libs/hwui/renderthread/CanvasContext.cpp - platform/frameworks/base - Gitiles

 /*
  * Copyright (C) 2014 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #define LOG_TAG "CanvasContext"

 #include "CanvasContext.h"

 #include <cutils/properties.h>
 #include <private/hwui/DrawGlInfo.h>
 #include <strings.h>

 #include "RenderThread.h"
 #include "../Caches.h"
 #include "../DeferredLayerUpdater.h"
 #include "../LayerRenderer.h"
 #include "../OpenGLRenderer.h"
 #include "../Stencil.h"

 #define PROPERTY_RENDER_DIRTY_REGIONS "debug.hwui.render_dirty_regions"
 #define GLES_VERSION 2

 #ifdef USE_OPENGL_RENDERER
 // Android-specific addition that is used to show when frames began in systrace
 EGLAPI void EGLAPIENTRY eglBeginFrame(EGLDisplay dpy, EGLSurface surface);
 #endif

 namespace android {
 namespace uirenderer {
 namespace renderthread {

 #define ERROR_CASE(x) case x: return #x;
 static const char* egl_error_str(EGLint error) {
     switch (error) {
         ERROR_CASE(EGL_SUCCESS)
         ERROR_CASE(EGL_NOT_INITIALIZED)
         ERROR_CASE(EGL_BAD_ACCESS)
         ERROR_CASE(EGL_BAD_ALLOC)
         ERROR_CASE(EGL_BAD_ATTRIBUTE)
         ERROR_CASE(EGL_BAD_CONFIG)
         ERROR_CASE(EGL_BAD_CONTEXT)
         ERROR_CASE(EGL_BAD_CURRENT_SURFACE)
         ERROR_CASE(EGL_BAD_DISPLAY)
         ERROR_CASE(EGL_BAD_MATCH)
         ERROR_CASE(EGL_BAD_NATIVE_PIXMAP)
         ERROR_CASE(EGL_BAD_NATIVE_WINDOW)
         ERROR_CASE(EGL_BAD_PARAMETER)
         ERROR_CASE(EGL_BAD_SURFACE)
         ERROR_CASE(EGL_CONTEXT_LOST)
     default:
         return "Unknown error";
     }
 }
 static const char* egl_error_str() {
     return egl_error_str(eglGetError());
 }

 static bool load_dirty_regions_property() {
     char buf[PROPERTY_VALUE_MAX];
     int len = property_get(PROPERTY_RENDER_DIRTY_REGIONS, buf, "true");
     return !strncasecmp("true", buf, len);
 }

 // This class contains the shared global EGL objects, such as EGLDisplay
 // and EGLConfig, which are re-used by CanvasContext
 class GlobalContext {
 public:
     static GlobalContext* get();

     // Returns true on success, false on failure
     void initialize();

     bool hasContext();

     void usePBufferSurface();
     EGLSurface createSurface(EGLNativeWindowType window);
     void destroySurface(EGLSurface surface);

     void destroy();

     bool isCurrent(EGLSurface surface) { return mCurrentSurface == surface; }
     void makeCurrent(EGLSurface surface);
     void beginFrame(EGLSurface surface, EGLint* width, EGLint* height);
     void swapBuffers(EGLSurface surface);

     bool enableDirtyRegions(EGLSurface surface);

 private:
     GlobalContext();
     // GlobalContext is never destroyed, method is purposely not implemented
     ~GlobalContext();

     void loadConfig();
     void createContext();
     void initAtlas();

     static GlobalContext* sContext;

     EGLDisplay mEglDisplay;
     EGLConfig mEglConfig;
     EGLContext mEglContext;
     EGLSurface mPBufferSurface;

     const bool mRequestDirtyRegions;
     bool mCanSetDirtyRegions;

     EGLSurface mCurrentSurface;
 };

 GlobalContext* GlobalContext::sContext = 0;

 GlobalContext* GlobalContext::get() {
     if (!sContext) {
         sContext = new GlobalContext();
     }
     return sContext;
 }

 GlobalContext::GlobalContext()
         : mEglDisplay(EGL_NO_DISPLAY)
         , mEglConfig(0)
         , mEglContext(EGL_NO_CONTEXT)
         , mPBufferSurface(EGL_NO_SURFACE)
         , mRequestDirtyRegions(load_dirty_regions_property())
         , mCurrentSurface(EGL_NO_SURFACE) {
     mCanSetDirtyRegions = mRequestDirtyRegions;
     ALOGD("Render dirty regions requested: %s", mRequestDirtyRegions ? "true" : "false");
 }

 void GlobalContext::initialize() {
     if (hasContext()) return;

     mEglDisplay = eglGetDisplay(EGL_DEFAULT_DISPLAY);
     LOG_ALWAYS_FATAL_IF(mEglDisplay == EGL_NO_DISPLAY,
             "Failed to get EGL_DEFAULT_DISPLAY! err=%s", egl_error_str());

