ComponentBase Class
Header: | #include <UnigineComponentSystem.h> |
This is a base class implementing basic functionality of C++ logic components.
Component Parameters#
When you create a component you should declare all parameters to be used. The list of available parameter types is the same as for properties as they are used as basis for components. Parameters of basic types (Int, Float, Node, Material, etc.) are declared using the PROP_PARAM macro, which has the following format:
PROP_PARAM(type, name, default_value, items, title, tooltip, group);
To declare complex parameters (structures and arrays) specific macros are used.
Structures#
Each structure, that you want to use in your component, must be inherited from the ComponentStruct class. This is required to ensure correct generation of the corresponding property file.
To declare a structured parameter use the following macro (the last three arguments are optional, see above):
PROP_STRUCT(type, name, title, tooltip, group);
Below is an example of a component named SomeComponent, that has multiple parameters of various types including structures (nested and inherited):
class SomeComponent: public Unigine::ComponentBase
{
public:
// constructor and destructor for our component
COMPONENT(SomeComponent, Unigine::ComponentBase);
// name of the property associated with the component
PROP_NAME("my_component");
// methods to be executed at certain stages of the execution sequence
COMPONENT_INIT(init);
// parameters
PROP_PARAM(Float, speed, 30.0f);
PROP_PARAM(Node, some_node);
// declaration of a structure (a property inside a property) named "ParentStruct"
struct ParentStruct : public Unigine::ComponentStruct
{
// parameters, that will be displayed in the UnigineEditor
PROP_PARAM(Int, var1, 1);
PROP_PARAM(Float, var2, 2.0f);
PROP_PARAM(Double, var3, 3.0f);
// auxiliary variables, that won't be visible in the UnigineEditor
float my_var1 = 2.0f;
int my_var2 = 10;
};
// declaration of the structured parameter named "my_struct" of the ParentStruct type declared above
PROP_STRUCT(ParentStruct, my_struct);
// declaration of a child structure named "ChildStruct" inherited from the ParentStruct
struct ChildStruct : public ParentStruct
{
// parameters, that will be displayed in the UnigineEditor
PROP_PARAM(Int, child_param1, 1);
PROP_PARAM(Double, child_param2, 2.0f);
// declaration of a nested structure
struct NestedStruct : public Unigine::ComponentStruct
{
// parameters, that will be displayed in the UnigineEditor
PROP_PARAM(String, string_param1, "This is my string!");
};
// declaration of the structured parameter named "my_nested_struct" of the NestedStruct type declared above
PROP_STRUCT(NestedStruct, my_nested_struct);
};
// declaration of the structured parameter named "my_struct2" of the ChildStruct type declared above
PROP_STRUCT(ChildStruct, my_struct2, "Child Struct", "Example of an inherited structure with a nested one");
// ...
};
Arrays#
Array-type parameters are declared using the following macros (the last three arguments are optional, see above):
PROP_ARRAY_STRUCT(struct_type, name, title, tooltip, group); // for arrays of structures
PROP_ARRAY(type, name, title, tooltip, group); // for arrays of all other types
E.g., to declare a simple array of integer elements and array of ParentStruct elements for the SomeComponent component described above we can use:
// ...
// declaring a simple array of integer elements named int_array
PROP_ARRAY(Int, int_array, "Integer Array", "This is an array of integer elements");
// declaring an array of ParentStruct elements named struct_array (ParentStruct should be declared earlier)
PROP_ARRAY_STRUCT(ParentStruct, struct_array);
// ...
Accessing Parameters#
Accessing parameters including array-type and structured ones inside the component is simple (much like what you would normally do with member variables). Below is an example of accessing the parameters of the SomeComponent component described above inside its init() method:
// ...
SomeComponent::init()
{
// ...
// changing the value of the speed parameter
speed = 120.0f;
// changing array's size and setting values of a couple of its elements
int_array.resize(5);
int_array[0] = 1;
int_array[4] = 10;
// setting the value of the var3 parameter of the first ParentStruct element of the array named struct_array
struct_array[0]->var3 = struct_array[0]->var3 + 20.0f;
// changing the value of the var1 parameter of the my_struct structured parameter
my_struct->var1 = 5;
// printing the value of string_param1 parameter of the nested structured parameter (my_nested_struct) inside the my_struct2 of the ChildStruct type inherited from the ParentStruct
Log::message("String parameter value: %s",my_struct2->my_nested_struct->string_param1.get());
// ...
}
Component Methods#
Each component can have an arbitrary set of methods implementing its logic. These methods are executed during the corresponding stages of the execution sequence. You can set multiple methods for each stage, they will be executed according to their order value (optional) or in the order they appear in the declaration.
COMPONENT_INIT(function_name, order);
COMPONENT_UPDATE_ASYNC_THREAD(function_name, order);
COMPONENT_UPDATE_SYNC_THREAD(function_name, order);
COMPONENT_UPDATE(function_name, order);
COMPONENT_POST_UPDATE(function_name, order);
COMPONENT_UPDATE_PHYSICS(function_name, order);
COMPONENT_SWAP(function_name, order);
COMPONENT_SHUTDOWN(function_name, order);
COMPONENT_DESTROY_RENDER_RESOURCES(function_name, order);
Methods Execution Order#
If several components are attached to a node, the order value determines the order in which their methods will be called during the corresponding stage of the execution sequence. E.g., suppose we have two components (Component1 and Component2) attached to a node and they both have init() functions declared as follows:
// Component1
COMPONENT_INIT(init, 2);
// ...
