path: root/0006-wayland-HiDPI-support.patch

From 53a8296a68c2742728339e9e38865d0434f9260c Mon Sep 17 00:00:00 2001
From: Sebastian Krzyszkowiak <dos@dosowisko.net>
Date: Tue, 19 Feb 2019 03:59:06 +0100
Subject: [PATCH 6/6] wayland: HiDPI support

---
 src/video/wayland/SDL_waylandopengles.c |  39 ++++++--
 src/video/wayland/SDL_waylandopengles.h |   1 +
 src/video/wayland/SDL_waylandvideo.c    |  22 +++--
 src/video/wayland/SDL_waylandvideo.h    |   5 +
 src/video/wayland/SDL_waylandwindow.c   | 116 ++++++++++++++++++++++--
 src/video/wayland/SDL_waylandwindow.h   |   8 +-
 6 files changed, 170 insertions(+), 21 deletions(-)

diff --git a/src/video/wayland/SDL_waylandopengles.c b/src/video/wayland/SDL_waylandopengles.c
index aafd71eb5..396fc0b4a 100644
--- a/src/video/wayland/SDL_waylandopengles.c
+++ b/src/video/wayland/SDL_waylandopengles.c
@@ -71,16 +71,24 @@ Wayland_GLES_SwapWindow(_THIS, SDL_Window *window)
 
     // Wayland-EGL forbids drawing calls in-between SwapBuffers and wl_egl_window_resize
     if (data->resize.pending) {
+        if (data->scale_factor != data->resize.scale_factor) {
+            window->w = 0;
+            window->h = 0;
+        }
         SDL_SendWindowEvent(window, SDL_WINDOWEVENT_RESIZED, data->resize.width, data->resize.height);
         window->w = data->resize.width;
         window->h = data->resize.height;
-
-        WAYLAND_wl_egl_window_resize(data->egl_window, window->w, window->h, 0, 0);
-
-        if (data->waylandData->shell.xdg) {
-           xdg_surface_ack_configure(data->shell_surface.xdg.surface, data->resize.serial);
-        } else if (data->waylandData->shell.zxdg) {
-           zxdg_surface_v6_ack_configure(data->shell_surface.zxdg.surface, data->resize.serial);
+        data->scale_factor = data->resize.scale_factor;
+        wl_surface_set_buffer_scale(data->surface, data->scale_factor);
+        WAYLAND_wl_egl_window_resize(data->egl_window, window->w * data->scale_factor, window->h * data->scale_factor, 0, 0);
+
+        if (data->resize.configure) {
+           if (data->waylandData->shell.xdg) {
+              xdg_surface_ack_configure(data->shell_surface.xdg.surface, data->resize.serial);
+           } else if (data->waylandData->shell.zxdg) {
+              zxdg_surface_v6_ack_configure(data->shell_surface.zxdg.surface, data->resize.serial);
+           }
+           data->resize.configure = SDL_FALSE;
         }
 
         region = wl_compositor_create_region(data->waylandData->compositor);
@@ -113,6 +121,23 @@ Wayland_GLES_MakeCurrent(_THIS, SDL_Window * window, SDL_GLContext context)
     return ret;
 }
 
+void
+Wayland_GLES_GetDrawableSize(_THIS, SDL_Window * window, int * w, int * h)
+{
+    SDL_WindowData *data;
+    if (window->driverdata) {
+        data = (SDL_WindowData *) window->driverdata;
+
+        if (w) {
+            *w = window->w * data->scale_factor;
+        }
+
+        if (h) {
+            *h = window->h * data->scale_factor;
+        }
+    }
+}
+
 void 
 Wayland_GLES_DeleteContext(_THIS, SDL_GLContext context)
 {
diff --git a/src/video/wayland/SDL_waylandopengles.h b/src/video/wayland/SDL_waylandopengles.h
index 58d7f9b08..d1023d612 100644
--- a/src/video/wayland/SDL_waylandopengles.h
+++ b/src/video/wayland/SDL_waylandopengles.h
@@ -42,6 +42,7 @@ extern int Wayland_GLES_LoadLibrary(_THIS, const char *path);
 extern SDL_GLContext Wayland_GLES_CreateContext(_THIS, SDL_Window * window);
 extern int Wayland_GLES_SwapWindow(_THIS, SDL_Window * window);
 extern int Wayland_GLES_MakeCurrent(_THIS, SDL_Window * window, SDL_GLContext context);
+extern void Wayland_GLES_GetDrawableSize(_THIS, SDL_Window * window, int * w, int * h);
 extern void Wayland_GLES_DeleteContext(_THIS, SDL_GLContext context);
 
