Support create ANGLE EGLContext from an external EGLContext

include/EGL/eglext_angle.h

@@ -337,6 +337,13 @@ EGLAPI EGLBoolean EGLAPIENTRY eglSwapBuffersWithFrameTokenANGLE(EGLDisplay dpy,
 #define EGL_DISPLAY_SEMAPHORE_SHARE_GROUP_ANGLE 0x348D
 #endif /* EGL_ANGLE_display_semaphore_share_group */
 
+#ifndef EGL_ANGLE_external_context_and_surface
+#define EGL_ANGLE_external_context_and_surface 1
+#define EGL_EXTERNAL_CONTEXT_ANGLE 0x348E
+#define EGL_EXTERNAL_SURFACE_ANGLE 0x348F
+#define EGL_EXTERNAL_CONTEXT_SAVE_STATE_ANGLE 0x3490
+#endif /* EGL_ANGLE_external_context_and_surface */
+
 // clang-format on
 
 #endif  // INCLUDE_EGL_EGLEXT_ANGLE_

src/libANGLE/Caps.cpp

@@ -1436,8 +1436,9 @@ std::vector<std::string> DisplayExtensions::getStrings() const
     InsertExtensionString("EGL_EXT_image_dma_buf_import",                        imageDmaBufImportEXT,               &extensionStrings);
     InsertExtensionString("EGL_EXT_image_dma_buf_import_modifiers",              imageDmaBufImportModifiersEXT,      &extensionStrings);
     InsertExtensionString("EGL_NOK_texture_from_pixmap",                         textureFromPixmapNOK,               &extensionStrings);
-    InsertExtensionString("EGL_NV_robustness_video_memory_purge",                robustnessVideoMemoryPurgeNV,               &extensionStrings);
+    InsertExtensionString("EGL_NV_robustness_video_memory_purge",                robustnessVideoMemoryPurgeNV,       &extensionStrings);
     InsertExtensionString("EGL_KHR_reusable_sync",                               reusableSyncKHR,                    &extensionStrings);
+    InsertExtensionString("EGL_ANGLE_external_context_and_surface",              externalContextAndSurface,          &extensionStrings);
     // clang-format on
 
     return extensionStrings;

src/libANGLE/Caps.h

@@ -1193,6 +1193,9 @@ struct DisplayExtensions
 
     // EGL_KHR_reusable_sync
     bool reusableSyncKHR = false;
+
+    // EGL_ANGLE_external_context_and_surface
+    bool externalContextAndSurface = false;
 };
 
 struct DeviceExtensions

src/libANGLE/Context.cpp

@@ -281,6 +281,17 @@ bool IsColorMaskedOut(const BlendStateExt &blendStateExt, const GLint drawbuffer
     ASSERT(static_cast<size_t>(drawbuffer) < blendStateExt.mMaxDrawBuffers);
     return blendStateExt.getColorMaskIndexed(static_cast<size_t>(drawbuffer)) == 0;
 }
+
+bool GetIsExternal(const egl::AttributeMap &attribs)
+{
+    return (attribs.get(EGL_EXTERNAL_CONTEXT_ANGLE, EGL_FALSE) == EGL_TRUE);
+}
+
+bool GetSaveAndRestoreState(const egl::AttributeMap &attribs)
+{
+    return (attribs.get(EGL_EXTERNAL_CONTEXT_SAVE_STATE_ANGLE, EGL_FALSE) == EGL_TRUE);
+}
+
 }  // anonymous namespace
 
 thread_local Context *gCurrentValidContext = nullptr;
@@ -339,7 +350,10 @@ Context::Context(egl::Display *display,
       mThreadPool(nullptr),
       mFrameCapture(new angle::FrameCapture),
       mRefCount(0),
-      mOverlay(mImplementation.get())
+      mOverlay(mImplementation.get()),
+      mIsExternal(GetIsExternal(attribs)),
+      mSaveAndRestoreState(GetSaveAndRestoreState(attribs)),
+      mIsCurrent(false)
 {
     for (angle::SubjectIndex uboIndex = kUniformBuffer0SubjectIndex;
          uboIndex < kUniformBufferMaxSubjectIndex; ++uboIndex)
@@ -675,6 +689,8 @@ egl::Error Context::makeCurrent(egl::Display *display,
 
     if (!mHasBeenCurrent)
     {
+        ASSERT(!mIsCurrent);
+
         initialize();
         initRendererString();
         initVersionStrings();

src/libANGLE/Context.h

@@ -406,6 +406,10 @@ class Context final : public egl::LabeledObject, angle::NonCopyable, public angl
     bool isVertexArrayGenerated(VertexArrayID vertexArray) const;
     bool isTransformFeedbackGenerated(TransformFeedbackID transformFeedback) const;
 
+    bool isExternal() const { return mIsExternal; }
+    bool saveAndRestoreState() const { return mSaveAndRestoreState; }
+    bool isCurrent() const { return mIsCurrent; }
+
     void getBooleanvImpl(GLenum pname, GLboolean *params) const;
     void getFloatvImpl(GLenum pname, GLfloat *params) const;
     void getIntegervImpl(GLenum pname, GLint *params) const;
@@ -772,7 +776,10 @@ class Context final : public egl::LabeledObject, angle::NonCopyable, public angl
 
     OverlayType mOverlay;
 
