tests/wayland: Add basic YCbCr ref-tests

The test makes sure the YCbCr formats create the expected image and we
don't accidentally break it.

Like all wayland tests, this is now part of mutter/wayland, mutter/tty,
and mutter/kvm and will use either shm or dma-buf depending on which
suite is chosen.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3371>

src/tests/meson.build

@@ -584,6 +584,7 @@ if have_native_tests
         test_client_executables.get('xdg-apply-limits'),
         test_client_executables.get('xdg-foreign'),
         test_client_executables.get('xdg-toplevel-bounds'),
+        test_client_executables.get('ycbcr'),
       ],
     },
   ]

src/tests/wayland-test-clients/meson.build

@@ -78,6 +78,9 @@ wayland_test_clients = [
   {
     'name': 'xdg-toplevel-bounds',
   },
+  {
+    'name': 'ycbcr',
+  },
 ]
 
 test_client_executables = {}

src/tests/wayland-test-clients/ycbcr.c

@@ -0,0 +1,231 @@
+/*
+ * Copyright (C) 2023 Red Hat, Inc.
+ *
+ * This program 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 of the
+ * License, or (at your option) any later version.
+ *
+ * This program 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 General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include <glib.h>
+#include <sys/mman.h>
+#include <unistd.h>
+#include <wayland-client.h>
+
+#include "wayland-test-client-utils.h"
+
+static WaylandDisplay *display;
+
+static struct wl_surface *surface;
+static struct xdg_surface *xdg_surface;
+static struct xdg_toplevel *xdg_toplevel;
+
+static gboolean waiting_for_configure = FALSE;
+
+static void
+shader_color_gradient (float  x,
+                       float  y,
+                       float *out_luma,
+                       float *out_cb,
+                       float *out_cr)
+{
+  *out_luma = 1.0;
+  *out_cb = x;
+  *out_cr = y;
+}
+
+static void
+shader_luma_gradient (float  x,
+                      float  y,
+                      float *out_luma,
+                      float *out_cb,
+                      float *out_cr)
+{
+  *out_luma = (x + y) / 2;
+  *out_cb = 0.5;
+  *out_cr = 0.5;
+}
+
+typedef void (*ShaderFunc) (float  x,
+                            float  y,
+                            float *out_luma,
+                            float *out_cb,
+                            float *out_cr);
+
+static void
+draw (uint32_t   drm_format,
+      ShaderFunc shader)
+{
+  WaylandBuffer *buffer;
+  uint8_t *planes[4];
+  size_t strides[4];
+  int x, y;
+
+#define BUFFER_WIDTH 64
+#define BUFFER_HEIGHT 64
+
+  buffer = wayland_buffer_create (display, NULL,
+                                  BUFFER_WIDTH, BUFFER_HEIGHT,
+                                  drm_format,
+                                  NULL, 0,
+                                  GBM_BO_USE_LINEAR);
+  if (!buffer)
+    g_error ("Failed to create buffer");
+
+  switch (drm_format)
+    {
+    case DRM_FORMAT_YUYV:
+      planes[0] = wayland_buffer_mmap_plane (buffer, 0, &strides[0]);
+      break;
+    case DRM_FORMAT_YUV420:
+      planes[0] = wayland_buffer_mmap_plane (buffer, 0, &strides[0]);
+      planes[1] = wayland_buffer_mmap_plane (buffer, 1, &strides[1]);
+      planes[2] = wayland_buffer_mmap_plane (buffer, 2, &strides[2]);
+      break;
+    }
+
+  for (y = 0; y < BUFFER_WIDTH; y++)
+    {
+      for (x = 0; x < BUFFER_WIDTH; x++)
+        {
+          uint8_t *pixel;
+          float luma;
+          float cb;
+          float cr;
+
+          shader (x / (BUFFER_WIDTH - 1.0),
+                  y / (BUFFER_HEIGHT - 1.0),
+                  &luma,
+                  &cb,
+                  &cr);
+
+          switch (drm_format)
+            {
+            case DRM_FORMAT_YUYV:
+              /* packed [31:0] Cr0:Y1:Cb0:Y0 8:8:8:8 little endian */
+              pixel = planes[0] + (y * strides[0]) + (x * 2);
+              pixel[0] = luma * 255;
+              if (x % 2 == 0)
+                pixel[1] = cb * 255;
+              else
+                pixel[1] = cr * 255;
+              break;
+            case DRM_FORMAT_YUV420:
+              /*
+               3 plane YCbCr
+               index 0: Y plane, [7:0] Y
