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f4e89dde36
This is actually a very nice simplification that should have been thought of years ago (sue me). In a nutshell, the story with the wayland code is that the frame callback and swap buffer behavior doesn't fit very well with mpv's rendering loop. It's been refactored/changed quite a few times over the years and works well enough but things could be better. The current iteration works with an external swapchain to check if we have frame callback before deciding whether or not to render. This logic was implemented in both egl and vulkan. This does have its warts however. There's some hidden state detection logic which works but is kind of ugly. Since wayland doesn't allow clients to know if they are actually visible (questionable but whatever), you can just reasonably assume that if a bunch of callbacks are missed in a row, you're probably not visible. That's fine, but it is indeed less than ideal since the threshold is basically entirely arbitrary and mpv does do a few wasteful renders before it decides that the window is actually hidden. The biggest urk in the vo_wayland_wait_frame is the use of wl_display_roundtrip. Wayland developers would probably be offended by the way mpv abuses that function, but essentially it was a way to have semi-blocking behavior needed for display-resample to work. Since the swap interval must be 0 on wayland (otherwise it will block the entire player's rendering loop), we need some other way to wait on vsync. The idea here was to dispatch and poll a bunch of wayland events, wait (with a timeout) until we get frame callback, and then wait for the compositor to process it. That pretty much perfectly waits on vsync and lets us keep all the good timings and all that jazz that we want for mpv. The problem is that wl_display_roundtrip is conceptually a bad function. It can internally call wl_display_dispatch which in certain instances, empty event queue, will block forever. Now strictly speaking, this probably will never, ever happen (once I was able to to trigger it by hardcoding an error into a compositor), but ideally vo_wayland_wait_frame should never infinitely block and stall the player. Unfortunately, removing that function always lead to problems with timings and unsteady vsync intervals so it survived many refactors. Until now, of course. In wayland, the ideal is to never do wasteful rendering (i.e. don't render if the window isn't visible). Instead of wrestling around with hidden states and possible missed vblanks, let's rearrange the wayland rendering logic so we only ever draw a frame when the frame callback is returned to use (within a reasonable timeout to avoid blocking forever). This slight rearrangement of the wait allows for several simplifications to be made. Namely, wl_display_roundtrip stops being needed. Instead, we can rely entirely on totally nonblocking calls (dispatch_pending, flush, and so on). We still need to poll the fd here to actually get the frame callback event from the compositor, but there's no longer any reason to do extra waiting. As soon as we get the callback, we immediately draw. This works quite well and has stable vsync (display-resample and audio). Additionally, all of the logic about hidden states is no longer needed. If vo_wayland_wait_frame times out, it's okay to assume immediately that the window is not visible and skip rendering. Unfortunately, there's one limitation on this new approach. It will only work correctly if the compositor implements presentation time. That means a reduced version of the old way still has to be carried around in vo_wayland_wait_frame. So if the compositor has no presentation time, then we are forced to use wl_display_roundtrip and juggle some funny assumptions about whether or not the window is hidden or not. Plasma is the only real notable compositor without presentation time at this stage so perhaps this "legacy" mechanism could be removed in the future.
162 lines
4.6 KiB
C
162 lines
4.6 KiB
C
/*
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* This file is part of mpv video player.