-    bool mIsCurrent = false;
+    const bool mIsExternal;
+    const bool mSaveAndRestoreState;
+
+    bool mIsCurrent;
 };
 
 // Thread-local current valid context bound to the thread.

src/libANGLE/ResourceManager.cpp

@@ -381,6 +381,11 @@ void FramebufferManager::setDefaultFramebuffer(Framebuffer *framebuffer)
     mObjectMap.assign(Framebuffer::kDefaultDrawFramebufferHandle, framebuffer);
 }
 
+Framebuffer *FramebufferManager::getDefaultFramebuffer() const
+{
+    return getFramebuffer(Framebuffer::kDefaultDrawFramebufferHandle);
+}
+
 void FramebufferManager::invalidateFramebufferCompletenessCache() const
 {
     for (const auto &framebuffer : mObjectMap)

src/libANGLE/ResourceManager.h

@@ -273,6 +273,7 @@ class FramebufferManager
     FramebufferID createFramebuffer();
     Framebuffer *getFramebuffer(FramebufferID handle) const;
     void setDefaultFramebuffer(Framebuffer *framebuffer);
+    Framebuffer *getDefaultFramebuffer() const;
 
     void invalidateFramebufferCompletenessCache() const;
 

src/libANGLE/State.cpp

@@ -1688,6 +1688,11 @@ Framebuffer *State::getTargetFramebuffer(GLenum target) const
     }
 }
 
+Framebuffer *State::getDefaultFramebuffer() const
+{
+    return mFramebufferManager->getDefaultFramebuffer();
+}
+
 bool State::removeReadFramebufferBinding(FramebufferID framebuffer)
 {
     if (mReadFramebuffer != nullptr && mReadFramebuffer->id() == framebuffer)

src/libANGLE/State.h

@@ -333,6 +333,7 @@ class State : angle::NonCopyable
     Framebuffer *getTargetFramebuffer(GLenum target) const;
     Framebuffer *getReadFramebuffer() const { return mReadFramebuffer; }
     Framebuffer *getDrawFramebuffer() const { return mDrawFramebuffer; }
+    Framebuffer *getDefaultFramebuffer() const;
 
     bool removeReadFramebufferBinding(FramebufferID framebuffer);
     bool removeDrawFramebufferBinding(FramebufferID framebuffer);

src/libANGLE/renderer/gl/FramebufferGL.cpp

@@ -1317,6 +1317,14 @@ GLuint FramebufferGL::getFramebufferID() const
     return mFramebufferID;
 }
 
+void FramebufferGL::updateDefaultFramebufferID(GLuint framebufferID)
+{
+    // We only update framebufferID for a default frambuffer, and the framebufferID is created
+    // externally. ANGLE doesn't owne it.
+    ASSERT(isDefault());
+    mFramebufferID = framebufferID;
+}
+
 bool FramebufferGL::isDefault() const
 {
     return mIsDefault;

src/libANGLE/renderer/gl/FramebufferGL.h

@@ -87,6 +87,7 @@ class FramebufferGL : public FramebufferImpl
                             gl::Command command) override;
 
     GLuint getFramebufferID() const;
+    void updateDefaultFramebufferID(GLuint framebufferID);
     bool isDefault() const;
 
     bool hasEmulatedAlphaChannelTextureAttachment() const;

src/libANGLE/renderer/gl/StateManagerGL.h

@@ -16,6 +16,7 @@
 #include "libANGLE/renderer/gl/functionsgl_typedefs.h"
 #include "platform/FeaturesGL.h"
 
+#include <array>
 #include <map>
 
 namespace gl
@@ -34,6 +35,86 @@ class TransformFeedbackGL;
 class VertexArrayGL;
 class QueryGL;
 
+// TODO(penghuang): use gl::State?
+struct ExternalContextState
+{
+    GLint packAlignment;
+    GLint unpackAlignment;
+
+    GLenum vertexArrayBufferBinding;
+    GLenum elementArrayBufferBinding;
+
+    bool depthTest;
+    bool cullFace;
+    GLenum cullFaceMode;
+    std::array<bool, 4> colorMask;
+    gl::ColorF colorClear;
+    gl::ColorF blendColor;
+    GLfloat depthClear;
+    GLenum currentProgram;
+    GLenum depthFunc;
+    bool depthMask;
+    GLfloat depthRage[2];
+    GLenum frontFace;
+    GLfloat lineWidth;
+    GLfloat polygonOffsetFactor;
+    GLfloat polygonOffsetUnits;
+    GLfloat sampleCoverageValue;
+    bool sampleCoverageInvert;
+    GLenum blendEquationRgb;
+    GLenum blendEquationAlpha;
+
+    bool enableDither;
+    bool enablePolygonOffsetFill;
+    bool enableSampleAlphaToCoverage;
+    bool enableSampleCoverage;
+    bool multisampleEnabled;
+
+    bool blendEnabled;
+    GLenum blendSrcRgb;
+    GLenum blendSrcAlpha;
+    GLenum blendDestRgb;
+    GLenum blendDestAlpha;
+    GLenum activeTexture;
+    gl::Rectangle viewport;
+    bool scissorTest;
+    gl::Rectangle scissorBox;
+
+    struct StencilState
+    {
+        bool stencilTestEnabled;
+        GLenum stencilFrontFunc;
+        GLint stencilFrontRef;
+        GLenum stencilFrontMask;
+        GLenum stencilBackFunc;
+        GLint stencilBackRef;
+        GLenum stencilBackMask;
+        GLint stencilClear;
+        GLenum stencilFrontWritemask;
+        GLenum stencilBackWritemask;
+        GLenum stencilFrontFailOp;
+        GLenum stencilFrontZFailOp;
+        GLenum stencilFrontZPassOp;
+        GLenum stencilBackFailOp;
+        GLenum stencilBackZFailOp;
+        GLenum stencilBackZPassOp;
+    };
+    StencilState stencilState;
+
+    GLenum framebufferBinding;
+
+    struct TextureBindings
+    {
+        GLenum texture2d;
+        GLenum textureCubeMap;
+        GLenum textureExternalOES;
+        // TODO(boliu): TEXTURE_RECTANGLE_ARB
+    };
+    std::vector<TextureBindings> textureBindings;
+
+    GLenum vertexArrayBinding;
+};
+
 class StateManagerGL final : angle::NonCopyable
 {
   public:
@@ -181,6 +262,9 @@ class StateManagerGL final : angle::NonCopyable
 
