use scopes for context lifetimes wherever possible

src/common/clglcontext.cpp

@@ -45,7 +45,8 @@ cv::Size CLGLContext::getSize() {
 
 void CLGLContext::opencl(std::function<void(cv::UMat&)> fn) {
     CLExecScope_t clExecScope(getCLExecContext());
-    CLGLContext::Scope fbScope(*this, frameBuffer_);
+    CLGLContext::GLScope glScope(*this);
+    CLGLContext::FrameBufferScope fbScope(*this, frameBuffer_);
     fn(frameBuffer_);
 }
 
@@ -85,7 +86,6 @@ void CLGLContext::end() {
 }
 
 void CLGLContext::acquireFromGL(cv::UMat &m) {
-    begin();
     GL_CHECK(cv::ogl::convertFromGLTexture2D(getTexture2D(), m));
     //FIXME
     cv::flip(m, m, 0);
@@ -95,7 +95,6 @@ void CLGLContext::releaseToGL(cv::UMat &m) {
     //FIXME
     cv::flip(m, m, 0);
     GL_CHECK(cv::ogl::convertToGLTexture2D(m, getTexture2D()));
-    end();
 }
 
 } /* namespace kb */

src/common/clglcontext.hpp

@@ -21,7 +21,6 @@ class Viz2D;
 class CLGLContext {
     friend class CLVAContext;
     friend class NanoVGContext;
-    friend class Viz2D;
     cv::ogl::Texture2D *frameBufferTex_;
     GLuint frameBufferID;
     GLuint renderBufferID;
@@ -29,19 +28,31 @@ class CLGLContext {
     CLExecContext_t context_;
     cv::Size frameBufferSize_;
 public:
-    class Scope {
+    class FrameBufferScope {
         CLGLContext& ctx_;
         cv::UMat& m_;
     public:
-        Scope(CLGLContext& ctx, cv::UMat& m) : ctx_(ctx), m_(m) {
+        FrameBufferScope(CLGLContext& ctx, cv::UMat& m) : ctx_(ctx), m_(m) {
             ctx_.acquireFromGL(m_);
         }
 
-        ~Scope() {
+        ~FrameBufferScope() {
             ctx_.releaseToGL(m_);
         }
     };
 
+    class GLScope {
+        CLGLContext& ctx_;
+    public:
+        GLScope(CLGLContext& ctx) : ctx_(ctx) {
+            ctx_.begin();
+        }
+
+        ~GLScope() {
+            ctx_.end();
+        }
+    };
+
     CLGLContext(const cv::Size& frameBufferSize);
     virtual ~CLGLContext();
     cv::ogl::Texture2D& getFrameBufferTexture();

src/common/clvacontext.cpp

@@ -29,7 +29,8 @@ bool CLVAContext::capture(std::function<void(cv::UMat&)> fn) {
     }
     {
         CLExecScope_t scope(clglContext_.getCLExecContext());
-        CLGLContext::Scope fbScope(clglContext_, frameBuffer_);
+        CLGLContext::GLScope glScope(clglContext_);
+        CLGLContext::FrameBufferScope fbScope(clglContext_, frameBuffer_);
         if (videoFrame_.empty())
             return false;
 
@@ -46,7 +47,8 @@ void CLVAContext::write(std::function<void(const cv::UMat&)> fn) {
     cv::Size fbSize = clglContext_.getSize();
     {
         CLExecScope_t scope(clglContext_.getCLExecContext());
-        CLGLContext::Scope fbScope(clglContext_, frameBuffer_);
+        CLGLContext::GLScope glScope(clglContext_);
+        CLGLContext::FrameBufferScope fbScope(clglContext_, frameBuffer_);
 
         cv::cvtColor(frameBuffer_, rgbBuffer_, cv::COLOR_BGRA2RGB);
         cv::resize(rgbBuffer_, videoFrame_, videoFrameSize_);

src/common/clvacontext.hpp

@@ -8,7 +8,6 @@ namespace kb {
 class Viz2D;
 
 class CLVAContext {
-    friend class Viz2D;
     CLExecContext_t context_;
     CLGLContext &clglContext_;
     cv::UMat frameBuffer_;

src/common/nanovgcontext.cpp

@@ -16,12 +16,12 @@ NanoVGContext::NanoVGContext(Viz2D &v2d, NVGcontext *context, CLGLContext &fbCon
 
 void NanoVGContext::render(std::function<void(NVGcontext*, const cv::Size&)> fn) {
     CLExecScope_t scope(clglContext_.getCLExecContext());
+    CLGLContext::GLScope glScope(clglContext_);
     NanoVGContext::Scope nvgScope(*this);
     fn(context_, clglContext_.getSize());
 }
 
 void NanoVGContext::begin() {
-    clglContext_.begin();
     float w = v2d_.getVideoFrameSize().width;
     float h = v2d_.getVideoFrameSize().height;
     float r = v2d_.getXPixelRatio();
@@ -34,6 +34,5 @@ void NanoVGContext::begin() {
 void NanoVGContext::end() {
     nvgEndFrame(context_);
     nvgRestore(context_);
-    clglContext_.end();
 }
 } /* namespace kb */

src/common/nanovgcontext.hpp

@@ -8,8 +8,6 @@
 #include "util.hpp"
 
 namespace kb {
-class Viz2D;
-
 class NanoVGContext {
     Viz2D& v2d_;
     NVGcontext *context_;

src/common/viz2d.cpp

@@ -167,9 +167,8 @@ void Viz2D::setVideoFrameSize(const cv::Size& sz) {
 
 void Viz2D::opengl(std::function<void(const cv::Size&)> fn) {
     CLExecScope_t scope(clglContext_->getCLExecContext());
-    clglContext_->begin();
+    CLGLContext::GLScope glScope(*clglContext_);
     fn(getFrameBufferSize());
-    clglContext_->end();
 }
 
 void Viz2D::opencl(std::function<void(cv::UMat&)> fn) {

src/common/viz2d.hpp

@@ -4,6 +4,7 @@
 #include <string>
 #include <opencv2/opencv.hpp>
 #include <opencv2/videoio.hpp>
+
 #include "clglcontext.hpp"
 #include "clvacontext.hpp"
 #include "nanovgcontext.hpp"