[client] egl: fix context binding enabling a lock free implementation

VERSION

@@ -1 +1 @@
-B1-209-g26eea64689+1
+B2-rc1-0-gae2ffd0a28+1

client/include/interface/renderer.h

@@ -109,8 +109,6 @@ typedef struct LG_Renderer
   LG_RendererOnFrameEvent on_frame_event;
   LG_RendererOnAlert      on_alert;
   LG_RendererRender       render_startup;
-  LG_RendererRender       render_begin;
-  LG_RendererRender       render_end;
   LG_RendererRender       render;
   LG_RendererUpdateFPS    update_fps;
 }

client/renderers/EGL/desktop.c

@@ -18,7 +18,6 @@ Place, Suite 330, Boston, MA 02111-1307 USA
 */
 
 #include "desktop.h"
-#include "egl.h"
 #include "common/debug.h"
 #include "common/option.h"
 #include "common/locking.h"
@@ -211,7 +210,6 @@ bool egl_desktop_update(EGL_Desktop * desktop, const bool sourceChanged, const L
     desktop->width  = format.width;
     desktop->height = format.height;
 
-    egl_lock(desktop->egl);
     if (!egl_texture_setup(
       desktop->texture,
       pixFmt,
@@ -221,27 +219,20 @@ bool egl_desktop_update(EGL_Desktop * desktop, const bool sourceChanged, const L
       true // streaming texture
     ))
     {
-      egl_unlock(desktop->egl);
       DEBUG_ERROR("Failed to setup the desktop texture");
       return false;
     }
-    egl_unlock(desktop->egl);
   }
 
   if (!egl_texture_update_from_frame(desktop->texture, frame))
     return false;
 
-  egl_lock(desktop->egl);
   enum EGL_TexStatus status;
   if ((status = egl_texture_process(desktop->texture)) != EGL_TEX_STATUS_OK)
   {
     if (status != EGL_TEX_STATUS_NOTREADY)
-    {
       DEBUG_ERROR("Failed to process the desktop texture");
-      egl_unlock(desktop->egl);
   }
-  }
-  egl_unlock(desktop->egl);
 
   return true;
 }

client/renderers/EGL/egl.c

@@ -59,7 +59,6 @@ struct Inst
   EGLDisplay           display;
   EGLConfig            configs;
   EGLSurface           surface;
-  LG_Lock              lock;
   EGLContext           context, frameContext;
 
   EGL_Desktop     * desktop; // the desktop
@@ -171,7 +170,6 @@ bool egl_create(void ** opaque, const LG_RendererParams params)
   this->scaleY       = 1.0f;
   this->screenScaleX = 1.0f;
   this->screenScaleY = 1.0f;
-  LG_LOCK_INIT(this->lock);
 
   this->font = LG_Fonts[0];
   if (!this->font->create(&this->fontObj, NULL, 16))
@@ -315,6 +313,27 @@ bool egl_on_frame_event(void * opaque, const LG_RendererFormat format, const Fra
 
   this->useNearest = this->width < format.width || this->height < format.height;
 
+  /* this event runs in a second thread so we need to init it here */
+  if (!this->frameContext)
+  {
+    static EGLint attrs[] = {
+      EGL_CONTEXT_CLIENT_VERSION, 2,
+      EGL_NONE
+    };
+
+    if (!(this->frameContext = eglCreateContext(this->display, this->configs, this->context, attrs)))
+    {
+      DEBUG_ERROR("Failed to create the frame context");
+      return false;
+    }
+
+    if (!eglMakeCurrent(this->display, EGL_NO_SURFACE, EGL_NO_SURFACE, this->frameContext))
+    {
+      DEBUG_ERROR("Failed to make the frame context current");
+      return false;
+    }
+  }
+
   if (!egl_desktop_update(this->desktop, sourceChanged, format, frame))
   {
     DEBUG_INFO("Failed to to update the desktop");
@@ -506,47 +525,6 @@ bool egl_render_startup(void * opaque, SDL_Window * window)
   return true;
 }
 
-void egl_lock(void * opaque)
-{
-  struct Inst * this = (struct Inst *)opaque;
-
-  if (!this->frameContext)
-  {
-    static EGLint attrs[] = {
-      EGL_CONTEXT_CLIENT_VERSION, 2,
-      EGL_NONE
-    };
-
-    if (!(this->frameContext = eglCreateContext(this->display, this->configs, this->context, attrs)))
-      DEBUG_ERROR("Failed to create the frame context");
-  }
-
-  LG_LOCK(this->lock);
-  eglMakeCurrent(this->display, this->surface, this->surface, this->frameContext);
-}
-
-void egl_unlock(void * opaque)
-{
-  struct Inst * this = (struct Inst *)opaque;
-  eglMakeCurrent(this->display, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
-  LG_UNLOCK(this->lock);
-}
-
-bool egl_render_begin(void * opaque, SDL_Window * window)
-{
-  struct Inst * this = (struct Inst *)opaque;
-  LG_LOCK(this->lock);
-  return eglMakeCurrent(this->display, this->surface, this->surface, this->context);
-}
-
-bool egl_render_end(void * opaque, SDL_Window * window)
-{
-  struct Inst * this = (struct Inst *)opaque;
-  bool ret = eglMakeCurrent(this->display, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
-  LG_UNLOCK(this->lock);
-  return ret;
-}
-
 bool egl_render(void * opaque, SDL_Window * window)
 {
   struct Inst * this = (struct Inst *)opaque;
@@ -623,8 +601,6 @@ struct LG_Renderer LGR_EGL =
   .on_frame_event = egl_on_frame_event,
   .on_alert       = egl_on_alert,
   .render_startup = egl_render_startup,
-  .render_begin   = egl_render_begin,
-  .render_end     = egl_render_end,
   .render         = egl_render,
   .update_fps     = egl_update_fps
 };

