src/third_party/angle/src/tests/egl_tests/EGLContextSharingTest.cpp - cobalt - Git at Google

 //
 // Copyright 2016 The ANGLE Project Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // EGLContextSharingTest.cpp:
 //   Tests relating to shared Contexts.

 #include <gtest/gtest.h>

 #include "test_utils/ANGLETest.h"
 #include "test_utils/angle_test_configs.h"
 #include "test_utils/gl_raii.h"
 #include "util/EGLWindow.h"

 #include <condition_variable>
 #include <mutex>
 #include <thread>

 using namespace angle;

 namespace
 {

 EGLBoolean SafeDestroyContext(EGLDisplay display, EGLContext &context)
 {
     EGLBoolean result = EGL_TRUE;
     if (context != EGL_NO_CONTEXT)
     {
         result  = eglDestroyContext(display, context);
         context = EGL_NO_CONTEXT;
     }
     return result;
 }

 class EGLContextSharingTest : public ANGLETest
 {
   public:
     EGLContextSharingTest() : mContexts{EGL_NO_CONTEXT, EGL_NO_CONTEXT}, mTexture(0) {}

     void testTearDown() override
     {
         glDeleteTextures(1, &mTexture);

         EGLDisplay display = getEGLWindow()->getDisplay();

         if (display != EGL_NO_DISPLAY)
         {
             for (auto &context : mContexts)
             {
                 SafeDestroyContext(display, context);
             }
         }

         // Set default test state to not give an error on shutdown.
         getEGLWindow()->makeCurrent();
     }

     EGLContext mContexts[2];
     GLuint mTexture;
 };

 // Tests that creating resources works after freeing the share context.
 TEST_P(EGLContextSharingTest, BindTextureAfterShareContextFree)
 {
     EGLDisplay display = getEGLWindow()->getDisplay();
     EGLConfig config   = getEGLWindow()->getConfig();
     EGLSurface surface = getEGLWindow()->getSurface();

     const EGLint contextAttribs[] = {EGL_CONTEXT_CLIENT_VERSION,
                                      getEGLWindow()->getClientMajorVersion(), EGL_NONE};

     mContexts[0] = eglCreateContext(display, config, nullptr, contextAttribs);
     ASSERT_EGL_SUCCESS();
     ASSERT_TRUE(mContexts[0] != EGL_NO_CONTEXT);
     mContexts[1] = eglCreateContext(display, config, mContexts[1], contextAttribs);
     ASSERT_EGL_SUCCESS();
     ASSERT_TRUE(mContexts[1] != EGL_NO_CONTEXT);

     ASSERT_EGL_TRUE(SafeDestroyContext(display, mContexts[0]));
     ASSERT_EGL_TRUE(eglMakeCurrent(display, surface, surface, mContexts[1]));
     ASSERT_EGL_SUCCESS();

     glGenTextures(1, &mTexture);
     glBindTexture(GL_TEXTURE_2D, mTexture);
     ASSERT_GL_NO_ERROR();
 }

 // Tests the creation of contexts using EGL_ANGLE_display_texture_share_group
 TEST_P(EGLContextSharingTest, DisplayShareGroupContextCreation)
 {
     EGLDisplay display = getEGLWindow()->getDisplay();
     EGLConfig config   = getEGLWindow()->getConfig();

     const EGLint inShareGroupContextAttribs[] = {
         EGL_CONTEXT_CLIENT_VERSION, 2, EGL_DISPLAY_TEXTURE_SHARE_GROUP_ANGLE, EGL_TRUE, EGL_NONE};

     // Test creating two contexts in the global share group
     mContexts[0] = eglCreateContext(display, config, nullptr, inShareGroupContextAttribs);
     mContexts[1] = eglCreateContext(display, config, mContexts[1], inShareGroupContextAttribs);

     if (!IsEGLDisplayExtensionEnabled(display, "EGL_ANGLE_display_texture_share_group"))
     {
         // Make sure an error is generated and early-exit
         ASSERT_EGL_ERROR(EGL_BAD_ATTRIBUTE);
         ASSERT_EQ(EGL_NO_CONTEXT, mContexts[0]);
         return;
     }

     ASSERT_EGL_SUCCESS();

     ASSERT_NE(EGL_NO_CONTEXT, mContexts[0]);
     ASSERT_NE(EGL_NO_CONTEXT, mContexts[1]);
     eglDestroyContext(display, mContexts[0]);

     // Try creating a context that is not in the global share group but tries to share with a
     // context that is
     const EGLint notInShareGroupContextAttribs[] = {
         EGL_CONTEXT_CLIENT_VERSION, 2, EGL_DISPLAY_TEXTURE_SHARE_GROUP_ANGLE, EGL_FALSE, EGL_NONE};
     mContexts[1] = eglCreateContext(display, config, mContexts[1], notInShareGroupContextAttribs);
     ASSERT_EGL_ERROR(EGL_BAD_ATTRIBUTE);
     ASSERT_TRUE(mContexts[1] == EGL_NO_CONTEXT);
 }

 // Tests the sharing of textures using EGL_ANGLE_display_texture_share_group
 TEST_P(EGLContextSharingTest, DisplayShareGroupObjectSharing)
 {
     EGLDisplay display = getEGLWindow()->getDisplay();
     if (!IsEGLDisplayExtensionEnabled(display, "EGL_ANGLE_display_texture_share_group"))
     {
         std::cout << "Test skipped because EGL_ANGLE_display_texture_share_group is not present."
                   << std::endl;
         return;
     }

     EGLConfig config   = getEGLWindow()->getConfig();
     EGLSurface surface = getEGLWindow()->getSurface();

     const EGLint inShareGroupContextAttribs[] = {
         EGL_CONTEXT_CLIENT_VERSION, 2, EGL_DISPLAY_TEXTURE_SHARE_GROUP_ANGLE, EGL_TRUE, EGL_NONE};

     // Create two contexts in the global share group but not in the same context share group
     mContexts[0] = eglCreateContext(display, config, nullptr, inShareGroupContextAttribs);
     mContexts[1] = eglCreateContext(display, config, nullptr, inShareGroupContextAttribs);

     ASSERT_EGL_SUCCESS();

     ASSERT_NE(EGL_NO_CONTEXT, mContexts[0]);
     ASSERT_NE(EGL_NO_CONTEXT, mContexts[1]);