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*
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* mpv is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* mpv is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with mpv. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef MPLAYER_WAYLAND_COMMON_H
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#define MPLAYER_WAYLAND_COMMON_H
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#include <wayland-client.h>
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#include <wayland-cursor.h>
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#include <xkbcommon/xkbcommon.h>
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#include "vo.h"
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#include "input/event.h"
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struct wayland_opts {
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int disable_vsync;
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int edge_pixels_pointer;
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int edge_pixels_touch;
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};
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struct vo_wayland_sync {
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int64_t ust;
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int64_t msc;
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int64_t sbc;
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bool filled;
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};
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struct vo_wayland_output {
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struct vo_wayland_state *wl;
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uint32_t id;
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struct wl_output *output;
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struct mp_rect geometry;
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int phys_width;
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int phys_height;
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int scale;
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uint32_t flags;
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double refresh_rate;
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char *make;
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char *model;
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bool has_surface;
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struct wl_list link;
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};
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struct vo_wayland_state {
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struct mp_log *log;
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struct vo *vo;
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struct wl_display *display;
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struct wl_shm *shm;
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struct wl_compositor *compositor;
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struct wl_registry *registry;
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struct wayland_opts *opts;
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struct m_config_cache *vo_opts_cache;
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struct mp_vo_opts *vo_opts;
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/* State */
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struct mp_rect geometry;
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struct mp_rect window_size;
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struct mp_rect vdparams;
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int gcd;
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int reduced_width;
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int reduced_height;
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bool frame_wait;
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bool state_change;
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bool toplevel_configured;
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bool activated;
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bool has_keyboard_input;
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bool focused;
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int timeout_count;
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int wakeup_pipe[2];
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int pending_vo_events;
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int mouse_x;
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int mouse_y;
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int mouse_unscaled_x;
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int mouse_unscaled_y;
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int scaling;
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int touch_entries;
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int toplevel_width;
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int toplevel_height;
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uint32_t pointer_id;
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int display_fd;
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struct wl_callback *frame_callback;
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struct wl_list output_list;
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struct vo_wayland_output *current_output;
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/* Shell */
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struct wl_surface *surface;
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struct xdg_wm_base *wm_base;
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struct xdg_toplevel *xdg_toplevel;
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struct xdg_surface *xdg_surface;
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struct wp_presentation *presentation;
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struct wp_presentation_feedback *feedback;
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struct zxdg_decoration_manager_v1 *xdg_decoration_manager;
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struct zxdg_toplevel_decoration_v1 *xdg_toplevel_decoration;
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struct zwp_idle_inhibit_manager_v1 *idle_inhibit_manager;
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struct zwp_idle_inhibitor_v1 *idle_inhibitor;
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/* Presentation Feedback */
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struct vo_wayland_sync *sync;
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int sync_size;
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int64_t last_ust;
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int64_t last_msc;
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int64_t last_skipped_vsyncs;
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int64_t last_queue_display_time;
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int64_t refresh_interval;
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int64_t vsync_duration;
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/* Input */
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uint32_t keyboard_code;
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struct wl_seat *seat;
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struct wl_pointer *pointer;
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struct wl_touch *touch;
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struct wl_keyboard *keyboard;
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struct xkb_context *xkb_context;
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struct xkb_keymap *xkb_keymap;
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struct xkb_state *xkb_state;
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/* DND */
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struct wl_data_device_manager *dnd_devman;
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struct wl_data_device *dnd_ddev;
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struct wl_data_offer *dnd_offer;
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enum mp_dnd_action dnd_action;
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char *dnd_mime_type;
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int dnd_mime_score;
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int dnd_fd;
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/* Cursor */
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struct wl_cursor_theme *cursor_theme;
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struct wl_cursor *default_cursor;
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struct wl_surface *cursor_surface;
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int allocated_cursor_scale;
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bool cursor_visible;
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};
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int vo_wayland_init(struct vo *vo);
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int vo_wayland_reconfig(struct vo *vo);
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int vo_wayland_control(struct vo *vo, int *events, int request, void *arg);
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int last_available_sync(struct vo_wayland_state *wl);
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void vo_wayland_uninit(struct vo *vo);
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void vo_wayland_wakeup(struct vo *vo);
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void vo_wayland_wait_events(struct vo *vo, int64_t until_time_us);
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bool vo_wayland_wait_frame(struct vo_wayland_state *wl);
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void vo_wayland_set_opaque_region(struct vo_wayland_state *wl, int alpha);
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void wayland_sync_swap(struct vo_wayland_state *wl);
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void vo_wayland_sync_shift(struct vo_wayland_state *wl);
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void queue_new_sync(struct vo_wayland_state *wl);
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#endif /* MPLAYER_WAYLAND_COMMON_H */
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