     EGLint major, minor;
     LOG_ALWAYS_FATAL_IF(eglInitialize(mEglDisplay, &major, &minor) == EGL_FALSE,
             "Failed to initialize display %p! err=%s", mEglDisplay, egl_error_str());

     ALOGI("Initialized EGL, version %d.%d", (int)major, (int)minor);

     loadConfig();
     createContext();
     usePBufferSurface();
     Caches::getInstance().init();
     initAtlas();
 }

 bool GlobalContext::hasContext() {
     return mEglDisplay != EGL_NO_DISPLAY;
 }

 void GlobalContext::loadConfig() {
     EGLint swapBehavior = mCanSetDirtyRegions ? EGL_SWAP_BEHAVIOR_PRESERVED_BIT : 0;
     EGLint attribs[] = {
             EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
             EGL_RED_SIZE, 8,
             EGL_GREEN_SIZE, 8,
             EGL_BLUE_SIZE, 8,
             EGL_ALPHA_SIZE, 8,
             EGL_DEPTH_SIZE, 0,
             EGL_CONFIG_CAVEAT, EGL_NONE,
             EGL_STENCIL_SIZE, Stencil::getStencilSize(),
             EGL_SURFACE_TYPE, EGL_WINDOW_BIT | swapBehavior,
             EGL_NONE
     };

     EGLint num_configs = 1;
     if (!eglChooseConfig(mEglDisplay, attribs, &mEglConfig, num_configs, &num_configs)
             || num_configs != 1) {
         // Failed to get a valid config
         if (mCanSetDirtyRegions) {
             ALOGW("Failed to choose config with EGL_SWAP_BEHAVIOR_PRESERVED, retrying without...");
             // Try again without dirty regions enabled
             mCanSetDirtyRegions = false;
             loadConfig();
         } else {
             LOG_ALWAYS_FATAL("Failed to choose config, error = %s", egl_error_str());
         }
     }
 }

 void GlobalContext::createContext() {
     EGLint attribs[] = { EGL_CONTEXT_CLIENT_VERSION, GLES_VERSION, EGL_NONE };
     mEglContext = eglCreateContext(mEglDisplay, mEglConfig, EGL_NO_CONTEXT, attribs);
     LOG_ALWAYS_FATAL_IF(mEglContext == EGL_NO_CONTEXT,
         "Failed to create context, error = %s", egl_error_str());
 }

 void GlobalContext::initAtlas() {
     // TODO implement
     // For now just run without an atlas
 }

 void GlobalContext::usePBufferSurface() {
     LOG_ALWAYS_FATAL_IF(mEglDisplay == EGL_NO_DISPLAY,
             "usePBufferSurface() called on uninitialized GlobalContext!");

     if (mPBufferSurface == EGL_NO_SURFACE) {
         EGLint attribs[] = { EGL_WIDTH, 1, EGL_HEIGHT, 1, EGL_NONE };
         mPBufferSurface = eglCreatePbufferSurface(mEglDisplay, mEglConfig, attribs);
     }
     makeCurrent(mPBufferSurface);
 }

 EGLSurface GlobalContext::createSurface(EGLNativeWindowType window) {
     initialize();
     return eglCreateWindowSurface(mEglDisplay, mEglConfig, window, NULL);
 }

 void GlobalContext::destroySurface(EGLSurface surface) {
     if (isCurrent(surface)) {
         makeCurrent(EGL_NO_SURFACE);
     }
     if (!eglDestroySurface(mEglDisplay, surface)) {
         ALOGW("Failed to destroy surface %p, error=%s", (void*)surface, egl_error_str());
     }
 }

 void GlobalContext::destroy() {
     if (mEglDisplay == EGL_NO_DISPLAY) return;

     usePBufferSurface();
     if (Caches::hasInstance()) {
         Caches::getInstance().terminate();
     }

     eglDestroyContext(mEglDisplay, mEglContext);
     eglDestroySurface(mEglDisplay, mPBufferSurface);
     eglMakeCurrent(mEglDisplay, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
     eglTerminate(mEglDisplay);
     eglReleaseThread();

