[vlc-devel] [PATCH 1/2] egl: Import GLES symbols with a direct library dlopen

[Paul Kocialkowski]

It appears that some EGL blobs (usually used with GLES) don't expose all
the required core GLES API functions through eglGetProcAddress.

Resort to mapping these symbols using dlopen directly instead.

Signed-off-by: Paul Kocialkowski <paul.kocialkowski at bootlin.com>
---
 modules/video_output/opengl/egl.c | 28 ++++++++++++++++++++++++++--
 1 file changed, 26 insertions(+), 2 deletions(-)

diff --git a/modules/video_output/opengl/egl.c b/modules/video_output/opengl/egl.c
index 9162675447..0477be5474 100644
--- a/modules/video_output/opengl/egl.c
+++ b/modules/video_output/opengl/egl.c
@@ -26,6 +26,7 @@
 
 #include <stdlib.h>
 #include <assert.h>
+#include <dlfcn.h>
 #include <EGL/egl.h>
 #include <EGL/eglext.h>
 
@@ -43,6 +44,8 @@
 # include "../android/utils.h"
 #endif
 
+#define LIBGLESv2_DL_NAME "libGLESv2.so.2"
+
 typedef struct vlc_gl_sys_t
 {
     EGLDisplay display;
@@ -57,6 +60,8 @@ typedef struct vlc_gl_sys_t
 #endif
     PFNEGLCREATEIMAGEKHRPROC    eglCreateImageKHR;
     PFNEGLDESTROYIMAGEKHRPROC   eglDestroyImageKHR;
+    bool is_gles;
+    void *gles_handle;
 } vlc_gl_sys_t;
 
 static int MakeCurrent (vlc_gl_t *gl)
@@ -101,8 +106,12 @@ static void SwapBuffers (vlc_gl_t *gl)
 
 static void *GetSymbol(vlc_gl_t *gl, const char *procname)
 {
-    (void) gl;
-    return (void *)eglGetProcAddress (procname);
+    vlc_gl_sys_t *sys = gl->sys;
+
+    if (sys->is_gles)
+        return dlsym(sys->gles_handle, procname);
+    else
+        return (void *)eglGetProcAddress (procname);
 }
 
 static const char *QueryString(vlc_gl_t *gl, int32_t name)
@@ -220,6 +229,10 @@ static void Close (vlc_object_t *obj)
     AWindowHandler_releaseANativeWindow(gl->surface->handle.anativewindow,
                                         AWindow_Video);
 #endif
+
+    if (sys->is_gles && sys->gles_handle != NULL)
+        dlclose(sys->gles_handle);
+
     free (sys);
 }
 
@@ -238,6 +251,8 @@ static int Open (vlc_object_t *obj, const struct gl_api *api)
     sys->surface = EGL_NO_SURFACE;
     sys->eglCreateImageKHR = NULL;
     sys->eglDestroyImageKHR = NULL;
+    sys->is_gles = api->api == EGL_OPENGL_ES_API;
+    sys->gles_handle = NULL;
 
     vout_window_t *wnd = gl->surface;
     EGLSurface (*createSurface)(EGLDisplay, EGLConfig, void *, const EGLint *)
@@ -392,6 +407,15 @@ static int Open (vlc_object_t *obj, const struct gl_api *api)
     }
     sys->context = ctx;
 
+    if (sys->is_gles) {
+        sys->gles_handle = dlopen(LIBGLESv2_DL_NAME, RTLD_NOW);
+	if (sys->gles_handle == NULL)
+        {
+            msg_Err (obj, "cannot get GLES library handle from dlopen");
+            goto error;
+        }
+    }
+
     /* Initialize OpenGL callbacks */
     gl->ext = VLC_GL_EXT_EGL;
     gl->makeCurrent = MakeCurrent;
-- 
2.17.0