Add a new exportable interface that outputs EGL images

This new interface is intended to make the backend easy to use by EGL-based applications. A single callback 'export_egl_image' will provide applications with an already constructed, ready to render EGL image. A side benefit of this is that the actual protocol used by the backend's nested compositor (wl_surface, linux-dmabuf, etc) becomes transparent to the application. This new interface is built conditionally by setting the -DEXPORTABLE_EGL cmake option. It is ON by default.
Igalia · May 31, 2018 · 462da6d · 462da6d
1 parent 1138dbf
commit 462da6d
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diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -58,6 +58,13 @@ set(WPEBACKEND_FDO_SOURCES
     src/ws.cpp
 )
 
+option(EXPORTABLE_EGL "Enable the exportable EGL interface" ON)
+
+if (EXPORTABLE_EGL)
+    list(APPEND WPEBACKEND_FDO_PUBLIC_HEADERS include/wpe-fdo/view-backend-exportable-egl.h)
+    list(APPEND WPEBACKEND_FDO_SOURCES src/view-backend-exportable-fdo-egl.cpp)
+endif ()
+
 add_library(WPEBackend-fdo SHARED ${WPEBACKEND_FDO_SOURCES})
 target_include_directories(WPEBackend-fdo PRIVATE ${WPEBACKEND_FDO_INCLUDE_DIRECTORIES})
 target_link_libraries(WPEBackend-fdo ${WPEBACKEND_FDO_LIBRARIES})

diff --git a/include/wpe-fdo/fdo-egl.h b/include/wpe-fdo/fdo-egl.h
@@ -33,6 +33,7 @@
 #define __WPE_FDO_EGL_H_INSIDE__
 
