adding in sandbox

sandbox/CMakeLists.txt

@@ -0,0 +1,22 @@
+# Vulkan playground. Links the engine (and its third-party libraries), and
+# can also include the engine's internal headers from engine/src.
+file(GLOB_RECURSE SOURCES CONFIGURE_DEPENDS *.cpp)
+
+add_executable(sandbox ${SOURCES})
+
+target_compile_definitions(sandbox PRIVATE
+  SANDBOX_SHADER_DIR="${CMAKE_CURRENT_SOURCE_DIR}/shaders"
+)
+
+# engine/include comes in through the engine's public include path.
+target_include_directories(sandbox PRIVATE
+  "${CMAKE_SOURCE_DIR}/engine/src"
+)
+
+# The engine publicly provides vulkan, vma, shaderc, glfw, glm, imgui, entt
+# and Tracy, plus the GLM defines. The rest are engine-private.
+target_link_libraries(sandbox PRIVATE
+  ${PROJECT_NAME}
+  imguizmo
+  stb_image
+)