Implement EGL_ANGLE_x11_visual

extensions/EGL_ANGLE_x11_visual.txt

+Name
+
+    ANGLE_x11_visual
+
+Name Strings
+
+    EGL_ANGLE_x11_visual
+
+Contributors
+
+    Corentin Wallez, Google
+    Shannon Woods, Google
+    Jamie Madill, Google
+    Geoff Lang, Google
+
+Contacts
+
+    Corentin Wallez, Google (cwallez 'at' chromium 'dot' org)
+
+Status
+
+    Draft
+
+Version
+
+    Version 1, 2015-11-13
+
+Number
+
+    EGL Extension XXX
+
+Extension Type
+
+    EGL client extension
+
+Dependencies
+
+    Requires EGL_EXT_client_extensions to query its existence without
+    a display.
+
+    Requires EGL_EXT_platform_base.
+
+    This extension is written against the wording of version 9 of the
+    EGL_EXT_platform_base specification.
+
+    Written based on the wording of the EGL 1.5 Specification
+    (August 7 2014).
+
+Overview
+
+    This extension allows passing the X11 visual ID used by the native
+    EGL surface types at display creation time. This will restrict
+    EGLSurfaces to be created from native types with this visual ID,
+    which may allow the created display to be more compatible and
+    performant.
+
+New Types
+
+    None
+
+New Procedures and Functions
+
+    None
+
+New Tokens
+
+    Accepted as an attribute name in the <attrib_list> argument of
+    eglGetPlatformDisplayEXT:
+
+        EGL_X11_VISUAL_ID_ANGLE 0x33A3
+
+Additions to the EGL Specification
+
+    Modify section 3.5.1 (Creating On-Screen Rendering Surfaces), p. 34
+
+    Append the following to the errors of CreateWindowSurface:
+
+    "If an X11 visual was specified at display creation time using
+    EGL_ANGLE_X11_VISUAL_ID that is not equal to the ID of the
+    native_window's visual, an EGL_BAD_MATCH error is generated and
+    EGL_NO_SURFACE is returned."
+
+New Behavior
+
+    To request a display created with a X11 visual ID, the value of
+    EGL_ANGLE_X11_VISUAL_ID should be set to a valid X11 visual ID. If
+    present, this ID will be used during display creation to make a
+    display that is more compatible and potentially more performant when
+    used with EGLsurfaces created from native types with this ID. If the
+    visual ID passed isn't a valid visual ID, eglGetPlatformDisplay will
+    return EGL_NO_DISPLAY and generate an EGL_NOT_INITIALIZED error.
+
+Issues
+
+    1) When the hint is present, should EGLsurface creation functions
+       only accept native types with the hint's visual ID?
+
+       RESOLVED: Yes, generate an error when the visual of the native
+       surface doesn't match. This will avoid having hidden performance
+       or compatibility losses when using this extension.
+
+Revision History
+
+    Version 1, 2015-11-13 (Corentin Wallez)
+      - Initial draft
+

include/EGL/eglext.h

@@ -499,6 +499,11 @@ EGLAPI EGLBoolean EGLAPIENTRY eglQuerySurfacePointerANGLE (EGLDisplay dpy, EGLSu
 #define EGL_FIXED_SIZE_ANGLE              0x3201
 #endif /* EGL_ANGLE_window_fixed_size */
 
+#ifndef EGL_ANGLE_x11_visual
+#define EGL_ANGLE_x11_visual
+#define EGL_X11_VISUAL_ID_ANGLE 0x33A3
+#endif /* EGL_ANGLE_x11_visual */
+
 #ifndef EGL_ARM_pixmap_multisample_discard
 #define EGL_ARM_pixmap_multisample_discard 1
 #define EGL_DISCARD_SAMPLES_ARM           0x3286

src/libANGLE/Caps.cpp

@@ -639,6 +639,7 @@ ClientExtensions::ClientExtensions()
       platformANGLE(false),
       platformANGLED3D(false),
       platformANGLEOpenGL(false),
+      x11Visual(false),
       clientGetAllProcAddresses(false)
 {
 }
@@ -654,6 +655,7 @@ std::vector<std::string> ClientExtensions::getStrings() const
     InsertExtensionString("EGL_ANGLE_platform_angle",              platformANGLE,             &extensionStrings);
     InsertExtensionString("EGL_ANGLE_platform_angle_d3d",          platformANGLED3D,          &extensionStrings);
     InsertExtensionString("EGL_ANGLE_platform_angle_opengl",       platformANGLEOpenGL,       &extensionStrings);
+    InsertExtensionString("EGL_ANGLE_x11_visual",                  x11Visual,                 &extensionStrings);
     InsertExtensionString("EGL_KHR_client_get_all_proc_addresses", clientGetAllProcAddresses, &extensionStrings);
     // clang-format on
 