     void validateState() const;
 
+    void syncFromNativeContext(const gl::Extensions &extensions, ExternalContextState *state);
+    void restoreNativeContext(const gl::Extensions &extensions, const ExternalContextState *state);
+
   private:
     void setTextureCubemapSeamlessEnabled(bool enabled);
 
@@ -195,6 +279,12 @@ class StateManagerGL final : angle::NonCopyable
     void updateDispatchIndirectBufferBinding(const gl::Context *context);
     void updateDrawIndirectBufferBinding(const gl::Context *context);
 
+    template <typename T>
+    void get(GLenum name, T *value);
+
+    template <size_t n, typename T>
+    void get(GLenum name, std::array<T, n> *values);
+
     void syncSamplersState(const gl::Context *context);
     void syncTransformFeedbackState(const gl::Context *context);
 
@@ -202,6 +292,40 @@ class StateManagerGL final : angle::NonCopyable
         const gl::Program *program,
         const gl::FramebufferState &drawFramebufferState) const;
 
+    void syncBlendFromNativeContext(const gl::Extensions &extensions, ExternalContextState *state);
+    void restoreBlendNativeContext(const gl::Extensions &extensions,
+                                   const ExternalContextState *state);
+
+    void syncFramebufferFromNativeContext(const gl::Extensions &extensions,
+                                          ExternalContextState *state);
+    void restoreFramebufferNativeContext(const gl::Extensions &extensions,
+                                         const ExternalContextState *state);
+
+    void syncPixelPackUnpackFromNativeContext(const gl::Extensions &extensions,
+                                              ExternalContextState *state);
+    void restorePixelPackUnpackNativeContext(const gl::Extensions &extensions,
+                                             const ExternalContextState *state);
+
+    void syncStencilFromNativeContext(const gl::Extensions &extensions,
+                                      ExternalContextState *state);
+    void restoreStencilNativeContext(const gl::Extensions &extensions,
+                                     const ExternalContextState *state);
+
+    void syncBufferBindingsFromNativeContext(const gl::Extensions &extensions,
+                                             ExternalContextState *state);
+    void restoreBufferBindingsNativeContext(const gl::Extensions &extensions,
+                                            const ExternalContextState *state);
+
+    void syncTextureUnitsFromNativeContext(const gl::Extensions &extensions,
+                                           ExternalContextState *state);
+    void restoreTextureUnitsNativeContext(const gl::Extensions &extensions,
+                                          const ExternalContextState *state);
+
+    void syncVertexArraysFromNativeContext(const gl::Extensions &extensions,
+                                           ExternalContextState *state);
+    void restoreVertexArraysNativeContext(const gl::Extensions &extensions,
+                                          const ExternalContextState *state);
+
     const FunctionsGL *mFunctions;
     const angle::FeaturesGL &mFeatures;
 
@@ -342,6 +466,7 @@ class StateManagerGL final : angle::NonCopyable
     gl::State::DirtyBits mLocalDirtyBits;
     gl::AttributesMask mLocalDirtyCurrentValues;
 };
+
 }  // namespace rx
 
 #endif  // LIBANGLE_RENDERER_GL_STATEMANAGERGL_H_

src/libANGLE/renderer/gl/egl/ContextEGL.cpp

@@ -6,8 +6,12 @@
 
 #include "libANGLE/renderer/gl/egl/ContextEGL.h"
 
+#include "libANGLE/renderer/gl/FramebufferGL.h"
+#include "libANGLE/renderer/gl/StateManagerGL.h"
+
 namespace rx
 {
+
 ContextEGL::ContextEGL(const gl::State &state,
                        gl::ErrorSet *errorSet,
                        const std::shared_ptr<RendererEGL> &renderer,
@@ -17,8 +21,42 @@ ContextEGL::ContextEGL(const gl::State &state,
 