     mEglDisplay = EGL_NO_DISPLAY;
     mEglContext = EGL_NO_CONTEXT;
     mPBufferSurface = EGL_NO_SURFACE;
     mCurrentSurface = EGL_NO_SURFACE;
 }

 void GlobalContext::makeCurrent(EGLSurface surface) {
     if (isCurrent(surface)) return;

     if (surface == EGL_NO_SURFACE) {
         // If we are setting EGL_NO_SURFACE we don't care about any of the potential
         // return errors, which would only happen if mEglDisplay had already been
         // destroyed in which case the current context is already NO_CONTEXT
         eglMakeCurrent(mEglDisplay, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
     } else if (!eglMakeCurrent(mEglDisplay, surface, surface, mEglContext)) {
         LOG_ALWAYS_FATAL("Failed to make current on surface %p, error=%s",
                 (void*)surface, egl_error_str());
     }
     mCurrentSurface = surface;
 }

 void GlobalContext::beginFrame(EGLSurface surface, EGLint* width, EGLint* height) {
     LOG_ALWAYS_FATAL_IF(surface == EGL_NO_SURFACE,
             "Tried to beginFrame on EGL_NO_SURFACE!");
     makeCurrent(surface);
     if (width) {
         eglQuerySurface(mEglDisplay, surface, EGL_WIDTH, width);
     }
     if (height) {
         eglQuerySurface(mEglDisplay, surface, EGL_HEIGHT, height);
     }
     eglBeginFrame(mEglDisplay, surface);
 }

 void GlobalContext::swapBuffers(EGLSurface surface) {
     eglSwapBuffers(mEglDisplay, surface);
     EGLint err = eglGetError();
     // TODO: Check whether we need to special case EGL_CONTEXT_LOST
     LOG_ALWAYS_FATAL_IF(err != EGL_SUCCESS,
             "Encountered EGL error %d %s during rendering", err, egl_error_str(err));
 }

 bool GlobalContext::enableDirtyRegions(EGLSurface surface) {
     if (!mRequestDirtyRegions) return false;

     if (mCanSetDirtyRegions) {
         if (!eglSurfaceAttrib(mEglDisplay, surface, EGL_SWAP_BEHAVIOR, EGL_BUFFER_PRESERVED)) {
             ALOGW("Failed to set EGL_SWAP_BEHAVIOR on surface %p, error=%s",
                     (void*) surface, egl_error_str());
             return false;
         }
         return true;
     }
     // Perhaps it is already enabled?
     EGLint value;
     if (!eglQuerySurface(mEglDisplay, surface, EGL_SWAP_BEHAVIOR, &value)) {
         ALOGW("Failed to query EGL_SWAP_BEHAVIOR on surface %p, error=%p",
                 (void*) surface, egl_error_str());
         return false;
     }
     return value == EGL_BUFFER_PRESERVED;
 }

 CanvasContext::CanvasContext(bool translucent)
         : mRenderThread(RenderThread::getInstance())
         , mEglSurface(EGL_NO_SURFACE)
         , mDirtyRegionsEnabled(false)
         , mOpaque(!translucent)
         , mCanvas(0)
         , mHaveNewSurface(false) {
     mGlobalContext = GlobalContext::get();
 }

 CanvasContext::~CanvasContext() {
     destroyCanvasAndSurface();
 }

 void CanvasContext::destroyCanvasAndSurface() {
     if (mCanvas) {
         delete mCanvas;
         mCanvas = 0;
     }
     setSurface(NULL);
 }

 void CanvasContext::setSurface(EGLNativeWindowType window) {
     if (mEglSurface != EGL_NO_SURFACE) {
         mGlobalContext->destroySurface(mEglSurface);
         mEglSurface = EGL_NO_SURFACE;
     }

     if (window) {
         mEglSurface = mGlobalContext->createSurface(window);
         LOG_ALWAYS_FATAL_IF(mEglSurface == EGL_NO_SURFACE,
                 "Failed to create EGLSurface for window %p, eglErr = %s",
                 (void*) window, egl_error_str());
     }

     if (mEglSurface != EGL_NO_SURFACE) {
         mDirtyRegionsEnabled = mGlobalContext->enableDirtyRegions(mEglSurface);
         mGlobalContext->makeCurrent(mEglSurface);
         mHaveNewSurface = true;
     }
 }

 void CanvasContext::swapBuffers() {
     mGlobalContext->swapBuffers(mEglSurface);
     mHaveNewSurface = false;
 }