 #endif /* SDL_waylandopengles_h_ */
diff --git a/src/video/wayland/SDL_waylandvideo.c b/src/video/wayland/SDL_waylandvideo.c
index ab4fde0e6..6e54897a9 100644
--- a/src/video/wayland/SDL_waylandvideo.c
+++ b/src/video/wayland/SDL_waylandvideo.c
@@ -172,6 +172,7 @@ Wayland_CreateDevice(int devindex)
     device->GL_SwapWindow = Wayland_GLES_SwapWindow;
     device->GL_GetSwapInterval = Wayland_GLES_GetSwapInterval;
     device->GL_SetSwapInterval = Wayland_GLES_SetSwapInterval;
+    device->GL_GetDrawableSize = Wayland_GLES_GetDrawableSize;
     device->GL_MakeCurrent = Wayland_GLES_MakeCurrent;
     device->GL_CreateContext = Wayland_GLES_CreateContext;
     device->GL_LoadLibrary = Wayland_GLES_LoadLibrary;
@@ -226,7 +227,6 @@ display_handle_geometry(void *data,
     SDL_VideoDisplay *display = data;
 
     display->name = SDL_strdup(model);
-    display->driverdata = output;
 }
 
 static void
@@ -237,15 +237,15 @@ display_handle_mode(void *data,
                     int height,
                     int refresh)
 {
-    SDL_VideoDisplay *display = data;
     SDL_DisplayMode mode;
+    SDL_VideoDisplay *display = data;
 
     SDL_zero(mode);
     mode.format = SDL_PIXELFORMAT_RGB888;
     mode.w = width;
     mode.h = height;
     mode.refresh_rate = refresh / 1000; // mHz to Hz
-    mode.driverdata = display->driverdata;
+    mode.driverdata = ((SDL_WaylandOutputData*)display->driverdata)->output;
     SDL_AddDisplayMode(display, &mode);
 
     if (flags & WL_OUTPUT_MODE_CURRENT) {
@@ -258,8 +258,10 @@ static void
 display_handle_done(void *data,
                     struct wl_output *output)
 {
+    /* !!! FIXME: this will fail on any further property changes! */
     SDL_VideoDisplay *display = data;
     SDL_AddVideoDisplay(display);
+    wl_output_set_user_data(output, display->driverdata);
     SDL_free(display->name);
     SDL_free(display);
 }
@@ -269,7 +271,8 @@ display_handle_scale(void *data,
                      struct wl_output *output,
                      int32_t factor)
 {
-    // TODO: do HiDPI stuff.
+    SDL_VideoDisplay *display = data;
+    ((SDL_WaylandOutputData*)display->driverdata)->scale_factor = factor;
 }
 
 static const struct wl_output_listener output_listener = {
@@ -283,6 +286,7 @@ static void
 Wayland_add_display(SDL_VideoData *d, uint32_t id)
 {
     struct wl_output *output;
+    SDL_WaylandOutputData *data;
     SDL_VideoDisplay *display = SDL_malloc(sizeof *display);
     if (!display) {
         SDL_OutOfMemory();
@@ -296,6 +300,10 @@ Wayland_add_display(SDL_VideoData *d, uint32_t id)
         SDL_free(display);
         return;
     }
+    data = SDL_malloc(sizeof *data);
+    data->output = output;
+    data->scale_factor = 1.0;
+    display->driverdata = data;
 
