source: GTP/trunk/Lib/Vis/Preprocessing/src/IntersectableWrapper.cpp @ 2571

#include "IntersectableWrapper.h"
#include "Mesh.h"
#include "Triangle3.h"
#include "KdTree.h"
#include "BvHierarchy.h"


namespace GtpVisibilityPreprocessor {


AxisAlignedBox3 TriangleIntersectable::GetBox() const
{       
        return mItem.GetBoundingBox();
}


int TriangleIntersectable::CastRay(Ray &ray)
{       
        float nearestT = MAX_FLOAT;
        float t;
        Vector3 nearestNormal;

        if (ray.GetType() == Ray::LOCAL_RAY && !ray.intersections.empty())
                nearestT = ray.intersections[0].mT;
        
        const int hitCode = mItem.CastRay(ray, t, nearestT, nearestNormal);

        nearestT = t;

        if (hitCode == Ray::INTERSECTION) {
                if (ray.GetType() == Ray::LOCAL_RAY && !ray.intersections.empty()) {
                        ray.intersections[0] = Ray::Intersection(nearestT,
                                                                                                         nearestNormal,
                                                                                                         this,
                                                                                                         0);
                }
                else {
                        ray.intersections.push_back(Ray::Intersection(nearestT,
                                                                                                                  nearestNormal,
                                                                                                                  this,
                                                                                                                  0));
                }
                
                return 1;
        }
        
        return 0;
}
        

int TriangleIntersectable::NumberOfFaces() const
{
        return 1;
}


Vector3 TriangleIntersectable::GetNormal(const int idx) const
{
        return mItem.GetNormal();
}


int
TriangleIntersectable::GetRandomSurfacePoint(Vector3 &point, Vector3 &normal)
{
        // random barycentric coordinates
        float a = RandomValue(0.0f, 1.0f);
        float b = RandomValue(0.0f, 1.0f);
        float c = RandomValue(0.0f, 1.0f);
        
        const float sum = a + b + c;

        // scale so we get vaccumated value of 1
        if (sum)
        {
                a /= sum;
                b /= sum;
                c /= sum;
        }

        //cout << "a: " << a << " b: " << b << " c: " << c << " sum: " << sum << endl;
        point = mItem.mVertices[0] * a + mItem.mVertices[1] * b + mItem.mVertices[2] * c;
        normal = mItem.GetNormal();

        return 0;
}


int
TriangleIntersectable::GetRandomSurfacePoint(const float u,
                                                                                         const float v,
                                                                                         Vector3 &point,
                                                                                         Vector3 &normal)
{
  // random barycentric coordinates
  float a = u;
  float b = v;
  float c = 1.0f - u - v;
  
  point = mItem.mVertices[0] * a + mItem.mVertices[1] * b + mItem.mVertices[2] * c;
  normal = mItem.GetNormal();
  
  return 0;
}



int TriangleIntersectable::GetRandomVisibleSurfacePoint(Vector3 &point,
                                                                                                                Vector3 &normal,
                                                                                                                const Vector3 &viewpoint,
                                                                                                                const int maxTries)
{
        return GetRandomSurfacePoint(point, normal);
}


int TriangleIntersectable::GetRandomEdgePoint(Vector3 &point, Vector3 &normal)
{
        const int edge = Random(3);

        const Vector3 a = mItem.mVertices[edge];
        const Vector3 b = mItem.mVertices[(edge + 1) % 3];

        const float factor = RandomValue(0.0f, 1.0f);

        point = a * factor + b * factor;
        normal = mItem.GetNormal();

        return edge;
}


KdIntersectable::KdIntersectable(KdNode *item, const AxisAlignedBox3 &box) :
  IntersectableWrapper<KdNode *>(item), mNumTriangles(-1), mBox(box)
{
}


int KdIntersectable::ComputeNumTriangles()
{
        Intersectable::NewMail();

        std::stack<KdNode *> tStack;
        tStack.push(mItem);

        if (mNumTriangles != -1)
                return mNumTriangles;

        mNumTriangles = 0;

        while (!tStack.empty())
        {
                KdNode *node = tStack.top();
                tStack.pop();

                if (!node->IsLeaf()) 
                {
                        KdInterior *kdInterior = static_cast<KdInterior *>(node);

                        tStack.push(kdInterior->mBack);
                        tStack.push(kdInterior->mFront);
                } 
                else 
                {
                        KdLeaf *leaf = static_cast<KdLeaf *>(node);

                        int tri = 0;

                        for (size_t i = 0; i < leaf->mObjects.size(); ++ i)
                        {
                                TriangleIntersectable *obj = 
                                        static_cast<TriangleIntersectable *>(leaf->mObjects[i]);
                                
                                // check if already rendered
                                if (!obj->Mailed())
                                {
                                        obj->Mail();
                                        ++ tri;
                                }
                        }

            mNumTriangles += tri;
                }
        }

        return mNumTriangles;
}

}