X C Bindings video output proof of concept plugin

This can really only output iamges at this point.
Critical yet-to-be-implemented features:
 - MIT-SHM shared memory support
 - XVideo hardware scaling & chroma conversion
 - keyboard event handling
 - mouse event handling
 - window (manager) event handling
 - cursor blanking
 - window provider submodule (so it can work without the Qt interface)
 - screen capture access module
 - GLX, perhaps?
 - etc

15, 16 and 24-bits color depth work. 32-bits depth was not tested due
to lack of suitable video adapter. 8-bits depth does not work due to a
bug in VLC chroma handling. B&W, grey and 16 color are not supported,
but are probably not worth it - the Xlib output does not support them
either.

Fullscreen should work, but was not tested.

modules/video_output/Modules.am

@@ -20,4 +20,15 @@ SOURCES_directfb = directfb.c
 SOURCES_vmem = vmem.c
 SOURCES_yuv = yuv.c
 
+# TODO: move to configure.ac once/if xcb plugin gets more functional
+XCB_LIBS = -lxcb
+XCB_AUX_LIBS = -lxcb-aux
+XCB_IMAGE_LIBS = -lxcb-image
 
+libxcb_plugin_la_SOURCES = xcb/xcb.c
+libxcb_plugin_la_CFLAGS = $(AM_CFLAGS) \
+	$(XCB_CFLAGS) $(XCB_AUX_CFLAGS) $(XCB_IMAGE_CFLAGS)
+libxcb_plugin_la_LIBADD = $(AM_LIBADD) \
+	$(XCB_LIBS) $(XCB_AUX_LIBS) $(XCB_IMAGE_LIBS)
+libxcb_plugin_la_DEPENDENCIES =
+EXTRA_LTLIBRARIES += libxcb_plugin.la

