added drag n drop function,

need to clean up before loading the next mesh

MshViewer/Header/callback.h

@@ -9,3 +9,5 @@ extern void mouseMove(GLFWwindow *window, double xpos, double ypos);
 extern void mouseWheel(GLFWwindow *window, double xoffset, double yoffset);
 
 extern void keyPress(GLFWwindow *window, int key, int scancode, int action, int mods);
+
+extern void dragNdrop(GLFWwindow* window, int count, const char** paths);
\ No newline at end of file

MshViewer/Source/OpenGlController.cpp

@@ -179,6 +179,7 @@ void OpenGLController::setCallbackFunctions()
 	glfwSetWindowSizeCallback(pWindow, windowResize);
 	glfwSetScrollCallback(pWindow, mouseWheel);
 	glfwSetKeyCallback(pWindow, keyPress);
+	glfwSetDropCallback(pWindow, dragNdrop);
 }
 
 glm::mat4 OpenGLController::getModelMatrix(unsigned int index)

MshViewer/Source/callback.cpp

@@ -98,3 +98,10 @@ void keyPress(GLFWwindow *window, int key, int scancode, int action, int mods)
 		}
 	}
 }
+
+void dragNdrop(GLFWwindow* window, int count, const char** paths)
+{
+	OpenGLController* controller = reinterpret_cast<OpenGLController*>(glfwGetWindowUserPointer(window));
+	if(count > 0)
+		controller->loadMsh(paths[0]);
+}