 void CanvasContext::requireSurface() {
     LOG_ALWAYS_FATAL_IF(mEglSurface == EGL_NO_SURFACE,
             "requireSurface() called but no surface set!");
     mGlobalContext->makeCurrent(mEglSurface);
 }

 bool CanvasContext::initialize(EGLNativeWindowType window) {
     if (mCanvas) return false;
     setSurface(window);
     mCanvas = new OpenGLRenderer();
     mCanvas->initProperties();
     return true;
 }

 void CanvasContext::updateSurface(EGLNativeWindowType window) {
     setSurface(window);
 }

 void CanvasContext::pauseSurface(EGLNativeWindowType window) {
     // TODO: For now we just need a fence, in the future suspend any animations
     // and such to prevent from trying to render into this surface
 }

 void CanvasContext::setup(int width, int height) {
     if (!mCanvas) return;
     mCanvas->setViewport(width, height);
 }

 void CanvasContext::makeCurrent() {
     mGlobalContext->makeCurrent(mEglSurface);
 }

 void CanvasContext::processLayerUpdates(const Vector<DeferredLayerUpdater*>* layerUpdaters,
         TreeInfo& info) {
     LOG_ALWAYS_FATAL_IF(!mCanvas, "Cannot process layer updates without a canvas!");
     makeCurrent();
     for (size_t i = 0; i < layerUpdaters->size(); i++) {
         DeferredLayerUpdater* update = layerUpdaters->itemAt(i);
         bool success = update->apply(info);
         LOG_ALWAYS_FATAL_IF(!success, "Failed to update layer!");
         if (update->backingLayer()->deferredUpdateScheduled) {
             mCanvas->pushLayerUpdate(update->backingLayer());
         }
     }
 }

 void CanvasContext::drawDisplayList(RenderNode* displayList, Rect* dirty) {
     LOG_ALWAYS_FATAL_IF(!mCanvas || mEglSurface == EGL_NO_SURFACE,
             "drawDisplayList called on a context with no canvas or surface!");

     EGLint width, height;
     mGlobalContext->beginFrame(mEglSurface, &width, &height);
     if (width != mCanvas->getViewportWidth() || height != mCanvas->getViewportHeight()) {
         mCanvas->setViewport(width, height);
         dirty = NULL;
     } else if (!mDirtyRegionsEnabled || mHaveNewSurface) {
         dirty = NULL;
     }

     status_t status;
     if (dirty) {
         status = mCanvas->prepareDirty(dirty->left, dirty->top,
                 dirty->right, dirty->bottom, mOpaque);
     } else {
         status = mCanvas->prepare(mOpaque);
     }

     Rect outBounds;
     status |= mCanvas->drawDisplayList(displayList, outBounds);

     // TODO: Draw debug info
     // TODO: Performance tracking

     mCanvas->finish();

     if (status & DrawGlInfo::kStatusDrew) {
         swapBuffers();
     }
 }

 void CanvasContext::invokeFunctor(Functor* functor) {
     ATRACE_CALL();
     DrawGlInfo::Mode mode = DrawGlInfo::kModeProcessNoContext;
     if (mGlobalContext->hasContext()) {
         requireGlContext();
         mode = DrawGlInfo::kModeProcess;
     }
     // TODO: Remove the dummy info in the future
     DrawGlInfo dummyInfo;
     memset(&dummyInfo, 0, sizeof(DrawGlInfo));
     (*functor)(mode, &dummyInfo);
 }

 bool CanvasContext::copyLayerInto(DeferredLayerUpdater* layer, SkBitmap* bitmap) {
     requireGlContext();
     TreeInfo info;
     layer->apply(info);
     return LayerRenderer::copyLayer(layer->backingLayer(), bitmap);
 }

 void CanvasContext::runWithGlContext(RenderTask* task) {
     requireGlContext();
     task->run();
 }

 Layer* CanvasContext::createRenderLayer(int width, int height) {
     requireSurface();
     return LayerRenderer::createRenderLayer(width, height);
 }

 Layer* CanvasContext::createTextureLayer() {
     requireSurface();
     return LayerRenderer::createTextureLayer();
 }

 void CanvasContext::requireGlContext() {
     if (mEglSurface != EGL_NO_SURFACE) {
         mGlobalContext->makeCurrent(mEglSurface);
     } else {
         mGlobalContext->usePBufferSurface();
     }
 }