src/libANGLE/Caps.h

@@ -476,6 +476,9 @@ struct ClientExtensions
     // EGL_ANGLE_platform_angle_opengl
     bool platformANGLEOpenGL;
 
+    // EGL_ANGLE_x11_visual
+    bool x11Visual;
+
     // EGL_KHR_client_get_all_proc_addresses
     bool clientGetAllProcAddresses;
 };

src/libANGLE/Display.cpp

@@ -711,6 +711,10 @@ static ClientExtensions GenerateClientExtensions()
     extensions.platformANGLEOpenGL = true;
 #endif
 
+#if defined(ANGLE_USE_X11)
+    extensions.x11Visual = true;
+#endif
+
     extensions.clientGetAllProcAddresses = true;
 
     return extensions;

src/libANGLE/renderer/gl/glx/DisplayGLX.cpp

@@ -57,6 +57,7 @@ class FunctionsGLGLX : public FunctionsGL
 DisplayGLX::DisplayGLX()
     : DisplayGL(),
       mFunctionsGL(nullptr),
+      mRequestedVisual(-1),
       mContextConfig(nullptr),
       mContext(nullptr),
       mDummyPbuffer(0),
@@ -80,6 +81,7 @@ egl::Error DisplayGLX::initialize(egl::Display *display)
 {
     mEGLDisplay = display;
     Display *xDisplay = display->getNativeDisplayId();
+    const auto &attribMap = display->getAttributeMap();
 
     // ANGLE_platform_angle allows the creation of a default display
     // using EGL_DEFAULT_DISPLAY (= nullptr). In this case just open
@@ -137,14 +139,42 @@ egl::Error DisplayGLX::initialize(egl::Display *display)
         mMinSwapInterval = 1;
     }
 
-    // When glXMakeCurrent is called, the context and the surface must be
-    // compatible which in glX-speak means that their config have the same
-    // color buffer type, are both RGBA or ColorIndex, and their buffers have
-    // the same depth, if they exist.
-    // Since our whole EGL implementation is backed by only one GL context, this
-    // context must be compatible with all the GLXFBConfig corresponding to the
-    // EGLconfigs that we will be exposing.
+    if (attribMap.contains(EGL_X11_VISUAL_ID_ANGLE))
     {
+        mRequestedVisual = attribMap.get(EGL_X11_VISUAL_ID_ANGLE, -1);
+
+        // There is no direct way to get the GLXFBConfig matching an X11 visual ID
+        // so we have to iterate over all the GLXFBConfigs to find the right one.
+        int nConfigs;
+        int attribList[] = {
+            None,
+        };
+        glx::FBConfig *allConfigs = mGLX.chooseFBConfig(attribList, &nConfigs);
+
+        for (int i = 0; i < nConfigs; ++i)
+        {
+            if (getGLXFBConfigAttrib(allConfigs[i], GLX_VISUAL_ID) == mRequestedVisual)
+            {
+                mContextConfig = allConfigs[i];
+                break;
+            }
+        }
+        XFree(allConfigs);
+
+        if (mContextConfig == nullptr)
+        {
+            return egl::Error(EGL_NOT_INITIALIZED, "Invalid visual ID requested.");
+        }
+    }
+    else
+    {
+        // When glXMakeCurrent is called, the context and the surface must be
+        // compatible which in glX-speak means that their config have the same
+        // color buffer type, are both RGBA or ColorIndex, and their buffers have
+        // the same depth, if they exist.
+        // Since our whole EGL implementation is backed by only one GL context, this
+        // context must be compatible with all the GLXFBConfig corresponding to the
+        // EGLconfigs that we will be exposing.
         int nConfigs;
         int attribList[] =
         {
@@ -168,7 +198,7 @@ egl::Error DisplayGLX::initialize(egl::Display *display)
             GLX_CONFIG_CAVEAT, GLX_NONE,
             None
         };
-        glx::FBConfig* candidates = mGLX.chooseFBConfig(attribList, &nConfigs);
+        glx::FBConfig *candidates = mGLX.chooseFBConfig(attribList, &nConfigs);
         if (nConfigs == 0)
         {
             XFree(candidates);
@@ -435,6 +465,14 @@ egl::ConfigSet DisplayGLX::generateConfigs() const
         config.nativeVisualType = getGLXFBConfigAttrib(glxConfig, GLX_X_VISUAL_TYPE);
         config.nativeRenderable = EGL_TRUE;
 
