[vlc-devel] [PATCH 01/27] opengl: introduce OpenGL filter API
Alexandre Janniaux
ajanni at videolabs.io
Fri Jun 26 17:30:16 CEST 2020
Hi,
On Fri, Jun 26, 2020 at 05:22:20PM +0200, Romain Vimont wrote:
> On Fri, Jun 26, 2020 at 10:58:40AM +0200, Alexandre Janniaux wrote:
> > Hi,
> >
> > IMHO, there is no point in mentionning that you extract a
> > superclass if in the end, you extract a specific field.
>
> I wanted to say that semantically, this commit extracts an
> "interface"/"super-class" containing what is specific to a filter. And
> that the renderer now "extends"/"implements" it (it is a specific
> filter).
>
> (We could also say that the filter trait is implemented for the
> renderer.) ;)
>
> > A superclass would probably be a direct pointer cast like
> >
> > > + struct vlc_gl_filter *renderer_filter = (strcut vlc_gl_filter*)vgl->renderer;
>
> It's just an implementation/code-style detail. We could move the filter
> field so that it becomes the first, and cast as you say (but I prefer to
> use the field explicitly for type-checking).
>
> However, I agree that it may be better to avoid concepts from other
> languages. I suggest to simplify as follow:
>
> Expose a filter API, and make renderer a specific filter.
>
> What do you think?
I agree, as you want for the message as long as it follows
what you said. :)
>
> >
> > Regards,
> > --
> > Alexandre Janniaux
> > Videolabs
> >
> > On Thu, Jun 25, 2020 at 02:22:48PM +0200, Romain Vimont wrote:
> > > Extract a "super-class" filter from renderer. A renderer is now a
> > > specific filter.
> > >
> > > Co-authored-by: Alexandre Janniaux <ajanni at videolabs.io>
> > > ---
> > > modules/video_output/opengl/Makefile.am | 1 +
> > > modules/video_output/opengl/filter.h | 42 +++++++++++++++++++++++
> > > modules/video_output/opengl/renderer.c | 16 +++++++--
> > > modules/video_output/opengl/renderer.h | 12 +++----
> > > modules/video_output/opengl/vout_helper.c | 4 ++-
> > > 5 files changed, 64 insertions(+), 11 deletions(-)
> > > create mode 100644 modules/video_output/opengl/filter.h
> > >
> > > diff --git a/modules/video_output/opengl/Makefile.am b/modules/video_output/opengl/Makefile.am
> > > index 58acc824fc..3be82c458c 100644
> > > --- a/modules/video_output/opengl/Makefile.am
> > > +++ b/modules/video_output/opengl/Makefile.am
> > > @@ -1,4 +1,5 @@
> > > OPENGL_COMMONSOURCES = video_output/opengl/vout_helper.c \
> > > + video_output/opengl/filter.h \
> > > video_output/opengl/gl_api.c \
> > > video_output/opengl/gl_api.h \
> > > video_output/opengl/gl_common.h \
> > > diff --git a/modules/video_output/opengl/filter.h b/modules/video_output/opengl/filter.h
> > > new file mode 100644
> > > index 0000000000..f4b3f8bbf2
> > > --- /dev/null
> > > +++ b/modules/video_output/opengl/filter.h
> > > @@ -0,0 +1,42 @@
> > > +/*****************************************************************************
> > > + * filter.h
> > > + *****************************************************************************
> > > + * Copyright (C) 2020 VLC authors and VideoLAN
> > > + * Copyright (C) 2020 Videolabs
> > > + *
> > > + * 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.
> > > + *****************************************************************************/
> > > +
> > > +#ifndef VLC_GL_FILTER_H
> > > +#define VLC_GL_FILTER_H
> > > +
> > > +struct vlc_gl_filter;
> > > +
> > > +struct vlc_gl_filter_ops {
> > > + /**
> > > + * Draw the result of the filter to the current framebuffer
> > > + */
> > > + int (*draw)(struct vlc_gl_filter *filter);
> > > +};
> > > +
> > > +/**
> > > + * OpenGL filter, in charge of a rendering pass.
