add command line interface handler and implement convert command from pano to jpg

engine/app_commands.cpp

@@ -0,0 +1,16 @@
+#include "pch.h"
+#include "app.h"
+#include "canvas.h"
+
+void App::cmd_convert(std::string pano_path, std::string out_path)
+{
+    glDisable(GL_DEPTH_TEST);
+    glEnable(GL_PROGRAM_POINT_SIZE);
+    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+    glBlendEquation(GL_FUNC_ADD);
+
+    ui::Canvas* canvas = new ui::Canvas;
+    canvas->create(CANVAS_RES, CANVAS_RES);
+    canvas->project_open_thread(pano_path);
+    canvas->export_equirectangular_thread(out_path);
+}