From b3ff1a4dab858fcd49de00b0cc662e6881e8b77a Mon Sep 17 00:00:00 2001
From: kallaballa <amir@viel-zu.com>
Date: Tue, 26 Sep 2023 19:56:31 +0200
Subject: [PATCH] implement async and threadsafe mode for source

---
 .../opencv2/v4d/detail/framebuffercontext.hpp |  4 +--
 modules/v4d/include/opencv2/v4d/source.hpp    |  3 +-
 modules/v4d/src/detail/framebuffercontext.cpp | 29 +++++++------------
 modules/v4d/src/source.cpp                    |  8 +++--
 modules/v4d/src/v4d.cpp                       | 28 ++++++++++--------
 5 files changed, 37 insertions(+), 35 deletions(-)

diff --git a/modules/v4d/include/opencv2/v4d/detail/framebuffercontext.hpp b/modules/v4d/include/opencv2/v4d/detail/framebuffercontext.hpp
index ede333480..5ffdc363a 100644
--- a/modules/v4d/include/opencv2/v4d/detail/framebuffercontext.hpp
+++ b/modules/v4d/include/opencv2/v4d/detail/framebuffercontext.hpp
@@ -111,8 +111,8 @@ class CV_EXPORTS FrameBufferContext {
     std::map<size_t, GLuint> copyTextures_;
     int index_;
 
-    void* current_sync_object_ = 0;
-    bool first_sync_ = true;
+    void* currentSyncObject_ = 0;
+    bool firstSync_ = true;
 public:
     /*!
      * Acquires and releases the framebuffer from and to OpenGL.
diff --git a/modules/v4d/include/opencv2/v4d/source.hpp b/modules/v4d/include/opencv2/v4d/source.hpp
index 63a926f6c..79503b0c3 100644
--- a/modules/v4d/include/opencv2/v4d/source.hpp
+++ b/modules/v4d/include/opencv2/v4d/source.hpp
@@ -34,7 +34,7 @@ public:
      * that it manipulates. This is ultimatively used to provide video data to #cv::viz::V4D
      * @param fps The fps the Source object provides data with.
      */
-    CV_EXPORTS Source(std::function<bool(cv::UMat&)> generator, float fps, bool async = true);
+    CV_EXPORTS Source(std::function<bool(cv::UMat&)> generator, float fps);
     /*!
      * Constructs a null Source that is never open or ready.
      */
@@ -49,6 +49,7 @@ public:
      */
     CV_EXPORTS bool isReady();
     CV_EXPORTS bool isAsync();
+    CV_EXPORTS void setAsync(bool as);
     CV_EXPORTS bool isThreadSafe();
     CV_EXPORTS void setThreadSafe(bool ts);
 
diff --git a/modules/v4d/src/detail/framebuffercontext.cpp b/modules/v4d/src/detail/framebuffercontext.cpp
index 3b6d10cde..2765d9711 100644
--- a/modules/v4d/src/detail/framebuffercontext.cpp
+++ b/modules/v4d/src/detail/framebuffercontext.cpp
@@ -686,7 +686,7 @@ void FrameBufferContext::blitFrameBufferToFrameBuffer(const cv::Rect& srcViewpor
 
 void FrameBufferContext::begin(GLenum framebufferTarget) {
     this->makeCurrent();
-    CV_Assert(this->wait() == true);
+    CV_Assert(this->wait(1000000000) == true);
     GL_CHECK(glBindFramebuffer(framebufferTarget, frameBufferID_));
     GL_CHECK(glBindTexture(GL_TEXTURE_2D, textureID_));
     GL_CHECK(glBindRenderbuffer(GL_RENDERBUFFER, renderBufferID_));
@@ -876,29 +876,22 @@ void FrameBufferContext::fence() {
 }
 
