Changeset 1500 for GTP/trunk/Lib/Vis/Preprocessing/src/GvsPreprocessor.cpp

Timestamp:

09/26/06 18:14:30 (18 years ago)

Author:

mattausch

Message:

worked on gvs sampling

File:

• GTP/trunk/Lib/Vis/Preprocessing/src/GvsPreprocessor.cpp (modified) (8 diffs)

GTP/trunk/Lib/Vis/Preprocessing/src/GvsPreprocessor.cpp

@@ -6 +6 @@
 #include "Triangle3.h"
 #include "IntersectableWrapper.h"
+#include "Plane3.h"
+
 
 
@@ -18 +20 @@
         Environment::GetSingleton()->GetIntValue("GvsPreprocessor.samplesPerPass", mSamplesPerPass);
         Environment::GetSingleton()->GetFloatValue("GvsPreprocessor.epsilon", mEps);
-                
+        Environment::GetSingleton()->GetFloatValue("GvsPreprocessor.threshold", mThreshold);    
 
         Debug << "Gvs preprocessor options" << endl;
@@ -29 +31 @@
 
 
-const bool GvsPreprocessor::DiscontinuityFound(const VssRay &ray, 
-                                                                                           const VssRay &oldRay) const
-{
-        //|predicted(x)-xp|-|hit(x)-xp| > ?,
-    //const Plane3 plane = tri->GetPlane();
+bool GvsPreprocessor::CheckDiscontinuity(const VssRay &currentRay,
+                                                                                 const Triangle3 &hitTriangle,
+                                                                                 const VssRay &oldRay)
+{
+        const float dist = Magnitude(oldRay.GetDir());
+        const float newDist = Magnitude(currentRay.GetDir());
+ 
+#if 0
+        if ((dist - newDist) > mThresHold)
+#else // rather take relative distance
+        if ((dist / newDist) > mThreshold)
+#endif
+        {
+                VssRay *newRay = ReverseSampling(currentRay, hitTriangle, oldRay);
+                HandleRay(*newRay);
+                return true;
+        }
+
         return false;
 }
 
 
-int GvsPreprocessor::HandleRay(const GvsRayInfo &gvsRay)
-{
-        VssRay *ray = gvsRay.mRay;
-
-        if (!mViewCellsManager->ComputeSampleContribution(*ray, true, false))
-                return 1;
-
-        if (gvsRay.mFoundDiscontinuity)
-        {
-                return ReverseSampling(*ray);
-        }
-        else
-        {
-                return AdaptiveBorderSampling(*ray);
-        }
-}
-
-/** Hepler function for adaptive border sampling. It finds 
-        new sample points around a triangle in a eps environment
+bool GvsPreprocessor::HandleRay(VssRay &vssRay)
+{
+        if (!mViewCellsManager->ComputeSampleContribution(vssRay, true, false))
+        {
+                mRayQueue.push(&vssRay);
+                return true;
+        }
+
+        return false;
+}
+
+
+/** Creates 3 new vertices for triangle vertex with specified index.
 */
-static void CreateNewRays(SimpleRayContainer &simpleRays, 
-                                                  const Triangle3 &hitTriangle,
-                                                  const VssRay &ray, 
-                                                  const int index,
-                                                  const float eps)
+static void CreateNewVertices(VertexContainer &vertices,
+                                                          const Triangle3 &hitTriangle,
+                                                          const VssRay &ray, 
+                                                          const int index,
+                                                          const float eps)
 {
         const int indexU = (index + 1) % 3;
@@ -75 +84 @@
         const Vector3 dir1 = CrossProd(a, b); //N((pi-xp)×(pi+1- pi));
         const Vector3 dir2 = CrossProd(a, c); // N((pi-xp)×(pi- pi-1))
-        const Vector3 dir3 = DotProd(dir1, dir2) > 0 ? 
-                Normalize(dir2 + dir1) : Normalize(CrossProd(a, dir2) + CrossProd(dir1, a)); // N((pi-xp)×di,i-1+di,i+1×(pi-xp))
+        const Vector3 dir3 = DotProd(dir1, dir2) > 0 ? // N((pi-xp)×di,i-1+di,i+1×(pi-xp))
+                Normalize(dir2 + dir1) : Normalize(CrossProd(a, dir2) + CrossProd(dir1, a)); 
 