modules/video_output/xcb/xcb.c

+/**
+ * @file xcb.c
+ * @brief X C Bindings video output module for VLC media player
+ */
+/*****************************************************************************
+ * Copyright © 2009 Rémi Denis-Courmont
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2.0
+ * of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ ****************************************************************************/
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <stdlib.h>
+#include <assert.h>
+
+#include <xcb/xcb.h>
+#include <xcb/xcb_aux.h>
+#include <xcb/xcb_image.h>
+
+#include <vlc_common.h>
+#include <vlc_plugin.h>
+#include <vlc_vout.h>
+#include <vlc_window.h>
+
+#define DISPLAY_TEXT N_("X11 display")
+#define DISPLAY_LONGTEXT N_( \
+    "X11 hardware display to use. By default VLC will " \
+    "use the value of the DISPLAY environment variable.")
+
+static int  Open (vlc_object_t *);
+static void Close (vlc_object_t *);
+
+/*
+ * Module descriptor
+ */
+vlc_module_begin ()
+    set_shortname (_("XCB"))
+    set_description (_("(Experimental) XCB video output"))
+    set_category (CAT_VIDEO)
+    set_subcategory (SUBCAT_VIDEO_VOUT)
+    set_capability ("video output", 0)
+    set_callbacks (Open, Close)
+
+    add_string ("x11-display", NULL, NULL,
+                DISPLAY_TEXT, DISPLAY_LONGTEXT, true)
+vlc_module_end ()
+
+struct vout_sys_t
+{
+    xcb_connection_t *conn;
+    xcb_screen_t *screen;
+    vout_window_t *embed; /* VLC window (when windowed) */
+
+    xcb_visualid_t vid;
+    xcb_window_t parent; /* parent X window */
+    xcb_window_t window; /* drawable X window */
+    xcb_gcontext_t gc; /* context to put images */
+};
+
+static int Init (vout_thread_t *);
+static void Deinit (vout_thread_t *);
+static void Display (vout_thread_t *, picture_t *);
+static int Manage (vout_thread_t *);
+
+static int CheckError (vout_thread_t *vout, const char *str,
+                       xcb_void_cookie_t ck)
+{
+    xcb_generic_error_t *err;
+
+    err = xcb_request_check (vout->p_sys->conn, ck);
+    if (err)
+    {
+        msg_Err (vout, "%s: X11 error %d", str, err->error_code);
+        return VLC_EGENERIC;
+    }
+    return VLC_SUCCESS;
+}
+
+#define p_vout vout
+
+/**
+ * Probe the X server.
+ */
+static int Open (vlc_object_t *obj)
+{
+    vout_thread_t *vout = (vout_thread_t *)obj;
+    vout_sys_t *p_sys = malloc (sizeof (*p_sys));
+    if (p_sys == NULL)
+        return VLC_ENOMEM;
+
+    vout->p_sys = p_sys;
+    p_sys->conn = NULL;
+#ifndef NDEBUG
+    p_sys->embed = NULL;
+#endif
+
+    /* Connect to X */
+    char *display = var_CreateGetNonEmptyString (vout, "x11-display");
+    int snum;
+    p_sys->conn = xcb_connect (display, &snum);
+    if (xcb_connection_has_error (p_sys->conn) /*== NULL*/)
+    {
+        msg_Err (vout, "cannot connect to X server %s",
+                 display ? display : "");
+        goto error;
+    }
+
+    /* Get the preferred screen */
+    xcb_screen_t *scr = xcb_aux_get_screen (p_sys->conn, snum);
+    p_sys->screen = scr;
+    assert (p_sys->screen);
+    msg_Dbg (vout, "using screen %d (depth %"PRIu8")", snum, scr->root_depth);
+
+    if (strchr ("\x08\x0f\x10\x18\x20", scr->root_depth) == NULL)
+    {
+        msg_Err (vout, "unsupported %"PRIu8"-bits color depth",
+                 scr->root_depth);
+        goto error;
+    }
+
+    /* Determine the visual (color depth and palette) */
+    xcb_visualtype_t *vt = NULL;
+    if ((vt = xcb_aux_find_visual_by_attrs (scr, XCB_VISUAL_CLASS_TRUE_COLOR,
+                                            scr->root_depth)) != NULL)
+        msg_Dbg (vout, "using TrueColor visual ID %d", (int)vt->visual_id);
+    else
+    if ((vt = xcb_aux_find_visual_by_attrs (scr,XCB_VISUAL_CLASS_STATIC_COLOR,
+                                            scr->root_depth)) != NULL)
+        msg_Dbg (vout, "using static color visual ID %d", (int)vt->visual_id);
+    else
+    {
+        vt = xcb_aux_get_visualtype (p_sys->conn, snum, scr->root_visual);
+        assert (vt);
+        msg_Err (vout, "unsupported visual class %"PRIu8, vt->_class);
+        goto error;
+    }
+    p_sys->vid = vt->visual_id;
+
+    vout->pf_init = Init;
+    vout->pf_end = Deinit;
+    vout->pf_display = Display;
+    vout->pf_manage = Manage;
+    return VLC_SUCCESS;
+
+error:
+    Close (obj);
+    return VLC_EGENERIC;
+}
+
+
+/**
+ * Disconnect from the X server.
+ */
+static void Close (vlc_object_t *obj)
+{
+    vout_thread_t *vout = (vout_thread_t *)obj;
+    vout_sys_t *p_sys = vout->p_sys;
+
+    assert (p_sys->embed == NULL);
+    if (p_sys->conn)
+        xcb_disconnect (p_sys->conn);
+    free (p_sys);
+}
+
+static void PictureRelease (picture_t *pic)
+{
+    xcb_image_t *img = (xcb_image_t *)pic->p_sys;
+    xcb_image_destroy (img);
+}
+
+/**
+ * Allocate drawable window and picture buffers.
+ */
+static int Init (vout_thread_t *vout)
+{
+    vout_sys_t *p_sys = vout->p_sys;
+    const xcb_screen_t *screen = p_sys->screen;
+    unsigned x, y, width, height;
+
+    /* Determine parent window */
+    if (vout->b_fullscreen)
+    {
+        p_sys->embed = NULL;
+        p_sys->parent = screen->root;
+        width = screen->width_in_pixels;
+        height = screen->height_in_pixels;
+    }
+    else
+    {