     wl_output_add_listener(output, &output_listener, display);
 }
@@ -351,7 +359,7 @@ display_handle_global(void *data, struct wl_registry *registry, uint32_t id,
     /*printf("WAYLAND INTERFACE: %s\n", interface);*/
 
     if (strcmp(interface, "wl_compositor") == 0) {
-        d->compositor = wl_registry_bind(d->registry, id, &wl_compositor_interface, 1);
+        d->compositor = wl_registry_bind(d->registry, id, &wl_compositor_interface, SDL_min(3, version));
     } else if (strcmp(interface, "wl_output") == 0) {
         Wayland_add_display(d, id);
     } else if (strcmp(interface, "wl_seat") == 0) {
@@ -466,7 +474,9 @@ Wayland_VideoQuit(_THIS)
 
     for (i = 0; i < _this->num_displays; ++i) {
         SDL_VideoDisplay *display = &_this->displays[i];
-        wl_output_destroy(display->driverdata);
+
+        wl_output_destroy(((SDL_WaylandOutputData*)display->driverdata)->output);
+        SDL_free(display->driverdata);
         display->driverdata = NULL;
 
         for (j = display->num_display_modes; j--;) {
diff --git a/src/video/wayland/SDL_waylandvideo.h b/src/video/wayland/SDL_waylandvideo.h
index d173b28e5..753754d68 100644
--- a/src/video/wayland/SDL_waylandvideo.h
+++ b/src/video/wayland/SDL_waylandvideo.h
@@ -82,6 +82,11 @@ typedef struct {
     int relative_mouse_mode;
 } SDL_VideoData;
 
+typedef struct {
+    struct wl_output *output;
+    float scale_factor;
+} SDL_WaylandOutputData;
+
 #endif /* SDL_waylandvideo_h_ */
 
 /* vi: set ts=4 sw=4 expandtab: */
diff --git a/src/video/wayland/SDL_waylandwindow.c b/src/video/wayland/SDL_waylandwindow.c
index 6c924c2cf..d5352fa74 100644
--- a/src/video/wayland/SDL_waylandwindow.c
+++ b/src/video/wayland/SDL_waylandwindow.c
@@ -38,6 +38,10 @@
 #include "xdg-decoration-unstable-v1-client-protocol.h"
 #include "org-kde-kwin-server-decoration-manager-client-protocol.h"
 
+static float get_window_scale_factor(SDL_Window *window) {
+      return ((SDL_WindowData*)window->driverdata)->scale_factor;
+}
+
 /* On modern desktops, we probably will use the xdg-shell protocol instead
    of wl_shell, but wl_shell might be useful on older Wayland installs that
    don't have the newer protocol, or embedded things that don't have a full
@@ -107,11 +111,14 @@ handle_configure_zxdg_shell_surface(void *data, struct zxdg_surface_v6 *zxdg, ui
     struct wl_region *region;
 
     if (!wind->shell_surface.zxdg.initial_configure_seen) {
+        window->w = 0;
+        window->h = 0;
         SDL_SendWindowEvent(window, SDL_WINDOWEVENT_RESIZED, wind->resize.width, wind->resize.height);
         window->w = wind->resize.width;
         window->h = wind->resize.height;
 
-        WAYLAND_wl_egl_window_resize(wind->egl_window, window->w, window->h, 0, 0);
+        wl_surface_set_buffer_scale(wind->surface, get_window_scale_factor(window));
+        WAYLAND_wl_egl_window_resize(wind->egl_window, window->w * get_window_scale_factor(window), window->h * get_window_scale_factor(window), 0, 0);
 
         zxdg_surface_v6_ack_configure(zxdg, serial);
 
@@ -123,6 +130,7 @@ handle_configure_zxdg_shell_surface(void *data, struct zxdg_surface_v6 *zxdg, ui
         wind->shell_surface.zxdg.initial_configure_seen = SDL_TRUE;
     } else {
         wind->resize.pending = SDL_TRUE;
+        wind->resize.configure = SDL_TRUE;
         wind->resize.serial = serial;
     }
 }
@@ -208,11 +216,14 @@ handle_configure_xdg_shell_surface(void *data, struct xdg_surface *xdg, uint32_t
     struct wl_region *region;
 
     if (!wind->shell_surface.xdg.initial_configure_seen) {
+        window->w = 0;
+        window->h = 0;
         SDL_SendWindowEvent(window, SDL_WINDOWEVENT_RESIZED, wind->resize.width, wind->resize.height);
         window->w = wind->resize.width;
         window->h = wind->resize.height;
 