 } /* namespace renderthread */
 } /* namespace uirenderer */
 } /* namespace android */
	/*
	* Copyright (C) 2014 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#define LOG_TAG "CanvasContext"

	#include "CanvasContext.h"

	#include <cutils/properties.h>
	#include <private/hwui/DrawGlInfo.h>
	#include <strings.h>

	#include "RenderThread.h"
	#include "../Caches.h"
	#include "../DeferredLayerUpdater.h"
	#include "../LayerRenderer.h"
	#include "../OpenGLRenderer.h"
	#include "../Stencil.h"

	#define PROPERTY_RENDER_DIRTY_REGIONS "debug.hwui.render_dirty_regions"
	#define GLES_VERSION 2

	#ifdef USE_OPENGL_RENDERER
	// Android-specific addition that is used to show when frames began in systrace
	EGLAPI void EGLAPIENTRY eglBeginFrame(EGLDisplay dpy, EGLSurface surface);
	#endif

	namespace android {
	namespace uirenderer {
	namespace renderthread {

	#define ERROR_CASE(x) case x: return #x;
	static const char* egl_error_str(EGLint error) {
	switch (error) {
	ERROR_CASE(EGL_SUCCESS)
	ERROR_CASE(EGL_NOT_INITIALIZED)
	ERROR_CASE(EGL_BAD_ACCESS)
	ERROR_CASE(EGL_BAD_ALLOC)
	ERROR_CASE(EGL_BAD_ATTRIBUTE)
	ERROR_CASE(EGL_BAD_CONFIG)
	ERROR_CASE(EGL_BAD_CONTEXT)
	ERROR_CASE(EGL_BAD_CURRENT_SURFACE)
	ERROR_CASE(EGL_BAD_DISPLAY)
	ERROR_CASE(EGL_BAD_MATCH)
	ERROR_CASE(EGL_BAD_NATIVE_PIXMAP)
	ERROR_CASE(EGL_BAD_NATIVE_WINDOW)
	ERROR_CASE(EGL_BAD_PARAMETER)
	ERROR_CASE(EGL_BAD_SURFACE)
	ERROR_CASE(EGL_CONTEXT_LOST)
	default:
	return "Unknown error";
	}
	}
	static const char* egl_error_str() {
	return egl_error_str(eglGetError());
	}

	static bool load_dirty_regions_property() {
	char buf[PROPERTY_VALUE_MAX];
	int len = property_get(PROPERTY_RENDER_DIRTY_REGIONS, buf, "true");
	return !strncasecmp("true", buf, len);
	}

	// This class contains the shared global EGL objects, such as EGLDisplay
	// and EGLConfig, which are re-used by CanvasContext
	class GlobalContext {
	public:
	static GlobalContext* get();

	// Returns true on success, false on failure
	void initialize();

	bool hasContext();

	void usePBufferSurface();
	EGLSurface createSurface(EGLNativeWindowType window);
	void destroySurface(EGLSurface surface);

	void destroy();

	bool isCurrent(EGLSurface surface) { return mCurrentSurface == surface; }
	void makeCurrent(EGLSurface surface);
	void beginFrame(EGLSurface surface, EGLint* width, EGLint* height);
	void swapBuffers(EGLSurface surface);

	bool enableDirtyRegions(EGLSurface surface);

	private:
	GlobalContext();
	// GlobalContext is never destroyed, method is purposely not implemented
	~GlobalContext();

	void loadConfig();
	void createContext();
	void initAtlas();

	static GlobalContext* sContext;

	EGLDisplay mEglDisplay;
	EGLConfig mEglConfig;
	EGLContext mEglContext;
	EGLSurface mPBufferSurface;

	const bool mRequestDirtyRegions;
	bool mCanSetDirtyRegions;

	EGLSurface mCurrentSurface;
	};

	GlobalContext* GlobalContext::sContext = 0;

	GlobalContext* GlobalContext::get() {
	if (!sContext) {
	sContext = new GlobalContext();
	}
	return sContext;
	}

	GlobalContext::GlobalContext()
	: mEglDisplay(EGL_NO_DISPLAY)
	, mEglConfig(0)
	, mEglContext(EGL_NO_CONTEXT)
	, mPBufferSurface(EGL_NO_SURFACE)
	, mRequestDirtyRegions(load_dirty_regions_property())
	, mCurrentSurface(EGL_NO_SURFACE) {
	mCanSetDirtyRegions = mRequestDirtyRegions;
	ALOGD("Render dirty regions requested: %s", mRequestDirtyRegions ? "true" : "false");
	}

	void GlobalContext::initialize() {
	if (hasContext()) return;

	mEglDisplay = eglGetDisplay(EGL_DEFAULT_DISPLAY);
	LOG_ALWAYS_FATAL_IF(mEglDisplay == EGL_NO_DISPLAY,
	"Failed to get EGL_DEFAULT_DISPLAY! err=%s", egl_error_str());