+        // When a visual ID has been specified with EGL_ANGLE_x11_visual we should
+        // only return configs with this visual: it will maximize performance by avoid
+        // blits in the driver when showing the window on the screen.
+        if (mRequestedVisual != -1 && config.nativeVisualID != mRequestedVisual)
+        {
+            continue;
+        }
+
         // Buffer sizes
         config.redSize = getGLXFBConfigAttrib(glxConfig, GLX_RED_SIZE);
         config.greenSize = getGLXFBConfigAttrib(glxConfig, GLX_GREEN_SIZE);
@@ -652,6 +690,11 @@ void DisplayGLX::setSwapInterval(glx::Drawable drawable, SwapControlData *data)
     }
 }
 
+bool DisplayGLX::isValidWindowVisualId(int visualId) const
+{
+    return mRequestedVisual == -1 || mRequestedVisual == visualId;
+}
+
 const FunctionsGL *DisplayGLX::getFunctionsGL() const
 {
     return mFunctionsGL;

src/libANGLE/renderer/gl/glx/DisplayGLX.h

@@ -79,6 +79,8 @@ class DisplayGLX : public DisplayGL
     // acts as expected.
     void setSwapInterval(glx::Drawable drawable, SwapControlData *data);
 
+    bool isValidWindowVisualId(int visualId) const;
+
   private:
     const FunctionsGL *getFunctionsGL() const override;
 
@@ -95,6 +97,7 @@ class DisplayGLX : public DisplayGL
     //TODO(cwallez) yuck, change generateConfigs to be non-const or add a userdata member to egl::Config?
     mutable std::map<int, glx::FBConfig> configIdToGLXConfig;
 
+    EGLint mRequestedVisual;
     glx::FBConfig mContextConfig;
     glx::Context mContext;
     // A pbuffer the context is current on during ANGLE initialization

src/libANGLE/renderer/gl/glx/WindowSurfaceGLX.cpp

@@ -52,12 +52,26 @@ WindowSurfaceGLX::~WindowSurfaceGLX()
 
 egl::Error WindowSurfaceGLX::initialize()
 {
+    // Check that the window's visual ID is valid, as part of the AMGLE_x11_visual
+    // extension.
+    {
+        XWindowAttributes windowAttributes;
+        XGetWindowAttributes(mDisplay, mParent, &windowAttributes);
+        int visualId = windowAttributes.visual->visualid;
+
+        if (!mGLXDisplay->isValidWindowVisualId(visualId))
+        {
+            return egl::Error(EGL_BAD_MATCH,
+                              "The visual of native_window doesn't match the visual given with "
+                              "ANGLE_X11_VISUAL_ID");
+        }
+    }
+
     // The visual of the X window, GLX window and GLX context must match,
     // however we received a user-created window that can have any visual
     // and wouldn't work with our GLX context. To work in all cases, we
     // create a child window with the right visual that covers all of its
     // parent.
-
     XVisualInfo *visualInfo = mGLX.getVisualFromFBConfig(mFBConfig);
     if (!visualInfo)
     {

src/tests/angle_end2end_tests.gypi

@@ -81,6 +81,10 @@
             # TODO(cwallez) for Linux, requires a portable implementation of threads
             '<(angle_path)/src/tests/egl_tests/EGLThreadTest.cpp',
         ],
+        'angle_end2end_tests_x11_sources':
+        [
+            '<(angle_path)/src/tests/egl_tests/EGLX11VisualTest.cpp',
+        ],
     },
     'dependencies':
     [
@@ -108,5 +112,12 @@
                 '<@(angle_end2end_tests_win_sources)',
             ],
         }],
+        ['use_x11==1',
+        {
+            'sources':
+            [
+                '<@(angle_end2end_tests_x11_sources)',
+            ],
+        }],
     ]
 }

