From 5b6329e5add77febca9ae4a89db01761a8a9c213 Mon Sep 17 00:00:00 2001
From: Christian Schmitt <chris@ilovelinux.de>
Date: Thu, 20 Dec 2012 18:53:20 +0100
Subject: [PATCH] The previous commit brought up some issues with certain
 source formats. We now create a copy of the original dataset and use that for
 processing, as GDAL needs to write some changes.

---
 src/Prep/GDALChop/gdalchop.cxx | 41 +++++++++++++++++++++++-----------
 1 file changed, 28 insertions(+), 13 deletions(-)

diff --git a/src/Prep/GDALChop/gdalchop.cxx b/src/Prep/GDALChop/gdalchop.cxx
index cb4b4f54..7fe38073 100644
--- a/src/Prep/GDALChop/gdalchop.cxx
+++ b/src/Prep/GDALChop/gdalchop.cxx
@@ -31,8 +31,10 @@
 #include <simgear/debug/logstream.hxx>
 #include <simgear/io/lowlevel.hxx>
 #include <simgear/misc/sg_path.hxx>
+#include <simgear/misc/sg_dir.hxx>
 
 #include <gdal.h>
+#include <gdal_alg.h>
 #include <gdal_priv.h>
 #include <gdalwarper.h>
 #include <ogr_spatialref.h>
@@ -124,7 +126,7 @@ public:
         return pxSizeY * 3600;
     }
 
-    void GetDataChunk(int *buffer,
+    void GetDataChunk(const SGPath &work_dir, int *buffer,
                       double x, double y,
                       double colstep, double rowstep,
                       int w, int h,
@@ -219,7 +221,7 @@ ImageInfo::ImageInfo(GDALDataset *dataset) :
            " e=" << east << " w=" << west);
 }
 
-void ImageInfo::GetDataChunk(int *buffer,
+void ImageInfo::GetDataChunk(const SGPath &work_dir, int *buffer,
                              double x, double y,
                              double colstep, double rowstep,
                              int w, int h,
@@ -247,9 +249,20 @@ void ImageInfo::GetDataChunk(int *buffer,
     xformData.col_step = colstep;
     xformData.row_step = rowstep;
 
-    // Interpolate nodata pixels in the source band
-    GDALRasterBand *mask = dataset->GetRasterBand(srcband)->GetMaskBand();
-    GDALFillNodata(dataset->GetRasterBand(srcband), mask, 100, 0, 0, NULL, NULL, NULL);
+    // Interpolate nodata pixels in the source band.
+    // Create a temporary copy of the original for the processing.
+    SGPath tmp_path = work_dir;
+    tmp_path.append(".gdal.tif");
+
+    const char *pszFormat = "GTiff";
+    GDALDriver *poDriver = GetGDALDriverManager()->GetDriverByName(pszFormat);
+    GDALDataset *interpolate = poDriver->CreateCopy( tmp_path.c_str(), dataset, FALSE,
+                                                     NULL, NULL, NULL );
+    GDALFillNodata( interpolate->GetRasterBand(srcband),
+                    interpolate->GetRasterBand(srcband)->GetMaskBand(),
+                    100.0, 0, 0, NULL, NULL, NULL );
+
+    dataset = interpolate;
 
     // TODO: check if this image can actually cover part of the chunk
 
@@ -300,6 +313,7 @@ void ImageInfo::GetDataChunk(int *buffer,
 
     GDALDestroyGenImgProjTransformer( xformData.pTransformerArg );
     GDALDestroyWarpOptions( psWarpOptions );
+    tmp_path.remove();
 }
 
 void write_bucket(const std::string& work_dir, SGBucket bucket,
@@ -338,7 +352,7 @@ void write_bucket(const std::string& work_dir, SGBucket bucket,
     gzclose(fp);
 }
 
-void process_bucket(const std::string& work_dir, SGBucket bucket,
+void process_bucket(const SGPath& work_dir, SGBucket bucket,
                     ImageInfo* images[], int imagecount,
                     bool forceWrite = false)
 {
@@ -377,7 +391,7 @@ void process_bucket(const std::string& work_dir, SGBucket bucket,
     ::memset(buffer.get(), 0, cellcount * sizeof(int));
 
     for (int i = 0; i < imagecount; i++) {
-        images[i]->GetDataChunk(buffer.get(),
+        images[i]->GetDataChunk(work_dir, buffer.get(),
                                 bwest, bsouth,
                                 col_step / 3600.0, row_step / 3600.0,
                                 span_x, span_y );
@@ -405,7 +419,7 @@ void process_bucket(const std::string& work_dir, SGBucket bucket,
     }
 
     /* ...and write it out */
-    write_bucket(work_dir, bucket,
+    write_bucket(work_dir.str(), bucket,
                  buffer.get(),
                  min_x, min_y,
                  span_x, span_y,
@@ -422,9 +436,10 @@ int main(int argc, const char **argv)
         exit(-1);
     }
 
-    SGPath work_dir( argv[1] );
-
-    work_dir.create_dir( 0755 );
+    SGPath work_dir(argv[1]);
+    simgear::Dir wd = simgear::Dir(work_dir);
+    wd.create(0755);
+    work_dir = wd.path();
 
     GDALAllRegister();
 
@@ -507,7 +522,7 @@ int main(int argc, const char **argv)
             for (int y = 0; y <= dy; y++) {
                 SGBucket bucket = sgBucketOffset(west, south, x, y);
 
-                process_bucket(work_dir.str(), bucket, images.get(), datasetcount);
+                process_bucket(work_dir, bucket, images.get(), datasetcount);
             }
         }
     } else {
@@ -518,7 +533,7 @@ int main(int argc, const char **argv)
         for (int i = 0; i < tilecount; i++) {
             SGBucket bucket(atol(tilenames[i]));
 
-            process_bucket(work_dir.str(), bucket, images.get(), datasetcount, true);
+            process_bucket(work_dir, bucket, images.get(), datasetcount, true);
         }
     }