[vlc-devel] [PATCH 2/6] opengl: add CreateOffscreen API

[Rémi Denis-Courmont]

Le tiistaina 23. helmikuuta 2021, 18.06.10 EET Romain Vimont a écrit :
> From: Alexandre Janniaux <ajanni at videolabs.io>
> 
> This will allow offscreen OpenGL implementations, which will produce
> picture_t.

Is there any point keeping the existing type of implementations?

> 
> Co-authored-by: Romain Vimont <rom1v at videolabs.io>
> ---
>  include/vlc_opengl.h      | 26 ++++++++++++++++++-
>  src/libvlccore.sym        |  1 +
>  src/video_output/opengl.c | 54 +++++++++++++++++++++++++++++++++++++++
>  3 files changed, 80 insertions(+), 1 deletion(-)
> 
> diff --git a/include/vlc_opengl.h b/include/vlc_opengl.h
> index a99c6ced64..798558e72a 100644
> --- a/include/vlc_opengl.h
> +++ b/include/vlc_opengl.h
> @@ -24,6 +24,8 @@
>  #ifndef VLC_GL_H
>  #define VLC_GL_H 1
> 
> +#include <vlc_es.h>
> +
>  /**
>   * \file
>   * This file defines GL structures and functions.
> @@ -37,6 +39,8 @@ struct vout_display_cfg;
>   * A VLC GL context (and its underlying surface)
>   */
>  typedef struct vlc_gl_t vlc_gl_t;
> +struct vlc_decoder_device;
> +struct vlc_video_context;
> 
>  enum vlc_gl_api_type {
>      VLC_OPENGL,
> @@ -47,14 +51,24 @@ struct vlc_gl_t
>  {
>      struct vlc_object_t obj;
> 
> +    struct vlc_decoder_device *device;
>      struct vout_window_t *surface;

It's strange to have a surface for offscreen rendering.

>      module_t *module;
>      void *sys;
> 
> +    vlc_fourcc_t offscreen_chroma_out;
> +    struct vlc_video_context *offscreen_vctx_out;
> +    /* Flag to indicate if the OpenGL implementation produces upside-down
> +     * pictures */
> +    bool offscreen_vflip;
> +
>      int  (*make_current)(vlc_gl_t *);
>      void (*release_current)(vlc_gl_t *);
>      void (*resize)(vlc_gl_t *, unsigned, unsigned);
> -    void (*swap)(vlc_gl_t *);
> +    union {
> +        void (*swap)(vlc_gl_t *);
> +        picture_t *(*swap_offscreen)(vlc_gl_t *);
> +    };
>      void*(*get_proc_address)(vlc_gl_t *, const char *);
>      void (*destroy)(vlc_gl_t *);
> 
> @@ -99,6 +113,11 @@ struct vlc_gl_t
>   */
>  VLC_API vlc_gl_t *vlc_gl_Create(const struct vout_display_cfg *cfg,
>                                  unsigned flags, const char *name) VLC_USED;
> +VLC_API vlc_gl_t *vlc_gl_CreateOffscreen(vlc_object_t *parent,
> +                                         struct vlc_decoder_device *device,
> +                                         unsigned width, unsigned height,
> +                                         unsigned flags, const char
> *name); +
>  VLC_API void vlc_gl_Release(vlc_gl_t *);
>  VLC_API void vlc_gl_Hold(vlc_gl_t *);
> 
> @@ -123,6 +142,11 @@ static inline void vlc_gl_Swap(vlc_gl_t *gl)
>      gl->swap(gl);
>  }
> 
> +static inline picture_t *vlc_gl_SwapOffscreen(vlc_gl_t *gl)
> +{
> +    return gl->swap_offscreen(gl);
> +}
> +
>  static inline void *vlc_gl_GetProcAddress(vlc_gl_t *gl, const char *name)
>  {
>      return gl->get_proc_address(gl, name);
> diff --git a/src/libvlccore.sym b/src/libvlccore.sym
> index 71267d5dfc..0c130543e5 100644
> --- a/src/libvlccore.sym
> +++ b/src/libvlccore.sym
> @@ -695,6 +695,7 @@ vlc_queue_Enqueue
>  vlc_queue_Dequeue
>  vlc_queue_DequeueAll
>  vlc_gl_Create
> +vlc_gl_CreateOffscreen
>  vlc_gl_Release
>  vlc_gl_Hold
>  vlc_gl_surface_Create
> diff --git a/src/video_output/opengl.c b/src/video_output/opengl.c
> index 8355c16135..cf0db8567f 100644
> --- a/src/video_output/opengl.c
> +++ b/src/video_output/opengl.c
> @@ -28,6 +28,7 @@
>  #include <vlc_common.h>
>  #include <vlc_atomic.h>
>  #include <vlc_opengl.h>
> +#include <vlc_codec.h>
>  #include <vlc_vout_display.h>
>  #include "libvlc.h"
>  #include <vlc_modules.h>
> @@ -96,6 +97,59 @@ vlc_gl_t *vlc_gl_Create(const struct vout_display_cfg
> *restrict cfg, return &glpriv->gl;
>  }
> 
> +vlc_gl_t *vlc_gl_CreateOffscreen(vlc_object_t *parent,
> +                                 struct vlc_decoder_device *device,
> +                                 unsigned width, unsigned height,
> +                                 unsigned flags, const char *name)
> +{
> +    struct vlc_gl_priv_t *glpriv;
> +    const char *type;
> +
> +    switch (flags /*& VLC_OPENGL_API_MASK*/)
> +    {
> +        case VLC_OPENGL:
> +            type = "opengl offscreen";
> +            break;
> +        case VLC_OPENGL_ES2:
> +            type = "opengl es2 offscreen";
> +            break;
> +        default:
> +            return NULL;
> +    }
> +
> +    glpriv = vlc_custom_create(parent, sizeof (*glpriv), "gl");
> +    if (unlikely(glpriv == NULL))
> +        return NULL;
> +
> +    vlc_gl_t *gl = &glpriv->gl;
> +
> +    gl->offscreen_chroma_out = VLC_CODEC_UNKNOWN;
> +    gl->offscreen_vflip = false;
> +    gl->offscreen_vctx_out = NULL;
> +
> +    gl->surface = NULL;
> +    gl->device = device ? vlc_decoder_device_Hold(device) : NULL;
> +    gl->module = vlc_module_load(gl, type, name, true, vlc_gl_start, gl,
> width, +                                 height);
> +    if (gl->module == NULL)
> +    {
> +        vlc_object_delete(gl);
> +        return NULL;
> +    }
> +
> +    /* The implementation must initialize the output chroma */
> +    assert(gl->offscreen_chroma_out != VLC_CODEC_UNKNOWN);
> +
> +    vlc_atomic_rc_init(&glpriv->rc);
> +
> +    assert(gl->make_current);
> +    assert(gl->release_current);
> +    assert(gl->swap_offscreen);
> +    assert(gl->get_proc_address);
> +
> +    return &glpriv->gl;
> +}
> +
>  void vlc_gl_Hold(vlc_gl_t *gl)
>  {
>      struct vlc_gl_priv_t *glpriv = (struct vlc_gl_priv_t *)gl;


-- 
Rémi Denis-Courmont
http://www.remlab.net/