# Unigine::WorldIntersection Class (CPP)

**Header:** #include <UnigineWorld.h>


This class stores the result of the world intersection (the coordinates of the intersection, the index of the intersected triangle and the index of the intersected surface).


#### Usage Example


The following example shows how you can get the intersection information by using the *WorldIntersection* class. In this example, the line is an invisible traced line from the point of the camera (*vec3 **p0***) to the point of the mouse pointer (*vec3 **p1***). The executing sequence is the following:


- Define and initialize two points (p0 and p1) by using the *[Player::getDirectionFromScreen()](../../../api/library/players/class.player_cpp.md#getDirectionFromScreen_Vec3_Vec3_int_int_int_int_int_int_void)* function.
- Create an instance of the *WorldIntersection* class to get the intersection information.
- Check, if there is a intersection with an object. The [*World::getIntersection()*](../../../api/library/engine/class.world_cpp.md#getIntersection_vec3_vec3_int_Variable_Object) function returns an intersected object when the object intersects with the traced line.
- In this example, when the object intersects with the traced line, all the surfaces of the intersected object change their material parameters. The *WorldIntersection* class instance gets the coordinates of the intersection point and the index of the intersected triangle. You can get all these fields by using [*getIndex()*](#getIndex_int) and [*getPoint()*](#getPoint_Vec3) functions


```cpp
/* ... */
// initialize points of the mouse direction
Vec3 p0, p1;

// get the current player (camera)
PlayerPtr player = Game::getPlayer();
if (player.get() == NULL)
	return 0;

// get the size (width and height) of the current application window
ivec2 main_size = ivec2_one;

EngineWindowPtr main_window = WindowManager::getMainWindow();
if (!main_window)
	Engine::get()->quit();

main_size = main_window->getSize();

// get the current X and Y coordinates of the mouse pointer
int mouse_x = Input::getMousePosition().x - main_window->getPosition().x;
int mouse_y = Input::getMousePosition().y - main_window->getPosition().y;

// get the mouse direction from the player's position (p0) to the mouse cursor pointer (p1)
player->getDirectionFromScreen(p0, p1, mouse_x, mouse_y, 0, 0, main_size.x, main_size.y);

// create an instance of the WorldIntersection class to get the result
WorldIntersectionPtr intersection = WorldIntersection::create();

// create an instance for intersected object and check the intersection
ObjectPtr object = World::getIntersection(p0, p1, 1, intersection);

// if the intersection has occurred, change the parameter of the object's material
if (object)
{
	for (int i = 0; i < object->getNumSurfaces(); i++)
	{
		object->setMaterialParameterFloat4("albedo_color", vec4(1.0f, 0.0f, 0.0f, 1.0f), i);

		// show intersection details in console
		Log::message("point: (%f %f %f) index: %i \n", intersection->getPoint().x, intersection->getPoint().y, intersection->getPoint().z, intersection->getIndex());
	}
}
/* ... */


```


## WorldIntersection Class

### Enums

## TYPE

| Name | Description |
|---|---|
| **WORLD_INTERSECTION** = 0 | The intersection point (coordinates), the index of the intersected triangle of the object and the index of the intersected surface. |
| **WORLD_INTERSECTION_NORMAL** = 1 | The normal of the intersection point. |
| **WORLD_INTERSECTION_TEX_COORD** = 2 | The texture coordinates of the intersection point. |
| **NUM_WORLD_INTERSECTIONS** = 3 | Total number of world intersections. |

### Members

## void setSurface ( int surface )

Sets a new intersected surface number.
### Arguments

- *int* **surface** - The intersected surface number.

## int getSurface () const

Returns the current intersected surface number.
### Return value

Current intersected surface number.
## void setInstance ( int instance )

Sets a new number of the intersected instance.
> **Notice:** Intersected instance number can be obtained for the following classes:
>
>
> - *[ObjectMeshSkinned](../../../api/library/objects/class.objectmeshskinned_cpp.md)*
> - *[ObjectMeshCluster](../../../api/library/objects/class.objectmeshcluster_cpp.md)*
> - *[ObjectMeshSplineCluster](../../../api/library/objects/class.objectmeshsplinecluster_cpp.md)*


### Arguments

- *int* **instance** - The intersected instance number.

## int getInstance () const

Returns the current number of the intersected instance.
> **Notice:** Intersected instance number can be obtained for the following classes:
>
>
> - *[ObjectMeshSkinned](../../../api/library/objects/class.objectmeshskinned_cpp.md)*
> - *[ObjectMeshCluster](../../../api/library/objects/class.objectmeshcluster_cpp.md)*
> - *[ObjectMeshSplineCluster](../../../api/library/objects/class.objectmeshsplinecluster_cpp.md)*


### Return value

Current intersected instance number.
## void setIndex ( int index )

Sets a new number of the intersected triangle.
### Arguments

- *int* **index** - The number of the intersected triangle.

## int getIndex () const

Returns the current number of the intersected triangle.
### Return value

Current number of the intersected triangle.
## void setPoint ( const const Math:: Vec3 && point )

Sets a new coordinates of the intersection point.
### Arguments

- *const const  Math::[Vec3](../../../api/library/math/class.vec3_cpp.md) &&* **point** - The coordinates of the intersection point.

## const Math:: Vec3 & getPoint () const

Returns the current coordinates of the intersection point.
### Return value

Current coordinates of the intersection point.
## const char * getTypeName () const

Returns the current *World Intersection* type name.
### Return value

Current *World Intersection* type name.
## WorldIntersection::TYPE getType () const

Returns the current [*World Intersection* type identifier](#WORLD_INTERSECTION).
### Return value

Current *World Intersection* type identifier.
---

## static WorldIntersectionPtr create ( )

The WorldIntersection constructor.