libplacebo: add libplacebo<->OpenGL wrapper module

Supports both GL and GLES2, configurably.

configure.ac

@@ -3291,6 +3291,10 @@ AS_IF([test "$enable_libplacebo" != "no"], [
   PKG_CHECK_MODULES([LIBPLACEBO], [libplacebo >= 1.7], [
     AC_DEFINE([HAVE_LIBPLACEBO], [1], [Define to 1 if libplacebo is enabled.])
     AC_CHECK_HEADER([libplacebo/vulkan.h], [VLC_ADD_PLUGIN([placebo_vk])])
+    AC_CHECK_HEADER([libplacebo/opengl.h], [
+        VLC_ADD_PLUGIN([placebo_gl])
+        VLC_ADD_PLUGIN([placebo_gles2])
+    ])
   ], [
     AS_IF([test -n "${enable_libplacebo}"], [
       AC_MSG_ERROR([${LIBPLACEBO_PKG_ERRORS}.])

modules/video_output/libplacebo/Makefile.am

@@ -35,3 +35,26 @@ if HAVE_VULKAN
 vout_LTLIBRARIES += $(LTLIBplacebo_vk)
 EXTRA_LTLIBRARIES += libplacebo_vk_plugin.la
 endif
+
+### OpenGL ###
+libplacebo_gl_plugin_la_SOURCES = $(LIBPLACEBO_COMMONSOURCES) \
+				  video_output/libplacebo/instance_opengl.c
+libplacebo_gl_plugin_la_CFLAGS = $(AM_CFLAGS) $(LIBPLACEBO_CFLAGS)
+libplacebo_gl_plugin_la_LIBADD = $(LIBPLACEBO_LIBS) libvlc_opengl.la
+libplacebo_gl_plugin_la_LDFLAGS = $(AM_LDFLAGS) -rpath '$(voutdir)'
+
+libplacebo_gles2_plugin_la_SOURCES = $(LIBPLACEBO_COMMONSOURCES) \
+				     video_output/libplacebo/instance_opengl.c
+libplacebo_gles2_plugin_la_CFLAGS = $(AM_CFLAGS) $(LIBPLACEBO_CFLAGS) -DUSE_OPENGL_ES2
+libplacebo_gles2_plugin_la_LIBADD = $(LIBPLACEBO_LIBS) libvlc_opengles.la
+libplacebo_gles2_plugin_la_LDFLAGS = $(AM_LDFLAGS) -rpath '$(voutdir)'
+
+if HAVE_GL
+vout_LTLIBRARIES += $(LTLIBplacebo_gl)
+EXTRA_LTLIBRARIES += libplacebo_gl_plugin.la
+endif
+
+if HAVE_GLES2
+vout_LTLIBRARIES += $(LTLIBplacebo_gles2)
+EXTRA_LTLIBRARIES += libplacebo_gles2_plugin.la
+endif