+        p_sys->embed = vout_RequestWindow (vout, &(int){ 0 }, &(int){ 0 },
+                                            &width, &height);
+        if (p_sys->embed == NULL)
+        {
+            msg_Err (vout, "cannot get window");
+            return VLC_EGENERIC;
+        }
+        p_sys->parent = (intptr_t)p_sys->embed->handle;
+    }
+
+    /* Determine our input format */
+    uint8_t depth = screen->root_depth, bpp = depth;
+    switch (depth)
+    {
+        case 24:
+            bpp = 32;
+        case 32: /* FIXME: untested */
+            vout->output.i_chroma = VLC_FOURCC ('R', 'V', '3', '2');
+            break;
+
+        case 16:
+            vout->output.i_chroma = VLC_FOURCC ('R', 'V', '1', '6');
+            break;
+
+        case 15:
+            bpp = 16;
+            vout->output.i_chroma = VLC_FOURCC ('R', 'V', '1', '5');
+            break;
+
+        case 8: /* FIXME: VLC cannot convert */
+            vout->output.i_chroma = VLC_FOURCC ('R', 'G', 'B', '2');
+            break;
+
+        default:
+            assert (0);
+    }
+
+    vout_PlacePicture (vout, width, height, &x, &y, &width, &height);
+    vout->output.i_width = width;
+    vout->output.i_height = height;
+    assert (height > 0);
+    vout->output.i_aspect = width * VOUT_ASPECT_FACTOR / height;
+    /* FIXME: I don't get the subtlety between output and fmt_out here */
+
+    /* Create window */
+    xcb_void_cookie_t c;
+    xcb_window_t window = xcb_generate_id (p_sys->conn);
+
+    p_sys->window = window;
+    c = xcb_create_window_checked (p_sys->conn, screen->root_depth, window,
+                                   p_sys->parent, x, y, width, height, 0,
+                                   XCB_WINDOW_CLASS_INPUT_OUTPUT,
+                                   screen->root_visual, 0, NULL);
+    if (CheckError (vout, "cannot create X11 window", c))
+        goto error;
+    msg_Dbg (vout, "using X11 window %08"PRIx32, p_sys->window);
+    xcb_map_window (p_sys->conn, window);
+
+    /* Create graphic context (I wonder why the heck do we need this) */
+    p_sys->gc = xcb_generate_id (p_sys->conn);
+    xcb_create_gc (p_sys->conn, p_sys->gc, p_sys->window, 0, NULL);
+    msg_Dbg (vout, "using X11 graphic context %08"PRIx32, p_sys->gc);
+    xcb_flush (p_sys->conn);
+
+    /* Allocate picture buffers */
+    do
+    {
+        picture_t *pic = vout->p_picture + I_OUTPUTPICTURES;
+
+        assert (pic->i_status == FREE_PICTURE);
+        vout_InitPicture (vout, pic, vout->output.i_chroma,
+                          vout->output.i_width, vout->output.i_height,
+                          vout->output.i_aspect);
+
+        xcb_image_t *img;
+        const unsigned real_width = pic->p->i_pitch / (bpp >> 3);
+        /* FIXME: anyway to getthing more intuitive than that?? */
+
+        /* NOTE: 32-bits scanline_pad assumed, FIXME? (see xdpyinfo) */
+        img = xcb_image_create (real_width, height, XCB_IMAGE_FORMAT_Z_PIXMAP,
+                                32, depth, bpp, bpp,
+#ifdef WORDS_BIGENDIAN
+                                XCB_IMAGE_ORDER_MSB_FIRST,
+#else
+                                XCB_IMAGE_ORDER_LSB_FIRST,
+#endif
+                                XCB_IMAGE_ORDER_MSB_FIRST,
+                                NULL, 0, NULL);
+        if (!img)
+            goto error;
+
+        pic->p_sys = (picture_sys_t *)img;
+        pic->pf_release = PictureRelease;
+        pic->p->p_pixels = img->data;
+
+        pic->i_status = DESTROYED_PICTURE;
+        pic->i_type = DIRECT_PICTURE;
+        PP_OUTPUTPICTURE[I_OUTPUTPICTURES++] = pic;
+    }
+    while (I_OUTPUTPICTURES < 2);
+
+    return VLC_SUCCESS;
+
+error:
+    Deinit (vout);
+    return VLC_EGENERIC;
+}
+
+/**
+ * Free picture buffers.
+ */
+static void Deinit (vout_thread_t *vout)
+{
+    vout_sys_t *p_sys = vout->p_sys;
+
+    while (I_OUTPUTPICTURES > 0)
+        picture_Release (PP_OUTPUTPICTURE[--I_OUTPUTPICTURES]);
+
+    xcb_unmap_window (p_sys->conn, p_sys->window);
+    xcb_destroy_window (p_sys->conn, p_sys->window);
+    vout_ReleaseWindow (p_sys->embed);
+    p_sys->embed = NULL;
+}
+
+/**
+ * Sends an image to the X server.
+ */
+static void Display (vout_thread_t *vout, picture_t *pic)
+{
+    vout_sys_t *p_sys = vout->p_sys;
+    xcb_image_t *img = (xcb_image_t *)pic->p_sys;
+    xcb_image_t *native = xcb_image_native (p_sys->conn, img, 1);
+
+    if (native == NULL)
+    {
+        msg_Err (vout, "image conversion failure");
+        return;
+    }
+
+    xcb_image_put (p_sys->conn, p_sys->window, p_sys->gc, native, 0, 0, 0);
+    xcb_flush (p_sys->conn);
+
+    if (native != img)
+    {
+        /*msg_Warn (vout, "image not in native X11 pixmap format");*/
+        xcb_image_destroy (native);
+    }
+}
+
+/**
+ * Process incoming X events.
+ */
+static int Manage (vout_thread_t *vout)
+{
+    vout_sys_t *p_sys = vout->p_sys;
+    xcb_generic_event_t *ev;
+
+    while ((ev = xcb_poll_for_event (p_sys->conn)) != NULL)
+    {
+        switch (ev->response_type & ~0x80)
+        {
+        default:
+            msg_Dbg (vout, "unhandled event %02x", (unsigned)ev->response_type);
+        }
+        free (ev);
+    }
+
+    if (xcb_connection_has_error (p_sys->conn))
+    {
+        msg_Err (vout, "X server failure");
+        return VLC_EGENERIC;
+    }
+    return VLC_SUCCESS;
+}