> > > + */
> > > +struct vlc_gl_filter {
> > > + const struct vlc_gl_filter_ops *ops;
> > > + void *sys;
> > > +};
> > > +
> > > +#endif
> > > diff --git a/modules/video_output/opengl/renderer.c b/modules/video_output/opengl/renderer.c
> > > index aa51f8b3a3..590fc3e46c 100644
> > > --- a/modules/video_output/opengl/renderer.c
> > > +++ b/modules/video_output/opengl/renderer.c
> > > @@ -37,6 +37,7 @@
> > > #include <vlc_es.h>
> > > #include <vlc_picture.h>
> > >
> > > +#include "filter.h"
> > > #include "gl_util.h"
> > > #include "internal.h"
> > > #include "vout_helper.h"
> > > @@ -321,6 +322,9 @@ vlc_gl_renderer_Delete(struct vlc_gl_renderer *renderer)
> > >
> > > static int SetupCoords(struct vlc_gl_renderer *renderer);
> > >
> > > +static int
> > > +Draw(struct vlc_gl_filter *filter);
> > > +
> > > struct vlc_gl_renderer *
> > > vlc_gl_renderer_New(vlc_gl_t *gl, const struct vlc_gl_api *api,
> > > struct vlc_gl_sampler *sampler)
> > > @@ -332,6 +336,12 @@ vlc_gl_renderer_New(vlc_gl_t *gl, const struct vlc_gl_api *api,
> > > if (!renderer)
> > > return NULL;
> > >
> > > + static const struct vlc_gl_filter_ops filter_ops = {
> > > + .draw = Draw,
> > > + };
> > > + renderer->filter.ops = &filter_ops;
> > > + renderer->filter.sys = renderer;
> > > +
> > > renderer->sampler = sampler;
> > >
> > > renderer->gl = gl;
> > > @@ -735,9 +745,11 @@ static int SetupCoords(struct vlc_gl_renderer *renderer)
> > > return VLC_SUCCESS;
> > > }
> > >
> > > -int
> > > -vlc_gl_renderer_Draw(struct vlc_gl_renderer *renderer)
> > > +static int
> > > +Draw(struct vlc_gl_filter *filter)
> > > {
> > > + struct vlc_gl_renderer *renderer = filter->sys;
> > > +
> > > const opengl_vtable_t *vt = renderer->vt;
> > >
> > > vt->Clear(GL_COLOR_BUFFER_BIT);
> > > diff --git a/modules/video_output/opengl/renderer.h b/modules/video_output/opengl/renderer.h
> > > index 7130cfb262..9aec83d2e2 100644
> > > --- a/modules/video_output/opengl/renderer.h
> > > +++ b/modules/video_output/opengl/renderer.h
> > > @@ -26,6 +26,7 @@
> > > #include <vlc_opengl.h>
> > > #include <vlc_plugin.h>
> > >
> > > +#include "filter.h"
> > > #include "gl_api.h"
> > > #include "gl_common.h"
> > > #include "interop.h"
> > > @@ -47,6 +48,9 @@ struct vlc_gl_renderer
> > > const struct vlc_gl_api *api;
> > > const opengl_vtable_t *vt; /* for convenience, same as &api->vt */
> > >
> > > + /* vlc_gl_renderer "extends" vlc_gl_filter */
> > > + struct vlc_gl_filter filter;
> > > +
> > > /* True to dump shaders */
> > > bool dump_shaders;
> > >
> > > @@ -108,14 +112,6 @@ vlc_gl_renderer_New(vlc_gl_t *gl, const struct vlc_gl_api *api,
> > > void
> > > vlc_gl_renderer_Delete(struct vlc_gl_renderer *renderer);
> > >
> > > -/**
> > > - * Draw the prepared picture
> > > - *
> > > - * \param sr the renderer
> > > - */
> > > -int
> > > -vlc_gl_renderer_Draw(struct vlc_gl_renderer *renderer);
> > > -
> > > int
> > > vlc_gl_renderer_SetViewpoint(struct vlc_gl_renderer *renderer,
> > > const vlc_viewpoint_t *p_vp);
> > > diff --git a/modules/video_output/opengl/vout_helper.c b/modules/video_output/opengl/vout_helper.c
> > > index b6105dd062..993bb405f1 100644
> > > --- a/modules/video_output/opengl/vout_helper.c
> > > +++ b/modules/video_output/opengl/vout_helper.c
> > > @@ -267,7 +267,9 @@ int vout_display_opengl_Display(vout_display_opengl_t *vgl)
> > > OpenGL providers can call vout_display_opengl_Display to force redraw.
> > > Currently, the OS X provider uses it to get a smooth window resizing */
> > >
> > > - int ret = vlc_gl_renderer_Draw(vgl->renderer);
> > > + /* Retrieve the "super-class" (renderer "extends" filter) */
> > > + struct vlc_gl_filter *renderer_filter = &vgl->renderer->filter;
> > > + int ret = renderer_filter->ops->draw(renderer_filter);
> > > if (ret != VLC_SUCCESS)
> > > return ret;
> > >
> > > --
> > > 2.27.0
> > >
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