From 0366e05c44410d3e38f2311865564c15b514e31b Mon Sep 17 00:00:00 2001
From: "Unknown W. Brackets" <checkins@unknownbrackets.org>
Date: Sun, 25 Mar 2018 14:45:43 -0700
Subject: [PATCH] Headless: Quick update to use render thread.

---
 headless/SDLHeadlessHost.cpp | 98 +++++++++++++++++++++++++++++++-----
 headless/SDLHeadlessHost.h   | 14 +++++-
 2 files changed, 97 insertions(+), 15 deletions(-)

diff --git a/headless/SDLHeadlessHost.cpp b/headless/SDLHeadlessHost.cpp
index ed60e409d9..a2ec3a9b51 100644
--- a/headless/SDLHeadlessHost.cpp
+++ b/headless/SDLHeadlessHost.cpp
@@ -32,11 +32,13 @@
 #include "GPU/GPUState.h"
 
 #include "base/logging.h"
+#include "base/timeutil.h"
 #include "gfx/gl_common.h"
 #include "gfx_es2/gpu_features.h"
 #include "file/vfs.h"
 #include "file/zip_read.h"
 #include "thin3d/thin3d_create.h"
+#include "thin3d/GLRenderManager.h"
 
 const bool WINDOW_VISIBLE = false;
 const int WINDOW_WIDTH = 480;
@@ -53,20 +55,47 @@ SDL_Window *CreateHiddenWindow() {
 class GLDummyGraphicsContext : public DummyGraphicsContext {
 public:
 	GLDummyGraphicsContext() {
-		CheckGLExtensions();
-		draw_ = Draw::T3DCreateGLContext();
-		SetGPUBackend(GPUBackend::OPENGL);
-		bool success = draw_->CreatePresets();
-		assert(success);
 	}
 	~GLDummyGraphicsContext() { delete draw_; }
 
+	bool InitFromRenderThread(std::string *errorMessage) override;
+
+	void ShutdownFromRenderThread() override {
+		delete draw_;
+		draw_ = nullptr;
+
+		SDL_GL_DeleteContext(glContext_);
+		glContext_ = nullptr;
+		SDL_DestroyWindow(screen_);
+		screen_ = nullptr;
+	}
+
 	Draw::DrawContext *GetDrawContext() override {
 		return draw_;
 	}
 
+	void ThreadStart() override {
+		renderManager_->ThreadStart();
+	}
+
+	bool ThreadFrame() override {
+		return renderManager_->ThreadFrame();
+	}
+
+	void ThreadEnd() override {
+		renderManager_->ThreadEnd();
+	}
+
+	void StopThread() override {
+		renderManager_->WaitUntilQueueIdle();
+		renderManager_->StopThread();
+	}
+
 private:
 	Draw::DrawContext *draw_;
+	GLRenderManager *renderManager_ = nullptr;
+	SDL_Window *screen_;
+	SDL_GLContext glContext_;
 };
 
 void SDLHeadlessHost::LoadNativeAssets() {
@@ -75,7 +104,7 @@ void SDLHeadlessHost::LoadNativeAssets() {
 	VFSRegister("", new DirectoryAssetReader("../"));
 }
 
-bool SDLHeadlessHost::InitGraphics(std::string *error_message, GraphicsContext **ctx) {
+bool GLDummyGraphicsContext::InitFromRenderThread(std::string *errorMessage) {
 	SDL_Init(SDL_INIT_VIDEO);
 
 	// TODO
@@ -115,29 +144,72 @@ bool SDLHeadlessHost::InitGraphics(std::string *error_message, GraphicsContext *
 	}
 #endif
 
+	CheckGLExtensions();
+	draw_ = Draw::T3DCreateGLContext();
+	renderManager_ = (GLRenderManager *)draw_->GetNativeObject(Draw::NativeObject::RENDER_MANAGER);
+	SetGPUBackend(GPUBackend::OPENGL);
+	bool success = draw_->CreatePresets();
+	assert(success);
+	renderManager_->SetSwapFunction([&]() {
+		SDL_GL_SwapWindow(screen_);
+	});
+
+	return success;
+}
+
+bool SDLHeadlessHost::InitGraphics(std::string *error_message, GraphicsContext **ctx) {
 	GraphicsContext *graphicsContext = new GLDummyGraphicsContext();
 	*ctx = graphicsContext;
 	gfx_ = graphicsContext;
 
+	std::thread th([&]{
+		while (threadState_ == RenderThreadState::IDLE)
+			sleep_ms(1);
+		threadState_ = RenderThreadState::STARTING;
+
+		std::string err;
+		if (!gfx_->InitFromRenderThread(&err)) {
+			threadState_ = RenderThreadState::START_FAILED;
+			return;
+		}
+		gfx_->ThreadStart();
+		threadState_ = RenderThreadState::STARTED;
+
+		while (threadState_ != RenderThreadState::STOP_REQUESTED) {
+			if (!gfx_->ThreadFrame()) {
+				break;
+			}
+			gfx_->SwapBuffers();
+		}
+
+		threadState_ = RenderThreadState::STOPPING;
+		gfx_->ThreadEnd();
+		gfx_->ShutdownFromRenderThread();
+		threadState_ = RenderThreadState::STOPPED;
+	});
+	th.detach();
+
 	LoadNativeAssets();
 
-	return true;
+	threadState_ = RenderThreadState::START_REQUESTED;
+	while (threadState_ == RenderThreadState::START_REQUESTED || threadState_ == RenderThreadState::STARTING)
+		sleep_ms(1);
+
+	return threadState_ == RenderThreadState::STARTED;
 }
 
 void SDLHeadlessHost::ShutdownGraphics() {
+	gfx_->StopThread();
+	while (threadState_ != RenderThreadState::STOPPED)
+		sleep_ms(1);
+
 	gfx_->Shutdown();
 	delete gfx_;
 	gfx_ = nullptr;
-
-	SDL_GL_DeleteContext(glContext_);
-	glContext_ = nullptr;
-	SDL_DestroyWindow(screen_);
-	screen_ = nullptr;
 }
 
 void SDLHeadlessHost::SwapBuffers() {
 	gfx_->SwapBuffers();
-	SDL_GL_SwapWindow(screen_);
 }
 
 #endif
diff --git a/headless/SDLHeadlessHost.h b/headless/SDLHeadlessHost.h
index 9f50c8931f..daa0fe0413 100644
--- a/headless/SDLHeadlessHost.h
+++ b/headless/SDLHeadlessHost.h
@@ -38,9 +38,19 @@ public:
 protected:
 	void LoadNativeAssets();
 
-	SDL_Window *screen_;
-	SDL_GLContext glContext_;
+	enum class RenderThreadState {
+		IDLE,
+		START_REQUESTED,
+		STARTING,
+		START_FAILED,
+		STARTED,
+		STOP_REQUESTED,
+		STOPPING,
+		STOPPED,
+	};
+
 	GraphicsContext *gfx_;
+	volatile RenderThreadState threadState_ = RenderThreadState::IDLE;
 };
 
 #endif