modules/video_output/libplacebo/instance_opengl.c

@@ -0,0 +1,173 @@
+/**
+ * @file instance_opengl.c
+ * @brief OpenGL specific libplacebo GPU wrapper
+ */
+/*****************************************************************************
+ * Copyright © 2021 Niklas Haas
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
+ *****************************************************************************/
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <vlc_common.h>
+#include <vlc_plugin.h>
+#include <vlc_opengl.h>
+
+#include <libplacebo/opengl.h>
+
+#include "instance.h"
+#include "utils.h"
+
+static int InitInstance(vlc_placebo_t *pl, const vout_display_cfg_t *cfg);
+static void CloseInstance(vlc_placebo_t *pl);
+static int MakeCurrent(vlc_placebo_t *pl);
+static void ReleaseCurrent(vlc_placebo_t *pl);
+
+#define GL_TEXT N_("OpenGL extension")
+#define GLES2_TEXT N_("OpenGL ES 2 extension")
+#define PROVIDER_LONGTEXT N_( \
+    "Extension through which to use the Open Graphics Library (OpenGL).")
+
+#define ALLOWSW_TEXT "Allow software rasterizers"
+#define ALLOWSW_LONGTEXT "If enabled, allow the use of OpenGL contexts detected as software rasterizers (e.g. llvmpipe, swrast)."
+
+#define SWAP_DEPTH_TEXT "Maximum frame latency"
+#define SWAP_DEPTH_LONGTEXT "Attempt limiting the maximum frame latency. The true frame latency may be lower than this setting, depending on OpenGL driver internals and the VLC clock settings."
+
+vlc_module_begin()
+    set_category(CAT_VIDEO)
+    set_subcategory(SUBCAT_VIDEO_VOUT)
+    set_capability("libplacebo gpu", 40)
+    set_callback(InitInstance)
+#ifdef USE_OPENGL_ES2
+# define API VLC_OPENGL_ES2
+# define MODULE_VARNAME "pl-gles2"
+    set_shortname("libplacebo OpenGL ES2")
+    set_description(N_("OpenGL ES2 based GPU instance"))
+    add_shortcut("pl_opengles2", "pl_gles2")
+    add_module(MODULE_VARNAME, "opengl es2", NULL, GLES2_TEXT, PROVIDER_LONGTEXT);
+#else // !USE_OPENGL_ES2
+# define API VLC_OPENGL
+# define MODULE_VARNAME "pl-gl"
+    set_shortname("libplacebo OpenGL")
+    set_description(N_("OpenGL based GPU instance"))
+    add_shortcut("pl_opengl", "pl_gl")
+    add_module(MODULE_VARNAME, "opengl", NULL, GL_TEXT, PROVIDER_LONGTEXT);
+#endif
+
+    set_section("Context settings", NULL)
+#if PL_API_VER >= 90
+    add_bool("gl-allow-sw", false, ALLOWSW_TEXT, ALLOWSW_LONGTEXT, false)
+#endif
+    add_integer_with_range("gl-swap-depth", 0,
+            0, 4, SWAP_DEPTH_TEXT, SWAP_DEPTH_LONGTEXT, false)
+vlc_module_end()
+
+struct vlc_placebo_system_t {
+    vlc_gl_t *gl;
+    const struct pl_opengl *opengl;
+};
+
+static const struct vlc_placebo_operations instance_opts =
+{
+    .close = CloseInstance,
+    .make_current = MakeCurrent,
+    .release_current = ReleaseCurrent,
+};
+
+static int InitInstance(vlc_placebo_t *pl, const vout_display_cfg_t *cfg)
+{
+    vlc_placebo_system_t *sys = pl->sys =
+        vlc_obj_calloc(VLC_OBJECT(pl), 1, sizeof (*sys));
+    if (unlikely(sys == NULL))
+        return VLC_ENOMEM;
+
+    bool current = false;
+
+    char *name = var_InheritString(pl, MODULE_VARNAME);
+    sys->gl = vlc_gl_Create(cfg, API, name);
+    free(name);
+    if (!sys->gl || vlc_gl_MakeCurrent(sys->gl) != VLC_SUCCESS)
+        goto error;
+
+    current = true;
+
+    // Create OpenGL wrapper
+    sys->opengl = pl_opengl_create(pl->ctx, &(struct pl_opengl_params) {
+#if PL_API_VER >= 90
+        .allow_software = var_InheritBool(pl, "gl-allow-sw"),
+#endif
+        .debug = true, // this only sets up the debug report callback
+    });
+    vlc_gl_ReleaseCurrent (sys->gl);
+    if (!sys->opengl)
+        goto error;
+
+
+    // Create swapchain for this surface
+    struct pl_opengl_swapchain_params swap_params = {
+        .swap_buffers = (void (*)(void *)) vlc_gl_Swap,
+        .max_swapchain_depth = var_InheritInteger(pl, "gl-swap-depth"),
+        .priv = sys->gl,
+    };
+
+    pl->swapchain = pl_opengl_create_swapchain(sys->opengl, &swap_params);
+    if (!pl->swapchain)
+        goto error;
+
+    vlc_gl_ReleaseCurrent(sys->gl);
+
+    pl->gpu = sys->opengl->gpu;
+    pl->ops = &instance_opts;
+    return VLC_SUCCESS;
+
+error:
+    if (current)
+        vlc_gl_ReleaseCurrent(sys->gl);
+    CloseInstance(pl);
+    return VLC_EGENERIC;
+}
+
+static void CloseInstance(vlc_placebo_t *pl)
+{
+    vlc_placebo_system_t *sys = pl->sys;
+
+    if (sys->gl != NULL) {
+        if (vlc_gl_MakeCurrent(sys->gl) == VLC_SUCCESS) {
+            pl_opengl_destroy(&sys->opengl);
+            vlc_gl_ReleaseCurrent(sys->gl);
+        }
+
+        vlc_gl_Release(sys->gl);
+    }
+
+    vlc_obj_free(VLC_OBJECT(pl), sys);
+    pl->sys = NULL;
+}
+
+static int MakeCurrent(vlc_placebo_t *pl)
+{
+    vlc_placebo_system_t *sys = pl->sys;
+    return vlc_gl_MakeCurrent(sys->gl);
+}
+
+static void ReleaseCurrent(vlc_placebo_t *pl)
+{
+    vlc_placebo_system_t *sys = pl->sys;
+    vlc_gl_ReleaseCurrent(sys->gl);
+}

po/POTFILES.in

@@ -1300,6 +1300,7 @@ modules/video_output/fb.c
 modules/video_output/glx.c
 modules/video_output/kva.c
 modules/video_output/libplacebo/display.c
+modules/video_output/libplacebo/instance_opengl.c
 modules/video_output/libplacebo/instance_vulkan.c
 modules/video_output/macosx.m
 modules/video_output/opengl/display.c