fix: Handle Vector4 default input values in visual shaders

scene/resources/visual_shader.cpp

@@ -2116,6 +2116,10 @@ Error VisualShader::_write_node(Type type, StringBuilder *p_global_code, StringB
 				Vector3 val = defval;
 				inputs[i] = "n_in" + itos(p_node) + "p" + itos(i);
 				node_code += "	vec3 " + inputs[i] + " = " + vformat("vec3(%.5f, %.5f, %.5f);\n", val.x, val.y, val.z);
+			} else if (defval.get_type() == Variant::VECTOR4) {
+				Vector4 val = defval;
+				inputs[i] = "n_in" + itos(p_node) + "p" + itos(i);
+				node_code += "	vec4 " + inputs[i] + " = " + vformat("vec4(%.5f, %.5f, %.5f, %.5f);\n", val.x, val.y, val.z, val.w);
 			} else if (defval.get_type() == Variant::QUATERNION) {
 				Quaternion val = defval;
 				inputs[i] = "n_in" + itos(p_node) + "p" + itos(i);