 ContextEGL::~ContextEGL() {}
 
+angle::Result ContextEGL::onMakeCurrent(const gl::Context *context)
+{
+    if (!context->isCurrent() && context->isExternal())
+    {
+        if (!mExtState)
+        {
+            mExtState        = std::make_unique<ExternalContextState>();
+            const auto &caps = getNativeCaps();
+            mExtState->textureBindings.resize(
+                static_cast<size_t>(caps.maxCombinedTextureImageUnits));
+        }
+        getStateManager()->syncFromNativeContext(getNativeExtensions(), mExtState.get());
+
+        // Use current FBO as the default framebuffer when the external context is current.
+        gl::Framebuffer *framebuffer = mState.getDefaultFramebuffer();
+        GetImplAs<FramebufferGL>(framebuffer)
+            ->updateDefaultFramebufferID(mExtState->framebufferBinding);
+    }
+    return ContextGL::onMakeCurrent(context);
+}
+
+angle::Result ContextEGL::onUnMakeCurrent(const gl::Context *context)
+{
+    if (context->saveAndRestoreState())
+    {
+        ASSERT(context->isExternal());
+        ASSERT(mExtState);
+        getStateManager()->restoreNativeContext(getNativeExtensions(), mExtState.get());
+    }
+
+    return ContextGL::onUnMakeCurrent(context);
+}
+
 EGLContext ContextEGL::getContext() const
 {
     return mRendererEGL->getContext();
 }
+
 }  // namespace rx

src/libANGLE/renderer/gl/egl/ContextEGL.h

@@ -14,6 +14,9 @@
 
 namespace rx
 {
+
+struct ExternalContextState;
+
 class ContextEGL : public ContextGL
 {
   public:
@@ -23,10 +26,14 @@ class ContextEGL : public ContextGL
                RobustnessVideoMemoryPurgeStatus robustnessVideoMemoryPurgeStatus);
     ~ContextEGL() override;
 
+    angle::Result onMakeCurrent(const gl::Context *context) override;
+    angle::Result onUnMakeCurrent(const gl::Context *context) override;
+
     EGLContext getContext() const;
 
   private:
     std::shared_ptr<RendererEGL> mRendererEGL;
+    std::unique_ptr<ExternalContextState> mExtState;
 };
 }  // namespace rx
 

src/libANGLE/renderer/gl/egl/DisplayEGL.cpp

@@ -280,7 +280,7 @@ egl::Error DisplayEGL::initialize(egl::Display *display)
     functionsGL->initialize(mDisplayAttributes);
 
     mRenderer.reset(
-        new RendererEGL(std::move(functionsGL), mDisplayAttributes, this, context, attribs));
+        new RendererEGL(std::move(functionsGL), mDisplayAttributes, this, context, attribs, false));
     const gl::Version &maxVersion = mRenderer->getMaxSupportedESVersion();
     if (maxVersion < gl::Version(2, 0))
     {
@@ -751,7 +751,7 @@ egl::Error DisplayEGL::createRenderer(EGLContext shareContext,
     functionsGL->initialize(mDisplayAttributes);
 
     outRenderer->reset(
-        new RendererEGL(std::move(functionsGL), mDisplayAttributes, this, context, attribs));
+        new RendererEGL(std::move(functionsGL), mDisplayAttributes, this, context, attribs, false));
 
     return egl::NoError();
 }

src/libANGLE/renderer/gl/egl/DisplayEGL.h

@@ -132,6 +132,9 @@ class DisplayEGL : public DisplayGL
     {
         EGLSurface surface = EGL_NO_SURFACE;
         EGLContext context = EGL_NO_CONTEXT;
+        // True if the current context is an external context. and both surface and context will be
+        // unset when an external context is current.
+        bool isExternalContext = false;
     };
     angle::HashMap<std::thread::id, CurrentNativeContext> mCurrentNativeContexts;
 

src/libANGLE/renderer/gl/egl/FunctionsEGL.cpp

@@ -45,6 +45,7 @@ struct FunctionsEGL::EGLDispatchTable
           destroyContextPtr(nullptr),
           destroySurfacePtr(nullptr),
           getConfigAttribPtr(nullptr),
+          getCurrentSurfacePtr(nullptr),
           getDisplayPtr(nullptr),
           getErrorPtr(nullptr),
           initializePtr(nullptr),
@@ -59,6 +60,8 @@ struct FunctionsEGL::EGLDispatchTable
           surfaceAttribPtr(nullptr),
           swapIntervalPtr(nullptr),
 
+          getCurrentContextPtr(nullptr),
+
           createImageKHRPtr(nullptr),
           destroyImageKHRPtr(nullptr),
 
@@ -93,6 +96,7 @@ struct FunctionsEGL::EGLDispatchTable
     PFNEGLDESTROYCONTEXTPROC destroyContextPtr;
     PFNEGLDESTROYSURFACEPROC destroySurfacePtr;
     PFNEGLGETCONFIGATTRIBPROC getConfigAttribPtr;
+    PFNEGLGETCURRENTSURFACEPROC getCurrentSurfacePtr;
     PFNEGLGETDISPLAYPROC getDisplayPtr;
     PFNEGLGETERRORPROC getErrorPtr;
     PFNEGLINITIALIZEPROC initializePtr;
@@ -108,6 +112,9 @@ struct FunctionsEGL::EGLDispatchTable
     PFNEGLSURFACEATTRIBPROC surfaceAttribPtr;
     PFNEGLSWAPINTERVALPROC swapIntervalPtr;
 