src/tests/egl_tests/EGLX11VisualTest.cpp

+//
+// Copyright (c) 2015 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.
+//
+
+// EGLX11VisualTest.cpp: tests for EGL_ANGLE_x11_visual extension
+
+#include <gtest/gtest.h>
+
+#include <EGL/egl.h>
+#include <EGL/eglext.h>
+#include <X11/Xlib.h>
+
+#include "OSWindow.h"
+#include "test_utils/ANGLETest.h"
+
+using namespace angle;
+
+namespace
+{
+
+const EGLint contextAttribs[] = {EGL_CONTEXT_CLIENT_VERSION, 2, EGL_NONE};
+}
+
+class EGLX11VisualHintTest : public ANGLETest
+{
+  public:
+    void SetUp() override
+    {
+        mEglGetPlatformDisplayEXT = reinterpret_cast<PFNEGLGETPLATFORMDISPLAYEXTPROC>(
+            eglGetProcAddress("eglGetPlatformDisplayEXT"));
+
+        mDisplay = XOpenDisplay(NULL);
+    }
+
+    std::vector<EGLint> getDisplayAttributes(int visualId) const
+    {
+        std::vector<EGLint> attribs;
+
+        attribs.push_back(EGL_PLATFORM_ANGLE_TYPE_ANGLE);
+        attribs.push_back(GetParam().getRenderer());
+        attribs.push_back(EGL_X11_VISUAL_ID_ANGLE);
+        attribs.push_back(visualId);
+        attribs.push_back(EGL_NONE);
+
+        return attribs;
+    }
+
+    unsigned int chooseDifferentVisual(unsigned int visualId)
+    {
+        int numVisuals;
+        XVisualInfo visualTemplate;
+        visualTemplate.screen = DefaultScreen(mDisplay);
+
+        XVisualInfo *visuals =
+            XGetVisualInfo(mDisplay, VisualScreenMask, &visualTemplate, &numVisuals);
+        EXPECT_TRUE(numVisuals >= 2);
+
+        for (int i = 0; i < numVisuals; ++i)
+        {
+            if (visuals[i].visualid != visualId)
+            {
+                int result = visuals[i].visualid;
+                XFree(visuals);
+                return result;
+            }
+        }
+
+        UNREACHABLE();
+        return -1;
+    }
+
+  protected:
+    PFNEGLGETPLATFORMDISPLAYEXTPROC mEglGetPlatformDisplayEXT;
+    Display *mDisplay;
+};
+
+// Test that display creation fails if the visual ID passed in invalid.
+TEST_P(EGLX11VisualHintTest, InvalidVisualID)
+{
+    static const int gInvalidVisualId = -1;
+    auto attributes                   = getDisplayAttributes(gInvalidVisualId);
+
+    EGLDisplay display =
+        mEglGetPlatformDisplayEXT(EGL_PLATFORM_ANGLE_ANGLE, EGL_DEFAULT_DISPLAY, attributes.data());
+    ASSERT_TRUE(display != EGL_NO_DISPLAY);
+
+    ASSERT_TRUE(EGL_FALSE == eglInitialize(display, nullptr, nullptr));
+    ASSERT_EGL_ERROR(EGL_NOT_INITIALIZED);
+}
+
+// Test that context creation with a visual ID succeeds, that the context exposes
+// only one config, and that a clear on a surface with this config works.
+TEST_P(EGLX11VisualHintTest, ValidVisualIDAndClear)
+{
+    // We'll test the extension with one visual ID but we don't care which one. This means we
+    // can use OSWindow to create a window and just grab its visual.
+    OSWindow *osWindow = CreateOSWindow();
+    osWindow->initialize("EGLX11VisualHintTest", 500, 500);
+    osWindow->setVisible(true);
+
+    Window xWindow = osWindow->getNativeWindow();
+
+    XWindowAttributes windowAttributes;
+    ASSERT_NE(0, XGetWindowAttributes(mDisplay, xWindow, &windowAttributes));
+    int visualId = windowAttributes.visual->visualid;
+
+    auto attributes = getDisplayAttributes(visualId);
