From 255e9e6435ca8b1d90c4479b98069d44eb191a0d Mon Sep 17 00:00:00 2001
From: Brad Davis <bdavis@saintandreas.org>
Date: Tue, 20 Sep 2016 19:46:26 -0700
Subject: [PATCH] Add support for executing arbitrary commands on the texture
 transfer thread

---
 libraries/gpu-gl/src/gpu/gl/GLTextureTransfer.cpp | 15 +++++++++++++--
 libraries/gpu-gl/src/gpu/gl/GLTextureTransfer.h   |  5 +++++
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/libraries/gpu-gl/src/gpu/gl/GLTextureTransfer.cpp b/libraries/gpu-gl/src/gpu/gl/GLTextureTransfer.cpp
index 4cb8e4fad1..7a709dfce3 100644
--- a/libraries/gpu-gl/src/gpu/gl/GLTextureTransfer.cpp
+++ b/libraries/gpu-gl/src/gpu/gl/GLTextureTransfer.cpp
@@ -97,12 +97,23 @@ void GLTextureTransferHelper::shutdown() {
 #endif
 }
 
+void GLTextureTransferHelper::queueExecution(VoidLambda lambda) {
+    Lock lock(_mutex);
+    _pendingCommands.push_back(lambda);
+}
+
 bool GLTextureTransferHelper::process() {
-    // Take any new textures off the queue
+    // Take any new textures or commands off the queue
+    VoidLambdaList pendingCommands;
     TextureList newTransferTextures;
     {
         Lock lock(_mutex);
         newTransferTextures.swap(_pendingTextures);
+        pendingCommands.swap(_pendingCommands);
+    }
+
+    for (auto command : pendingCommands) {
+        command();
     }
 
     if (!newTransferTextures.empty()) {
@@ -144,7 +155,7 @@ bool GLTextureTransferHelper::process() {
         gltexture->finishTransfer();
         //glNamedFramebufferTexture(_readFramebuffer, GL_COLOR_ATTACHMENT0, gltexture->_id, 0);
         //glBlitNamedFramebuffer(_readFramebuffer, _drawFramebuffer, 0, 0, 1, 1, 0, 0, 1, 1, GL_COLOR_BUFFER_BIT, GL_NEAREST);
-        //clientWait();
+        clientWait();
         gltexture->_contentStamp = gltexture->_gpuObject.getDataStamp();
         gltexture->updateSize();
         gltexture->setSyncState(gpu::gl::GLSyncState::Transferred);
diff --git a/libraries/gpu-gl/src/gpu/gl/GLTextureTransfer.h b/libraries/gpu-gl/src/gpu/gl/GLTextureTransfer.h
index fe7414e370..289aec40bb 100644
--- a/libraries/gpu-gl/src/gpu/gl/GLTextureTransfer.h
+++ b/libraries/gpu-gl/src/gpu/gl/GLTextureTransfer.h
@@ -28,10 +28,13 @@ using TextureListIterator = TextureList::iterator;
 
 class GLTextureTransferHelper : public GenericThread {
 public:
+    using VoidLambda = std::function<void()>;
+    using VoidLambdaList = std::list<VoidLambda>;
     using Pointer = std::shared_ptr<GLTextureTransferHelper>;
     GLTextureTransferHelper();
     ~GLTextureTransferHelper();
     void transferTexture(const gpu::TexturePointer& texturePointer);
+    void queueExecution(VoidLambda lambda);
 
     void setup() override;
     void shutdown() override;
@@ -47,6 +50,8 @@ private:
 #endif
     // A mutex for protecting items access on the render and transfer threads
     Mutex _mutex;
+    // Commands that have been submitted for execution on the texture transfer thread
+    VoidLambdaList _pendingCommands;
     // Textures that have been submitted for transfer
     TextureList _pendingTextures;
     // Textures currently in the transfer process