Module com.marginallyclever.robotoverlord

Package com.marginallyclever.ro3.raypicking

Class RayPickSystem

java.lang.Object

com.marginallyclever.ro3.raypicking.RayPickSystem

public class RayPickSystem
extends Object

RayPickSystem is for finding the MeshInstances that collide with a Ray. This is used for ray picking and path tracing.

For path tracing, it is important to optimize the ray/mesh intersection tests as much as possible. This is done by transforming each mesh into world space in a PathMesh. For ray picking, the optimization is less important, so the meshes are tested in their local space.

To use the RayPickSystem, create an instance, call reset(optimize), and then

Constructor Summary

Constructors

Constructor	Description
RayPickSystem()

Method Summary

Modifier and Type	Method	Description
List<Hit>	findRayIntersections(Ray ray)	Traverse the scene and find all the MeshInstances that collide with the ray.
Hit	getFirstHit(Ray ray)	Traverse the scene and find the nearest MeshInstance that collides with the ray.
static Material	getMaterial(Node meshInstance)	Find the nearest Material in the scene graph, starting from the given MeshInstance.
Hit	getRandomEmissiveSurface()	Guaranteed to return one valid result if there is at least one emissive triangle in the scene.
void	reset(boolean optimize)	Reset the system and rebuild the list of scene elements.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

RayPickSystem

public RayPickSystem()

Method Details

reset

public void reset(boolean optimize)

Reset the system and rebuild the list of scene elements. This should be called whenever the scene graph changes.

Parameters:

optimize - true if extra steps should be taken to optimize, typically for path tracing. If false, the system will do less work and use less memory, but ray/mesh intersection tests will be slower.

getMaterial

public static Material getMaterial(Node meshInstance)

Find the nearest Material in the scene graph, starting from the given MeshInstance. The nearest material is the first one found in the given mesh instance or its parents.

Parameters:

meshInstance - the mesh instance to start searching from.

Returns:

the nearest Material, or null if none is found.

getFirstHit

public Hit getFirstHit(Ray ray)

Traverse the scene and find the nearest MeshInstance that collides with the ray. This computes all intersections and then sorts them by distance, so it is a good idea to keep the ray length short.

Parameters:

ray - the ray to test.

Returns:

the nearest Hit by the ray, or null if no entity was hit.

findRayIntersections

public List<Hit> findRayIntersections(Ray ray)

Traverse the scene and find all the MeshInstances that collide with the ray.

Parameters:

ray - the ray to test.

optimize - true if extra steps should be taken to optimize, typically for path tracing.

Returns:

all Hit by the ray, sorted by distance.

getRandomEmissiveSurface

public Hit getRandomEmissiveSurface()

Guaranteed to return one valid result if there is at least one emissive triangle in the scene.

Returns:

a Hit on a random emissive surface, or null if there are no emissive surfaces.