ofxRaycaster

Donation:

If you find this project useful please consider a donation.

Table of Contents

How to use it

Methods for 2D and 3D rays

2D Intersection Methods

3D Intersection Methods

Mouse Picker

Showcase

This addon contains a c++ class to works with rays in 2D and 3D dimension, and it includes methods to check the intersection with segments, spheres, triangles, planes, ofPrimitive, ofPolyline and ofMesh, wrapping the methods already presents in the glm library, the default math library oin OF.

How to use it:

Download this addon in your addons folder. Create a new project with the project generator and add as addon ofxRaycaster. In your project, add at the top of your ofApp.h file

#include "ofxRaycaster.h"

To get started using a 2D ray in your project, declare a ray variable in your ofApp.h header file:

ofxraycaster::Ray2D ray;

If you want to use a 3D ray, declare the ray like this.

ofxraycaster::Ray ray;

Generic methods, for both 2D and 3D rays:

setup

void setup(glm::vec2 origin, glm::vec2 direction)

Set the origin and direction of a ray. For example, for a 2D ray:

ray.setup(glm::vec2(10,5), glm::vec2(1,0));

getOrigin

glm::vec2 getOrigin();

Return the origin of the vector. For example, for the 2D ray previously greated:

ray.getOrigin(); // returns glm::vec2(10,5)

getDirection

glm::vec2 getDirection();

Return the direction of the vector. For example, for the 2D ray previously greated:

ray.getDirection(); // returns glm::vec2(1,0)

setOrigin

void setOrigin(glm::vec3 origin);

Set the origin of the ray;

setDirection

void setDirection(glm::vec2 _origin);

Set the direction of the ray;

draw

void draw(float radius = 20.);

Draw a red circle indicating the position and a blue line indicating the direction, useful when debugging. It accepts a parameter to scale the dimension of the line representing the direction.

2D intersection methods:

example-polyline-intersection	example-segment-intersection

intersectsPolyline

See example example-polyline-intersection

bool intersectsPolyline(const ofPolyline & poly, float & distance, glm::vec2& surfaceNormal);

Check the intersection between a ray and an ofPolyline. If there is an intersection, it stores in distance and surfaceNormal respectively the distance from the origin to the intersection point, and a 2D normal of the segment of the polyline hit by the ray.

ofxraycaster::Ray2D ray;
ofPolyline poly;

glm::vec2 surfaceNormal; // store the intersection value
float distance; // store the intersection value

if (ray.intersectsPolyline(poly, distance, surfaceNormal)) {
    glm::vec2 intersection = ray.getOrigin() + ray.getDirection() * distance;
    ofDrawLine(ray.getOrigin(), intersection);
}

intersectsSegment

See example example-segment-intersection

bool intersectsSegment(const glm::vec2 & a, const glm::vec2 & b, float & distance)

Check the intersection between a ray and a segment. If there is an intersection, it stores in the variable distance the distance from the origin to the intersection point.

ofxraycaster::Ray2D ray;
auto a = glm::vec2(10, 30);
auto b = glm::vec2(50, 50);
// the segment goes from point a to point b

float distance; // store the intersection value

if (ray.intersectsSegment(a, b, distance)) {
    glm::vec2 intersection = ray.getOrigin() + ray.getDirection() * distance;
    ofDrawLine(ray.getOrigin(), intersection);
}

3D intersection methods:

example-multiple-rays	example-mesh-intersection	example-3D

intersectsTriangle

Check the intersection between a ray and a triangle. See example-3D.

bool intersectsTriangle(glm::vec3 const & vert0, glm::vec3 const & vert1, glm::vec3 const & vert2, glm::vec2 & baryPosition, float & distance)

intersectsSphere

Check the intersection between a ray and a sphere. See example-3D.

bool intersectsSphere(const glm::vec3 & _center, const float & _radius, glm::vec3& _position, glm::vec3 & _normal)

intersectsPrimitive

Check the intersection between a ray and an ofPrimitive. See example-3D.

bool intersectsPrimitive(const of3dPrimitive& primitive,  glm::vec2 & baricentricCoords, float & distance, glm::vec3 & intNormal)

intersectsPlane

Check the intersection between a ray and an ofxraycaster::Plane. See example-3D.

bool intersectsPlane(ofxraycaster::Plane plane, float & distance);

intersectsMesh

Check the intersection between a ray and a mesh. See example-mesh-intersection.

bool intersectsMesh(const ofMesh& mesh,  glm::vec2 & baricentricCoords, float & distance, glm::vec3 & intNormal);

Example:

void ofApp::draw(){
    cam.begin();
    mesh.draw();
    ray.draw();

    glm::vec2 baricentricCoordinates; // stores the barycentric coordinate of the triangle hit by the ray.
    float distance;
    glm::vec3 surfaceNormal; // stores the normal of the surface hit by the ray.
    bool intersects = ray.intersectsMesh(mesh, baricentricCoordinates, distance, surfaceNormal);

    // is there an intersection between the mesh and the ray?
    if (intersects) {
        auto intersection =
            ray.getOrigin() + ray.getDirection() * distance;
        // draw the ray hitting the mesh
        ofDrawLine(ray.getOrigin(), intersection);
        // draw the intersection point
        ofDrawSphere(intersection, 5);

        // draw the reflected light
        auto reflLight = glm::reflect(ray.getDirection(), surfaceNormal);
        ofDrawLine(intersection, intersection + 100 * reflLight);
    }
    cam.end();
}

When a glm::mat4 containing the transformation matrix of the mesh is given as second argument, it takes the transformation into account. See example-mesh-intersection.

bool intersectsMesh(const ofMesh& mesh, const glm::mat4& transformationMatrix,  glm::vec2 & baricentricCoords, float & distance, glm::vec3 & intNormal);

Mousepicker:

example-mousepicker

setFromCamera

void setFromCamera(const glm::vec2 mouseCoords, const ofCamera camera);

Set the origin and the direction of the ray giving as argument an ofCamera and the mouse coordinates. See example example-mousepicker.

draw

void draw(const float radius = 20);

Draw a sphere under the mouse.

getRay

Ray& getRay();

Return the 3D ray that goes from the camera towards the mouse.

Showcase:

This addon was used in the following projects:

• Border Tuner / Sintonizador Fronterizo

• Sphere Packing - Bach

• Sun and Moon

If you want to add your project to this list, please open an issue.