// Component2
COMPONENT_INIT(init, 3);
// ...
These functions will be called in the following order:
- Component1::init()
- Component2::init()
Classes Execution Order#
You can use the macro-based inheritance to control the execution order of base and inherited classes.
To override the base class method:
class A
{
COMPONENT_UPDATE(update);
void update();
};
class B: public class A
{
COMPONENT_UPDATE(update);
void update();
};
// In this case only B::update() will be executed. It doesn't matter that A::update() is not virtual.
To run the base class method before a derived one:
class A
{
COMPONENT_UPDATE(update, -1);
void update();
};
class B: public class A
{
COMPONENT_UPDATE(update);
void update();
};
// In this case A::update() is run first, and then B::update().
To run a derived class method before the base one:
class A
{
COMPONENT_UPDATE(update);
void update();
};
class B: public class A
{
COMPONENT_UPDATE(update, -1);
void update();
};
// In this case B::update() is run first, and then A::update().
Usage Example#
Below you'll find an example of declaration of a logic component (MyComponent.h) along with logic implementation (MyComponent.cpp).
The implementation file of the component (*.cpp) must contain the following macro to ensure its automatic registration by C++ Component System, when it is initialized:
REGISTER_COMPONENT ( your_component_name );
MyComponent.h
class MyComponent: public Unigine::ComponentBase
{
public:
// constructor and destructor for our component
COMPONENT(MyComponent, Unigine::ComponentBase);
// name of the property associated with the component
PROP_NAME("my_component");
// methods to be executed at certain stages of the execution sequence (see the "protected" section)
COMPONENT_INIT(init);
COMPONENT_UPDATE(update1, 3);
COMPONENT_UPDATE(update2, 5);
// parameters
PROP_PARAM(Float, speed, 30.0f);
PROP_PARAM(Node, some_node);
// declaration of a structure (a property inside a property) named "ParentStruct"
struct ParentStruct : public Unigine::ComponentStruct
{
// parameters, that will be displayed in the UnigineEditor
PROP_PARAM(Int, var1, 1);
PROP_PARAM(Float, var2, 2.0f);
PROP_PARAM(Double, var3, 3.0f);
// auxiliary variables, that won't be visible in the UnigineEditor
float my_var1 = 2.0f;
int my_var2 = 10;
};
// declaration of the structured parameter named "my_struct" of the ParentStruct type declared above
PROP_STRUCT(ParentStruct, my_struct);
// declaration of a child structure named "ChildStruct" inherited from the ParentStruct
struct ChildStruct : public ParentStruct
{
// parameters, that will be displayed in the UnigineEditor
PROP_PARAM(Int, child_param1, 1);
PROP_PARAM(Double, child_param2, 2.0f);
// declaration of a nested structure
struct NestedStruct : public Unigine::ComponentStruct
{
// parameters, that will be displayed in the UnigineEditor
PROP_PARAM(String, string_param1, "This is my string!");
};
// declaration of the structured parameter named "my_nested_struct" of the NestedStruct type declared above
PROP_STRUCT(NestedStruct, my_nested_struct);
};
// declaration of the structured parameter named "my_struct2" of the ChildStruct type declared above
PROP_STRUCT(ChildStruct, my_struct2, "Child Struct", "Example of an inherited structure with a nested one");
// declaration of a simple array of integer elements named int_array
PROP_ARRAY(Int, int_array, "Integer Array", "This is an array of integer elements");
// declaration of an array of ParentStruct elements named struct_array (ParentStruct should be declared earlier)
PROP_ARRAY_STRUCT(ParentStruct, struct_array);
protected:
// world main loop
void init();
void update1();
void update2();
};
MyComponent.cpp
#include "MyComponent.h"
REGISTER_COMPONENT( MyComponent ); // macro for component registration by C++ Component System
using namespace Unigine;
using namespace Math;
// method to be called on component initialization
void MyComponent::init()
{
// changing the value of the speed parameter
speed = 120.0f;
// changing array's size and setting values of a couple of its elements
int_array.resize(5);
int_array[0] = 1;
int_array[4] = 10;
// setting the value of the var3 parameter of the first ParentStruct element of the array named struct_array
struct_array[0]->var3 = struct_array[0]->var3 + 20.0f;
// changing the value of the var1 parameter of the my_struct structured parameter
my_struct->var1 = 5;
// printing the value of string_param1 parameter of the nested structured parameter (my_nested_struct) inside the my_struct2 of the ChildStruct type inherited from the ParentStruct
Log::message("\nString parameter value: %s",my_struct2->my_nested_struct->string_param1.get());
}
// first method to be called on world update
void MyComponent::update1()
{
Log::message("\nMyComponent::update1() method!");
}
// second method to be called on world update
void MyComponent::update2()
{
Log::message("\nMyComponent::update2() method!");
}
See Also#
- C++ Component System usage example for more details on using C++ Component System.