-        WAYLAND_wl_egl_window_resize(wind->egl_window, window->w, window->h, 0, 0);
+        wl_surface_set_buffer_scale(wind->surface, get_window_scale_factor(window));
+        WAYLAND_wl_egl_window_resize(wind->egl_window, window->w * get_window_scale_factor(window), window->h * get_window_scale_factor(window), 0, 0);
 
         xdg_surface_ack_configure(xdg, serial);
 
@@ -224,6 +235,7 @@ handle_configure_xdg_shell_surface(void *data, struct xdg_surface *xdg, uint32_t
         wind->shell_surface.xdg.initial_configure_seen = SDL_TRUE;
     } else {
         wind->resize.pending = SDL_TRUE;
+        wind->resize.configure = SDL_TRUE;
         wind->resize.serial = serial;
     }
 }
@@ -330,6 +342,78 @@ static const struct qt_extended_surface_listener extended_surface_listener = {
 };
 #endif /* SDL_VIDEO_DRIVER_WAYLAND_QT_TOUCH */
 
+static void
+update_scale_factor(SDL_WindowData *window) {
+   float old_factor = window->scale_factor, new_factor = 0.0;
+
+   if (!(window->sdlwindow->flags & SDL_WINDOW_ALLOW_HIGHDPI)) {
+       return;
+   }
+
+   if (!window->num_outputs) {
+       new_factor = old_factor;
+   }
+
+   if (FULLSCREEN_VISIBLE(window->sdlwindow) && window->sdlwindow->fullscreen_mode.driverdata) {
+       new_factor = ((SDL_WaylandOutputData*)(wl_output_get_user_data(window->sdlwindow->fullscreen_mode.driverdata)))->scale_factor;
+   }
+
+   for (int i = 0; i < window->num_outputs; i++) {
+       float factor = ((SDL_WaylandOutputData*)(wl_output_get_user_data(window->outputs[i])))->scale_factor;
+       if (factor > new_factor) {
+           new_factor = factor;
+       }
+   }
+
+   if (new_factor != old_factor) {
+       /* force the resize event to trigger, as the logical size didn't change */
+       window->resize.width = window->sdlwindow->w;
+       window->resize.height = window->sdlwindow->h;
+       window->resize.scale_factor = new_factor;
+       window->resize.pending = SDL_TRUE;
+   }
+}
+
+static void
+handle_surface_enter(void *data, struct wl_surface *surface,
+        struct wl_output *output) {
+    SDL_WindowData *window = data;
+
+    window->outputs = SDL_realloc(window->outputs, (window->num_outputs + 1) * sizeof *window->outputs);
+    window->outputs[window->num_outputs++] = output;
+    update_scale_factor(window);
+}
+
+static void
+handle_surface_leave(void *data, struct wl_surface *surface,
+        struct wl_output *output) {
+    SDL_WindowData *window = data;
+
+    if (window->num_outputs > 1) {
+       struct wl_output **new_outputs = SDL_malloc((window->num_outputs - 1) * sizeof *window->outputs), **iter = new_outputs;
+       for (int i=0; i < window->num_outputs; i++) {
+           if (window->outputs[i] != output) {
+               *iter = window->outputs[i];
+               iter++;
+           }
+       }
+       SDL_free(window->outputs);
+       window->outputs = new_outputs;
+       window->num_outputs--;
+    } else {
+       window->num_outputs = 0;
+       SDL_free(window->outputs);
+       window->outputs = NULL;
+    }
+
+    update_scale_factor(window);
+}
+
+static const struct wl_surface_listener surface_listener = {
+    handle_surface_enter,
+    handle_surface_leave
+};
+
 SDL_bool
 Wayland_GetWindowWMInfo(_THIS, SDL_Window * window, SDL_SysWMinfo * info)
 {
@@ -475,7 +559,7 @@ void
 Wayland_SetWindowFullscreen(_THIS, SDL_Window * window,
                             SDL_VideoDisplay * _display, SDL_bool fullscreen)
 {
-    struct wl_output *output = (struct wl_output *) _display->driverdata;
+    struct wl_output *output = ((SDL_WaylandOutputData*) _display->driverdata)->output;
     SetFullscreen(_this, window, fullscreen ? output : NULL);
 }
 
