1 files changed, 92 insertions, 1 deletions

diff --git a/linden/indra/newview/llvosurfacepatch.cpp b/linden/indra/newview/llvosurfacepatch.cpp
index 310a745..66c8dac 100644
--- a/linden/indra/newview/llvosurfacepatch.cpp
+++ b/linden/indra/newview/llvosurfacepatch.cpp
@@ -4,7 +4,7 @@
  *
  * $LicenseInfo:firstyear=2001&license=viewergpl$
  * 
- * Copyright (c) 2001-2008, Linden Research, Inc.
+ * Copyright (c) 2001-2009, Linden Research, Inc.
  * 
  * Second Life Viewer Source Code
  * The source code in this file ("Source Code") is provided by Linden Lab
@@ -916,6 +916,97 @@ void LLVOSurfacePatch::getGeomSizesEast(const S32 stride, const S32 east_stride,
         }
 }
 
+BOOL LLVOSurfacePatch::lineSegmentIntersect(const LLVector3& start, const LLVector3& end, S32 face, BOOL pick_transparent, S32 *face_hitp,
+                                                                          LLVector3* intersection,LLVector2* tex_coord, LLVector3* normal, LLVector3* bi_normal)
+        
+{
+
+        if (!lineSegmentBoundingBox(start, end))
+        {
+                return FALSE;
+        }
+
+        LLVector3 delta = end-start;
+                
+        LLVector3 pdelta = delta;
+        pdelta.mV[2] = 0;
+
+        F32 plength = pdelta.length();
+        
+        F32 tdelta = 1.f/plength;
+
+        LLVector3 origin = start - mRegionp->getOriginAgent();
+
+        if (mRegionp->getLandHeightRegion(origin) > origin.mV[2])
+        {
+                //origin is under ground, treat as no intersection
+                return FALSE;
+        }
+
+        //step one meter at a time until intersection point found
+
+        const LLVector3* ext = mDrawable->getSpatialExtents();
+        F32 rad = (delta*tdelta).magVecSquared();
+
+        F32 t = 0.f;
+        while ( t <= 1.f)
+        {
+                LLVector3 sample = origin + delta*t;
+                
+                if (AABBSphereIntersectR2(ext[0], ext[1], sample+mRegionp->getOriginAgent(), rad))
+                {
+                        F32 height = mRegionp->getLandHeightRegion(sample);
+                        if (height > sample.mV[2])
+                        { //ray went below ground, positive intersection
+                                //quick and dirty binary search to get impact point
+                                tdelta = -tdelta*0.5f;
+                                F32 err_dist = 0.001f;
+                                F32 dist = fabsf(sample.mV[2] - height);
+
+                                while (dist > err_dist && tdelta*tdelta > 0.0f)
+                                {
+                                        t += tdelta;
+                                        sample = origin+delta*t;
+                                        height = mRegionp->getLandHeightRegion(sample);
+                                        if ((tdelta < 0 && height < sample.mV[2]) ||
+                                                (height > sample.mV[2] && tdelta > 0))
+                                        { //jumped over intersection point, go back
+                                                tdelta = -tdelta;
+                                        }
+                                        tdelta *= 0.5f;
+                                        dist = fabsf(sample.mV[2] - height);
+                                }
+
+                                if (intersection)
+                                {
+                                        F32 height = mRegionp->getLandHeightRegion(sample);
+                                        if (fabsf(sample.mV[2]-height) < delta.length()*tdelta)
+                                        {
+                                                sample.mV[2] = mRegionp->getLandHeightRegion(sample);
+                                        }
+                                        *intersection = sample + mRegionp->getOriginAgent();
+                                }
+
+                                if (normal)
+                                {
+                                        *normal = mRegionp->getLand().resolveNormalGlobal(mRegionp->getPosGlobalFromRegion(sample));
+                                }
+
+                                return TRUE;
+                        }
+                }
+
+                t += tdelta;
+                if (t > 1 && t < 1.f+tdelta*0.99f)
+                { //make sure end point is checked (saves vertical lines coming up negative)
+                        t = 1.f;
+                }
+        }
+
+
+        return FALSE;
+}
+
 void LLVOSurfacePatch::updateSpatialExtents(LLVector3& newMin, LLVector3 &newMax)
 {
         LLVector3 posAgent = getPositionAgent();