Save height-adjusted line for SD processing instead of raw line.

Author: abellgithub

alg/viewshed/viewshed_executor.cpp

@@ -234,8 +234,10 @@ void ViewshedExecutor::setOutputNormal(Lines &lines, int pos, double dfZ)
             result += adjustment;
     }
     else
-        result = (cur + oOpts.targetHeight < dfZ) ? oOpts.invisibleVal
-                                                  : oOpts.visibleVal;
+    {
+        double cellHeight = cur + oOpts.targetHeight;
+        result = (cellHeight < dfZ) ? oOpts.invisibleVal : oOpts.visibleVal;
+    }
     cur = std::max(cur, dfZ);
 }
 
@@ -287,7 +289,6 @@ bool ViewshedExecutor::readLine(int nLine, Lines &lines)
 
     if (sdMode())
     {
-        lines.input = lines.cur;
         double nodata = m_sdBand.GetNoDataValue();
         CPLErr sdStatus = m_sdBand.RasterIO(
             GF_Read, oOutExtent.xStart, nLine, oOutExtent.xSize(), 1,
@@ -490,6 +491,11 @@ bool ViewshedExecutor::processFirstLine(Lines &lines)
         m_dfZObserver += lines.cur[m_nX];
 
     LineLimits ll = adjustHeight(nYOffset, lines);
+
+    std::vector<double> savedInput;
+    if (sdMode())
+        savedInput = lines.cur;
+
     if (oCurExtent.containsX(m_nX))
     {
         if (ll.leftMin != ll.rightMin)
@@ -517,7 +523,7 @@ bool ViewshedExecutor::processFirstLine(Lines &lines)
     lines.prev = lines.cur;
     if (sdMode())
     {
-        lines.cur = std::move(lines.input);
+        lines.cur = std::move(savedInput);
         process(true);
         lines.prevTmp = lines.cur;
     }
@@ -1013,6 +1019,10 @@ bool ViewshedExecutor::processLine(int nLine, Lines &lines)
     // Adjust height of the read line.
     LineLimits ll = adjustHeight(nYOffset, lines);
 
+    std::vector<double> savedLine;
+    if (sdMode())
+        savedLine = lines.cur;
+
     auto process = [this, nYOffset, &ll, &lines](bool sdCalc)
     {
         CPLJobQueuePtr pQueue = m_pool.CreateJobQueue();
@@ -1043,7 +1053,7 @@ bool ViewshedExecutor::processLine(int nLine, Lines &lines)
     {
         lines.prev = std::move(lines.prevTmp);
         lines.prevTmp = std::move(lines.cur);
-        lines.cur = std::move(lines.input);
+        lines.cur = std::move(savedLine);
         // Handle initial position on the line.
         if (!masked && oCurExtent.containsX(m_nX))
         {

alg/viewshed/viewshed_executor.h

@@ -36,21 +36,19 @@ struct Lines
     std::vector<double> result;  //!< Result values for current line
     std::vector<double> prev;    //!< Height values for previous line
     std::vector<double>
-        pitchMask;              //!< Height/indicator values for pitch masking.
-    std::vector<double> input;  //!< Copy of input data when in SD mode.
+        pitchMask;  //!< Height/indicator values for pitch masking.
     std::vector<double> prevTmp;  //!< Saved prev values when in SD mode.
     std::vector<double> sd;       //!< SD mask.
 
     /// Constructor
-    Lines() : cur(), result(), prev(), pitchMask(), input(), prevTmp(), sd()
+    Lines() : cur(), result(), prev(), pitchMask(), prevTmp(), sd()
     {
     }
 
     /// Constructor that initializes to line length
     /// \param lineLen  Line length.
     explicit Lines(size_t lineLen)
-        : cur(lineLen), result(lineLen), prev(), pitchMask(), input(),
-          prevTmp(), sd()
+        : cur(lineLen), result(lineLen), prev(), pitchMask(), prevTmp(), sd()
     {
     }
 };