From 882764a13d9c52416d1745c2d78b93f642aaaff9 Mon Sep 17 00:00:00 2001
From: Trygve <trygve@posteo.net>
Date: Sat, 27 Apr 2024 18:01:43 +0200
Subject: [PATCH] Created a lookup table

---
 src/main.cpp | 72 +++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 49 insertions(+), 23 deletions(-)

diff --git a/src/main.cpp b/src/main.cpp
index 9383f98..15049e5 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -56,13 +56,33 @@ std::vector<CellMap> vector_cellmap(HeightMap* heightmap, int interval)
 std::tuple<double, double> local_to_projected(double* geotransform, int x, int y)
 {
     return {
-            geotransform[1] * x + geotransform[2] * y +
-            geotransform[1] * 0.5 + geotransform[2] * 0.5 + geotransform[0],
-            geotransform[4] * x + geotransform[5] * y +
-            geotransform[4] * 0.5 + geotransform[5] * 0.5 + geotransform[3]
-            };
+        geotransform[1] * x + geotransform[2] * y +
+        geotransform[1] * 0.5 + geotransform[2] * 0.5 + geotransform[0],
+        geotransform[4] * x + geotransform[5] * y +
+        geotransform[4] * 0.5 + geotransform[5] * 0.5 + geotransform[3]
+        };
 }
 
+constexpr std::tuple<double, double, double, double> marching_squares_lookup(int mcase)
+{
+    switch (mcase) {
+        case 1: return {0, 0.5, 0.5, 0};
+        case 2: return {1, 0.5, 0.5, 0};
+        case 3: return {0, 0.5, 1, 0};
+        case 4: return {0.5, 1, 1, 0.5};
+        case 5: return {0, 0, 0, 0}; //FIXME
+        case 6: return {0.5, 1, 0.5, 0};
+        case 7: return {0, 0.5, 0.5, 1};
+        case 8: return {0, 0.5, 0.5, 1};
+        case 9: return {0.5, 1, 0.5, 0};
+        case 10: return {0, 0, 0, 0}; //FIXME
+        case 11: return {0.5, 1, 1, 0.5};
+        case 12: return {0, 0.5, 1, 0.5};
+        case 13: return {0.5, 0, 1, 0.5};
+        case 14: return {0, 0.5, 0.5, 0};
+    }
+    
+}
 void write_output_file(std::vector<CellMap> cellmaps, const char *filepath)
 {
 
@@ -108,35 +128,41 @@ void write_output_file(std::vector<CellMap> cellmaps, const char *filepath)
     for (int j = 0; j < cellmaps.size(); j++)
     {
         CellMap* cellmap = &cellmaps[j];
-        OGRFeature *feature;
-        OGRLineString *geometry = new OGRLineString();
-        feature = OGRFeature::CreateFeature( poLayer->GetLayerDefn() );
-        feature->SetField( "Name", j );
+
         for (int i = 0; i < cellmap->height*cellmap->width; i++) 
         {
             if (*(cellmap->cells + i) != 0 && *(cellmap->cells + i) != 15)
             {
+                OGRFeature *feature;
+                OGRLineString *geometry = new OGRLineString();
+                feature = OGRFeature::CreateFeature( poLayer->GetLayerDefn() );
+                feature->SetField( "Name", j );
                 int x_raw = i%cellmap->width;
                 int y_raw = i/cellmap->width;
                 auto [x, y] = local_to_projected(cellmap->geotransform, x_raw, y_raw);
+                auto [x_bl, y_bl, x_tr, y_tr] = marching_squares_lookup(*(cellmap->cells + i) );
                 //std::cout << x << ", " << y << "  ";
-                geometry->setPoint( geometry->getNumPoints(), x, y );   
-            }
+                geometry->setPoint( geometry->getNumPoints(), x+x_tr*0.25, y+y_tr*0.25 ); 
+                geometry->setPoint( geometry->getNumPoints(), x+x_bl*0.25, y+y_bl*0.25 ); 
+                
+
+                if ( feature->SetGeometry(geometry) != OGRERR_NONE)
+                {
+                    printf( "Failed to set geometry.\n" );
+                    exit( 1 );
+                }
+                OGRGeometryFactory::destroyGeometry(geometry);
+                if( poLayer->CreateFeature( feature ) != OGRERR_NONE )
+                {
+                    printf( "Failed to create feature in shapefile.\n" );
+                    exit( 1 );
+                }
+                OGRFeature::DestroyFeature( feature );  
+                    }
             
         }
         
-        if ( feature->SetGeometry(geometry) != OGRERR_NONE)
-        {
-            printf( "Failed to set geometry.\n" );
-            exit( 1 );
-        }
-        OGRGeometryFactory::destroyGeometry(geometry);
-        if( poLayer->CreateFeature( feature ) != OGRERR_NONE )
-        {
-            printf( "Failed to create feature in shapefile.\n" );
-            exit( 1 );
-        }
-        OGRFeature::DestroyFeature( feature );
+
     }
 
     GDALClose( poDS );