[vlc-devel] [PATCH v2 1/3] vgl: provide a module to allow rendering in a user defined opengl context

[Pierre Lamot]

  This module aims to provide the same kind of functionnality as vmem but for
  opengl rendering.

  Users will have to provide different callbacks:

  * vgl-resize-cb will be called when video size changes
  * vgl-cleanup-cb to release resources
  * vgl-swap-cb that will be called once the current frame has been rendered
  * vgl-make-current-cb to enter/leave the opengl context
  * vgl-get-proc-address-cb to provide opengl functions

  Note that users will have to ensure synchronisation on their side since
  VLC will run and render OpenGL in its own thread.
---
 modules/video_output/Makefile.am          |   2 +
 modules/video_output/opengl/vout_helper.c |   1 +
 modules/video_output/vgl.c                | 161 ++++++++++++++++++++++
 3 files changed, 164 insertions(+)
 create mode 100644 modules/video_output/vgl.c

diff --git a/modules/video_output/Makefile.am b/modules/video_output/Makefile.am
index 3013e3fd1d..9df738fff3 100644
--- a/modules/video_output/Makefile.am
+++ b/modules/video_output/Makefile.am
@@ -454,10 +454,12 @@ libvdummy_plugin_la_SOURCES = video_output/vdummy.c
 libvmem_plugin_la_SOURCES = video_output/vmem.c
 libwdummy_plugin_la_SOURCES = video_output/wdummy.c
 libyuv_plugin_la_SOURCES = video_output/yuv.c
+libvgl_plugin_la_SOURCES = video_output/vgl.c
 
 vout_LTLIBRARIES += \
 	libflaschen_plugin.la \
 	libvdummy_plugin.la \
 	libvmem_plugin.la \
 	libwdummy_plugin.la \
+	libvgl_plugin.la \
 	libyuv_plugin.la
diff --git a/modules/video_output/opengl/vout_helper.c b/modules/video_output/opengl/vout_helper.c
index 33f738f579..e9b458515b 100644
--- a/modules/video_output/opengl/vout_helper.c
+++ b/modules/video_output/opengl/vout_helper.c
@@ -979,6 +979,7 @@ vout_display_opengl_t *vout_display_opengl_New(video_format_t *fmt,
     }
 
     GL_ASSERT_NOERROR();
+
     return vgl;
 }
 
diff --git a/modules/video_output/vgl.c b/modules/video_output/vgl.c
new file mode 100644
index 0000000000..b565da4bea
--- /dev/null
+++ b/modules/video_output/vgl.c
@@ -0,0 +1,161 @@
+/*****************************************************************************
+ * vgl.c: virtual LibVLC OpenGL extension
+ *****************************************************************************
+ * Copyright (c) 2018 VLC authors and VideoLAN
+ *
+ * Authors: Pierre Lamot <pierre at videolabs.io>
+ *
+ * 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_vout_display.h>
+#include <vlc_opengl.h>
+
+
+/*****************************************************************************
+ * Local prototypes.
+ *****************************************************************************/
+
+struct vout_display_sys_t
+{
+    vlc_gl_t              *gl;
+
+    bool (*makeCurrentCb)(void* opaque, bool);
+    void* (*getProcAddressCb)(void* opaque, const char *name);
+    void (*swapCb)(void* opaque);
+    void (*resizeCb)(void* opaque, unsigned, unsigned);
+    void (*cleanupCb)(void* opaque);
+
+    void* opaque;
+    unsigned width;
+    unsigned height;
+};
+
+
+static void *OurGetProcAddress(vlc_gl_t *gl, const char *name)
+{
+    vout_display_sys_t *sys = gl->sys;
+    return sys->getProcAddressCb(sys->opaque, name);
+}
+
+static int MakeCurrent(vlc_gl_t *gl)
+{
+    vout_display_sys_t *sys = gl->sys;
+    bool success = sys->makeCurrentCb(sys->opaque, true);
+    return success ? VLC_SUCCESS : VLC_EGENERIC;
+}
+
+static void ReleaseCurrent(vlc_gl_t *gl)
+{
+    vout_display_sys_t *sys = gl->sys;
+    sys->makeCurrentCb(sys->opaque, false);
+}
+
+static void SwapBuffers(vlc_gl_t *gl)
+{
+    vout_display_sys_t *sys = gl->sys;
+    sys->swapCb(sys->opaque);
+}
+
+static void Resize(vlc_gl_t * gl, unsigned w, unsigned h)
+{
+    vout_display_sys_t *sys = gl->sys;
+    if ( sys->width == w && sys->height == h )
+        return;
+
+    if ( !sys->resizeCb )
+        return;
+
+    MakeCurrent(gl);
+    sys->resizeCb(sys->opaque, w, h);
+    ReleaseCurrent(gl);
+    sys->width = w;
+    sys->height = h;
+}
+
+static void Close(vlc_object_t *object)
+{
+    vlc_gl_t *gl = (vlc_gl_t *)object;
+    vout_display_sys_t *sys = gl->sys;
+    if (sys->cleanupCb)
+        sys->cleanupCb(sys->opaque);
+    free(sys);
+}
+
+
+#define SET_CALLBACK_ADDR(var, varname) \
+    do {                                                           \
+        var = var_InheritAddress(gl, varname);                     \
+        if (! var) {                                               \
+            msg_Err( gl, varname " address is missing" );          \
+            goto error;                                            \
+        }                                                          \
+    } while(0)
+
+static int Open(vlc_object_t *object)
+{
+    vlc_gl_t *gl = (vlc_gl_t *)object;
+    vout_display_sys_t *sys;
+
+    /* Allocate structure */
+    gl->sys = sys = calloc(1, sizeof(*sys));
+    if (!sys)
+        return VLC_ENOMEM;
+
+    sys->opaque = var_InheritAddress(gl, "vgl-opaque");
+    sys->resizeCb = var_InheritAddress(gl, "vgl-resize-cb");
+    sys->cleanupCb = var_InheritAddress(gl, "vgl-cleanup-cb");
+    SET_CALLBACK_ADDR(sys->makeCurrentCb, "vgl-make-current-cb");
+    SET_CALLBACK_ADDR(sys->getProcAddressCb, "vgl-get-proc-address-cb");
+    SET_CALLBACK_ADDR(sys->swapCb, "vgl-swap-cb");
+
+    gl->makeCurrent = MakeCurrent;
+    gl->releaseCurrent = ReleaseCurrent;
+    gl->resize = Resize;
+    gl->swap = SwapBuffers;
+    gl->getProcAddress = OurGetProcAddress;
+    return VLC_SUCCESS;
+
+error:
+    Close(object);
+    return VLC_EGENERIC;
+}
+
+#undef SET_CALLBACK_ADDR
+
+/*****************************************************************************
+ * Module descriptor
+ *****************************************************************************/
+
+vlc_module_begin()
+    set_shortname(N_("GL texture"))
+    set_description(N_("GL texture output"))
+    set_category(CAT_VIDEO)
+    set_subcategory(SUBCAT_VIDEO_VOUT)
+
+    set_capability("opengl", 0)
+    set_callbacks(Open, Close)
+    add_shortcut("vglmem")
+
+    add_submodule ()
+    set_capability ("opengl es2", 0)
+    set_callbacks (Open, Close)
+    add_shortcut ("vglmem")
+vlc_module_end()
-- 
2.17.1