     ASSERT_EGL_TRUE(eglMakeCurrent(display, surface, surface, mContexts[0]));
     ASSERT_EGL_SUCCESS();

     // Create a texture and buffer in ctx 0
     GLuint textureFromCtx0 = 0;
     glGenTextures(1, &textureFromCtx0);
     glBindTexture(GL_TEXTURE_2D, textureFromCtx0);
     glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 1, 1, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
     glBindTexture(GL_TEXTURE_2D, 0);
     ASSERT_GL_TRUE(glIsTexture(textureFromCtx0));

     GLuint bufferFromCtx0 = 0;
     glGenBuffers(1, &bufferFromCtx0);
     glBindBuffer(GL_ARRAY_BUFFER, bufferFromCtx0);
     glBufferData(GL_ARRAY_BUFFER, 1, nullptr, GL_STATIC_DRAW);
     glBindBuffer(GL_ARRAY_BUFFER, 0);
     ASSERT_GL_TRUE(glIsBuffer(bufferFromCtx0));

     ASSERT_GL_NO_ERROR();

     // Switch to context 1 and verify that the texture is accessible but the buffer is not
     ASSERT_EGL_TRUE(eglMakeCurrent(display, surface, surface, mContexts[1]));
     ASSERT_EGL_SUCCESS();

     ASSERT_GL_TRUE(glIsTexture(textureFromCtx0));

     ASSERT_GL_FALSE(glIsBuffer(bufferFromCtx0));
     glDeleteBuffers(1, &bufferFromCtx0);
     ASSERT_GL_NO_ERROR();

     // Call readpixels on the texture to verify that the backend has proper support
     GLuint fbo = 0;
     glGenFramebuffers(1, &fbo);
     glBindFramebuffer(GL_FRAMEBUFFER, fbo);
     glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, textureFromCtx0, 0);

     GLubyte pixel[4];
     glReadPixels(0, 0, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, pixel);
     ASSERT_GL_NO_ERROR();

     glDeleteFramebuffers(1, &fbo);

     glDeleteTextures(1, &textureFromCtx0);
     ASSERT_GL_NO_ERROR();
     ASSERT_GL_FALSE(glIsTexture(textureFromCtx0));

     // Switch back to context 0 and delete the buffer
     ASSERT_EGL_TRUE(eglMakeCurrent(display, surface, surface, mContexts[0]));
     ASSERT_EGL_SUCCESS();

     ASSERT_GL_TRUE(glIsBuffer(bufferFromCtx0));
     glDeleteBuffers(1, &bufferFromCtx0);
     ASSERT_GL_NO_ERROR();
 }

 // Tests that shared textures using EGL_ANGLE_display_texture_share_group are released when the last
 // context is destroyed
 TEST_P(EGLContextSharingTest, DisplayShareGroupReleasedWithLastContext)
 {
     EGLDisplay display = getEGLWindow()->getDisplay();
     if (!IsEGLDisplayExtensionEnabled(display, "EGL_ANGLE_display_texture_share_group"))
     {
         std::cout << "Test skipped because EGL_ANGLE_display_texture_share_group is not present."
                   << std::endl;
         return;
     }

     EGLConfig config   = getEGLWindow()->getConfig();
     EGLSurface surface = getEGLWindow()->getSurface();

     const EGLint inShareGroupContextAttribs[] = {
         EGL_CONTEXT_CLIENT_VERSION, 2, EGL_DISPLAY_TEXTURE_SHARE_GROUP_ANGLE, EGL_TRUE, EGL_NONE};

     // Create two contexts in the global share group but not in the same context share group
     mContexts[0] = eglCreateContext(display, config, nullptr, inShareGroupContextAttribs);
     mContexts[1] = eglCreateContext(display, config, nullptr, inShareGroupContextAttribs);

     // Create a texture and buffer in ctx 0
     ASSERT_EGL_TRUE(eglMakeCurrent(display, surface, surface, mContexts[0]));
     GLuint textureFromCtx0 = 0;
     glGenTextures(1, &textureFromCtx0);
     glBindTexture(GL_TEXTURE_2D, textureFromCtx0);
     glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 1, 1, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
     glBindTexture(GL_TEXTURE_2D, 0);
     ASSERT_GL_TRUE(glIsTexture(textureFromCtx0));

     // Switch to context 1 and verify that the texture is accessible
     ASSERT_EGL_TRUE(eglMakeCurrent(display, surface, surface, mContexts[1]));
     ASSERT_GL_TRUE(glIsTexture(textureFromCtx0));

     // Destroy both contexts, the texture should be cleaned up automatically
     ASSERT_EGL_TRUE(eglDestroyContext(display, mContexts[0]));
     ASSERT_EGL_TRUE(eglDestroyContext(display, mContexts[1]));

     // Create a new context and verify it cannot access the texture previously created
     mContexts[0] = eglCreateContext(display, config, nullptr, inShareGroupContextAttribs);

     ASSERT_GL_FALSE(glIsTexture(textureFromCtx0));
 }

 // Tests that deleting an object on one Context doesn't destroy it ahead-of-time. Mostly focused
 // on the Vulkan back-end where we manage object lifetime manually.
 TEST_P(EGLContextSharingTest, TextureLifetime)
 {
     EGLWindow *eglWindow = getEGLWindow();
     EGLConfig config     = getEGLWindow()->getConfig();
     EGLDisplay display   = getEGLWindow()->getDisplay();

     // Create a pbuffer surface for use with a shared context.
     EGLSurface surface     = eglWindow->getSurface();
     EGLContext mainContext = eglWindow->getContext();

     // Initialize a shared context.
     mContexts[0] = eglCreateContext(display, config, mainContext, nullptr);
     ASSERT_NE(mContexts[0], EGL_NO_CONTEXT);

     // Create a Texture on the shared context.
     ASSERT_EGL_TRUE(eglMakeCurrent(display, surface, surface, mContexts[0]));

     constexpr GLsizei kTexSize                  = 2;
     const GLColor kTexData[kTexSize * kTexSize] = {GLColor::red, GLColor::green, GLColor::blue,
                                                    GLColor::yellow};
     GLTexture tex;
     glBindTexture(GL_TEXTURE_2D, tex);
     glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kTexSize, kTexSize, 0, GL_RGBA, GL_UNSIGNED_BYTE,
                  kTexData);
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

     // Make the main Context current and draw with the texture.
     ASSERT_EGL_TRUE(eglMakeCurrent(display, surface, surface, mainContext));

     glBindTexture(GL_TEXTURE_2D, tex);
     ANGLE_GL_PROGRAM(program, essl1_shaders::vs::Texture2D(), essl1_shaders::fs::Texture2D());
     glUseProgram(program);

     // No uniform update because the update seems to hide the error on Vulkan.