 bool FrameBufferContext::wait(const uint64_t& timeout) {
-    if(first_sync_) {
+    if(firstSync_) {
         currentSyncObject_ = 0;
-        first_sync_ = false;
+        firstSync_ = false;
         return true;
     }
     CV_Assert(currentSyncObject_ != 0);
-    if (timeout > 0) {
-        GLuint ret = glClientWaitSync(static_cast<GLsync>(currentSyncObject_),
-        GL_SYNC_FLUSH_COMMANDS_BIT, timeout);
-        GL_CHECK();
-        CV_Assert(GL_ALREADY_SIGNALED != ret);
-        CV_Assert(GL_WAIT_FAILED != ret);
-        if(GL_CONDITION_SATISFIED == ret) {
-            currentSyncObject_ = 0;
-            return true;
-        } else {
-            currentSyncObject_ = 0;
-            return false;
-        }
-    } else {
-        GL_CHECK(glWaitSync(static_cast<GLsync>(currentSyncObject_), 0, GL_TIMEOUT_IGNORED));
+    GLuint ret = glClientWaitSync(static_cast<GLsync>(currentSyncObject_),
+    GL_SYNC_FLUSH_COMMANDS_BIT, timeout);
+    GL_CHECK();
+    CV_Assert(GL_WAIT_FAILED != ret);
+    if(GL_CONDITION_SATISFIED == ret || GL_ALREADY_SIGNALED == ret) {
         currentSyncObject_ = 0;
         return true;
+    } else {
+        currentSyncObject_ = 0;
+        return false;
     }
 }
 }
diff --git a/modules/v4d/src/source.cpp b/modules/v4d/src/source.cpp
index 9442985e8..52c7a621c 100644
--- a/modules/v4d/src/source.cpp
+++ b/modules/v4d/src/source.cpp
@@ -8,8 +8,8 @@
 namespace cv {
 namespace v4d {
 
-Source::Source(std::function<bool(cv::UMat&)> generator, float fps, bool async) :
-        generator_(generator), fps_(fps), async_(async) {
+Source::Source(std::function<bool(cv::UMat&)> generator, float fps) :
+        generator_(generator), fps_(fps) {
 }
 
 Source::Source() :
@@ -34,6 +34,10 @@ bool Source::isAsync() {
     return async_;
 }
 
+void Source::setAsync(bool as) {
+    async_ = as;
+}
+
 bool Source::isThreadSafe() {
     return threadSafe_;
 }
diff --git a/modules/v4d/src/v4d.cpp b/modules/v4d/src/v4d.cpp
index 7d88ccd96..93df66163 100644
--- a/modules/v4d/src/v4d.cpp
+++ b/modules/v4d/src/v4d.cpp
@@ -300,8 +300,8 @@ cv::_InputArray V4D::fetch() {
 }
 
 bool V4D::capture() {
-    if(source_) {
-        if(source_->isAsync()) {
+    if (source_) {
+        if (source_->isAsync()) {
             return this->capture([this](cv::UMat& videoFrame) {
                 if (source_->isReady()) {
                     auto p = source_->operator()();
@@ -310,17 +310,21 @@ bool V4D::capture() {
                 }
             });
         } else {
-            if(source_->fps() > 0) {
-                fb([this](cv::UMat& frameBuffer){
-                    if (source_->isReady()) {
-                        auto p = source_->operator()();
-                        currentSeqNr_ = p.first;
-                        p.second.copyTo(frameBuffer);
-                    }
-                });
+            if (source_->isReady()) {
+                if (source_->fps() > 0) {
+                    auto p = source_->operator()();
+                    currentSeqNr_ = p.first;
+                    feed(p.second);
+                } else {
+                    auto p = source_->operator()();
+                    currentSeqNr_ = p.first;
+                }
             } else {
-                auto p = source_->operator()();
-                currentSeqNr_ = p.first;
+#ifndef __EMSCRIPTEN__
+                return false;
+#else
+                return true;
+#endif
             }
 
             return true;