source: code/branches/ode/ode-0.9/contrib/dRay/dRay_Plane.cpp @ 216

// Ripped from Paul Bourke

#include "Include\dRay.h"
#include "dxRay.h"

int dCollidePR(dxGeom* RayGeom, dxGeom* PlaneGeom, int Flags, dContactGeom* Contact, int Stride){
        dVector3 Plane;
        dGeomPlaneGetParams(PlaneGeom, Plane);

        dVector3 Origin, Direction;
        dGeomRayGet(RayGeom, Origin, Direction);

        dReal Length = dGeomRayGetLength(RayGeom);

        dReal Denom = Plane[0] * Direction[0] + Plane[1] * Direction[1] + Plane[2] * Direction[2];
        if (dFabs(Denom) < 0.00001f){
                return 0;       // Ray never hits
        }
        
        float T = -(Plane[3] + Plane[0] * Origin[0] + Plane[1] * Origin[1] + Plane[2] * Origin[2]) / Denom;
        
        if (T < 0 || T > Length){
                return 0;       // Ray hits but not within boundaries
        }

        Contact->pos[0] = Origin[0] + T * Direction[0];
        Contact->pos[1] = Origin[1] + T * Direction[1];
        Contact->pos[2] = Origin[2] + T * Direction[2];
        Contact->pos[3] = REAL(0.0);
        //Contact->normal = 0;
        Contact->depth = 0.0f;
        Contact->g1 = RayGeom;
        Contact->g2 = PlaneGeom;
        return 1;
}