From afd8b95450c3a0f55e590b73ece260be6c1f93a1 Mon Sep 17 00:00:00 2001
From: Merlin Nimier-David <merlin.nimier@gmail.com>
Date: Fri, 5 Dec 2025 15:18:01 +0100
Subject: [PATCH 1/3] Add customizable drag & drop callback (GLFW)

---
 include/polyscope/options.h          |  4 ++++
 src/options.cpp                      |  1 +
 src/render/opengl/gl_engine_glfw.cpp | 17 +++++++++++++++--
 3 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/include/polyscope/options.h b/include/polyscope/options.h
index 27163c5c..a65035cd 100644
--- a/include/polyscope/options.h
+++ b/include/polyscope/options.h
@@ -5,6 +5,7 @@
 #include <functional>
 #include <string>
 #include <tuple>
+#include <vector>
 
 #include "imgui.h"
 
@@ -141,6 +142,9 @@ extern std::function<void()> configureImGuiStyleCallback;
 // assign your own function to create custom styles. If this callback is null, default fonts will be used.
 extern std::function<std::tuple<ImFontAtlas*, ImFont*, ImFont*>()> prepareImGuiFontsCallback;
 
+// A callback function which will be invoked when a file is dropped on the Polyscope window. No action is taken by default.
+extern std::function<void(const std::vector<std::string>&)> filesDroppedCallback;
+
 // === Backend and low-level options
 
 // When using the EGL backend, which device to try to initialize with
diff --git a/src/options.cpp b/src/options.cpp
index fb229bc8..5ad8f665 100644
--- a/src/options.cpp
+++ b/src/options.cpp
@@ -66,6 +66,7 @@ bool renderScene = true;
 bool openImGuiWindowForUserCallback = true;
 std::function<void()> configureImGuiStyleCallback = configureImGuiStyle;
 std::function<std::tuple<ImFontAtlas*, ImFont*, ImFont*>()> prepareImGuiFontsCallback = prepareImGuiFonts;
+std::function<void(const std::vector<std::string>&)> filesDroppedCallback = nullptr;
 
 // Backend and low-level options
 int eglDeviceIndex = -1; // means "try all of them"
diff --git a/src/render/opengl/gl_engine_glfw.cpp b/src/render/opengl/gl_engine_glfw.cpp
index 5f49aa20..34f619ec 100644
--- a/src/render/opengl/gl_engine_glfw.cpp
+++ b/src/render/opengl/gl_engine_glfw.cpp
@@ -80,8 +80,21 @@ void GLEngineGLFW::initialize() {
 
   setWindowResizable(view::windowResizable);
 
-// === Initialize openGL
-// Load openGL functions (using GLAD)
+  // Drag & drop support
+  glfwSetDropCallback(mainWindow, [](GLFWwindow* window, int path_count, const char* paths[]) {
+    if (!options::filesDroppedCallback)
+      return;
+
+    std::vector<std::string> pathsVec(path_count);
+    for (int i = 0; i < path_count; i++) {
+      pathsVec[i] = paths[i];
+    }
+    options::filesDroppedCallback(pathsVec);
+  });
+
+
+  // === Initialize openGL
+  // Load openGL functions (using GLAD)
 #ifndef __APPLE__
   if (!gladLoadGL()) {
     exception("ERROR: Failed to load openGL using GLAD");

From 2dc2cd4a154edd53e0fa73a444abe3702a83d71b Mon Sep 17 00:00:00 2001
From: Merlin Nimier-David <merlin.nimier@gmail.com>
Date: Tue, 9 Dec 2025 11:14:14 +0100
Subject: [PATCH 2/3] Clear callbacks at shutdown

---
 src/polyscope.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/polyscope.cpp b/src/polyscope.cpp
index 9d9b360e..aa5f46ca 100644
--- a/src/polyscope.cpp
+++ b/src/polyscope.cpp
@@ -1167,6 +1167,9 @@ void shutdown(bool allowMidFrameShutdown) {
   removeAllSlicePlanes();
   clearMessages();
   state::userCallback = nullptr;
+  options::configureImGuiStyleCallback = nullptr;
+  options::prepareImGuiFontsCallback = nullptr;
+  options::filesDroppedCallback = nullptr;
 
   // Shut down the render engine
   render::engine->shutdown();

From 0fa98f30dbefc27ae0715295cd8bdec2e1f9b711 Mon Sep 17 00:00:00 2001
From: Merlin Nimier-David <merlin.nimier@gmail.com>
Date: Wed, 10 Dec 2025 15:17:12 +0100
Subject: [PATCH 3/3] Slice plane: make center & normal getters public

---
 include/polyscope/slice_plane.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/polyscope/slice_plane.h b/include/polyscope/slice_plane.h
index f1286011..ecb617f8 100644
--- a/include/polyscope/slice_plane.h
+++ b/include/polyscope/slice_plane.h
@@ -49,6 +49,8 @@ class SlicePlane {
   void setPose(glm::vec3 planePosition, glm::vec3 planeNormal);
 
   // == Some getters and setters
+  glm::vec3 getCenter();
+  glm::vec3 getNormal();
 
   bool getActive();
   void setActive(bool newVal);
@@ -104,8 +106,6 @@ class SlicePlane {
   void setSliceAttributes(render::ShaderProgram& p);
   void createVolumeSliceProgram();
   void prepare();
-  glm::vec3 getCenter();
-  glm::vec3 getNormal();
   void updateWidgetEnabled();
 };