     // Enqueue the draw call.
     drawQuad(program, essl1_shaders::PositionAttrib(), 0.5f);
     EXPECT_GL_NO_ERROR();

     // Delete the texture in the main context to orphan it.
     // Do not read back the data to keep the commands in the graph.
     tex.reset();

     // Bind and delete the test context. This should trigger texture garbage collection.
     ASSERT_EGL_TRUE(eglMakeCurrent(display, surface, surface, mContexts[0]));
     SafeDestroyContext(display, mContexts[0]);

     // Bind the main context to clean up the test.
     ASSERT_EGL_TRUE(eglMakeCurrent(display, surface, surface, mainContext));
 }

 // Tests that deleting an object on one Context doesn't destroy it ahead-of-time. Mostly focused
 // on the Vulkan back-end where we manage object lifetime manually.
 TEST_P(EGLContextSharingTest, SamplerLifetime)
 {
     EGLWindow *eglWindow = getEGLWindow();
     EGLConfig config     = getEGLWindow()->getConfig();
     EGLDisplay display   = getEGLWindow()->getDisplay();

     ANGLE_SKIP_TEST_IF(getClientMajorVersion() < 3);
     ANGLE_SKIP_TEST_IF(!IsEGLDisplayExtensionEnabled(display, "EGL_KHR_create_context"));

     // Create a pbuffer surface for use with a shared context.
     EGLSurface surface     = eglWindow->getSurface();
     EGLContext mainContext = eglWindow->getContext();

     std::vector<EGLint> contextAttributes;
     contextAttributes.push_back(EGL_CONTEXT_MAJOR_VERSION_KHR);
     contextAttributes.push_back(getClientMajorVersion());
     contextAttributes.push_back(EGL_NONE);

     // Initialize a shared context.
     mContexts[0] = eglCreateContext(display, config, mainContext, contextAttributes.data());
     ASSERT_NE(mContexts[0], EGL_NO_CONTEXT);

     // Create a Texture on the shared context. Also create a Sampler object.
     ASSERT_EGL_TRUE(eglMakeCurrent(display, surface, surface, mContexts[0]));

     constexpr GLsizei kTexSize                  = 2;
     const GLColor kTexData[kTexSize * kTexSize] = {GLColor::red, GLColor::green, GLColor::blue,
                                                    GLColor::yellow};
     GLTexture tex;
     glBindTexture(GL_TEXTURE_2D, tex);
     glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kTexSize, kTexSize, 0, GL_RGBA, GL_UNSIGNED_BYTE,
                  kTexData);

     GLSampler sampler;
     glBindSampler(0, sampler);
     glSamplerParameteri(sampler, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
     glSamplerParameteri(sampler, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

     // Make the main Context current and draw with the texture and sampler.
     ASSERT_EGL_TRUE(eglMakeCurrent(display, surface, surface, mainContext));

     glBindTexture(GL_TEXTURE_2D, tex);
     glBindSampler(0, sampler);
     ANGLE_GL_PROGRAM(program, essl1_shaders::vs::Texture2D(), essl1_shaders::fs::Texture2D());
     glUseProgram(program);

     // No uniform update because the update seems to hide the error on Vulkan.

     // Enqueue the draw call.
     drawQuad(program, essl1_shaders::PositionAttrib(), 0.5f);
     EXPECT_GL_NO_ERROR();

     // Delete the texture and sampler in the main context to orphan them.
     // Do not read back the data to keep the commands in the graph.
     tex.reset();
     sampler.reset();

     // Bind and delete the test context. This should trigger texture garbage collection.
     ASSERT_EGL_TRUE(eglMakeCurrent(display, surface, surface, mContexts[0]));
     SafeDestroyContext(display, mContexts[0]);

     // Bind the main context to clean up the test.
     ASSERT_EGL_TRUE(eglMakeCurrent(display, surface, surface, mainContext));
 }

 // Test that deleting an object reading from a shared object in one context doesn't cause the other
 // context to crash.  Mostly focused on the Vulkan back-end where we track resource dependencies in
 // a graph.
 TEST_P(EGLContextSharingTest, DeleteReaderOfSharedTexture)
 {
     ANGLE_SKIP_TEST_IF(!platformSupportsMultithreading());

     // Bug in the Vulkan backend. http://anglebug.com/4130
     ANGLE_SKIP_TEST_IF(IsVulkan());

     // Initialize contexts
     EGLWindow *window = getEGLWindow();
     EGLDisplay dpy    = window->getDisplay();
     EGLConfig config  = window->getConfig();

     constexpr size_t kThreadCount    = 2;
     EGLSurface surface[kThreadCount] = {EGL_NO_SURFACE, EGL_NO_SURFACE};
     EGLContext ctx[kThreadCount]     = {EGL_NO_CONTEXT, EGL_NO_CONTEXT};

     EGLint pbufferAttributes[] = {EGL_WIDTH, 1, EGL_HEIGHT, 1, EGL_NONE, EGL_NONE};

     for (size_t t = 0; t < kThreadCount; ++t)
     {
         surface[t] = eglCreatePbufferSurface(dpy, config, pbufferAttributes);
         EXPECT_EGL_SUCCESS();

         ctx[t] = window->createContext(t == 0 ? EGL_NO_CONTEXT : ctx[0]);
         EXPECT_NE(EGL_NO_CONTEXT, ctx[t]);
     }

     // Initialize test resources.  They are done outside the threads to reduce the sources of
     // errors and thus deadlock-free teardown.
     ASSERT_EGL_TRUE(eglMakeCurrent(dpy, surface[1], surface[1], ctx[1]));

     // Shared texture to read from.
     constexpr GLsizei kTexSize = 1;
     const GLColor kTexData     = GLColor::red;

