vo_opengl: make use of newer OpenGL logging API

GL_ARB_debug_output provides a logging callback, which can be used to
diagnose problems etc. in case the driver supports it. It's enabled only
if the vo_opengl "debug" suboption is set.

video/out/gl_common.c

@@ -107,6 +107,7 @@ static const struct feature features[] = {
     {MPGL_CAP_TEX_RG,           "RG textures"},
     {MPGL_CAP_1ST_CLASS_ARRAYS, "1st class shader arrays"},
     {MPGL_CAP_3D_TEX,           "3D textures"},
+    {MPGL_CAP_DEBUG,            "debugging extensions"},
     {MPGL_CAP_SW,               "suspected software renderer"},
     {0},
 };
@@ -462,6 +463,16 @@ static const struct gl_functions gl_functions[] = {
         .extension = "GL_APPLE_rgb_422",
         .provides = MPGL_CAP_APPLE_RGB_422,
     },
+    {
+        .ver_core = 430,
+        .extension = "GL_ARB_debug_output",
+        .provides = MPGL_CAP_DEBUG,
+        .functions = (const struct gl_function[]) {
+            // (only functions needed by us)
+            DEF_FN(DebugMessageCallback),
+            {0}
+        },
+    },
 };
 
 #undef FN_OFFS
@@ -972,6 +983,8 @@ MPGLContext *mpgl_init(struct vo *vo, const char *backend_name,
             goto cleanup;
     }
 
+    ctx->gl->debug_context = !!(vo_flags & VOFLAG_GL_DEBUG);
+
     return ctx;
 
 cleanup:

video/out/gl_common.h

@@ -81,6 +81,7 @@ enum {
     MPGL_CAP_APPLE_RGB_422      = (1 << 12),    // GL_APPLE_rgb_422
     MPGL_CAP_1ST_CLASS_ARRAYS   = (1 << 13),
     MPGL_CAP_3D_TEX             = (1 << 14),
+    MPGL_CAP_DEBUG              = (1 << 15),
     MPGL_CAP_SW                 = (1 << 30),    // indirect or sw renderer
 };
 
@@ -171,6 +172,9 @@ void mpgl_load_functions2(GL *gl, void *(*get_fn)(void *ctx, const char *n),
 // log, lev: module and log level, as in mp_msg()
 void mp_log_source(struct mp_log *log, int lev, const char *src);
 
+typedef void (GLAPIENTRY *MP_GLDEBUGPROC)(GLenum, GLenum, GLuint, GLenum,
+                                          GLsizei, const GLchar *,const void *);
+
 //function pointers loaded from the OpenGL library
 struct GL {
     int version;                // MPGL_VER() mangled (e.g. 210 for 2.1)
@@ -178,6 +182,7 @@ struct GL {
     int glsl_version;           // e.g. 130 for GLSL 1.30
     char *extensions;           // Equivalent to GL_EXTENSIONS
     int mpgl_caps;              // Bitfield of MPGL_CAP_* constants
+    bool debug_context;         // use of e.g. GLX_CONTEXT_DEBUG_BIT_ARB
 
     void (GLAPIENTRY *Begin)(GLenum);
     void (GLAPIENTRY *End)(void);
@@ -326,6 +331,9 @@ struct GL {
 
     GLint (GLAPIENTRY *GetVideoSync)(GLuint *);
     GLint (GLAPIENTRY *WaitVideoSync)(GLint, GLint, unsigned int *);
+
+    void (GLAPIENTRY *DebugMessageCallback)(MP_GLDEBUGPROC callback,
+                                            const void *userParam);
 };
 
 #endif /* MPLAYER_GL_COMMON_H */

video/out/gl_video.c

@@ -127,6 +127,7 @@ struct gl_video {
     struct mp_log *log;
     struct gl_video_opts opts;
     bool gl_debug;
+    bool debug_cb_set;
 
     int depth_g;
 
@@ -434,9 +435,39 @@ static void debug_check_gl(struct gl_video *p, const char *msg)
         glCheckError(p->gl, p->log, msg);
 }
 
+
+static void GLAPIENTRY gl_debug_cb(GLenum source, GLenum type, GLuint id,
+                                   GLenum severity, GLsizei length,
+                                   const GLchar *message, const void *userParam)
+{
+    // keep in mind that the debug callback can be asynchronous
+    struct gl_video *p = (void *)userParam;
+    int level = MSGL_ERR;
+    switch (severity) {
+    case GL_DEBUG_SEVERITY_NOTIFICATION:level = MSGL_V; break;
+    case GL_DEBUG_SEVERITY_LOW:         level = MSGL_INFO; break;
+    case GL_DEBUG_SEVERITY_MEDIUM:      level = MSGL_WARN; break;
+    case GL_DEBUG_SEVERITY_HIGH:        level = MSGL_ERR; break;
+    }
+    MP_MSG(p, level, "GL: %s\n", message);
+}
+
 void gl_video_set_debug(struct gl_video *p, bool enable)
 {
+    GL *gl = p->gl;
+
     p->gl_debug = enable;
+
+    if (p->debug_cb_set != enable && gl->debug_context &&
+        gl->DebugMessageCallback)
+    {
+        if (enable) {
+            gl->DebugMessageCallback(gl_debug_cb, p);
+        } else {
+            gl->DebugMessageCallback(NULL, NULL);
+        }
+        p->debug_cb_set = enable;
+    }
 }
 
 static void texture_size(struct gl_video *p, int w, int h, int *texw, int *texh)
@@ -2247,6 +2278,9 @@ void gl_video_uninit(struct gl_video *p)
 
     mpgl_osd_destroy(p->osd);
 
+    if (p->debug_cb_set)
+        gl->DebugMessageCallback(NULL, NULL);
+
     talloc_free(p);
 }
 
@@ -2452,13 +2486,13 @@ struct gl_video *gl_video_init(GL *gl, struct mp_log *log, struct osd_state *osd
         .osd_state = osd,
         .opts = gl_video_opts_def,
         .gl_target = GL_TEXTURE_2D,
-        .gl_debug = true,
         .scalers = {
             { .index = 0, .name = "bilinear" },
             { .index = 1, .name = "bilinear" },
         },
         .scratch = talloc_zero_array(p, char *, 1),
     };
+    gl_video_set_debug(p, true);
     init_gl(p);
     recreate_osd(p);
     return p;

video/out/vo_opengl.c

@@ -127,7 +127,7 @@ static void flip_page(struct vo *vo)
     p->glctx->swapGlBuffers(p->glctx);
 
     p->frames_rendered++;
-    if (p->frames_rendered > 5)
+    if (p->frames_rendered > 5 && !p->use_gl_debug)
         gl_video_set_debug(p->renderer, false);
 
     if (p->use_glFinish)

video/out/vo_opengl_cb.c

@@ -214,6 +214,7 @@ int mpv_opengl_cb_render(struct mpv_opengl_cb_context *ctx, int fbo, int vp[4])
         gl_video_config(ctx->renderer, &ctx->img_params);
         struct vo_priv *p = vo->priv;
         gl_video_set_options(ctx->renderer, p->renderer_opts);
+        ctx->gl->debug_context = p->use_gl_debug;
         gl_video_set_debug(ctx->renderer, p->use_gl_debug);
     }