- Property File Format article to learn more about the property file format (*.prop).
- C++ Sample: source/samples/Api/Logics/ComponentSystem
ComponentBase Class
Members
static ComponentBasePtr create ( const NodePtr & node, int num ) #
Constructor. Creates a new component and adds it to the specified node. The created component will be associated with the node property having the specified number.Arguments
- const NodePtr & node - Node, to which the created component is to be added.
- int num - Number of the node property, with which the created component will be associated.
const char * getClassName ( ) #
Returns the name of the class associated with the component.Return value
Component class name.const char * getPropertyName ( ) #
Returns the name of the property associated with the component.Return value
Property name.void save_property ( const char * name ) #
Saves all parameters of the property associated with the component to the specified prop-file.Arguments
- const char * name - Name of the target .prop-file.
void setEnabled ( int enable ) #
Enables or disables the component.Arguments
- int enable - Use 1 to enable the component, 0 - to disable it.
int isEnabled ( ) #
Returns a value indicating whether the component is enabled.Return value
1 if the component is enabled; otherwise 0.int isInitialized ( ) #
Returns a value indicating whether the component is initialized (its init() method was already called).Return value
1 if the component is initialized; otherwise 0.int isAutoSaveProperty ( ) #
Returns a value indicating whether the property file associated with the component should be automatically generated each time C++ Component System is initialized or createPropertyFiles() method is called.PROP_AUTOSAVE(0);
Return value
1 if the property file associated with the component should be automatically generated each time C++ Component System is initialized or createPropertyFiles() method is called; otherwise 0.const PropertyPtr & getProperty ( ) #
Returns the property associated with the component.Return value
Property associated with the component.int getPropertyNum ( ) #
Returns the number of the property associated with the component.Return value
Number of the property in the list of properties assigned to the node.template <C class>
C * addComponent ( const NodePtr & node ) #
Adds the component to the specified node. This method is equivalent to ComponentSystem::addComponent() method.Arguments
- const NodePtr & node - Node, to which the component is to be added.
Return value
Pointer to the new added component, if it was successfully added to the specified node; otherwise nullptr.template <C class>
int removeComponent ( const NodePtr & node ) #
Removes the component from the specified node. This method is equivalent to ComponentSystem::removeComponent() method.Arguments
- const NodePtr & node - Node, from which the component is to be removed.
Return value
1 if the component was successfully removed from the specified node; otherwise 0.template <C class>
C * getComponent ( const NodePtr & node ) #
Returns the first component of the specified type associated with the specified node. This method is equivalent to ComponentSystem::getComponent() method.Arguments
- const NodePtr & node - Node, for which the component of this type is to be found.
Return value
Pointer to the component if it exists; otherwise, nullptr.template <C class>
void getComponents ( const NodePtr & node, Vector<C *> & components ) #
Returns all components of this type assigned to the specified node and puts them to the specified buffer vector. This method is equivalent to ComponentSystem::getComponents() method.Arguments
- const NodePtr & node - Node, whose components are to be retrieved.
- Vector<C *> & components - Buffer vector, to which all found components of this type will be put.
template <C class>
C * getComponentInChildren ( const NodePtr & node ) #
Returns the first component of this type found among all the children of the specified node (including the node itself). This method searches for the component in the following order:- node itself
- node reference
- node's children
- children of node's children
Arguments
- const NodePtr & node - Node, whose hierarchy is to be checked for the components of this type.
Return value
Pointer to the component if it exists; otherwise, nullptr.template <C class>
void getComponentsInChildren ( const NodePtr & node, Vector<C *> & components ) #
Searches for all components of this type down the hierarchy of the specified node and puts them to the given buffer vector. This method is equivalent to ComponentSystem::getComponentsInChildren() method.Arguments
- const NodePtr & node - Node, whose hierarchy is to be checked for the components of this type.
- Vector<C *> & components - Buffer vector, to which all found components of this type will be put.
template <C class>
C * getComponentInParent ( const NodePtr & node ) #
Returns the first component of this type found among all predecessors and posessors of the specified node. This method is equivalent to ComponentSystem::getComponentInParent() method.Arguments
- const NodePtr & node - Node, whose hierarchy is to be checked for the components of this type.
Return value
Pointer to the component if it exists; otherwise, nullptr.template <C class>
void getComponentsInParent ( const NodePtr & node, Vector<C *> & components ) #
Searches for all components of this type up the hierarchy of the specified node and puts them to the given buffer vector. This method is equivalent to ComponentSystem::getComponentsInParent() method.Arguments
- const NodePtr & node - Node, whose hierarchy is to be checked for the components of this type.
- Vector<C *> & components - Buffer vector, to which all found components of this type will be put.
const NodePtr & getNode ( ) #
Returns the node, to which the component is attached.Return value
Node, to which the component is attached.void setDestroyCallback ( Unigine::CallbackBase * func ) #
Sets a callback function to be called before destroying the component. This function can be used to implement certain actions to be performed when a component is destroyed.Arguments
- Unigine::CallbackBase * func - Callback function.