+    // 1.4
+    PFNEGLGETCURRENTCONTEXTPROC getCurrentContextPtr;
+
     // EGL_KHR_image
     PFNEGLCREATEIMAGEKHRPROC createImageKHRPtr;
     PFNEGLDESTROYIMAGEKHRPROC destroyImageKHRPtr;
@@ -169,6 +176,7 @@ egl::Error FunctionsEGL::initialize(EGLNativeDisplayType nativeDisplay)
     ANGLE_GET_PROC_OR_ERROR(&mFnPtrs->destroyContextPtr, eglDestroyContext);
     ANGLE_GET_PROC_OR_ERROR(&mFnPtrs->destroySurfacePtr, eglDestroySurface);
     ANGLE_GET_PROC_OR_ERROR(&mFnPtrs->getConfigAttribPtr, eglGetConfigAttrib);
+    ANGLE_GET_PROC_OR_ERROR(&mFnPtrs->getCurrentSurfacePtr, eglGetCurrentSurface);
     ANGLE_GET_PROC_OR_ERROR(&mFnPtrs->getDisplayPtr, eglGetDisplay);
     ANGLE_GET_PROC_OR_ERROR(&mFnPtrs->getErrorPtr, eglGetError);
     ANGLE_GET_PROC_OR_ERROR(&mFnPtrs->initializePtr, eglInitialize);
@@ -201,6 +209,8 @@ egl::Error FunctionsEGL::initialize(EGLNativeDisplayType nativeDisplay)
         return egl::Error(mFnPtrs->getErrorPtr(), "Failed to bind API in system egl");
     }
 
+    ANGLE_GET_PROC_OR_ERROR(&mFnPtrs->getCurrentContextPtr, eglGetCurrentContext);
+
     const char *extensions = queryString(EGL_EXTENSIONS);
     if (!extensions)
     {
@@ -333,6 +343,11 @@ EGLBoolean FunctionsEGL::getConfigAttrib(EGLConfig config, EGLint attribute, EGL
     return mFnPtrs->getConfigAttribPtr(mEGLDisplay, config, attribute, value);
 }
 
+EGLSurface FunctionsEGL::getCurrentSurface(EGLint readdraw) const
+{
+    return mFnPtrs->getCurrentSurfacePtr(readdraw);
+}
+
 EGLContext FunctionsEGL::createContext(EGLConfig config,
                                        EGLContext share_context,
                                        EGLint const *attrib_list) const
@@ -402,6 +417,11 @@ EGLBoolean FunctionsEGL::swapInterval(EGLint interval) const
     return mFnPtrs->swapIntervalPtr(mEGLDisplay, interval);
 }
 
+EGLContext FunctionsEGL::getCurrentContext() const
+{
+    return mFnPtrs->getCurrentContextPtr();
+}
+
 EGLImageKHR FunctionsEGL::createImageKHR(EGLContext context,
                                          EGLenum target,
                                          EGLClientBuffer buffer,

src/libANGLE/renderer/gl/egl/FunctionsEGL.h

@@ -46,6 +46,7 @@ class FunctionsEGL
                             EGLint config_size,
                             EGLint *num_config) const;
     EGLBoolean getConfigAttrib(EGLConfig config, EGLint attribute, EGLint *value) const;
+    EGLSurface getCurrentSurface(EGLint readdraw) const;
     EGLContext createContext(EGLConfig config,
                              EGLContext share_context,
                              EGLint const *attrib_list) const;
@@ -65,6 +66,8 @@ class FunctionsEGL
     EGLBoolean surfaceAttrib(EGLSurface surface, EGLint attribute, EGLint value) const;
     EGLBoolean swapInterval(EGLint interval) const;
 
+    EGLContext getCurrentContext() const;
+
     EGLImageKHR createImageKHR(EGLContext context,
                                EGLenum target,
                                EGLClientBuffer buffer,

src/libANGLE/renderer/gl/egl/RendererEGL.cpp

@@ -15,17 +15,22 @@ RendererEGL::RendererEGL(std::unique_ptr<FunctionsGL> functionsGL,
                          const egl::AttributeMap &attribMap,
                          DisplayEGL *display,
                          EGLContext context,
-                         const native_egl::AttributeVector attribs)
+                         const native_egl::AttributeVector attribs,
+                         bool isExternalContext)
     : RendererGL(std::move(functionsGL), attribMap, display),
       mDisplay(display),
       mContext(context),
-      mAttribs(attribs)
+      mAttribs(attribs),
+      mIsExternalContext(isExternalContext)
 {}
 
 RendererEGL::~RendererEGL()
 {
-    mDisplay->destroyNativeContext(mContext);
-    mContext = nullptr;
+    if (!mIsExternalContext)
+    {
+        mDisplay->destroyNativeContext(mContext);
+        mContext = nullptr;
+    }
 }
 
 EGLContext RendererEGL::getContext() const

src/libANGLE/renderer/gl/egl/RendererEGL.h

@@ -23,7 +23,8 @@ class RendererEGL : public RendererGL
                 const egl::AttributeMap &attribMap,
                 DisplayEGL *display,
                 EGLContext context,
-                const native_egl::AttributeVector attribs);
+                const native_egl::AttributeVector attribs,
+                bool isExternalContext);
     ~RendererEGL() override;
 
