vo_opengl: x11egl: retrieve framebuffer depth

This is used for dithering, although I'm not aware of anyone who got
higher than 8 bit depth support to work on Linux.

Also put this into egl_helpers.c. Since EGL is pseudo-portable at best I
have no hope that the EGL context creation code in all the backends can
be fully shared. But some self-contained functionality can definitely be
shared.

6 files changed, 56 insertions, 2 deletions

diff --git a/TOOLS/old-makefile b/TOOLS/old-makefile
index f74f6e6fb7..64094b8a57 100644
--- a/TOOLS/old-makefile
+++ b/TOOLS/old-makefile
@@ -70,7 +70,8 @@ SOURCES-$(ENCODING)             += video/out/vo_lavc.c audio/out/ao_lavc.c \
                                    common/encode_lavc.c
 
 SOURCES-$(GL_X11)               += video/out/x11_common.c video/out/opengl/x11.c
-SOURCES-$(EGL_X11)              += video/out/x11_common.c video/out/opengl/x11egl.c
+SOURCES-$(EGL_X11)              += video/out/x11_common.c video/out/opengl/x11egl.c \
+                                   video/out/opengl/egl_helpers.c
 SOURCES-$(GL_WAYLAND)           += video/out/wayland_common.c \
                                    video/out/opengl/wayland.c
 
diff --git a/video/out/opengl/egl_helpers.c b/video/out/opengl/egl_helpers.c
new file mode 100644
index 0000000000..3455e5a203
--- /dev/null
+++ b/video/out/opengl/egl_helpers.c
@@ -0,0 +1,35 @@
+/*
+ * This file is part of mpv.
+ *
+ * mpv is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with mpv.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * You can alternatively redistribute this file 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.
+ */
+
+#include "egl_helpers.h"
+#include "common.h"
+
+void mp_egl_get_depth(struct GL *gl, EGLConfig fbc)
+{
+    EGLint tokens[] = {EGL_RED_SIZE, EGL_GREEN_SIZE, EGL_BLUE_SIZE};
+    int *ptrs[] =     {&gl->fb_r,    &gl->fb_g,      &gl->fb_b};
+    for (int n = 0; n < MP_ARRAY_SIZE(tokens); n++) {
+        EGLint depth = 0;
+        if (eglGetConfigAttrib(eglGetCurrentDisplay(), fbc, tokens[n], &depth))
+            *ptrs[n] = depth;
+    }
+}
diff --git a/video/out/opengl/egl_helpers.h b/video/out/opengl/egl_helpers.h
new file mode 100644
index 0000000000..f9961fee48
--- /dev/null
+++ b/video/out/opengl/egl_helpers.h
@@ -0,0 +1,10 @@
+#ifndef MP_GL_EGL_HELPERS_H
+#define MP_GL_EGL_HELPERS_H
+
+#include <EGL/egl.h>
+#include <EGL/eglext.h>
+
+struct GL;
+void mp_egl_get_depth(struct GL *gl, EGLConfig fbc);
+
+#endif
diff --git a/video/out/opengl/x11egl.c b/video/out/opengl/x11egl.c
index 64d9b69974..405350d7bb 100644
--- a/video/out/opengl/x11egl.c
+++ b/video/out/opengl/x11egl.c
@@ -29,6 +29,7 @@
 #include "common/common.h"
 #include "video/out/x11_common.h"
 #include "common.h"
+#include "egl_helpers.h"
 
 struct priv {
     EGLDisplay egl_display;
@@ -156,6 +157,7 @@ static int mpegl_init(struct MPGLContext *ctx, int flags)
 
     void *(*gpa)(const GLubyte*) = (void *(*)(const GLubyte*))eglGetProcAddress;
     mpgl_load_functions(ctx->gl, gpa, egl_exts, vo->log);
+    mp_egl_get_depth(ctx->gl, config);
 
     ctx->native_display_type = "x11";
     ctx->native_display = vo->x11->display;
diff --git a/wscript b/wscript
index a5e6914133..9d09170fac 100644
--- a/wscript
+++ b/wscript
@@ -760,7 +760,12 @@ video_output_features = [
     } , {
         'name': '--gl',
         'desc': 'OpenGL video outputs',
-        'deps_any': [ 'gl-cocoa', 'gl-x11', 'egl-drm', 'gl-win32', 'gl-wayland', 'rpi' ],
+        'deps_any': [ 'gl-cocoa', 'gl-x11', 'egl-x11', 'egl-drm', 'gl-win32', 'gl-wayland', 'rpi' ],
+        'func': check_true
+    }, {
+        'name': 'egl-helpers',
+        'desc': 'EGL helper functions',
+        'deps_any': [ 'egl-x11' ],
         'func': check_true
     }
 ]
diff --git a/wscript_build.py b/wscript_build.py
index ab2df805e2..e72da41056 100644
--- a/wscript_build.py
+++ b/wscript_build.py
@@ -313,6 +313,7 @@ def build(ctx):
         ( "video/out/filter_kernels.c" ),
         ( "video/out/opengl/cocoa.c",            "gl-cocoa" ),
         ( "video/out/opengl/common.c",           "gl" ),
+        ( "video/out/opengl/egl_helpers.c",      "egl-helpers" ),
         ( "video/out/opengl/rpi.c",              "rpi" ),
         ( "video/out/opengl/hwdec.c",            "gl" ),
         ( "video/out/opengl/hwdec_dxva2.c",      "gl-win32" ),