     GLTexture sharedTex;
     glBindTexture(GL_TEXTURE_2D, sharedTex);
     glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kTexSize, kTexSize, 0, GL_RGBA, GL_UNSIGNED_BYTE,
                  &kTexData);
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

     // Resources for each context.
     GLRenderbuffer renderbuffer[kThreadCount];
     GLFramebuffer fbo[kThreadCount];
     GLProgram program[kThreadCount];

     for (size_t t = 0; t < kThreadCount; ++t)
     {
         ASSERT_EGL_TRUE(eglMakeCurrent(dpy, surface[t], surface[t], ctx[t]));

         glBindRenderbuffer(GL_RENDERBUFFER, renderbuffer[t]);
         constexpr int kRenderbufferSize = 4;
         glRenderbufferStorage(GL_RENDERBUFFER, GL_RGBA8, kRenderbufferSize, kRenderbufferSize);

         glBindFramebuffer(GL_FRAMEBUFFER, fbo[t]);
         glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER,
                                   renderbuffer[t]);

         glBindTexture(GL_TEXTURE_2D, sharedTex);
         program[t].makeRaster(essl1_shaders::vs::Texture2D(), essl1_shaders::fs::Texture2D());
         ASSERT_TRUE(program[t].valid());
     }

     EXPECT_EGL_TRUE(eglMakeCurrent(dpy, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT));

     // Synchronization tools to ensure the two threads are interleaved as designed by this test.
     std::mutex mutex;
     std::condition_variable condVar;

     enum class Step
     {
         Start,
         Thread0Draw,
         Thread1Draw,
         Thread0Delete,
         Finish,
         Abort,
     };
     Step currentStep = Step::Start;

     // Helper functions to synchronize the threads so that the operations are executed in the
     // specific order the test is written for.
     auto waitForStep = [&](Step waitStep) -> bool {
         std::unique_lock<std::mutex> lock(mutex);
         while (currentStep != waitStep)
         {
             // If necessary, abort execution as the other thread has encountered a GL error.
             if (currentStep == Step::Abort)
             {
                 return false;
             }
             condVar.wait(lock);
         }

         return true;
     };
     auto nextStep = [&](Step newStep) {
         {
             std::unique_lock<std::mutex> lock(mutex);
             currentStep = newStep;
         }
         condVar.notify_one();
     };

     class AbortOnFailure
     {
       public:
         AbortOnFailure(Step *currentStep, std::mutex *mutex, std::condition_variable *condVar)
             : mCurrentStep(currentStep), mMutex(mutex), mCondVar(condVar)
         {}

         ~AbortOnFailure()
         {
             bool isAborting = false;
             {
                 std::unique_lock<std::mutex> lock(*mMutex);
                 isAborting = *mCurrentStep != Step::Finish;

                 if (isAborting)
                 {
                     *mCurrentStep = Step::Abort;
                 }
             }
             mCondVar->notify_all();
         }

       private:
         Step *mCurrentStep;
         std::mutex *mMutex;
         std::condition_variable *mCondVar;
     };

     std::thread deletingThread = std::thread([&]() {
         AbortOnFailure abortOnFailure(&currentStep, &mutex, &condVar);

         EXPECT_EGL_TRUE(eglMakeCurrent(dpy, surface[0], surface[0], ctx[0]));
         EXPECT_EGL_SUCCESS();

         ASSERT_TRUE(waitForStep(Step::Start));

         // Draw using the shared texture.
         drawQuad(program[0].get(), essl1_shaders::PositionAttrib(), 0.5f);

         // Wait for the other thread to also draw using the shared texture.
         nextStep(Step::Thread0Draw);
         ASSERT_TRUE(waitForStep(Step::Thread1Draw));

         // Delete this thread's framebuffer (reader of the shared texture).
         fbo[0].reset();

         // Flush to make sure the graph nodes associated with this context are deleted.
         glFlush();

         // Wait for the other thread to use the shared texture again before unbinding the
         // context (so no implicit flush happens).
         nextStep(Step::Thread0Delete);
         ASSERT_TRUE(waitForStep(Step::Finish));

         EXPECT_GL_NO_ERROR();
         EXPECT_EGL_TRUE(eglMakeCurrent(dpy, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT));
         EXPECT_EGL_SUCCESS();
     });

     std::thread continuingThread = std::thread([&]() {
         AbortOnFailure abortOnFailure(&currentStep, &mutex, &condVar);

         EXPECT_EGL_TRUE(eglMakeCurrent(dpy, surface[1], surface[1], ctx[1]));
         EXPECT_EGL_SUCCESS();

         // Wait for first thread to draw using the shared texture.
         ASSERT_TRUE(waitForStep(Step::Thread0Draw));

         // Draw using the shared texture.
         drawQuad(program[0].get(), essl1_shaders::PositionAttrib(), 0.5f);

         // Wait for the other thread to delete its framebuffer.
         nextStep(Step::Thread1Draw);
         ASSERT_TRUE(waitForStep(Step::Thread0Delete));

         // Write to the shared texture differently, so a dependency is created from the previous
         // readers of the shared texture (the two framebuffers of the two threads) to the new
         // commands being recorded for the shared texture.
         //
         // If the backend attempts to create a dependency from nodes associated with the
         // previous readers of the texture to the new node that will contain the following
         // commands, there will be a use-after-free error.
         const GLColor kTexData2 = GLColor::green;
         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kTexSize, kTexSize, 0, GL_RGBA, GL_UNSIGNED_BYTE,
                      &kTexData2);
         drawQuad(program[0].get(), essl1_shaders::PositionAttrib(), 0.5f);

         nextStep(Step::Finish);

         EXPECT_EGL_TRUE(eglMakeCurrent(dpy, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT));
         EXPECT_EGL_SUCCESS();
     });

     deletingThread.join();
     continuingThread.join();

     ASSERT_NE(currentStep, Step::Abort);

     // Clean up
     for (size_t t = 0; t < kThreadCount; ++t)
     {
         eglDestroySurface(dpy, surface[t]);
         eglDestroyContext(dpy, ctx[t]);
     }
 }
 }  // anonymous namespace

 ANGLE_INSTANTIATE_TEST(EGLContextSharingTest,
                        ES2_D3D9(),
                        ES2_D3D11(),
                        ES3_D3D11(),
                        ES2_OPENGL(),
                        ES3_OPENGL(),
                        ES2_VULKAN(),
                        ES3_VULKAN());
	//
	// Copyright 2016 The ANGLE Project Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.
	//
	// EGLContextSharingTest.cpp:
	// Tests relating to shared Contexts.