+               index 1: Cb plane, [7:0] Cb
+               index 2: Cr plane, [7:0] Cr
+               2x2 subsampled Cb (1) and Cr (2) planes */
+              pixel = planes[0] + (y * strides[0]) + x;
+              pixel[0] = luma * 255;
+              pixel = planes[1] + (y / 2 * strides[1]) + x / 2;
+              pixel[0] = cb * 255;
+              pixel = planes[2] + (y / 2 * strides[2]) + x / 2;
+              pixel[0] = cr * 255;
+              break;
+            default:
+              g_assert_not_reached ();
+            }
+        }
+    }
+
+  wl_surface_damage_buffer (surface, 0, 0, BUFFER_WIDTH, BUFFER_HEIGHT);
+  wl_surface_attach (surface, wayland_buffer_get_wl_buffer (buffer), 0, 0);
+}
+
+static void
+handle_xdg_toplevel_configure (void                *data,
+                               struct xdg_toplevel *xdg_toplevel,
+                               int32_t              width,
+                               int32_t              height,
+                               struct wl_array     *state)
+{
+}
+
+static void
+handle_xdg_toplevel_close (void                *data,
+                           struct xdg_toplevel *xdg_toplevel)
+{
+  g_assert_not_reached ();
+}
+
+static const struct xdg_toplevel_listener xdg_toplevel_listener = {
+  handle_xdg_toplevel_configure,
+  handle_xdg_toplevel_close,
+};
+
+static void
+handle_xdg_surface_configure (void               *data,
+                              struct xdg_surface *xdg_surface,
+                              uint32_t            serial)
+{
+  xdg_surface_ack_configure (xdg_surface, serial);
+
+  waiting_for_configure = FALSE;
+}
+
+static const struct xdg_surface_listener xdg_surface_listener = {
+  handle_xdg_surface_configure,
+};
+
+static void
+wait_for_configure (void)
+{
+  waiting_for_configure = TRUE;
+  while (waiting_for_configure)
+    {
+      if (wl_display_dispatch (display->display) == -1)
+        exit (EXIT_FAILURE);
+    }
+}
+
+int
+main (int    argc,
+      char **argv)
+{
+  display = wayland_display_new (WAYLAND_DISPLAY_CAPABILITY_TEST_DRIVER);
+
+  surface = wl_compositor_create_surface (display->compositor);
+  xdg_surface = xdg_wm_base_get_xdg_surface (display->xdg_wm_base, surface);
+  xdg_surface_add_listener (xdg_surface, &xdg_surface_listener, NULL);
+  xdg_toplevel = xdg_surface_get_toplevel (xdg_surface);
+  xdg_toplevel_add_listener (xdg_toplevel, &xdg_toplevel_listener, NULL);
+  xdg_toplevel_set_title (xdg_toplevel, "ycbcr");
+  xdg_toplevel_set_fullscreen (xdg_toplevel, NULL);
+  wl_surface_commit (surface);
+
+  wait_for_configure ();
+
+  draw (DRM_FORMAT_YUYV, shader_luma_gradient);
+  wl_surface_commit (surface);
+  wait_for_effects_completed (display, surface);
+  wait_for_view_verified (display, 0);
+
+  draw (DRM_FORMAT_YUYV, shader_color_gradient);
+  wl_surface_commit (surface);
+  wait_for_view_verified (display, 1);
+
+  draw (DRM_FORMAT_YUV420, shader_luma_gradient);
+  wl_surface_commit (surface);
+  wait_for_view_verified (display, 2);
+
+  draw (DRM_FORMAT_YUV420, shader_color_gradient);
+  wl_surface_commit (surface);
+  wait_for_view_verified (display, 3);
+
+  g_clear_pointer (&xdg_toplevel, xdg_toplevel_destroy);
+  g_clear_pointer (&xdg_surface, xdg_surface_destroy);
+
+  g_clear_object (&display);
+}

src/tests/wayland-unit-tests.c

@@ -81,6 +81,16 @@ buffer_single_pixel_buffer (void)
   meta_wayland_test_client_finish (wayland_test_client);
 }
 
+static void
+buffer_ycbcr_basic (void)
+{
+  MetaWaylandTestClient *wayland_test_client;
+
+  wayland_test_client =
+    meta_wayland_test_client_new (test_context, "ycbcr");
+  meta_wayland_test_client_finish (wayland_test_client);
+}
+
 static gboolean
 set_true (gpointer user_data)
 {
@@ -878,6 +888,8 @@ init_tests (void)
                    buffer_transform);
   g_test_add_func ("/wayland/buffer/single-pixel-buffer",
                    buffer_single_pixel_buffer);
+  g_test_add_func ("/wayland/buffer/ycbcr-basic",
+                   buffer_ycbcr_basic);
   g_test_add_func ("/wayland/idle-inhibit/instant-destroy",
                    idle_inhibit_instant_destroy);
   g_test_add_func ("/wayland/registry/filter",