	EGLint major, minor;
	LOG_ALWAYS_FATAL_IF(eglInitialize(mEglDisplay, &major, &minor) == EGL_FALSE,
	"Failed to initialize display %p! err=%s", mEglDisplay, egl_error_str());

	ALOGI("Initialized EGL, version %d.%d", (int)major, (int)minor);

	loadConfig();
	createContext();
	usePBufferSurface();
	Caches::getInstance().init();
	initAtlas();
	}

	bool GlobalContext::hasContext() {
	return mEglDisplay != EGL_NO_DISPLAY;
	}

	void GlobalContext::loadConfig() {
	EGLint swapBehavior = mCanSetDirtyRegions ? EGL_SWAP_BEHAVIOR_PRESERVED_BIT : 0;
	EGLint attribs[] = {
	EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
	EGL_RED_SIZE, 8,
	EGL_GREEN_SIZE, 8,
	EGL_BLUE_SIZE, 8,
	EGL_ALPHA_SIZE, 8,
	EGL_DEPTH_SIZE, 0,
	EGL_CONFIG_CAVEAT, EGL_NONE,
	EGL_STENCIL_SIZE, Stencil::getStencilSize(),
	EGL_SURFACE_TYPE, EGL_WINDOW_BIT \| swapBehavior,
	EGL_NONE
	};

	EGLint num_configs = 1;
	if (!eglChooseConfig(mEglDisplay, attribs, &mEglConfig, num_configs, &num_configs)
	\|\| num_configs != 1) {
	// Failed to get a valid config
	if (mCanSetDirtyRegions) {
	ALOGW("Failed to choose config with EGL_SWAP_BEHAVIOR_PRESERVED, retrying without...");
	// Try again without dirty regions enabled
	mCanSetDirtyRegions = false;
	loadConfig();
	} else {
	LOG_ALWAYS_FATAL("Failed to choose config, error = %s", egl_error_str());
	}
	}
	}

	void GlobalContext::createContext() {
	EGLint attribs[] = { EGL_CONTEXT_CLIENT_VERSION, GLES_VERSION, EGL_NONE };
	mEglContext = eglCreateContext(mEglDisplay, mEglConfig, EGL_NO_CONTEXT, attribs);
	LOG_ALWAYS_FATAL_IF(mEglContext == EGL_NO_CONTEXT,
	"Failed to create context, error = %s", egl_error_str());
	}

	void GlobalContext::initAtlas() {
	// TODO implement
	// For now just run without an atlas
	}

	void GlobalContext::usePBufferSurface() {
	LOG_ALWAYS_FATAL_IF(mEglDisplay == EGL_NO_DISPLAY,
	"usePBufferSurface() called on uninitialized GlobalContext!");

	if (mPBufferSurface == EGL_NO_SURFACE) {
	EGLint attribs[] = { EGL_WIDTH, 1, EGL_HEIGHT, 1, EGL_NONE };
	mPBufferSurface = eglCreatePbufferSurface(mEglDisplay, mEglConfig, attribs);
	}
	makeCurrent(mPBufferSurface);
	}

	EGLSurface GlobalContext::createSurface(EGLNativeWindowType window) {
	initialize();
	return eglCreateWindowSurface(mEglDisplay, mEglConfig, window, NULL);
	}

	void GlobalContext::destroySurface(EGLSurface surface) {
	if (isCurrent(surface)) {
	makeCurrent(EGL_NO_SURFACE);
	}
	if (!eglDestroySurface(mEglDisplay, surface)) {
	ALOGW("Failed to destroy surface %p, error=%s", (void*)surface, egl_error_str());
	}
	}

	void GlobalContext::destroy() {
	if (mEglDisplay == EGL_NO_DISPLAY) return;

	usePBufferSurface();
	if (Caches::hasInstance()) {
	Caches::getInstance().terminate();
	}

	eglDestroyContext(mEglDisplay, mEglContext);
	eglDestroySurface(mEglDisplay, mPBufferSurface);
	eglMakeCurrent(mEglDisplay, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
	eglTerminate(mEglDisplay);
	eglReleaseThread();