	#include <gtest/gtest.h>

	#include "test_utils/ANGLETest.h"
	#include "test_utils/angle_test_configs.h"
	#include "test_utils/gl_raii.h"
	#include "util/EGLWindow.h"

	#include <condition_variable>
	#include <mutex>
	#include <thread>

	using namespace angle;

	namespace
	{

	EGLBoolean SafeDestroyContext(EGLDisplay display, EGLContext &context)
	{
	EGLBoolean result = EGL_TRUE;
	if (context != EGL_NO_CONTEXT)
	{
	result = eglDestroyContext(display, context);
	context = EGL_NO_CONTEXT;
	}
	return result;
	}

	class EGLContextSharingTest : public ANGLETest
	{
	public:
	EGLContextSharingTest() : mContexts{EGL_NO_CONTEXT, EGL_NO_CONTEXT}, mTexture(0) {}

	void testTearDown() override
	{
	glDeleteTextures(1, &mTexture);

	EGLDisplay display = getEGLWindow()->getDisplay();

	if (display != EGL_NO_DISPLAY)
	{
	for (auto &context : mContexts)
	{
	SafeDestroyContext(display, context);
	}
	}

	// Set default test state to not give an error on shutdown.
	getEGLWindow()->makeCurrent();
	}

	EGLContext mContexts[2];
	GLuint mTexture;
	};

	// Tests that creating resources works after freeing the share context.
	TEST_P(EGLContextSharingTest, BindTextureAfterShareContextFree)
	{
	EGLDisplay display = getEGLWindow()->getDisplay();
	EGLConfig config = getEGLWindow()->getConfig();
	EGLSurface surface = getEGLWindow()->getSurface();

	const EGLint contextAttribs[] = {EGL_CONTEXT_CLIENT_VERSION,
	getEGLWindow()->getClientMajorVersion(), EGL_NONE};

	mContexts[0] = eglCreateContext(display, config, nullptr, contextAttribs);
	ASSERT_EGL_SUCCESS();
	ASSERT_TRUE(mContexts[0] != EGL_NO_CONTEXT);
	mContexts[1] = eglCreateContext(display, config, mContexts[1], contextAttribs);
	ASSERT_EGL_SUCCESS();
	ASSERT_TRUE(mContexts[1] != EGL_NO_CONTEXT);

	ASSERT_EGL_TRUE(SafeDestroyContext(display, mContexts[0]));
	ASSERT_EGL_TRUE(eglMakeCurrent(display, surface, surface, mContexts[1]));
	ASSERT_EGL_SUCCESS();

	glGenTextures(1, &mTexture);
	glBindTexture(GL_TEXTURE_2D, mTexture);
	ASSERT_GL_NO_ERROR();
	}

	// Tests the creation of contexts using EGL_ANGLE_display_texture_share_group
	TEST_P(EGLContextSharingTest, DisplayShareGroupContextCreation)
	{
	EGLDisplay display = getEGLWindow()->getDisplay();
	EGLConfig config = getEGLWindow()->getConfig();

	const EGLint inShareGroupContextAttribs[] = {
	EGL_CONTEXT_CLIENT_VERSION, 2, EGL_DISPLAY_TEXTURE_SHARE_GROUP_ANGLE, EGL_TRUE, EGL_NONE};

	// Test creating two contexts in the global share group
	mContexts[0] = eglCreateContext(display, config, nullptr, inShareGroupContextAttribs);
	mContexts[1] = eglCreateContext(display, config, mContexts[1], inShareGroupContextAttribs);

	if (!IsEGLDisplayExtensionEnabled(display, "EGL_ANGLE_display_texture_share_group"))
	{
	// Make sure an error is generated and early-exit
	ASSERT_EGL_ERROR(EGL_BAD_ATTRIBUTE);
	ASSERT_EQ(EGL_NO_CONTEXT, mContexts[0]);
	return;
	}

	ASSERT_EGL_SUCCESS();

	ASSERT_NE(EGL_NO_CONTEXT, mContexts[0]);
	ASSERT_NE(EGL_NO_CONTEXT, mContexts[1]);
	eglDestroyContext(display, mContexts[0]);

	// Try creating a context that is not in the global share group but tries to share with a
	// context that is
	const EGLint notInShareGroupContextAttribs[] = {
	EGL_CONTEXT_CLIENT_VERSION, 2, EGL_DISPLAY_TEXTURE_SHARE_GROUP_ANGLE, EGL_FALSE, EGL_NONE};
	mContexts[1] = eglCreateContext(display, config, mContexts[1], notInShareGroupContextAttribs);
	ASSERT_EGL_ERROR(EGL_BAD_ATTRIBUTE);
	ASSERT_TRUE(mContexts[1] == EGL_NO_CONTEXT);
	}

	// Tests the sharing of textures using EGL_ANGLE_display_texture_share_group
	TEST_P(EGLContextSharingTest, DisplayShareGroupObjectSharing)
	{
	EGLDisplay display = getEGLWindow()->getDisplay();
	if (!IsEGLDisplayExtensionEnabled(display, "EGL_ANGLE_display_texture_share_group"))
	{
	std::cout << "Test skipped because EGL_ANGLE_display_texture_share_group is not present."
	<< std::endl;
	return;
	}

	EGLConfig config = getEGLWindow()->getConfig();
	EGLSurface surface = getEGLWindow()->getSurface();

	const EGLint inShareGroupContextAttribs[] = {
	EGL_CONTEXT_CLIENT_VERSION, 2, EGL_DISPLAY_TEXTURE_SHARE_GROUP_ANGLE, EGL_TRUE, EGL_NONE};

	// Create two contexts in the global share group but not in the same context share group
	mContexts[0] = eglCreateContext(display, config, nullptr, inShareGroupContextAttribs);
	mContexts[1] = eglCreateContext(display, config, nullptr, inShareGroupContextAttribs);

	ASSERT_EGL_SUCCESS();

	ASSERT_NE(EGL_NO_CONTEXT, mContexts[0]);
	ASSERT_NE(EGL_NO_CONTEXT, mContexts[1]);