         // compute the new three hit points
-        // pi, i + 1
-        const Vector3 pt1 = hitTriangle.mVertices[index] + eps * len * dir1; //pi+ e·|pi-xp|·di, j
-        // pi, i - 1
-    const Vector3 pt2 = hitTriangle.mVertices[index] + eps * len * dir2; //pi+ e·|pi-xp|·di, j
-        // pi, i
-        const Vector3 pt3 = hitTriangle.mVertices[index] + eps * len * dir3; //pi+ e·|pi-xp|·di, j
-        
-        /// create simple rays and store them in container
-        Vector3 rayDir;
-        rayDir = Normalize(pt1 - ray.GetOrigin());
-        simpleRays.push_back(SimpleRay(rayDir, ray.GetOrigin()));
-        rayDir = Normalize(pt2 - ray.GetOrigin());
-        simpleRays.push_back(SimpleRay(rayDir, ray.GetOrigin()));
-        rayDir = Normalize(pt3 - ray.GetOrigin());
-        simpleRays.push_back(SimpleRay(rayDir, ray.GetOrigin()));
-}
-
-
-
-int GvsPreprocessor::AdaptiveBorderSampling(const VssRay &prevRay)
+        // pi, i + 1:  pi+ e·|pi-xp|·di, j
+        const Vector3 pt1 = hitTriangle.mVertices[index] + eps * len * dir1;
+        // pi, i - 1:  pi+ e·|pi-xp|·di, j
+    const Vector3 pt2 = hitTriangle.mVertices[index] + eps * len * dir2;
+        // pi, i:  pi+ e·|pi-xp|·di, j
+        const Vector3 pt3 = hitTriangle.mVertices[index] + eps * len * dir3;
+        
+        vertices.push_back(pt1);
+        vertices.push_back(pt2);
+        vertices.push_back(pt3);
+}
+
+
+void GvsPreprocessor::EnlargeTriangle(VertexContainer &vertices,
+                                                                          const Triangle3 &hitTriangle,
+                                                                          const VssRay &ray)
+{
+        CreateNewVertices(vertices, hitTriangle, ray, 0, mEps);
+        CreateNewVertices(vertices, hitTriangle, ray, 1, mEps);
+        CreateNewVertices(vertices, hitTriangle, ray, 2, mEps);
+}
+
+
+static Vector3 CalcPredictedHitPoint(const VssRay &newRay, 
+                                                                         const Triangle3 &hitTriangle,
+                                                                         const VssRay &oldRay)
+{
+        Plane3 plane(hitTriangle.GetNormal(), hitTriangle.mVertices[0]);
+
+        const Vector3 hitPt = 
+                plane.FindIntersection(newRay.mTermination, newRay.mOrigin);
+        
+        return hitPt;
+}
+
+
+static bool EqualVisibility(const VssRay &a, const VssRay &b)
+{
+        return a.mTerminationObject == b.mTerminationObject;
+}
+
+
+int GvsPreprocessor::SubdivideEdge(const Triangle3 &hitTriangle,
+                                                                   const Vector3 &p1, 
+                                                                   const Vector3 &p2, 
+                                                                   const VssRay &x, 
+                                                                   const VssRay &y,
+                                                                   const VssRay &oldRay)
+{
+        // the predicted hitpoint expects to hit the same mesh again
+        const Vector3 predictedHitX = CalcPredictedHitPoint(x, hitTriangle, oldRay);
+        const Vector3 predictedHitY = CalcPredictedHitPoint(y, hitTriangle, oldRay);
+
+        CheckDiscontinuity(x, hitTriangle, oldRay);
+        CheckDiscontinuity(y, hitTriangle, oldRay);
+
+        if (EqualVisibility(x, y))
+        {
+                return 2;
+        }
+        else
+        {
+                const Vector3 p = (p1 + p2) * 0.5f;
+                SimpleRay sray(oldRay.mOrigin, p - oldRay.mOrigin);
+                VssRay *newRay = NULL;
+                //VssRay *newRay = CastSingleRay(sray);
+                HandleRay(*newRay);
+
+                const int s1 = SubdivideEdge(hitTriangle, p1, p, x, *newRay, oldRay);
+                const int s2 = SubdivideEdge(hitTriangle, p, p2, *newRay, y, oldRay);
+                                                                  
+        return s1 + s2;
+        }
+}
+
+
+int GvsPreprocessor::AdaptiveBorderSampling(const VssRay &currentRay)
 {
         cout << "a";
-        Intersectable *tObj = prevRay.mTerminationObject;
+        Intersectable *tObj = currentRay.mTerminationObject;
         Triangle3 hitTriangle;
 
@@ -110 +176 @@
         }
 
+        VertexContainer enlargedTriangle;
+        
+        /// create 3 new hit points for each vertex
+        EnlargeTriangle(enlargedTriangle, hitTriangle, currentRay);
+        
+        /// create rays from sample points and handle them
         SimpleRayContainer simpleRays;
         simpleRays.reserve(9);
 
