client API: deprecate opengl-cb API and introduce a replacement API

The purpose of the new API is to make it useable with other APIs than
OpenGL, especially D3D11 and vulkan. In theory it's now possible to
support other vo_gpu backends, as well as backends that don't use the
vo_gpu code at all.

This also aims to get rid of the dumb mpv_get_sub_api() function. The
life cycle of the new mpv_render_context is a bit different from
mpv_opengl_cb_context, and you explicitly create/destroy the new
context, instead of calling init/uninit on an object returned by
mpv_get_sub_api().

In other to make the render API generic, it's annoyingly EGL style, and
requires you to pass in API-specific objects to generic functions. This
is to avoid explicit objects like the internal ra API has, because that
sounds more complicated and annoying for an API that's supposed to never
change.

The opengl_cb API will continue to exist for a bit longer, but
internally there are already a few tradeoffs, like reduced
thread-safety.

Mostly untested. Seems to work fine with mpc-qt.

2 files changed, 220 insertions, 0 deletions

diff --git a/video/out/gpu/libmpv_gpu.c b/video/out/gpu/libmpv_gpu.c
new file mode 100644
index 0000000000..bd597c302a
--- /dev/null
+++ b/video/out/gpu/libmpv_gpu.c
@@ -0,0 +1,182 @@
+#include "config.h"
+#include "hwdec.h"
+#include "libmpv_gpu.h"
+#include "video.h"
+#include "video/out/libmpv.h"
+
+static const struct libmpv_gpu_context_fns *context_backends[] = {
+#if HAVE_GL
+    &libmpv_gpu_context_gl,
+#endif
+    NULL
+};
+
+struct priv {
+    struct libmpv_gpu_context *context;
+
+    struct gl_video *renderer;
+};
+
+static int init(struct render_backend *ctx, mpv_render_param *params)
+{
+    ctx->priv = talloc_zero(NULL, struct priv);
+    struct priv *p = ctx->priv;
+
+    char *api = get_mpv_render_param(params, MPV_RENDER_PARAM_API_TYPE, NULL);
+    if (!api)
+        return MPV_ERROR_INVALID_PARAMETER;
+
+    for (int n = 0; context_backends[n]; n++) {
+        const struct libmpv_gpu_context_fns *backend = context_backends[n];
+        if (strcmp(backend->api_name, api) == 0) {
+            p->context = talloc_zero(NULL, struct libmpv_gpu_context);
+            *p->context = (struct libmpv_gpu_context){
+                .global = ctx->global,
+                .log = ctx->log,
+                .fns = backend,
+            };
+            break;
+        }
+    }
+
+    if (!p->context)
+        return MPV_ERROR_INVALID_PARAMETER;
+
+    int err = p->context->fns->init(p->context, params);
+    if (err < 0)
+        return err;
+
+    p->renderer = gl_video_init(p->context->ra, ctx->log, ctx->global);
+
+    ctx->hwdec_devs = hwdec_devices_create();
+    gl_video_load_hwdecs(p->renderer, ctx->hwdec_devs, true);
+    ctx->driver_caps = VO_CAP_ROTATE90;
+    return 0;
+}
+
+static bool check_format(struct render_backend *ctx, int imgfmt)
+{
+    struct priv *p = ctx->priv;
+
+    return gl_video_check_format(p->renderer, imgfmt);
+}
+
+static int set_parameter(struct render_backend *ctx, mpv_render_param param)
+{
+    struct priv *p = ctx->priv;
+
+    switch (param.type) {
+    case MPV_RENDER_PARAM_ICC_PROFILE: {
+        mpv_byte_array *data = param.data;
+        gl_video_set_icc_profile(p->renderer, (bstr){data->data, data->size});
+        return 0;
+    }
+    case MPV_RENDER_PARAM_AMBIENT_LIGHT: {
+        int lux = *(int *)param.data;
+        gl_video_set_ambient_lux(p->renderer, lux);
+        return 0;
+    }
+    default:
+        return MPV_ERROR_NOT_IMPLEMENTED;
+    }
+}
+
+static void reconfig(struct render_backend *ctx, struct mp_image_params *params)
+{
+    struct priv *p = ctx->priv;
+
+    gl_video_config(p->renderer, params);
+}
+
+static void reset(struct render_backend *ctx)
+{
+    struct priv *p = ctx->priv;
+
+    gl_video_reset(p->renderer);
+}
+
+static void update_external(struct render_backend *ctx, struct vo *vo)
+{
+    struct priv *p = ctx->priv;
+
+    gl_video_set_osd_source(p->renderer, vo ? vo->osd : NULL);
+    if (vo)
+        gl_video_configure_queue(p->renderer, vo);
+}
+
