+	const std::filesystem::path& outputPath,
+	unsigned width,
+	unsigned height,
+	const std::vector<unsigned char>& bgraPixels,
+	std::string& error)
+{
+	if (width == 0 || height == 0 || bgraPixels.size() < static_cast<std::size_t>(width) * height * 4)
+	{
+		error = "Invalid screenshot dimensions or pixel buffer.";
+		return false;
+	}
+
+	HRESULT initializeResult = CoInitializeEx(nullptr, COINIT_MULTITHREADED);
+	const bool shouldUninitialize = SUCCEEDED(initializeResult);
+	if (FAILED(initializeResult) && initializeResult != RPC_E_CHANGED_MODE)
+	{
+		error = "CoInitializeEx failed: " + HResultToString(initializeResult);
+		return false;
+	}
+
+	CComPtr<IWICImagingFactory> factory;
+	HRESULT result = CoCreateInstance(
+		CLSID_WICImagingFactory,
+		nullptr,
+		CLSCTX_INPROC_SERVER,
+		IID_PPV_ARGS(&factory));
+	if (FAILED(result))
+	{
+		error = "Could not create WIC imaging factory: " + HResultToString(result);
+		if (shouldUninitialize)
+			CoUninitialize();
+		return false;
+	}
+
+	CComPtr<IWICStream> stream;
+	result = factory->CreateStream(&stream);
+	if (SUCCEEDED(result))
+		result = stream->InitializeFromFilename(outputPath.wstring().c_str(), GENERIC_WRITE);
+	if (FAILED(result))
+	{
+		error = "Could not open screenshot output file: " + HResultToString(result);
+		if (shouldUninitialize)
+			CoUninitialize();
+		return false;
+	}
+
+	CComPtr<IWICBitmapEncoder> encoder;
+	result = factory->CreateEncoder(GUID_ContainerFormatPng, nullptr, &encoder);
+	if (SUCCEEDED(result))
+		result = encoder->Initialize(stream, WICBitmapEncoderNoCache);
+	if (FAILED(result))
+	{
+		error = "Could not initialize PNG encoder: " + HResultToString(result);
+		if (shouldUninitialize)
+			CoUninitialize();
+		return false;
+	}
+
+	CComPtr<IWICBitmapFrameEncode> frame;
+	CComPtr<IPropertyBag2> propertyBag;
+	result = encoder->CreateNewFrame(&frame, &propertyBag);
+	if (SUCCEEDED(result))
+		result = frame->Initialize(propertyBag);
+	if (SUCCEEDED(result))
+		result = frame->SetSize(width, height);
+
+	WICPixelFormatGUID pixelFormat = GUID_WICPixelFormat32bppBGRA;
+	if (SUCCEEDED(result))
+		result = frame->SetPixelFormat(&pixelFormat);
+	if (SUCCEEDED(result) && pixelFormat != GUID_WICPixelFormat32bppBGRA)
+	{
+		error = "PNG encoder did not accept BGRA pixel format.";
+		result = E_FAIL;
+	}
+
+	const UINT stride = width * 4;
+	const UINT imageSize = stride * height;
+	if (SUCCEEDED(result))
+		result = frame->WritePixels(height, stride, imageSize, const_cast<BYTE*>(bgraPixels.data()));
+	if (SUCCEEDED(result))
+		result = frame->Commit();
+	if (SUCCEEDED(result))
+		result = encoder->Commit();
+
+	if (shouldUninitialize)
+		CoUninitialize();
+
+	if (FAILED(result))
+	{
+		error = "Could not write screenshot PNG: " + HResultToString(result);
+		std::error_code ignored;
+		std::filesystem::remove(outputPath, ignored);
+		return false;
+	}
+
+	return true;
+}
+}
+
+void WritePngFileAsync(
+	const std::filesystem::path& outputPath,
+	unsigned width,
+	unsigned height,
+	std::vector<unsigned char> rgbaPixels)
+{
+	std::thread(
+		[outputPath, width, height, pixels = std::move(rgbaPixels)]() mutable
+		{
+			for (std::size_t index = 0; index + 3 < pixels.size(); index += 4)
+				std::swap(pixels[index], pixels[index + 2]);
+
+			std::string error;
+			if (!WritePngFile(outputPath, width, height, pixels, error))
+				OutputDebugStringA(("Screenshot write failed: " + error + "\n").c_str());
+			else
+				OutputDebugStringA(("Screenshot written: " + outputPath.string() + "\n").c_str());
+		}).detach();
+}