-        CreateNewRays(simpleRays, hitTriangle, prevRay, 0, mEps);
-        CreateNewRays(simpleRays, hitTriangle, prevRay, 1, mEps);
-        CreateNewRays(simpleRays, hitTriangle, prevRay, 2, mEps);
-
+        VertexContainer::const_iterator vit, vit_end = enlargedTriangle.end();
+
+        for (vit = enlargedTriangle.begin(); vit != vit_end; ++ vit)
+        {
+                const Vector3 rayDir = (*vit) - currentRay.GetOrigin();
+                simpleRays.push_back(SimpleRay(*vit, rayDir));
+        }
+
+        // establish visibility
         VssRayContainer vssRays;
-        
         CastRays(simpleRays, vssRays);
         // add to ray queue
         EnqueueRays(vssRays);
 
+    // recursivly subdivide each edge
+        for (int i = 0; i < 9; ++ i)
+        {
+                SubdivideEdge(
+                        hitTriangle,
+                        enlargedTriangle[i], 
+                        enlargedTriangle[(i + 1) % 9], 
+                        *vssRays[i], 
+                        *vssRays[(i + 1) % 9],
+                        currentRay);
+        }
+
         return (int)vssRays.size();
 }
 
 
-int GvsPreprocessor::ReverseSampling(const VssRay &oldRay)
+static Vector3 GetPassingPoint(const VssRay &currentRay,
+                                                                                 const Triangle3 &hitTriangle,
+                                                                                 const VssRay &oldRay)
+{
+        // intersect triangle plane with plane spanned by current samples
+        Plane3 plane(currentRay.GetOrigin(), currentRay.GetTermination(), oldRay.GetTermination());
+        Plane3 triPlane(hitTriangle.GetNormal(), hitTriangle.mVertices[0]);
+
+        SimpleRay intersectLine = GetPlaneIntersection(plane, triPlane);
+
+        // Evaluate new hitpoint just outside the triangle
+        const float factor = 0.95f;
+        float t = triPlane.FindT(intersectLine);
+
+        const Vector3 newPoint = intersectLine.mOrigin + t * factor * intersectLine.mDirection;
+
+        return newPoint;
+}
+
+
+VssRay *GvsPreprocessor::ReverseSampling(const VssRay &currentRay,
+                                                                                 const Triangle3 &hitTriangle,
+                                                                                 const VssRay &oldRay)
 {
         cout << "r" << endl;
-        // TODO
-        return 1;
+        
+        
+        //-- The plane p = (xp, hit(x), hit(xold)) is intersected
+        //-- with the newly found triangle (xold is the previous ray from
+        //-- which x was generated). On the intersecting line, we select a point
+        //-- pnew which lies just outside of the new triangle so the ray
+        //-- just passes by inside the gap
+    const Vector3 newPoint = GetPassingPoint(currentRay, hitTriangle, oldRay);
+        const Vector3 predicted = CalcPredictedHitPoint(currentRay, hitTriangle, oldRay);
+
+        //-- Construct the mutated ray with xnew,dir = predicted(x)- pnew 
+        //-- as direction vector
+        const Vector3 newDir = predicted - newPoint ;
+        // take xnew,p = intersect(viewcell, line(pnew, predicted(x)) as origin ?
+        // difficult to say!!
+        const Vector3 newOrigin = newDir * -5000.0f;
+
+        return new VssRay(currentRay);
 }
 
@@ -157 +283 @@
 
 
-void GvsPreprocessor::EnqueueRays(VssRayContainer &samples, VssRay *oldRay)
+void GvsPreprocessor::EnqueueRays(VssRayContainer &samples)
 {
         // add samples to ray queue
         VssRayContainer::const_iterator vit, vit_end = samples.end();
+        
         for (vit = samples.begin(); vit != vit_end; ++ vit)
         {
-                /// if there is no old ray, no discontinuity
-                const bool gap = oldRay ? DiscontinuityFound(*(*vit), *oldRay) : false;
-                mRayQueue.push(GvsRayInfo(*vit, gap));
+                HandleRay(*(*vit));
         }
 }
@@ -196 +321 @@
         {
                 // handle next ray
-                GvsRayInfo rayInfo = mRayQueue.top();
+                VssRay *ray = mRayQueue.top();
                 mRayQueue.pop();
                 
-                castSamples += HandleRay(rayInfo);
+                castSamples += HandleRay(*ray);
         }
 
@@ -227 +352 @@
                 castSamples += passSamples;
                 
-                /////////////
-                // -- stats
+                ////////
+                //-- stats
                 cout << "+";
                 cout << "\nsamples cast " << passSamples << " (=" << castSamples << " of " << mTotalSamples << ")" << endl;