+static void resize(struct render_backend *ctx, struct mp_rect *src,
+                   struct mp_rect *dst, struct mp_osd_res *osd)
+{
+    struct priv *p = ctx->priv;
+
+    gl_video_resize(p->renderer, src, dst, osd);
+}
+
+static int get_target_size(struct render_backend *ctx, mpv_render_param *params,
+                           int *out_w, int *out_h)
+{
+    struct priv *p = ctx->priv;
+
+    // Mapping the surface is cheap, better than adding new backend entrypoints.
+    struct ra_tex *tex;
+    int err = p->context->fns->wrap_fbo(p->context, params, &tex);
+    if (err < 0)
+        return err;
+    *out_w = tex->params.w;
+    *out_h = tex->params.h;
+    return 0;
+}
+
+static int render(struct render_backend *ctx, mpv_render_param *params,
+                  struct vo_frame *frame)
+{
+    struct priv *p = ctx->priv;
+
+    // Mapping the surface is cheap, better than adding new backend entrypoints.
+    struct ra_tex *tex;
+    int err = p->context->fns->wrap_fbo(p->context, params, &tex);
+    if (err < 0)
+        return err;
+
+    int depth = *(int *)get_mpv_render_param(params, MPV_RENDER_PARAM_DEPTH,
+                                             &(int){0});
+    gl_video_set_fb_depth(p->renderer, depth);
+
+    bool flip = *(int *)get_mpv_render_param(params, MPV_RENDER_PARAM_FLIP_Y,
+                                             &(int){0});
+
+    struct ra_fbo target = {.tex = tex, .flip = flip};
+    gl_video_render_frame(p->renderer, frame, target, RENDER_FRAME_DEF);
+    p->context->fns->done_frame(p->context, frame->display_synced);
+
+    return 0;
+}
+
+static void destroy(struct render_backend *ctx)
+{
+    struct priv *p = ctx->priv;
+
+    if (p->renderer)
+        gl_video_uninit(p->renderer);
+
+    hwdec_devices_destroy(ctx->hwdec_devs);
+
+    if (p->context) {
+        p->context->fns->destroy(p->context);
+        talloc_free(p->context->priv);
+        talloc_free(p->context);
+    }
+}
+
+const struct render_backend_fns render_backend_gpu = {
+    .init = init,
+    .check_format = check_format,
+    .set_parameter = set_parameter,
+    .reconfig = reconfig,
+    .reset = reset,
+    .update_external = update_external,
+    .resize = resize,
+    .get_target_size = get_target_size,
+    .render = render,
+    .destroy = destroy,
+};
diff --git a/video/out/gpu/libmpv_gpu.h b/video/out/gpu/libmpv_gpu.h
new file mode 100644
index 0000000000..5b41116f14
--- /dev/null
+++ b/video/out/gpu/libmpv_gpu.h
@@ -0,0 +1,38 @@
+#pragma once
+
+#include "video/out/libmpv.h"
+
+struct libmpv_gpu_context {
+    struct mpv_global *global;
+    struct mp_log *log;
+    const struct libmpv_gpu_context_fns *fns;
+
+    struct ra *ra;
+    void *priv;
+};
+
+// Manage backend specific interaction between libmpv and ra backend, that can't
+// be managed by ra itself (initialization and passing FBOs).
+struct libmpv_gpu_context_fns {
+    // The libmpv API type name, see MPV_RENDER_PARAM_API_TYPE.
+    const char *api_name;
+    // Pretty much works like render_backend_fns.init, except that the
+    // API type is already checked by the caller.
+    // Successful init must set ctx->ra.
+    int (*init)(struct libmpv_gpu_context *ctx, mpv_render_param *params);
+    // Wrap the surface passed to mpv_render_context_render() (via the params
+    // array) into a ra_tex and return it. Returns a libmpv error code, and sets
+    // *out to a temporary object on success. The returned object is valid until
+    // another wrap_fbo() or done_frame() is called.
+    // This does not need to care about generic attributes, like flipping.
+    int (*wrap_fbo)(struct libmpv_gpu_context *ctx, mpv_render_param *params,
+                    struct ra_tex **out);
+    // Signal that the ra_tex object obtained with wrap_fbo is no longer used.
+    // For certain backends, this might also be used to signal the end of
+    // rendering (like OpenGL doing weird crap).
+    void (*done_frame)(struct libmpv_gpu_context *ctx, bool ds);
+    // Free all data in ctx->priv.
+    void (*destroy)(struct libmpv_gpu_context *ctx);
+};
+
+extern const struct libmpv_gpu_context_fns libmpv_gpu_context_gl;