     EGLContext getContext() const;
@@ -34,6 +35,7 @@ class RendererEGL : public RendererGL
     DisplayEGL *mDisplay;
     EGLContext mContext;
     const native_egl::AttributeVector mAttribs;
+    const bool mIsExternalContext;
 };
 }  // namespace rx
 

src/libANGLE/renderer/gl/egl/SurfaceEGL.cpp

@@ -237,4 +237,9 @@ egl::Error SurfaceEGL::getFrameTimestamps(EGLuint64KHR frameId,
     return egl::NoError();
 }
 
+bool SurfaceEGL::isExternal() const
+{
+    return false;
+}
+
 }  // namespace rx

src/libANGLE/renderer/gl/egl/SurfaceEGL.h

@@ -58,6 +58,7 @@ class SurfaceEGL : public SurfaceGL
                                   EGLnsecsANDROID *values) const override;
 
     EGLSurface getSurface() const;
+    virtual bool isExternal() const;
 
   protected:
     const FunctionsEGL *mEGL;

src/libANGLE/renderer/gl/egl/android/DisplayAndroid.cpp

@@ -152,7 +152,7 @@ egl::Error DisplayAndroid::initialize(egl::Display *display)
         mConfig           = configWithFormat;
     }
 
-    ANGLE_TRY(createRenderer(EGL_NO_CONTEXT, true, &mRenderer));
+    ANGLE_TRY(createRenderer(EGL_NO_CONTEXT, true, false, &mRenderer));
 
     const gl::Version &maxVersion = mRenderer->getMaxSupportedESVersion();
     if (maxVersion < gl::Version(2, 0))
@@ -205,14 +205,19 @@ ContextImpl *DisplayAndroid::createContext(const gl::State &state,
                                            const egl::AttributeMap &attribs)
 {
     std::shared_ptr<RendererEGL> renderer;
-    if (mVirtualizedContexts)
+    bool usingExternalContext = attribs.get(EGL_EXTERNAL_CONTEXT_ANGLE, EGL_FALSE) == EGL_TRUE;
+    if (mVirtualizedContexts && !usingExternalContext)
     {
         renderer = mRenderer;
     }
     else
     {
         EGLContext nativeShareContext = EGL_NO_CONTEXT;
-        if (shareContext)
+        if (usingExternalContext)
+        {
+            ASSERT(!shareContext);
+        }
+        else if (shareContext)
         {
             ContextEGL *shareContextEGL = GetImplAs<ContextEGL>(shareContext);
             nativeShareContext          = shareContextEGL->getContext();
@@ -221,7 +226,8 @@ ContextImpl *DisplayAndroid::createContext(const gl::State &state,
         // Create a new renderer for this context.  It only needs to share with the user's requested
         // share context because there are no internal resources in DisplayAndroid that are shared
         // at the GL level.
-        egl::Error error = createRenderer(nativeShareContext, false, &renderer);
+        egl::Error error =
+            createRenderer(nativeShareContext, false, usingExternalContext, &renderer);
         if (error.isError())
         {
             ERR() << "Failed to create a shared renderer: " << error.getMessage();
@@ -233,11 +239,67 @@ ContextImpl *DisplayAndroid::createContext(const gl::State &state,
                           RobustnessVideoMemoryPurgeStatus::NOT_REQUESTED);
 }
 
+class ExternalSurfaceEGL : public SurfaceEGL
+{
+  public:
+    ExternalSurfaceEGL(const egl::SurfaceState &state,
+                       const FunctionsEGL *egl,
+                       EGLConfig config,
+                       EGLint width,
+                       EGLint height)
+        : SurfaceEGL(state, egl, config), mWidth(width), mHeight(height)
+    {}
+    ~ExternalSurfaceEGL() override = default;
+
+    egl::Error initialize(const egl::Display *display) override { return egl::NoError(); }
+    EGLint getSwapBehavior() const override { return EGL_BUFFER_DESTROYED; }
+    EGLint getWidth() const override { return mWidth; }
+    EGLint getHeight() const override { return mHeight; }
+    bool isExternal() const override { return true; }
+
+  private:
+    const EGLint mWidth;
+    const EGLint mHeight;
+};
+
+SurfaceImpl *DisplayAndroid::createPbufferFromClientBuffer(const egl::SurfaceState &state,
+                                                           EGLenum buftype,
+                                                           EGLClientBuffer clientBuffer,
+                                                           const egl::AttributeMap &attribs)
+{
+    if (buftype == EGL_EXTERNAL_SURFACE_ANGLE)
+    {
+        ASSERT(clientBuffer == nullptr);
+
+        EGLint width  = static_cast<EGLint>(attribs.get(EGL_WIDTH, 0));
+        EGLint height = static_cast<EGLint>(attribs.get(EGL_HEIGHT, 0));
+
+        // Use the ExternalSurfaceEGL, so ANGLE can know the framebuffer size.
+        return new ExternalSurfaceEGL(state, mEGL, EGL_NO_CONFIG_KHR, width, height);
+    }
+
+    return DisplayEGL::createPbufferFromClientBuffer(state, buftype, clientBuffer, attribs);
+}
+
 bool DisplayAndroid::isValidNativeWindow(EGLNativeWindowType window) const
 {
     return ANativeWindow_getFormat(window) >= 0;
 }
 