	mEglDisplay = EGL_NO_DISPLAY;
	mEglContext = EGL_NO_CONTEXT;
	mPBufferSurface = EGL_NO_SURFACE;
	mCurrentSurface = EGL_NO_SURFACE;
	}

	void GlobalContext::makeCurrent(EGLSurface surface) {
	if (isCurrent(surface)) return;

	if (surface == EGL_NO_SURFACE) {
	// If we are setting EGL_NO_SURFACE we don't care about any of the potential
	// return errors, which would only happen if mEglDisplay had already been
	// destroyed in which case the current context is already NO_CONTEXT
	eglMakeCurrent(mEglDisplay, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
	} else if (!eglMakeCurrent(mEglDisplay, surface, surface, mEglContext)) {
	LOG_ALWAYS_FATAL("Failed to make current on surface %p, error=%s",
	(void*)surface, egl_error_str());
	}
	mCurrentSurface = surface;
	}

	void GlobalContext::beginFrame(EGLSurface surface, EGLint* width, EGLint* height) {
	LOG_ALWAYS_FATAL_IF(surface == EGL_NO_SURFACE,
	"Tried to beginFrame on EGL_NO_SURFACE!");
	makeCurrent(surface);
	if (width) {
	eglQuerySurface(mEglDisplay, surface, EGL_WIDTH, width);
	}
	if (height) {
	eglQuerySurface(mEglDisplay, surface, EGL_HEIGHT, height);
	}
	eglBeginFrame(mEglDisplay, surface);
	}

	void GlobalContext::swapBuffers(EGLSurface surface) {
	eglSwapBuffers(mEglDisplay, surface);
	EGLint err = eglGetError();
	// TODO: Check whether we need to special case EGL_CONTEXT_LOST
	LOG_ALWAYS_FATAL_IF(err != EGL_SUCCESS,
	"Encountered EGL error %d %s during rendering", err, egl_error_str(err));
	}

	bool GlobalContext::enableDirtyRegions(EGLSurface surface) {
	if (!mRequestDirtyRegions) return false;

	if (mCanSetDirtyRegions) {
	if (!eglSurfaceAttrib(mEglDisplay, surface, EGL_SWAP_BEHAVIOR, EGL_BUFFER_PRESERVED)) {
	ALOGW("Failed to set EGL_SWAP_BEHAVIOR on surface %p, error=%s",
	(void*) surface, egl_error_str());
	return false;
	}
	return true;
	}
	// Perhaps it is already enabled?
	EGLint value;
	if (!eglQuerySurface(mEglDisplay, surface, EGL_SWAP_BEHAVIOR, &value)) {
	ALOGW("Failed to query EGL_SWAP_BEHAVIOR on surface %p, error=%p",
	(void*) surface, egl_error_str());
	return false;
	}
	return value == EGL_BUFFER_PRESERVED;
	}

	CanvasContext::CanvasContext(bool translucent)
	: mRenderThread(RenderThread::getInstance())
	, mEglSurface(EGL_NO_SURFACE)
	, mDirtyRegionsEnabled(false)
	, mOpaque(!translucent)
	, mCanvas(0)
	, mHaveNewSurface(false) {
	mGlobalContext = GlobalContext::get();
	}

	CanvasContext::~CanvasContext() {
	destroyCanvasAndSurface();
	}

	void CanvasContext::destroyCanvasAndSurface() {
	if (mCanvas) {
	delete mCanvas;
	mCanvas = 0;
	}
	setSurface(NULL);
	}

	void CanvasContext::setSurface(EGLNativeWindowType window) {
	if (mEglSurface != EGL_NO_SURFACE) {
	mGlobalContext->destroySurface(mEglSurface);
	mEglSurface = EGL_NO_SURFACE;
	}

	if (window) {
	mEglSurface = mGlobalContext->createSurface(window);
	LOG_ALWAYS_FATAL_IF(mEglSurface == EGL_NO_SURFACE,
	"Failed to create EGLSurface for window %p, eglErr = %s",
	(void*) window, egl_error_str());
	}

	if (mEglSurface != EGL_NO_SURFACE) {
	mDirtyRegionsEnabled = mGlobalContext->enableDirtyRegions(mEglSurface);
	mGlobalContext->makeCurrent(mEglSurface);
	mHaveNewSurface = true;
	}
	}

	void CanvasContext::swapBuffers() {
	mGlobalContext->swapBuffers(mEglSurface);
	mHaveNewSurface = false;
	}