+    EGLDisplay display =
+        mEglGetPlatformDisplayEXT(EGL_PLATFORM_ANGLE_ANGLE, EGL_DEFAULT_DISPLAY, attributes.data());
+    ASSERT_NE(EGL_NO_DISPLAY, display);
+
+    ASSERT_TRUE(EGL_TRUE == eglInitialize(display, nullptr, nullptr));
+
+    // While this is not required by the extension, test that our implementation returns only one
+    // config, with the same native visual Id that we provided.
+    int nConfigs = 0;
+    ASSERT_TRUE(EGL_TRUE == eglGetConfigs(display, nullptr, 0, &nConfigs));
+    ASSERT_EQ(1, nConfigs);
+
+    int nReturnedConfigs = 0;
+    EGLConfig config;
+    ASSERT_TRUE(EGL_TRUE == eglGetConfigs(display, &config, 1, &nReturnedConfigs));
+    ASSERT_EQ(nConfigs, nReturnedConfigs);
+
+    EGLint eglNativeId;
+    ASSERT_TRUE(EGL_TRUE == eglGetConfigAttrib(display, config, EGL_NATIVE_VISUAL_ID, &eglNativeId));
+    ASSERT_EQ(visualId, eglNativeId);
+
+    // Finally, try to do a clear on the window.
+    EGLContext context = eglCreateContext(display, config, EGL_NO_CONTEXT, contextAttribs);
+    ASSERT_NE(EGL_NO_CONTEXT, context);
+
+    EGLSurface window = eglCreateWindowSurface(display, config, xWindow, nullptr);
+    ASSERT_EGL_SUCCESS();
+
+    eglMakeCurrent(display, window, window, context);
+    ASSERT_EGL_SUCCESS();
+
+    glViewport(0, 0, 500, 500);
+    glClearColor(0.0f, 0.0f, 1.0f, 1.0f);
+    glClear(GL_COLOR_BUFFER_BIT);
+    ASSERT_GL_NO_ERROR();
+    EXPECT_PIXEL_EQ(250, 250, 0, 0, 255, 255);
+
+    // Teardown
+    eglDestroySurface(display, window);
+    ASSERT_EGL_SUCCESS();
+
+    eglDestroyContext(display, context);
+    ASSERT_EGL_SUCCESS();
+
+    SafeDelete(osWindow);
+
+    eglMakeCurrent(display, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
+    eglTerminate(display);
+}
+
+// Test that EGL_BAD_MATCH is generated when trying to create an EGL window from
+// an X11 window whose visual ID doesn't match the visual ID passed at display creation.
+TEST_P(EGLX11VisualHintTest, InvalidWindowVisualID)
+{
+    OSWindow *osWindow = CreateOSWindow();
+    osWindow->initialize("EGLX11VisualHintTest", 500, 500);
+    osWindow->setVisible(true);
+
+    Window xWindow = osWindow->getNativeWindow();
+
+    XWindowAttributes windowAttributes;
+    ASSERT_NE(0, XGetWindowAttributes(mDisplay, xWindow, &windowAttributes));
+    int visualId = windowAttributes.visual->visualid;
+
+    // Initialize the display with a visual ID different from the window's visualId
+    int otherVisualId = chooseDifferentVisual(visualId);
+    ASSERT_NE(visualId, otherVisualId);
+
+    auto attributes = getDisplayAttributes(otherVisualId);
+    EGLDisplay display =
+        mEglGetPlatformDisplayEXT(EGL_PLATFORM_ANGLE_ANGLE, EGL_DEFAULT_DISPLAY, attributes.data());
+    ASSERT_NE(EGL_NO_DISPLAY, display);
+
+    ASSERT_TRUE(EGL_TRUE == eglInitialize(display, nullptr, nullptr));
+
+    // Creating the EGL window should fail with EGL_BAD_MATCH
+    int nReturnedConfigs = 0;
+    EGLConfig config;
+    ASSERT_TRUE(EGL_TRUE == eglGetConfigs(display, &config, 1, &nReturnedConfigs));
+    ASSERT_EQ(1, nReturnedConfigs);
+
+    EGLSurface window = eglCreateWindowSurface(display, config, xWindow, nullptr);
+    ASSERT_EQ(EGL_NO_SURFACE, window);
+    ASSERT_EGL_ERROR(EGL_BAD_MATCH);
+}
+
+ANGLE_INSTANTIATE_TEST(EGLX11VisualHintTest, ES2_OPENGL());