+egl::Error DisplayAndroid::validateClientBuffer(const egl::Config *configuration,
+                                                EGLenum buftype,
+                                                EGLClientBuffer clientBuffer,
+                                                const egl::AttributeMap &attribs) const
+{
+
+    if (buftype == EGL_EXTERNAL_SURFACE_ANGLE)
+    {
+        ASSERT(clientBuffer == nullptr);
+        return egl::NoError();
+    }
+    return DisplayEGL::validateClientBuffer(configuration, buftype, clientBuffer, attribs);
+}
+
 egl::Error DisplayAndroid::validateImageClientBuffer(const gl::Context *context,
                                                      EGLenum target,
                                                      EGLClientBuffer clientBuffer,
@@ -290,6 +352,35 @@ egl::Error DisplayAndroid::makeCurrent(egl::Display *display,
         newContext             = contextEGL->getContext();
     }
 
+    if (currentContext.isExternalContext || (context && context->isExternal()))
+    {
+        ASSERT(currentContext.context == EGL_NO_CONTEXT);
+        ASSERT(currentContext.surface == EGL_NO_SURFACE);
+
+        if (!currentContext.isExternalContext)
+        {
+            // Switch to an ANGLE external context.
+            ASSERT(context);
+            currentContext.isExternalContext = true;
+
+            // We only support using external surface with external context.
+            ASSERT(GetImplAs<SurfaceEGL>(drawSurface)->isExternal());
+        }
+        else
+        {
+            //  We don't support switching surfaces for external context.
+            ASSERT(!context);
+            // Release the ANGLE external context.
+            ASSERT(newSurface == EGL_NO_CONTEXT);
+            ASSERT(newContext == EGL_NO_SURFACE);
+            currentContext.isExternalContext = false;
+        }
+
+        // Do not need to call eglMakeCurrent(), since we don't support swtiching EGLSurface for
+        // external context.
+        return DisplayGL::makeCurrent(display, drawSurface, readSurface, context);
+    }
+
     // The context should never change when context virtualization is being used, even when a null
     // context is being bound.
     if (mVirtualizedContexts)
@@ -341,27 +432,46 @@ void DisplayAndroid::generateExtensions(egl::DisplayExtensions *outExtensions) c
     // Surfaceless can be support if the native driver supports it or we know that we are running on
     // a single thread (mVirtualizedContexts == true)
     outExtensions->surfacelessContext = mSupportsSurfaceless || mVirtualizedContexts;
+
+    outExtensions->externalContextAndSurface = true;
 }
 
 egl::Error DisplayAndroid::createRenderer(EGLContext shareContext,
                                           bool makeNewContextCurrent,
+                                          bool isExternalContext,
                                           std::shared_ptr<RendererEGL> *outRenderer)
 {
     EGLContext context = EGL_NO_CONTEXT;
     native_egl::AttributeVector attribs;
-    ANGLE_TRY(initializeContext(shareContext, mDisplayAttributes, &context, &attribs));
 
-    if (mEGL->makeCurrent(mMockPbuffer, context) == EGL_FALSE)
+    // If isExternalContext is true, the external context is current, so we don't need to make the
+    // mMockPbuffer current.
+    if (isExternalContext)
     {
-        return egl::EglNotInitialized()
-               << "eglMakeCurrent failed with " << egl::Error(mEGL->getError());
+        ASSERT(shareContext == EGL_NO_CONTEXT);
+        ASSERT(!makeNewContextCurrent);
+        // Should we consider creating a share context to avoid querying and restoring GL context
+        // state?
+        context = mEGL->getCurrentContext();
+        ASSERT(context != EGL_NO_CONTEXT);
+        // TODO: get the version from the current context.
+        attribs = {EGL_CONTEXT_MAJOR_VERSION, 2, EGL_CONTEXT_MINOR_VERSION, 0, EGL_NONE};
+    }
+    else
+    {
+        ANGLE_TRY(initializeContext(shareContext, mDisplayAttributes, &context, &attribs));
+        if (mEGL->makeCurrent(mMockPbuffer, context) == EGL_FALSE)
+        {
+            return egl::EglNotInitialized()
+                   << "eglMakeCurrent failed with " << egl::Error(mEGL->getError());
+        }
     }
 
     std::unique_ptr<FunctionsGL> functionsGL(mEGL->makeFunctionsGL());
     functionsGL->initialize(mDisplayAttributes);
 
-    outRenderer->reset(
-        new RendererEGL(std::move(functionsGL), mDisplayAttributes, this, context, attribs));
+    outRenderer->reset(new RendererEGL(std::move(functionsGL), mDisplayAttributes, this, context,
+                                       attribs, isExternalContext));
 
     CurrentNativeContext &currentContext = mCurrentNativeContexts[std::this_thread::get_id()];
     if (makeNewContextCurrent)
@@ -369,7 +479,7 @@ egl::Error DisplayAndroid::createRenderer(EGLContext shareContext,
         currentContext.surface = mMockPbuffer;
         currentContext.context = context;
     }
-    else
+    else if (!isExternalContext)
     {
         // Reset the current context back to the previous state
         if (mEGL->makeCurrent(currentContext.surface, currentContext.context) == EGL_FALSE)

