vo_opengl: refactor into vo_gpu

This is done in several steps:

1. refactor MPGLContext -> struct ra_ctx
2. move GL-specific stuff in vo_opengl into opengl/context.c
3. generalize context creation to support other APIs, and add --gpu-api
4. rename all of the --opengl- options that are no longer opengl-specific
5. move all of the stuff from opengl/* that isn't GL-specific into gpu/
   (note: opengl/gl_utils.h became opengl/utils.h)
6. rename vo_opengl to vo_gpu
7. to handle window screenshots, the short-term approach was to just add
   it to ra_swchain_fns. Long term (and for vulkan) this has to be moved to
   ra itself (and vo_gpu altered to compensate), but this was a stop-gap
   measure to prevent this commit from getting too big
8. move ra->fns->flush to ra_gl_ctx instead
9. some other minor changes that I've probably already forgotten

Note: This is one half of a major refactor, the other half of which is
provided by rossy's following commit. This commit enables support for
all linux platforms, while his version enables support for all non-linux
platforms.

Note 2: vo_opengl_cb.c also re-uses ra_gl_ctx so it benefits from the
--opengl- options like --opengl-early-flush, --opengl-finish etc. Should
be a strict superset of the old functionality.

Disclaimer: Since I have no way of compiling mpv on all platforms, some
of these ports were done blindly. Specifically, the blind ports included
context_mali_fbdev.c and context_rpi.c. Since they're both based on
egl_helpers, the port should have gone smoothly without any major
changes required. But if somebody complains about a compile error on
those platforms (assuming anybody actually uses them), you know where to
complain.