	ASSERT_EGL_TRUE(eglMakeCurrent(display, surface, surface, mContexts[0]));
	ASSERT_EGL_SUCCESS();

	// Create a texture and buffer in ctx 0
	GLuint textureFromCtx0 = 0;
	glGenTextures(1, &textureFromCtx0);
	glBindTexture(GL_TEXTURE_2D, textureFromCtx0);
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 1, 1, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
	glBindTexture(GL_TEXTURE_2D, 0);
	ASSERT_GL_TRUE(glIsTexture(textureFromCtx0));

	GLuint bufferFromCtx0 = 0;
	glGenBuffers(1, &bufferFromCtx0);
	glBindBuffer(GL_ARRAY_BUFFER, bufferFromCtx0);
	glBufferData(GL_ARRAY_BUFFER, 1, nullptr, GL_STATIC_DRAW);
	glBindBuffer(GL_ARRAY_BUFFER, 0);
	ASSERT_GL_TRUE(glIsBuffer(bufferFromCtx0));

	ASSERT_GL_NO_ERROR();

	// Switch to context 1 and verify that the texture is accessible but the buffer is not
	ASSERT_EGL_TRUE(eglMakeCurrent(display, surface, surface, mContexts[1]));
	ASSERT_EGL_SUCCESS();

	ASSERT_GL_TRUE(glIsTexture(textureFromCtx0));

	ASSERT_GL_FALSE(glIsBuffer(bufferFromCtx0));
	glDeleteBuffers(1, &bufferFromCtx0);
	ASSERT_GL_NO_ERROR();

	// Call readpixels on the texture to verify that the backend has proper support
	GLuint fbo = 0;
	glGenFramebuffers(1, &fbo);
	glBindFramebuffer(GL_FRAMEBUFFER, fbo);
	glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, textureFromCtx0, 0);

	GLubyte pixel[4];
	glReadPixels(0, 0, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, pixel);
	ASSERT_GL_NO_ERROR();

	glDeleteFramebuffers(1, &fbo);

	glDeleteTextures(1, &textureFromCtx0);
	ASSERT_GL_NO_ERROR();
	ASSERT_GL_FALSE(glIsTexture(textureFromCtx0));

	// Switch back to context 0 and delete the buffer
	ASSERT_EGL_TRUE(eglMakeCurrent(display, surface, surface, mContexts[0]));
	ASSERT_EGL_SUCCESS();

	ASSERT_GL_TRUE(glIsBuffer(bufferFromCtx0));
	glDeleteBuffers(1, &bufferFromCtx0);
	ASSERT_GL_NO_ERROR();
	}

	// Tests that shared textures using EGL_ANGLE_display_texture_share_group are released when the last
	// context is destroyed
	TEST_P(EGLContextSharingTest, DisplayShareGroupReleasedWithLastContext)
	{
	EGLDisplay display = getEGLWindow()->getDisplay();
	if (!IsEGLDisplayExtensionEnabled(display, "EGL_ANGLE_display_texture_share_group"))
	{
	std::cout << "Test skipped because EGL_ANGLE_display_texture_share_group is not present."
	<< std::endl;
	return;
	}

	EGLConfig config = getEGLWindow()->getConfig();
	EGLSurface surface = getEGLWindow()->getSurface();

	const EGLint inShareGroupContextAttribs[] = {
	EGL_CONTEXT_CLIENT_VERSION, 2, EGL_DISPLAY_TEXTURE_SHARE_GROUP_ANGLE, EGL_TRUE, EGL_NONE};

	// Create two contexts in the global share group but not in the same context share group
	mContexts[0] = eglCreateContext(display, config, nullptr, inShareGroupContextAttribs);
	mContexts[1] = eglCreateContext(display, config, nullptr, inShareGroupContextAttribs);

	// Create a texture and buffer in ctx 0
	ASSERT_EGL_TRUE(eglMakeCurrent(display, surface, surface, mContexts[0]));
	GLuint textureFromCtx0 = 0;
	glGenTextures(1, &textureFromCtx0);
	glBindTexture(GL_TEXTURE_2D, textureFromCtx0);
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 1, 1, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
	glBindTexture(GL_TEXTURE_2D, 0);
	ASSERT_GL_TRUE(glIsTexture(textureFromCtx0));

	// Switch to context 1 and verify that the texture is accessible
	ASSERT_EGL_TRUE(eglMakeCurrent(display, surface, surface, mContexts[1]));
	ASSERT_GL_TRUE(glIsTexture(textureFromCtx0));

	// Destroy both contexts, the texture should be cleaned up automatically
	ASSERT_EGL_TRUE(eglDestroyContext(display, mContexts[0]));
	ASSERT_EGL_TRUE(eglDestroyContext(display, mContexts[1]));

	// Create a new context and verify it cannot access the texture previously created
	mContexts[0] = eglCreateContext(display, config, nullptr, inShareGroupContextAttribs);

	ASSERT_GL_FALSE(glIsTexture(textureFromCtx0));
	}

	// Tests that deleting an object on one Context doesn't destroy it ahead-of-time. Mostly focused
	// on the Vulkan back-end where we manage object lifetime manually.
	TEST_P(EGLContextSharingTest, TextureLifetime)
	{
	EGLWindow *eglWindow = getEGLWindow();
	EGLConfig config = getEGLWindow()->getConfig();
	EGLDisplay display = getEGLWindow()->getDisplay();

	// Create a pbuffer surface for use with a shared context.
	EGLSurface surface = eglWindow->getSurface();
	EGLContext mainContext = eglWindow->getContext();

	// Initialize a shared context.
	mContexts[0] = eglCreateContext(display, config, mainContext, nullptr);
	ASSERT_NE(mContexts[0], EGL_NO_CONTEXT);

	// Create a Texture on the shared context.
	ASSERT_EGL_TRUE(eglMakeCurrent(display, surface, surface, mContexts[0]));

	constexpr GLsizei kTexSize = 2;
	const GLColor kTexData[kTexSize * kTexSize] = {GLColor::red, GLColor::green, GLColor::blue,
	GLColor::yellow};
	GLTexture tex;
	glBindTexture(GL_TEXTURE_2D, tex);
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kTexSize, kTexSize, 0, GL_RGBA, GL_UNSIGNED_BYTE,
	kTexData);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

	// Make the main Context current and draw with the texture.
	ASSERT_EGL_TRUE(eglMakeCurrent(display, surface, surface, mainContext));

	glBindTexture(GL_TEXTURE_2D, tex);
	ANGLE_GL_PROGRAM(program, essl1_shaders::vs::Texture2D(), essl1_shaders::fs::Texture2D());
	glUseProgram(program);

	// No uniform update because the update seems to hide the error on Vulkan.

