Default shaders

engine/src/serial.cxx

@@ -25,8 +25,13 @@ namespace engine {
   }
 
   flyweight<graphics::shader_program> to_program(Json::Value const & json) {
-    return graphics::shader_program::create(json["fragmentShader"].asString(),
-                                            json["vertexShader"].asString());
+    using graphics::shader_program;
+    if (json.empty()) {
+      return shader_program::create("data/shaders/BlankShader.fragment.glsl",
+                                    "data/shaders/BlankShader.vertex.glsl");
+    }
+    return shader_program::create(json["fragmentShader"].asString(),
+                                  json["vertexShader"].asString());
   }
 
   flyweight<graphics::material> to_material(Json::Value const & json) {