From b1ade2698d44723b34187c76e5d34dd75d1b0a4e Mon Sep 17 00:00:00 2001
From: ExMix <rahuba.youri@mapswithme.com>
Date: Tue, 12 Nov 2013 17:30:49 +0300
Subject: [PATCH] [drape] -remove unbind method. Binded VAO will be currect
 before other VAO not bind -move creation of VAO from constructor to Build for
 correct behavior in multithread env -for build VAO we not need set program as
 current

---
 drape/vertex_array_buffer.cpp | 42 +++++++++++++++++------------------
 drape/vertex_array_buffer.hpp | 13 +++++++----
 drape_head/glwidget.cpp       |  4 ++--
 3 files changed, 32 insertions(+), 27 deletions(-)

diff --git a/drape/vertex_array_buffer.cpp b/drape/vertex_array_buffer.cpp
index 3afa8cde4f..4eedbc262f 100644
--- a/drape/vertex_array_buffer.cpp
+++ b/drape/vertex_array_buffer.cpp
@@ -7,44 +7,42 @@ VertexArrayBuffer::VertexArrayBuffer(uint32_t indexBufferSize, uint32_t dataBuff
   : m_VAO(0)
   , m_dataBufferSize(dataBufferSize)
 {
-  m_VAO = GLFunctions::glGenVertexArray();
   m_indexBuffer.Reset(new IndexBuffer(indexBufferSize));
 }
 
 VertexArrayBuffer::~VertexArrayBuffer()
 {
-  Unbind();
-
   buffers_map_t::iterator it = m_buffers.begin();
   for (; it != m_buffers.end(); ++it)
     it->second.Destroy();
 
   m_buffers.clear();
-  GLFunctions::glDeleteVertexArray(m_VAO);
-}
 
-void VertexArrayBuffer::Bind()
-{
-  GLFunctions::glBindVertexArray(m_VAO);
-}
-
-void VertexArrayBuffer::Unbind()
-{
-  GLFunctions::glBindVertexArray(0);
+  if (m_VAO != 0)
+  {
+    /// Build called only when VertexArrayBuffer fulled and transfer to FrontendRenderer
+    /// but if user move screen before all geometry readed from MWM we delete VertexArrayBuffer on BackendRenderer
+    /// in this case m_VAO will be equal a 0
+    GLFunctions::glDeleteVertexArray(m_VAO);
+  }
 }
 
 void VertexArrayBuffer::Render()
 {
-  Bind();
-  GLFunctions::glDrawElements(m_indexBuffer->GetCurrentSize());
+  if (!m_buffers.empty())
+  {
+    Bind();
+    GLFunctions::glDrawElements(m_indexBuffer->GetCurrentSize());
+  }
 }
 
-void VertexArrayBuffer::BuildVertexArray(ReferencePoiner<GpuProgram> program)
+void VertexArrayBuffer::Build(ReferencePoiner<GpuProgram> program)
 {
+  ASSERT(m_VAO == 0, ("No-no-no! You can't rebuild VertexArrayBuffer"));
   if (m_buffers.empty())
     return;
 
-  program->Bind();
+  m_VAO = GLFunctions::glGenVertexArray();
   Bind();
 
   buffers_map_t::iterator it = m_buffers.begin();
@@ -67,13 +65,9 @@ void VertexArrayBuffer::BuildVertexArray(ReferencePoiner<GpuProgram> program)
                                             decl.m_stride,
                                             decl.m_offset);
     }
-    buffer->Unbind();
   }
 
   m_indexBuffer->Bind();
-  Unbind();
-  m_indexBuffer->Unbind();
-  program->Unbind();
 }
 
 ReferencePoiner<GLBuffer> VertexArrayBuffer::GetBuffer(const BindingInfo & bindingInfo)
@@ -129,3 +123,9 @@ void VertexArrayBuffer::UploadIndexes(uint16_t * data, uint16_t count)
   ASSERT(count <= m_indexBuffer->GetAvailableSize(), ());
   m_indexBuffer->UploadData(data, count);
 }
+
+void VertexArrayBuffer::Bind()
+{
+  ASSERT(m_VAO != 0, ("You need to call Build method before bind it and render"));
+  GLFunctions::glBindVertexArray(m_VAO);
+}
diff --git a/drape/vertex_array_buffer.hpp b/drape/vertex_array_buffer.hpp
index d7dbbbd31f..169088b52b 100644
--- a/drape/vertex_array_buffer.hpp
+++ b/drape/vertex_array_buffer.hpp
@@ -14,11 +14,13 @@ public:
   VertexArrayBuffer(uint32_t indexBufferSize, uint32_t dataBufferSize);
   ~VertexArrayBuffer();
 
-  void Bind();
-  void Unbind();
+  ///{@
+  /// On devices where implemented OES_vertex_array_object extensions we use it for build VertexArrayBuffer
+  /// OES_vertex_array_object create OpenGL resource that belong only one GL context (which was created by)
+  /// by this reason Build/Bind and Render must be called only on Frontendrendere thread
   void Render();
-
-  void BuildVertexArray(ReferencePoiner<GpuProgram> program);
+  void Build(ReferencePoiner<GpuProgram> program);
+  ///@}
 
   ReferencePoiner<GLBuffer> GetBuffer(const BindingInfo & bindingInfo);
 
@@ -27,6 +29,9 @@ public:
   uint16_t GetStartIndexValue() const;
   void UploadIndexes(uint16_t * data, uint16_t count);
 
+private:
+  void Bind();
+
 private:
   int m_VAO;
   typedef map<BindingInfo, OwnedPointer<DataBuffer> > buffers_map_t;
diff --git a/drape_head/glwidget.cpp b/drape_head/glwidget.cpp
index 0bb99abcdd..3de56dbfd9 100644
--- a/drape_head/glwidget.cpp
+++ b/drape_head/glwidget.cpp
@@ -10,14 +10,14 @@ GLWidget::GLWidget()
 void GLWidget::FlushFullBucket(const GLState & state, OwnedPointer<VertexArrayBuffer> bucket)
 {
   ReferencePoiner<GpuProgram> program = m_programManager->GetProgram(state.GetProgramIndex());
-  bucket->BuildVertexArray(program);
+  bucket->Build(program);
   m_frames[state].push_back(bucket);
 }
 
 void GLWidget::UseIncompleteBucket(const GLState &state, ReferencePoiner<VertexArrayBuffer> bucket)
 {
   ReferencePoiner<GpuProgram> program = m_programManager->GetProgram(state.GetProgramIndex());
-  bucket->BuildVertexArray(program);
+  bucket->Build(program);
   renderBucket(state, bucket);
 }