Update placefile icon texture coordinates when the texture atlas changes

scwx-qt/source/scwx/qt/gl/draw/draw_item.cpp

@@ -41,6 +41,17 @@ DrawItem::~DrawItem() = default;
 DrawItem::DrawItem(DrawItem&&) noexcept            = default;
 DrawItem& DrawItem::operator=(DrawItem&&) noexcept = default;
 
+void DrawItem::Render(
+   const QMapLibreGL::CustomLayerRenderParameters& /* params */)
+{
+}
+
+void DrawItem::Render(const QMapLibreGL::CustomLayerRenderParameters& params,
+                      bool /* textureAtlasChanged */)
+{
+   Render(params);
+}
+
 void DrawItem::UseDefaultProjection(
    const QMapLibreGL::CustomLayerRenderParameters& params,
    GLint                                           uMVPMatrixLocation)

scwx-qt/source/scwx/qt/gl/draw/draw_item.hpp

@@ -28,8 +28,9 @@ public:
    DrawItem& operator=(DrawItem&&) noexcept;
 
    virtual void Initialize() = 0;
-   virtual void
-   Render(const QMapLibreGL::CustomLayerRenderParameters& params) = 0;
+   virtual void Render(const QMapLibreGL::CustomLayerRenderParameters& params);
+   virtual void Render(const QMapLibreGL::CustomLayerRenderParameters& params,
+                       bool textureAtlasChanged);
    virtual void Deinitialize() = 0;
 
 protected:

scwx-qt/source/scwx/qt/gl/draw/placefile_icons.cpp

@@ -37,8 +37,6 @@ struct PlacefileIconInfo
       auto baseUrl = QUrl::fromUserInput(QString::fromStdString(baseUrlString));
       auto relativeUrl = QUrl(QString::fromStdString(iconFile->filename_));
       resolvedUrl_     = baseUrl.resolved(relativeUrl).toString().toStdString();
-
-      UpdateTextureInfo();
    }
 
    void UpdateTextureInfo();
@@ -78,10 +76,9 @@ public:
 
    std::mutex iconMutex_;
 
-   boost::unordered_flat_map<std::size_t, const PlacefileIconInfo>
+   boost::unordered_flat_map<std::size_t, PlacefileIconInfo>
       currentIconFiles_ {};
-   boost::unordered_flat_map<std::size_t, const PlacefileIconInfo>
-      newIconFiles_ {};
+   boost::unordered_flat_map<std::size_t, PlacefileIconInfo> newIconFiles_ {};
 
    std::vector<std::shared_ptr<const gr::Placefile::IconDrawItem>>
       currentIconList_ {};
@@ -103,7 +100,7 @@ public:
    GLsizei numVertices_;
 
    void UpdateBuffers();
-   void Update();
+   void Update(bool textureAtlasChanged);
 };
 
 PlacefileIcons::PlacefileIcons(std::shared_ptr<GlContext> context) :
@@ -203,7 +200,8 @@ void PlacefileIcons::Initialize()
 }
 
 void PlacefileIcons::Render(
-   const QMapLibreGL::CustomLayerRenderParameters& params)
+   const QMapLibreGL::CustomLayerRenderParameters& params,
+   bool                                            textureAtlasChanged)
 {
    std::unique_lock lock {p->iconMutex_};
 
@@ -213,7 +211,7 @@ void PlacefileIcons::Render(
 
       gl.glBindVertexArray(p->vao_);
 
-      p->Update();
+      p->Update(textureAtlasChanged);
       p->shaderProgram_->Use();
       UseRotationProjection(params, p->uMVPMatrixLocation_);
       UseMapProjection(
@@ -329,8 +327,6 @@ void PlacefileIcons::FinishIcons()
    p->newIconList_.clear();
    p->newIconFiles_.clear();
 
-   p->UpdateBuffers();
-
    // Mark the draw item dirty
    p->dirty_ = true;
 }
@@ -434,8 +430,21 @@ void PlacefileIcons::Impl::UpdateBuffers()
    dirty_ = true;
 }
 
-void PlacefileIcons::Impl::Update()
+void PlacefileIcons::Impl::Update(bool textureAtlasChanged)
 {
+   // If the texture atlas has changed
+   if (textureAtlasChanged)
+   {
+      // Update texture coordinates
+      for (auto& iconFile : currentIconFiles_)
+      {
+         iconFile.second.UpdateTextureInfo();
+      }
+
+      // Update OpenGL buffer data
+      UpdateBuffers();
+   }
+
    if (dirty_)
    {
       gl::OpenGLFunctions& gl = context_->gl();

scwx-qt/source/scwx/qt/gl/draw/placefile_icons.hpp

@@ -30,7 +30,8 @@ public:
    void set_thresholded(bool thresholded);
 
    void Initialize() override;
-   void Render(const QMapLibreGL::CustomLayerRenderParameters& params) override;
+   void Render(const QMapLibreGL::CustomLayerRenderParameters& params,
+               bool textureAtlasChanged) override;
    void Deinitialize() override;
 
    /**

scwx-qt/source/scwx/qt/gl/gl_context.cpp

@@ -52,6 +52,11 @@ gl::OpenGLFunctions& GlContext::gl()
    return p->gl_;
 }
 
+std::uint64_t GlContext::texture_buffer_count() const
+{
+   return p->textureBufferCount_;
+}
+
 std::shared_ptr<gl::ShaderProgram>
 GlContext::GetShaderProgram(const std::string& vertexPath,
                             const std::string& fragmentPath)

scwx-qt/source/scwx/qt/gl/gl_context.hpp

@@ -24,6 +24,8 @@ public:
 
    gl::OpenGLFunctions& gl();
 
+   std::uint64_t texture_buffer_count() const;
+
    std::shared_ptr<gl::ShaderProgram>
    GetShaderProgram(const std::string& vertexPath,
                     const std::string& fragmentPath);

scwx-qt/source/scwx/qt/map/draw_layer.cpp

@@ -24,6 +24,8 @@ public:
    std::shared_ptr<MapContext>                      context_;
    std::vector<std::shared_ptr<gl::draw::DrawItem>> drawList_;
    GLuint                                           textureAtlas_;
+
+   std::uint64_t textureAtlasBuildCount_ {};
 };
 
 DrawLayer::DrawLayer(std::shared_ptr<MapContext> context) :
@@ -47,13 +49,21 @@ void DrawLayer::Render(const QMapLibreGL::CustomLayerRenderParameters& params)
    gl::OpenGLFunctions& gl = p->context_->gl();
    p->textureAtlas_        = p->context_->GetTextureAtlas();
 
+   // Determine if the texture atlas changed since last render
+   std::uint64_t newTextureAtlasBuildCount =
+      p->context_->texture_buffer_count();
+   bool textureAtlasChanged =
+      newTextureAtlasBuildCount != p->textureAtlasBuildCount_;
+
    gl.glActiveTexture(GL_TEXTURE0);
    gl.glBindTexture(GL_TEXTURE_2D, p->textureAtlas_);
 
    for (auto& item : p->drawList_)
    {
-      item->Render(params);
+      item->Render(params, textureAtlasChanged);
    }
+
+   p->textureAtlasBuildCount_ = newTextureAtlasBuildCount;
 }
 
 void DrawLayer::Deinitialize()