re organisation

apps/LoopThroughWithOpenGLCompositing/gl/shader/ShaderBuildQueue.cpp

@@ -0,0 +1,134 @@
+#include "ShaderBuildQueue.h"
+
+#include "RuntimeHost.h"
+
+#include <chrono>
+#include <utility>
+
+namespace
+{
+constexpr auto kShaderBuildDebounce = std::chrono::milliseconds(400);
+}
+
+ShaderBuildQueue::ShaderBuildQueue(RuntimeHost& runtimeHost) :
+	mRuntimeHost(runtimeHost),
+	mWorkerThread([this]() { WorkerLoop(); })
+{
+}
+
+ShaderBuildQueue::~ShaderBuildQueue()
+{
+	Stop();
+}
+
+void ShaderBuildQueue::RequestBuild(unsigned outputWidth, unsigned outputHeight)
+{
+	{
+		std::lock_guard<std::mutex> lock(mMutex);
+		mHasRequest = true;
+		++mRequestedGeneration;
+		mRequestedOutputWidth = outputWidth;
+		mRequestedOutputHeight = outputHeight;
+		mHasReadyBuild = false;
+	}
+	mCondition.notify_one();
+}
+
+bool ShaderBuildQueue::TryConsumeReadyBuild(PreparedShaderBuild& build)
+{
+	std::lock_guard<std::mutex> lock(mMutex);
+	if (!mHasReadyBuild)
+		return false;
+
+	build = std::move(mReadyBuild);
+	mReadyBuild = PreparedShaderBuild();
+	mHasReadyBuild = false;
+	return true;
+}
+
+void ShaderBuildQueue::Stop()
+{
+	{
+		std::lock_guard<std::mutex> lock(mMutex);
+		if (mStopping)
+			return;
+		mStopping = true;
+	}
+	mCondition.notify_one();
+	if (mWorkerThread.joinable())
+		mWorkerThread.join();
+}
+
+void ShaderBuildQueue::WorkerLoop()
+{
+	for (;;)
+	{
+		uint64_t generation = 0;
+		unsigned outputWidth = 0;
+		unsigned outputHeight = 0;
+		{
+			std::unique_lock<std::mutex> lock(mMutex);
+			mCondition.wait(lock, [this]() { return mStopping || mHasRequest; });
+			if (mStopping)
+				return;
+
+			generation = mRequestedGeneration;
+			outputWidth = mRequestedOutputWidth;
+			outputHeight = mRequestedOutputHeight;
+			mHasRequest = false;
+		}
+
+		for (;;)
+		{
+			std::unique_lock<std::mutex> lock(mMutex);
+			if (mCondition.wait_for(lock, kShaderBuildDebounce, [this, generation]() {
+				return mStopping || (mHasRequest && mRequestedGeneration != generation);
+			}))
+			{
+				if (mStopping)
+					return;
+
+				generation = mRequestedGeneration;
+				outputWidth = mRequestedOutputWidth;
+				outputHeight = mRequestedOutputHeight;
+				mHasRequest = false;
+				continue;
+			}
+			break;
+		}
+
+		PreparedShaderBuild build = Build(generation, outputWidth, outputHeight);
+
+		std::lock_guard<std::mutex> lock(mMutex);
+		if (mStopping)
+			return;
+		if (generation != mRequestedGeneration)
+			continue;
+		mReadyBuild = std::move(build);
+		mHasReadyBuild = true;
+	}
+}
+
+PreparedShaderBuild ShaderBuildQueue::Build(uint64_t generation, unsigned outputWidth, unsigned outputHeight)
+{
+	PreparedShaderBuild build;
+	build.generation = generation;
+	build.layerStates = mRuntimeHost.GetLayerRenderStates(outputWidth, outputHeight);
+	build.layers.reserve(build.layerStates.size());
+
+	for (const RuntimeRenderState& state : build.layerStates)
+	{
+		PreparedLayerShader layer;
+		layer.state = state;
+		if (!mRuntimeHost.BuildLayerFragmentShaderSource(state.layerId, layer.fragmentShaderSource, build.message))
+		{
+			build.succeeded = false;
+			return build;
+		}
+		build.layers.push_back(std::move(layer));
+	}
+
+	build.succeeded = true;
+	build.message = "Shader layers prepared successfully.";
+	return build;
+}