 #include <wpe/initialize-egl.h>
+#include <wpe/view-backend-exportable-egl.h>
 
 #undef __WPE_FDO_EGL_H_INSIDE__
 

diff --git a/include/wpe-fdo/view-backend-exportable-egl.h b/include/wpe-fdo/view-backend-exportable-egl.h
@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2018 Igalia S.L.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+ * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#if !defined(__WPE_FDO_EGL_H_INSIDE__) && !defined(WPE_FDO_COMPILATION)
+#error "Only <wpe/fdo-egl.h> can be included directly."
+#endif
+
+#ifndef __view_backend_exportable_egl_h__
+#define __view_backend_exportable_egl_h__
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <wpe/wpe.h>
+
+typedef void* EGLImageKHR;
+
+struct wpe_view_backend_exportable_fdo;
+
+struct wpe_view_backend_exportable_fdo_egl_client {
+    void (*export_egl_image)(void* data, EGLImageKHR image);
+    void (*_wpe_reserved0)(void);
+    void (*_wpe_reserved1)(void);
+    void (*_wpe_reserved2)(void);
+    void (*_wpe_reserved3)(void);
+};
+
+struct wpe_view_backend_exportable_fdo*
+wpe_view_backend_exportable_fdo_egl_create(struct wpe_view_backend_exportable_fdo_egl_client*, void*, uint32_t width, uint32_t height);
+
+void
+wpe_view_backend_exportable_fdo_egl_dispatch_release_image(struct wpe_view_backend_exportable_fdo* exportable, EGLImageKHR image);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __view_backend_exportable_egl_h___ */
diff --git a/src/view-backend-exportable-fdo-egl.cpp b/src/view-backend-exportable-fdo-egl.cpp
@@ -0,0 +1,149 @@
+/*
+ * Copyright (C) 2018 Igalia S.L.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+ * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <assert.h>
+#include "ws.h"
+#include "view-backend-exportable-fdo.h"
+#include "wpe-fdo/view-backend-exportable-egl.h"
+#include <EGL/egl.h>
+#include <EGL/eglext.h>
+#include <list>
+
+namespace {
+
+struct buffer_data {
+    struct wl_resource *buffer_resource;
+    EGLImageKHR egl_image;
+};
+
+class ClientBundleEGL : public ClientBundleBase {
+public:
+    ClientBundleEGL(struct wpe_view_backend_exportable_fdo_egl_client* _client, void* data,
+                    ViewBackend* viewBackend, uint32_t initialWidth, uint32_t initialHeight)
+        : ClientBundleBase(data, viewBackend, initialWidth, initialHeight)
+        , client(_client)
+    {
+        m_eglDisplay = WS::Instance::singleton().getEGLDisplay();
+        assert (m_eglDisplay);
+
+        eglCreateImage = (PFNEGLCREATEIMAGEKHRPROC) eglGetProcAddress ("eglCreateImageKHR");
+        assert (eglCreateImage);
+
+        eglDestroyImage = (PFNEGLDESTROYIMAGEKHRPROC)
+            eglGetProcAddress ("eglDestroyImageKHR");
+        assert (eglDestroyImage);
+    }
+
+    ~ClientBundleEGL()
+    {
+        for (auto* buf_data : m_buffers) {
+            assert(buf_data->egl_image);
+            eglDestroyImage(m_eglDisplay, buf_data->egl_image);
+
+            delete buf_data;
+        }
+        m_buffers.clear();
+    }
+
+    void exportBuffer(struct wl_resource *bufferResource) override
+    {
+        static const EGLint image_attrs[] = {
+            EGL_WAYLAND_PLANE_WL, 0,
+            EGL_NONE
+        };
+        EGLImageKHR image = eglCreateImage (m_eglDisplay,
+                                            EGL_NO_CONTEXT,
+                                            EGL_WAYLAND_BUFFER_WL,
+                                            bufferResource,
+                                            image_attrs);
+        if (!image)
+            return;
+
+        auto* buf_data = new struct buffer_data;
+        buf_data->buffer_resource = bufferResource;
+        buf_data->egl_image = image;
+        m_buffers.push_back(buf_data);
+
+        client->export_egl_image(data, image);
+    }
+
+    struct buffer_data* releaseImage(EGLImageKHR image)
+    {
+        for (auto* buf_data : m_buffers)
+            if (buf_data->egl_image == image) {
+                m_buffers.remove(buf_data);
+                eglDestroyImage(m_eglDisplay, buf_data->egl_image);
+
+                return buf_data;
+            }
+
+        return nullptr;
+    }
+
+    struct wpe_view_backend_exportable_fdo_egl_client* client;
+
+private:
+    EGLDisplay m_eglDisplay;
+    PFNEGLCREATEIMAGEKHRPROC eglCreateImage;
+    PFNEGLDESTROYIMAGEKHRPROC eglDestroyImage;
+
+    std::list<struct buffer_data*> m_buffers;
+};
+
+} // namespace
+
+extern "C" {
+
+__attribute__((visibility("default")))
+struct wpe_view_backend_exportable_fdo*
+wpe_view_backend_exportable_fdo_egl_create(struct wpe_view_backend_exportable_fdo_egl_client* client, void* data, uint32_t width, uint32_t height)
+{
+    auto* clientBundle = new ClientBundleEGL(client, data, nullptr, width, height);
+
+    return wpe_view_backend_exportable_fdo_new(clientBundle);
+}
+
+__attribute__((visibility("default")))
+void
+wpe_view_backend_exportable_fdo_egl_dispatch_release_image(struct wpe_view_backend_exportable_fdo* exportable, EGLImageKHR image)
+{
+    auto* clientBundle = reinterpret_cast<ClientBundleEGL*>
+        (wpe_view_backend_exportable_fdo_get_client_bundle(exportable));
+
+    auto* buffer_data = clientBundle->releaseImage(image);
+    if (!buffer_data)
+        return;
+
+    /* the EGL image has already been destroyed by ClientBundleEGL */
+
+    if (buffer_data->buffer_resource) {
+        wpe_view_backend_exportable_fdo_dispatch_release_buffer(exportable,
+                                                                buffer_data->buffer_resource);
+    }
+
+    delete buffer_data;
+}
+
+}