	void CanvasContext::requireSurface() {
	LOG_ALWAYS_FATAL_IF(mEglSurface == EGL_NO_SURFACE,
	"requireSurface() called but no surface set!");
	mGlobalContext->makeCurrent(mEglSurface);
	}

	bool CanvasContext::initialize(EGLNativeWindowType window) {
	if (mCanvas) return false;
	setSurface(window);
	mCanvas = new OpenGLRenderer();
	mCanvas->initProperties();
	return true;
	}

	void CanvasContext::updateSurface(EGLNativeWindowType window) {
	setSurface(window);
	}

	void CanvasContext::pauseSurface(EGLNativeWindowType window) {
	// TODO: For now we just need a fence, in the future suspend any animations
	// and such to prevent from trying to render into this surface
	}

	void CanvasContext::setup(int width, int height) {
	if (!mCanvas) return;
	mCanvas->setViewport(width, height);
	}

	void CanvasContext::makeCurrent() {
	mGlobalContext->makeCurrent(mEglSurface);
	}

	void CanvasContext::processLayerUpdates(const Vector<DeferredLayerUpdater> layerUpdaters,
	TreeInfo& info) {
	LOG_ALWAYS_FATAL_IF(!mCanvas, "Cannot process layer updates without a canvas!");
	makeCurrent();
	for (size_t i = 0; i < layerUpdaters->size(); i++) {
	DeferredLayerUpdater* update = layerUpdaters->itemAt(i);
	bool success = update->apply(info);
	LOG_ALWAYS_FATAL_IF(!success, "Failed to update layer!");
	if (update->backingLayer()->deferredUpdateScheduled) {
	mCanvas->pushLayerUpdate(update->backingLayer());
	}
	}
	}

	void CanvasContext::drawDisplayList(RenderNode* displayList, Rect* dirty) {
	LOG_ALWAYS_FATAL_IF(!mCanvas \|\| mEglSurface == EGL_NO_SURFACE,
	"drawDisplayList called on a context with no canvas or surface!");

	EGLint width, height;
	mGlobalContext->beginFrame(mEglSurface, &width, &height);
	if (width != mCanvas->getViewportWidth() \|\| height != mCanvas->getViewportHeight()) {
	mCanvas->setViewport(width, height);
	dirty = NULL;
	} else if (!mDirtyRegionsEnabled \|\| mHaveNewSurface) {
	dirty = NULL;
	}

	status_t status;
	if (dirty) {
	status = mCanvas->prepareDirty(dirty->left, dirty->top,
	dirty->right, dirty->bottom, mOpaque);
	} else {
	status = mCanvas->prepare(mOpaque);
	}

	Rect outBounds;
	status \|= mCanvas->drawDisplayList(displayList, outBounds);

	// TODO: Draw debug info
	// TODO: Performance tracking

	mCanvas->finish();

	if (status & DrawGlInfo::kStatusDrew) {
	swapBuffers();
	}
	}

	void CanvasContext::invokeFunctor(Functor* functor) {
	ATRACE_CALL();
	DrawGlInfo::Mode mode = DrawGlInfo::kModeProcessNoContext;
	if (mGlobalContext->hasContext()) {
	requireGlContext();
	mode = DrawGlInfo::kModeProcess;
	}
	// TODO: Remove the dummy info in the future
	DrawGlInfo dummyInfo;
	memset(&dummyInfo, 0, sizeof(DrawGlInfo));
	(*functor)(mode, &dummyInfo);
	}

	bool CanvasContext::copyLayerInto(DeferredLayerUpdater* layer, SkBitmap* bitmap) {
	requireGlContext();
	TreeInfo info;
	layer->apply(info);
	return LayerRenderer::copyLayer(layer->backingLayer(), bitmap);
	}

	void CanvasContext::runWithGlContext(RenderTask* task) {
	requireGlContext();
	task->run();
	}

	Layer* CanvasContext::createRenderLayer(int width, int height) {
	requireSurface();
	return LayerRenderer::createRenderLayer(width, height);
	}

	Layer* CanvasContext::createTextureLayer() {
	requireSurface();
	return LayerRenderer::createTextureLayer();
	}

	void CanvasContext::requireGlContext() {
	if (mEglSurface != EGL_NO_SURFACE) {
	mGlobalContext->makeCurrent(mEglSurface);
	} else {
	mGlobalContext->usePBufferSurface();
	}
	}

	} /* namespace renderthread */
	} /* namespace uirenderer */
	} /* namespace android */