1 files changed, 186 insertions, 0 deletions

diff --git a/video/out/gpu/context.c b/video/out/gpu/context.c
new file mode 100644
index 0000000000..dbabba8b3b
--- /dev/null
+++ b/video/out/gpu/context.c
@@ -0,0 +1,186 @@
+/*
+ * This file is part of mpv.
+ *
+ * mpv 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.
+ *
+ * mpv 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 mpv.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdbool.h>
+#include <math.h>
+#include <assert.h>
+
+#include "config.h"
+#include "common/common.h"
+#include "common/msg.h"
+#include "options/options.h"
+#include "options/m_option.h"
+#include "video/out/vo.h"
+
+#include "context.h"
+
+extern const struct ra_ctx_fns ra_ctx_glx;
+extern const struct ra_ctx_fns ra_ctx_glx_probe;
+extern const struct ra_ctx_fns ra_ctx_x11_egl;
+extern const struct ra_ctx_fns ra_ctx_drm_egl;
+extern const struct ra_ctx_fns ra_ctx_cocoa;
+extern const struct ra_ctx_fns ra_ctx_wayland_egl;
+extern const struct ra_ctx_fns ra_ctx_wgl;
+extern const struct ra_ctx_fns ra_ctx_angle;
+extern const struct ra_ctx_fns ra_ctx_dxinterop;
+extern const struct ra_ctx_fns ra_ctx_rpi;
+extern const struct ra_ctx_fns ra_ctx_mali;
+extern const struct ra_ctx_fns ra_ctx_vdpauglx;
+
+static const struct ra_ctx_fns *contexts[] = {
+// OpenGL contexts:
+#if HAVE_RPI
+    &ra_ctx_rpi,
+#endif
+/*
+#if HAVE_GL_COCOA
+    &ra_ctx_cocoa,
+#endif
+#if HAVE_EGL_ANGLE_WIN32
+    &ra_ctx_angle,
+#endif
+#if HAVE_GL_WIN32
+    &ra_ctx_wgl,
+#endif
+#if HAVE_GL_DXINTEROP
+    &ra_ctx_dxinterop,
+#endif
+*/
+#if HAVE_GL_X11
+    &ra_ctx_glx_probe,
+#endif
+#if HAVE_EGL_X11
+    &ra_ctx_x11_egl,
+#endif
+#if HAVE_GL_X11
+    &ra_ctx_glx,
+#endif
+#if HAVE_GL_WAYLAND
+    &ra_ctx_wayland_egl,
+#endif
+#if HAVE_EGL_DRM
+    &ra_ctx_drm_egl,
+#endif
+#if HAVE_MALI_FBDEV
+    &ra_ctx_mali,
+#endif
+#if HAVE_VDPAU_GL_X11
+    &ra_ctx_vdpauglx,
+#endif
+};
+
+static bool get_help(struct mp_log *log, struct bstr param)
+{
+    if (bstr_equals0(param, "help")) {
+        mp_info(log, "GPU contexts / APIs:\n");
+        mp_info(log, "    auto (autodetect)\n");
+        for (int n = 0; n < MP_ARRAY_SIZE(contexts); n++)
+            mp_info(log, "    %s (%s)\n", contexts[n]->name, contexts[n]->type);
+        return true;
+    }
+
+    return false;
+}
+
+int ra_ctx_validate_api(struct mp_log *log, const struct m_option *opt,
+                        struct bstr name, struct bstr param)
+{
+    if (get_help(log, param))
+        return M_OPT_EXIT;
+    if (bstr_equals0(param, "auto"))
+        return 1;
+    for (int i = 0; i < MP_ARRAY_SIZE(contexts); i++) {
+        if (bstr_equals0(param, contexts[i]->type))
+            return 1;
+    }
+    return M_OPT_INVALID;
+}
+
+int ra_ctx_validate_context(struct mp_log *log, const struct m_option *opt,
+                            struct bstr name, struct bstr param)
+{
+    if (get_help(log, param))
+        return M_OPT_EXIT;
+    if (bstr_equals0(param, "auto"))
+        return 1;
+    for (int i = 0; i < MP_ARRAY_SIZE(contexts); i++) {
+        if (bstr_equals0(param, contexts[i]->name))
+            return 1;
+    }
+    return M_OPT_INVALID;
+}
+
+// Create a VO window and create a RA context on it.
+//  vo_flags: passed to the backend's create window function
+struct ra_ctx *ra_ctx_create(struct vo *vo, const char *context_type,
+                             const char *context_name, struct ra_ctx_opts opts)
+{
+    bool api_auto = !context_type || strcmp(context_type, "auto") == 0;
+    bool ctx_auto = !context_name || strcmp(context_name, "auto") == 0;
+
+    if (ctx_auto) {
+        MP_VERBOSE(vo, "Probing for best GPU context.\n");
+        opts.probing = true;
+    }
+
+    // Hack to silence backend (X11/Wayland/etc.) errors. Kill it once backends
+    // are separate from `struct vo`
+    bool old_probing = vo->probing;
+    vo->probing = opts.probing;
+
+    for (int i = 0; i < MP_ARRAY_SIZE(contexts); i++) {
+        if (!opts.probing && strcmp(contexts[i]->name, context_name) != 0)
+            continue;
+        if (!api_auto && strcmp(contexts[i]->type, context_type) != 0)
+            continue;
+
+        struct ra_ctx *ctx = talloc_ptrtype(NULL, ctx);
+        *ctx = (struct ra_ctx) {
+            .vo = vo,
+            .global = vo->global,
+            .log = mp_log_new(ctx, vo->log, contexts[i]->type),
+            .opts = opts,
+            .fns = contexts[i],
+        };
+
+        MP_VERBOSE(ctx, "Initializing GPU context '%s'\n", ctx->fns->name);
+        if (contexts[i]->init(ctx)) {
+            vo->probing = old_probing;
+            return ctx;
+        }
+
+        talloc_free(ctx);
+    }
+
+    // If we've reached this point, then none of the contexts matched the name
+    // requested, or the backend creation failed for all of them.
+    MP_ERR(vo, "Failed initializing any suitable GPU context!\n");
+    vo->probing = old_probing;
+    return NULL;
+}
+
+void ra_ctx_destroy(struct ra_ctx **ctx)
+{
+    if (*ctx)
+        (*ctx)->fns->uninit(*ctx);
+    talloc_free(*ctx);
+    *ctx = NULL;
+}