viewer: implement GPU-based picker

Author: cdcseacave

.github/copilot-instructions.md

@@ -63,10 +63,9 @@ VERBOSE("Info: %s", str);   // General logging
 
 ### Common Typedefs
 ```cpp
-typedef uint32_t IDX;              // Array indices
 typedef SEACAVE::Point3f Point3f;  // 3D points
 typedef SEACAVE::String String;    // String type
-#define NO_ID ((IDX)-1)           // Invalid index
+#define NO_ID ((uint32_t)-1)       // Invalid index
 ```
 Most of OpenMVS code uses custom point and matrix types derived from OpenCV types, e.g., `SEACAVE::Point3f`, `SEACAVE::Matrix4f`. Hoewever, some components use Eigen3 types, e.g. `SEACAVE::AABB3d` and `SEACAVE::Ray3d` classes. There custom types support convertion operation to and from Eigen3 types.
 

apps/Viewer/ArcballControls.cpp

@@ -241,7 +241,8 @@ void ArcballControls::panCamera(const Eigen::Vector2d& delta) {
 }
 
 void ArcballControls::zoomCamera(double delta) {
-	const double speed = MAXF(0.001, 0.15 * (camera.GetTarget() - camera.GetPosition()).norm() * zoomSensitivity);
+	const double distance = MINF(camera.GetSceneDistance()*0.3, (camera.GetPosition() - camera.GetTarget()).norm());
+	const double speed = MAXF(0.001, 0.15 * distance * zoomSensitivity);
 	zoom(delta * speed);
 }
 

apps/Viewer/BufferObjects.cpp

@@ -92,6 +92,31 @@ void VBO::SetSubData(const void* data, size_t size, size_t offset) {
 	GL_CHECK(glBufferSubData(target, offset, size, data));
 }
 
+// Readback implementations
+template<typename T>
+void VBO::GetData(T* out, size_t count) {
+	ASSERT(count > 0);
+	Bind();
+	GL_CHECK(glGetBufferSubData(target, 0, count * sizeof(T), out));
+}
+
+template<typename T>
+void VBO::GetData(std::vector<T>& out) {
+	GetData(out.data(), out.size());
+}
+
+template<typename T>
+void VBO::GetSubData(T* out, size_t count, size_t offset) {
+	Bind();
+	GL_CHECK(glGetBufferSubData(target, offset * sizeof(T), count * sizeof(T), out));
+}
+
+template<typename T>
+void VBO::GetSubData(std::vector<T>& out, size_t offset) {
+	if (out.empty()) return;
+	GetSubData(out.data(), out.size(), offset);
+}
+
 // Explicit template instantiations
 template void VBO::SetData<float>(const std::vector<float>&, GLenum);
 template void VBO::SetData<uint32_t>(const std::vector<uint32_t>&, GLenum);
@@ -107,6 +132,21 @@ template void VBO::SetSubData<float>(const float*, size_t, size_t);
 template void VBO::SetSubData<uint32_t>(const uint32_t*, size_t, size_t);
 template void VBO::SetSubData<uint8_t>(const uint8_t*, size_t, size_t);
 
+// Explicit template instantiations for readback
+template void VBO::GetData<float>(float*, size_t);
+template void VBO::GetData<uint32_t>(uint32_t*, size_t);
+template void VBO::GetData<uint8_t>(uint8_t*, size_t);
+template void VBO::GetData<float>(std::vector<float>&);
+template void VBO::GetData<uint32_t>(std::vector<uint32_t>&);
+template void VBO::GetData<uint8_t>(std::vector<uint8_t>&);
+
+template void VBO::GetSubData<float>(float*, size_t, size_t);
+template void VBO::GetSubData<uint32_t>(uint32_t*, size_t, size_t);
+template void VBO::GetSubData<uint8_t>(uint8_t*, size_t, size_t);
+template void VBO::GetSubData<float>(std::vector<float>&, size_t);
+template void VBO::GetSubData<uint32_t>(std::vector<uint32_t>&, size_t);
+template void VBO::GetSubData<uint8_t>(std::vector<uint8_t>&, size_t);
+
 // VAO Implementation
 VAO::VAO() {
 	GL_CHECK(glGenVertexArrays(1, &id));

apps/Viewer/BufferObjects.h

@@ -82,6 +82,19 @@ class VBO {
 
 	void SetSubData(const void* data, size_t size, size_t offset);
 
+	// Read back buffer data
+	template<typename T>
+	void GetData(T* out, size_t count);
+
+	template<typename T>
+	void GetData(std::vector<T>& out);
+
+	template<typename T>
+	void GetSubData(T* out, size_t count, size_t offset);
+
+	template<typename T>
+	void GetSubData(std::vector<T>& out, size_t offset);
+
 	GLuint GetID() const { return id; }
 };
 

apps/Viewer/CMakeLists.txt

@@ -41,10 +41,10 @@ else()
 	FILE(GLOB LIBRARY_FILES_C "*.cpp")
 endif()
 FILE(GLOB LIBRARY_FILES_H "*.h" "*.inl")
-FILE(GLOB SHADERS_LIBRARY_FILES "Shaders/*.*")
+FILE(GLOB SHADERS_LIBRARY_FILES "shaders/*.*")
 SOURCE_GROUP("Shaders" FILES ${SHADERS_LIBRARY_FILES})
 
-cxx_executable_with_flags(${VIEWER_NAME} "Apps" "${cxx_default}" "MVS;glad::glad;${GLFW_STATIC_LIBRARIES};${glfw3_LIBRARY};${GLFW3_LIBRARY};glfw;imgui::imgui" ${LIBRARY_FILES_C} ${LIBRARY_FILES_H})
+cxx_executable_with_flags(${VIEWER_NAME} "Apps" "${cxx_default}" "MVS;glad::glad;${GLFW_STATIC_LIBRARIES};${glfw3_LIBRARY};${GLFW3_LIBRARY};glfw;imgui::imgui" ${LIBRARY_FILES_C} ${LIBRARY_FILES_H} ${SHADERS_LIBRARY_FILES})
 
 # Build the Viewer as a GUI application on platforms that support it so
 # launching from the desktop does not open or attach a console/terminal.

apps/Viewer/OpenGLDebug.h

@@ -116,6 +116,7 @@ inline bool CheckOpenGLError(const char* function, const char* file, int line) {
     if (error == GL_NO_ERROR)
         return true; // No error, everything is fine
     DEBUG("OpenGL Error: %s (0x%X)\n  Function: %s\n  File: %s:%d", errorString.c_str(), error, function, file, line);
+    ASSERT("OpenGL error detected!" == NULL);
     return false;
 }