src/libANGLE/renderer/gl/egl/android/DisplayAndroid.h

@@ -34,8 +34,15 @@ class DisplayAndroid : public DisplayEGL
                                const egl::Config *configuration,
                                const gl::Context *shareContext,
                                const egl::AttributeMap &attribs) override;
-
+    SurfaceImpl *createPbufferFromClientBuffer(const egl::SurfaceState &state,
+                                               EGLenum buftype,
+                                               EGLClientBuffer clientBuffer,
+                                               const egl::AttributeMap &attribs) override;
     bool isValidNativeWindow(EGLNativeWindowType window) const override;
+    egl::Error validateClientBuffer(const egl::Config *configuration,
+                                    EGLenum buftype,
+                                    EGLClientBuffer clientBuffer,
+                                    const egl::AttributeMap &attribs) const override;
     egl::Error validateImageClientBuffer(const gl::Context *context,
                                          EGLenum target,
                                          EGLClientBuffer clientBuffer,
@@ -62,6 +69,7 @@ class DisplayAndroid : public DisplayEGL
 
     egl::Error createRenderer(EGLContext shareContext,
                               bool makeNewContextCurrent,
+                              bool isExternalContext,
                               std::shared_ptr<RendererEGL> *outRenderer);
 
     bool mVirtualizedContexts;

src/libANGLE/renderer/gl/egl/gbm/DisplayGbm.cpp

@@ -530,7 +530,7 @@ egl::Error DisplayGbm::initialize(egl::Display *display)
     functionsGL->initialize(display->getAttributeMap());
 
     mRenderer.reset(new RendererEGL(std::move(functionsGL), display->getAttributeMap(), this,
-                                    context, attribs));
+                                    context, attribs, false));
     const gl::Version &maxVersion = mRenderer->getMaxSupportedESVersion();
     if (maxVersion < gl::Version(2, 0))
     {

src/libANGLE/validationEGL.cpp

@@ -1948,6 +1948,47 @@ bool ValidateCreateContext(const ValidationContext *val,
                 }
                 break;
 
+            case EGL_EXTERNAL_CONTEXT_ANGLE:
+                if (!display->getExtensions().externalContextAndSurface)
+                {
+                    val->setError(EGL_BAD_ATTRIBUTE,
+                                  "Attribute "
+                                  "EGL_EXTERNAL_CONTEXT_ANGLE requires "
+                                  "EGL_ANGLE_external_context_and_surface.");
+                    return false;
+                }
+                if (value != EGL_TRUE && value != EGL_FALSE)
+                {
+                    val->setError(EGL_BAD_ATTRIBUTE,
+                                  "EGL_EXTERNAL_CONTEXT_ANGLE must "
+                                  "be either EGL_TRUE or EGL_FALSE.");
+                    return false;
+                }
+                if (value == EGL_TRUE && shareContext)
+                {
+                    val->setError(
+                        EGL_BAD_ATTRIBUTE,
+                        "EGL_EXTERNAL_CONTEXT_ANGLE doesn't allow creating with sharedContext.");
+                    return false;
+                }
+                break;
+            case EGL_EXTERNAL_CONTEXT_SAVE_STATE_ANGLE:
+                if (!display->getExtensions().externalContextAndSurface)
+                {
+                    val->setError(EGL_BAD_ATTRIBUTE,
+                                  "Attribute "
+                                  "EGL_EXTERNAL_CONTEXT_SAVE_STATE_ANGLE requires "
+                                  "EGL_ANGLE_external_context_and_surface.");
+                    return false;
+                }
+                if (value != EGL_TRUE && value != EGL_FALSE)
+                {
+                    val->setError(EGL_BAD_ATTRIBUTE,
+                                  "EGL_EXTERNAL_CONTEXT_SAVE_STATE_ANGLE must "
+                                  "be either EGL_TRUE or EGL_FALSE.");
+                    return false;
+                }
+                break;
             default:
                 val->setError(EGL_BAD_ATTRIBUTE, "Unknown attribute.");
                 return false;
@@ -2380,6 +2421,21 @@ bool ValidateCreatePbufferFromClientBuffer(const ValidationContext *val,
                 return false;
             }
             break;
+        case EGL_EXTERNAL_SURFACE_ANGLE:
+            if (!display->getExtensions().externalContextAndSurface)
+            {
+                val->setError(EGL_BAD_ATTRIBUTE,
+                              "Attribute "
+                              "EGL_EXTERNAL_SURFACE_ANGLE requires "
+                              "EGL_ANGLE_external_context_and_surface.");
+                return false;
+            }
+            if (buffer != nullptr)
+            {
+                val->setError(EGL_BAD_PARAMETER, "<buffer> must be null");
+                return false;
+            }
+            break;
 
         default:
             val->setError(EGL_BAD_PARAMETER);
@@ -2397,10 +2453,11 @@ bool ValidateCreatePbufferFromClientBuffer(const ValidationContext *val,
             case EGL_WIDTH:
             case EGL_HEIGHT:
                 if (buftype != EGL_D3D_TEXTURE_2D_SHARE_HANDLE_ANGLE &&
-                    buftype != EGL_D3D_TEXTURE_ANGLE && buftype != EGL_IOSURFACE_ANGLE)
+                    buftype != EGL_D3D_TEXTURE_ANGLE && buftype != EGL_IOSURFACE_ANGLE &&
+                    buftype != EGL_EXTERNAL_SURFACE_ANGLE)
                 {
                     val->setError(EGL_BAD_PARAMETER,
-                                  "Width and Height are not supported for thie <buftype>");
+                                  "Width and Height are not supported for this <buftype>");
                     return false;
                 }
                 if (value < 0)