client/renderers/EGL/egl.h

@@ -1,28 +0,0 @@
-/*
-Looking Glass - KVM FrameRelay (KVMFR) Client
-Copyright (C) 2017-2020 Geoffrey McRae <geoff@hostfission.com>
-https://looking-glass.hostfission.com
-
-This program 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.
-
-This program 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
-this program; if not, write to the Free Software Foundation, Inc., 59 Temple
-Place, Suite 330, Boston, MA 02111-1307 USA
-*/
-
-#pragma once
-
-#include <stdbool.h>
-
-#include "interface/renderer.h"
-
-/* helpers to lock and make current the secondary context for the desktop */
-void egl_lock(void * opaque);
-void egl_unlock(void * opaque);

client/renderers/EGL/texture.c

@@ -104,7 +104,11 @@ void egl_texture_free(EGL_Texture ** texture)
     if (t->hasPBO)
     {
       glBindBuffer(GL_PIXEL_UNPACK_BUFFER, t->pbo);
+      if ((*texture)->tex[i].map)
+      {
         glUnmapBuffer(GL_PIXEL_UNPACK_BUFFER);
+        (*texture)->tex[i].map = NULL;
+      }
       glDeleteBuffers(1, &t->pbo);
       if (t->sync)
         glDeleteSync(t->sync);
@@ -149,8 +153,12 @@ static void egl_texture_unmap(EGL_Texture * texture)
 {
   for(int i = 0; i < TEXTURE_COUNT; ++i)
   {
+    if (!texture->tex[i].map)
+      continue;
+
     glBindBuffer(GL_PIXEL_UNPACK_BUFFER, texture->tex[i].pbo);
     glUnmapBuffer(GL_PIXEL_UNPACK_BUFFER);
+    texture->tex[i].map = NULL;
   }
 }
 
@@ -273,11 +281,7 @@ bool egl_texture_setup(EGL_Texture * texture, enum EGL_PixelFormat pixFmt, size_
   for(int i = 0; i < TEXTURE_COUNT; ++i)
   {
     if (texture->tex[i].hasPBO)
-    {
-      glBindBuffer(GL_PIXEL_UNPACK_BUFFER, texture->tex[i].pbo);
-      glUnmapBuffer(GL_PIXEL_UNPACK_BUFFER);
       glDeleteBuffers(1, &texture->tex[i].pbo);
-    }
 
     glGenBuffers(1, &texture->tex[i].pbo);
     texture->tex[i].hasPBO = true;
@@ -400,6 +404,9 @@ enum EGL_TexStatus egl_texture_process(EGL_Texture * texture)
   texture->tex[s.u].sync =
     glFenceSync(GL_SYNC_GPU_COMMANDS_COMPLETE, 0);
 
+  /* we must flush to ensure the sync is in the command buffer */
+  glFlush();
+
   atomic_store_explicit(&texture->state.u, nextu, memory_order_release);
 
   /* remap the for the next update */
@@ -421,7 +428,7 @@ enum EGL_TexStatus egl_texture_bind(EGL_Texture * texture)
 
     if (texture->tex[s.s].sync != 0)
     {
-      switch(glClientWaitSync(texture->tex[s.s].sync, 0, 20000000))
+      switch(glClientWaitSync(texture->tex[s.s].sync, 0, 20000000)) // 20ms
       {
         case GL_ALREADY_SIGNALED:
         case GL_CONDITION_SATISFIED:
@@ -436,6 +443,7 @@ enum EGL_TexStatus egl_texture_bind(EGL_Texture * texture)
           break;
 
         case GL_WAIT_FAILED:
+        case GL_INVALID_VALUE:
           glDeleteSync(texture->tex[s.s].sync);
           texture->tex[s.s].sync = 0;
           EGL_ERROR("glClientWaitSync failed");

client/src/main.c

@@ -175,10 +175,6 @@ static int renderThread(void * unused)
       }
     }
 
-    if (state.lgr->render_begin && !state.lgr->render_begin(state.lgrData,
-          state.window))
-      break;
-
     if (state.lgrResize)
     {
       if (state.lgr)
@@ -208,10 +204,6 @@ static int renderThread(void * unused)
       }
     }
 
-    if (state.lgr->render_end && !state.lgr->render_end(state.lgrData,
-          state.window))
-      break;
-
     if (!state.resizeDone && state.resizeTimeout < microtime())
     {
       SDL_SetWindowSize(