	// Enqueue the draw call.
	drawQuad(program, essl1_shaders::PositionAttrib(), 0.5f);
	EXPECT_GL_NO_ERROR();

	// Delete the texture in the main context to orphan it.
	// Do not read back the data to keep the commands in the graph.
	tex.reset();

	// Bind and delete the test context. This should trigger texture garbage collection.
	ASSERT_EGL_TRUE(eglMakeCurrent(display, surface, surface, mContexts[0]));
	SafeDestroyContext(display, mContexts[0]);

	// Bind the main context to clean up the test.
	ASSERT_EGL_TRUE(eglMakeCurrent(display, surface, surface, mainContext));
	}

	// Tests that deleting an object on one Context doesn't destroy it ahead-of-time. Mostly focused
	// on the Vulkan back-end where we manage object lifetime manually.
	TEST_P(EGLContextSharingTest, SamplerLifetime)
	{
	EGLWindow *eglWindow = getEGLWindow();
	EGLConfig config = getEGLWindow()->getConfig();
	EGLDisplay display = getEGLWindow()->getDisplay();

	ANGLE_SKIP_TEST_IF(getClientMajorVersion() < 3);
	ANGLE_SKIP_TEST_IF(!IsEGLDisplayExtensionEnabled(display, "EGL_KHR_create_context"));

	// Create a pbuffer surface for use with a shared context.
	EGLSurface surface = eglWindow->getSurface();
	EGLContext mainContext = eglWindow->getContext();

	std::vector<EGLint> contextAttributes;
	contextAttributes.push_back(EGL_CONTEXT_MAJOR_VERSION_KHR);
	contextAttributes.push_back(getClientMajorVersion());
	contextAttributes.push_back(EGL_NONE);

	// Initialize a shared context.
	mContexts[0] = eglCreateContext(display, config, mainContext, contextAttributes.data());
	ASSERT_NE(mContexts[0], EGL_NO_CONTEXT);

	// Create a Texture on the shared context. Also create a Sampler object.
	ASSERT_EGL_TRUE(eglMakeCurrent(display, surface, surface, mContexts[0]));

	constexpr GLsizei kTexSize = 2;
	const GLColor kTexData[kTexSize * kTexSize] = {GLColor::red, GLColor::green, GLColor::blue,
	GLColor::yellow};
	GLTexture tex;
	glBindTexture(GL_TEXTURE_2D, tex);
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kTexSize, kTexSize, 0, GL_RGBA, GL_UNSIGNED_BYTE,
	kTexData);

	GLSampler sampler;
	glBindSampler(0, sampler);
	glSamplerParameteri(sampler, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
	glSamplerParameteri(sampler, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

	// Make the main Context current and draw with the texture and sampler.
	ASSERT_EGL_TRUE(eglMakeCurrent(display, surface, surface, mainContext));

	glBindTexture(GL_TEXTURE_2D, tex);
	glBindSampler(0, sampler);
	ANGLE_GL_PROGRAM(program, essl1_shaders::vs::Texture2D(), essl1_shaders::fs::Texture2D());
	glUseProgram(program);

	// No uniform update because the update seems to hide the error on Vulkan.

	// Enqueue the draw call.
	drawQuad(program, essl1_shaders::PositionAttrib(), 0.5f);
	EXPECT_GL_NO_ERROR();

	// Delete the texture and sampler in the main context to orphan them.
	// Do not read back the data to keep the commands in the graph.
	tex.reset();
	sampler.reset();

	// Bind and delete the test context. This should trigger texture garbage collection.
	ASSERT_EGL_TRUE(eglMakeCurrent(display, surface, surface, mContexts[0]));
	SafeDestroyContext(display, mContexts[0]);

	// Bind the main context to clean up the test.
	ASSERT_EGL_TRUE(eglMakeCurrent(display, surface, surface, mainContext));
	}

	// Test that deleting an object reading from a shared object in one context doesn't cause the other
	// context to crash. Mostly focused on the Vulkan back-end where we track resource dependencies in
	// a graph.
	TEST_P(EGLContextSharingTest, DeleteReaderOfSharedTexture)
	{
	ANGLE_SKIP_TEST_IF(!platformSupportsMultithreading());

	// Bug in the Vulkan backend. http://anglebug.com/4130
	ANGLE_SKIP_TEST_IF(IsVulkan());

	// Initialize contexts
	EGLWindow *window = getEGLWindow();
	EGLDisplay dpy = window->getDisplay();
	EGLConfig config = window->getConfig();

	constexpr size_t kThreadCount = 2;
	EGLSurface surface[kThreadCount] = {EGL_NO_SURFACE, EGL_NO_SURFACE};
	EGLContext ctx[kThreadCount] = {EGL_NO_CONTEXT, EGL_NO_CONTEXT};

	EGLint pbufferAttributes[] = {EGL_WIDTH, 1, EGL_HEIGHT, 1, EGL_NONE, EGL_NONE};

	for (size_t t = 0; t < kThreadCount; ++t)
	{
	surface[t] = eglCreatePbufferSurface(dpy, config, pbufferAttributes);
	EXPECT_EGL_SUCCESS();

	ctx[t] = window->createContext(t == 0 ? EGL_NO_CONTEXT : ctx[0]);
	EXPECT_NE(EGL_NO_CONTEXT, ctx[t]);
	}

	// Initialize test resources. They are done outside the threads to reduce the sources of
	// errors and thus deadlock-free teardown.
	ASSERT_EGL_TRUE(eglMakeCurrent(dpy, surface[1], surface[1], ctx[1]));

	// Shared texture to read from.
	constexpr GLsizei kTexSize = 1;
	const GLColor kTexData = GLColor::red;