@@ -553,11 +637,28 @@ int Wayland_CreateWindow(_THIS, SDL_Window *window)
     data->waylandData = c;
     data->sdlwindow = window;
 
+    data->scale_factor = 1.0;
+
+    if (window->flags & SDL_WINDOW_ALLOW_HIGHDPI) {
+        for (int i=0; i < SDL_GetVideoDevice()->num_displays; i++) {
+            float scale = ((SDL_WaylandOutputData*)SDL_GetVideoDevice()->displays[i].driverdata)->scale_factor;
+            if (scale > data->scale_factor) {
+                data->scale_factor = scale;
+            }
+        }
+    }
+
     data->resize.pending = SDL_FALSE;
+    data->resize.width = window->w;
+    data->resize.height = window->h;
+    data->resize.scale_factor = data->scale_factor;
+
+    data->outputs = NULL;
+    data->num_outputs = 0;
 
     data->surface =
         wl_compositor_create_surface(c->compositor);
-    wl_surface_set_user_data(data->surface, data);
+    wl_surface_add_listener(data->surface, &surface_listener, data);
 
     if (c->shell.xdg) {
         data->shell_surface.xdg.surface = xdg_wm_base_get_xdg_surface(c->shell.xdg, data->surface);
@@ -587,7 +688,7 @@ int Wayland_CreateWindow(_THIS, SDL_Window *window)
 #endif /* SDL_VIDEO_DRIVER_WAYLAND_QT_TOUCH */
 
     data->egl_window = WAYLAND_wl_egl_window_create(data->surface,
-                                            window->w, window->h);
+                                            window->w * data->scale_factor, window->h * data->scale_factor);
 
     /* Create the GLES window surface */
     data->egl_surface = SDL_EGL_CreateSurface(_this, (NativeWindowType) data->egl_window);
@@ -676,9 +777,10 @@ void Wayland_SetWindowSize(_THIS, SDL_Window * window)
     SDL_WindowData *wind = window->driverdata;
     struct wl_region *region;
 
-    WAYLAND_wl_egl_window_resize(wind->egl_window, window->w, window->h, 0, 0);
+    wl_surface_set_buffer_scale(wind->surface, get_window_scale_factor(window));
+    WAYLAND_wl_egl_window_resize(wind->egl_window, window->w * get_window_scale_factor(window), window->h * get_window_scale_factor(window), 0, 0);
 
-    region =wl_compositor_create_region(data->compositor);
+    region = wl_compositor_create_region(data->compositor);
     wl_region_add(region, 0, 0, window->w, window->h);
     wl_surface_set_opaque_region(wind->surface, region);
     wl_region_destroy(region);
diff --git a/src/video/wayland/SDL_waylandwindow.h b/src/video/wayland/SDL_waylandwindow.h
index 4b69f7a4e..7b993a19e 100644
--- a/src/video/wayland/SDL_waylandwindow.h
+++ b/src/video/wayland/SDL_waylandwindow.h
@@ -71,11 +71,16 @@ typedef struct {
 #endif /* SDL_VIDEO_DRIVER_WAYLAND_QT_TOUCH */
 
     struct {
-        SDL_bool pending;
+        SDL_bool pending, configure;
         uint32_t serial;
         int width, height;
+        float scale_factor;
     } resize;
 
+    struct wl_output **outputs;
+    int num_outputs;
+
+    float scale_factor;
 } SDL_WindowData;
 
 extern void Wayland_ShowWindow(_THIS, SDL_Window *window);
-- 
2.20.1