# WorldIntersection Class

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
*Unigine::getPlayerMouseDirection()*function from core/scripts/utils.h. - Create an instance of the WorldIntersection class to get the intersection information.
- Check, if there is a intersection with an object. The
*engine.world.getIntersection()*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, the index of the surface and the index of the intersected triangle. You can get all these fields by using
*getIndex()*,*getPoint()*and*getSurface()*functions

```
#include <core/scripts/utils.h>
/* ... */
// define two vec3 coordinates
vec3 p0,p1;
// get the mouse direction from camera (p0) to cursor pointer (p1)
Unigine::getPlayerMouseDirection(p0,p1);
// create an instance of the WorldIntersection class to get the result
WorldIntersection intersection = new WorldIntersection();
// create an instance for intersected object and check the intersection
Object object = engine.world.getIntersection(p0,p1,1,intersection);
// if the intersection has been occurred, change the parameter and the texture of the object's material
if(object != NULL)
{
forloop(int i=0; object.getNumSurfaces())
{
object.setMaterialParameter("diffuse_color", vec4(1.0f, 0.0f, 0.0f, 1.0f),i);
object.setMaterialTexture("diffuse","", i);
// show intersection details in console
log.message("point: %s index: %i surface: %i \n", typeinfo(intersection.getPoint()), intersection.getIndex(), intersection.getSurface());
}
}
/* ... */
```

## WorldIntersection Class

### Members

## WorldIntersection ()

The WorldIntersection constructor.## int getIndex ()

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

Intersected triangle number.## vec3 getPoint ()

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

Coordinates of the intersection point.## int getSurface ()

Returns the intersected surface number.### Return value

Intersected surface number.## void setIndex (int index)

Sets the new intersection triangle number.### Arguments

*int*- Intersection triangle number.**index**

## void setPoint (vec3 point)

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

*vec3*- Coordinates of the intersection point.**point**

## void setSurface (int surface)

Sets the new intersection surface number.### Arguments

*int*- Intersection surface number.**surface**

Last update: 2017-07-03

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