	GLTexture sharedTex;
	glBindTexture(GL_TEXTURE_2D, sharedTex);
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kTexSize, kTexSize, 0, GL_RGBA, GL_UNSIGNED_BYTE,
	&kTexData);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

	// Resources for each context.
	GLRenderbuffer renderbuffer[kThreadCount];
	GLFramebuffer fbo[kThreadCount];
	GLProgram program[kThreadCount];

	for (size_t t = 0; t < kThreadCount; ++t)
	{
	ASSERT_EGL_TRUE(eglMakeCurrent(dpy, surface[t], surface[t], ctx[t]));

	glBindRenderbuffer(GL_RENDERBUFFER, renderbuffer[t]);
	constexpr int kRenderbufferSize = 4;
	glRenderbufferStorage(GL_RENDERBUFFER, GL_RGBA8, kRenderbufferSize, kRenderbufferSize);

	glBindFramebuffer(GL_FRAMEBUFFER, fbo[t]);
	glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER,
	renderbuffer[t]);

	glBindTexture(GL_TEXTURE_2D, sharedTex);
	program[t].makeRaster(essl1_shaders::vs::Texture2D(), essl1_shaders::fs::Texture2D());
	ASSERT_TRUE(program[t].valid());
	}

	EXPECT_EGL_TRUE(eglMakeCurrent(dpy, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT));

	// Synchronization tools to ensure the two threads are interleaved as designed by this test.
	std::mutex mutex;
	std::condition_variable condVar;

	enum class Step
	{
	Start,
	Thread0Draw,
	Thread1Draw,
	Thread0Delete,
	Finish,
	Abort,
	};
	Step currentStep = Step::Start;

	// Helper functions to synchronize the threads so that the operations are executed in the
	// specific order the test is written for.
	auto waitForStep = [&](Step waitStep) -> bool {
	std::unique_lock<std::mutex> lock(mutex);
	while (currentStep != waitStep)
	{
	// If necessary, abort execution as the other thread has encountered a GL error.
	if (currentStep == Step::Abort)
	{
	return false;
	}
	condVar.wait(lock);
	}

	return true;
	};
	auto nextStep = [&](Step newStep) {
	{
	std::unique_lock<std::mutex> lock(mutex);
	currentStep = newStep;
	}
	condVar.notify_one();
	};

	class AbortOnFailure
	{
	public:
	AbortOnFailure(Step currentStep, std::mutex mutex, std::condition_variable *condVar)
	: mCurrentStep(currentStep), mMutex(mutex), mCondVar(condVar)
	{}

	~AbortOnFailure()
	{
	bool isAborting = false;
	{
	std::unique_lock<std::mutex> lock(*mMutex);
	isAborting = *mCurrentStep != Step::Finish;

	if (isAborting)
	{
	*mCurrentStep = Step::Abort;
	}
	}
	mCondVar->notify_all();
	}

	private:
	Step *mCurrentStep;
	std::mutex *mMutex;
	std::condition_variable *mCondVar;
	};

	std::thread deletingThread = std::thread([&]() {
	AbortOnFailure abortOnFailure(&currentStep, &mutex, &condVar);

	EXPECT_EGL_TRUE(eglMakeCurrent(dpy, surface[0], surface[0], ctx[0]));
	EXPECT_EGL_SUCCESS();

	ASSERT_TRUE(waitForStep(Step::Start));

	// Draw using the shared texture.
	drawQuad(program[0].get(), essl1_shaders::PositionAttrib(), 0.5f);

	// Wait for the other thread to also draw using the shared texture.
	nextStep(Step::Thread0Draw);
	ASSERT_TRUE(waitForStep(Step::Thread1Draw));

	// Delete this thread's framebuffer (reader of the shared texture).
	fbo[0].reset();

	// Flush to make sure the graph nodes associated with this context are deleted.
	glFlush();

	// Wait for the other thread to use the shared texture again before unbinding the
	// context (so no implicit flush happens).
	nextStep(Step::Thread0Delete);
	ASSERT_TRUE(waitForStep(Step::Finish));

	EXPECT_GL_NO_ERROR();
	EXPECT_EGL_TRUE(eglMakeCurrent(dpy, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT));
	EXPECT_EGL_SUCCESS();
	});

	std::thread continuingThread = std::thread([&]() {
	AbortOnFailure abortOnFailure(&currentStep, &mutex, &condVar);

	EXPECT_EGL_TRUE(eglMakeCurrent(dpy, surface[1], surface[1], ctx[1]));
	EXPECT_EGL_SUCCESS();

	// Wait for first thread to draw using the shared texture.
	ASSERT_TRUE(waitForStep(Step::Thread0Draw));

	// Draw using the shared texture.
	drawQuad(program[0].get(), essl1_shaders::PositionAttrib(), 0.5f);

	// Wait for the other thread to delete its framebuffer.
	nextStep(Step::Thread1Draw);
	ASSERT_TRUE(waitForStep(Step::Thread0Delete));

	// Write to the shared texture differently, so a dependency is created from the previous
	// readers of the shared texture (the two framebuffers of the two threads) to the new
	// commands being recorded for the shared texture.
	//
	// If the backend attempts to create a dependency from nodes associated with the
	// previous readers of the texture to the new node that will contain the following
	// commands, there will be a use-after-free error.
	const GLColor kTexData2 = GLColor::green;
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kTexSize, kTexSize, 0, GL_RGBA, GL_UNSIGNED_BYTE,
	&kTexData2);
	drawQuad(program[0].get(), essl1_shaders::PositionAttrib(), 0.5f);

	nextStep(Step::Finish);

	EXPECT_EGL_TRUE(eglMakeCurrent(dpy, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT));
	EXPECT_EGL_SUCCESS();
	});

	deletingThread.join();
	continuingThread.join();

	ASSERT_NE(currentStep, Step::Abort);

	// Clean up
	for (size_t t = 0; t < kThreadCount; ++t)
	{
	eglDestroySurface(dpy, surface[t]);
	eglDestroyContext(dpy, ctx[t]);
	}
	}
	} // anonymous namespace

	ANGLE_INSTANTIATE_TEST(EGLContextSharingTest,
	ES2_D3D9(),
	ES2_D3D11(),
	ES3_D3D11(),
	ES2_OPENGL(),
	ES3_OPENGL(),
	ES2_VULKAN(),
	ES3_VULKAN());