Add method to invert the face-orientations of a TileModel

Author: TBlueF

core/src/main/java/de/bluecolored/bluemap/core/map/hires/ArrayTileModel.java

@@ -186,6 +186,39 @@ public ArrayTileModel setMaterialIndex(int face, int m) {
         return this;
     }
 
+    public ArrayTileModel invertOrientation(int face) {
+        int index;
+        float x, y, z;
+
+        // swap first and last positions
+        index = face * FI_POSITION;
+
+        x = position[index    ];
+        y = position[index + 1];
+        z = position[index + 2];
+
+        position[index    ] = position[index + 6    ];
+        position[index + 1] = position[index + 6 + 1];
+        position[index + 2] = position[index + 6 + 2];
+
+        position[index + 6    ] = x;
+        position[index + 6 + 1] = y;
+        position[index + 6 + 2] = z;
+
+        // swap first and last uvs
+        index = face * FI_UV;
+        x = uv[index    ];
+        y = uv[index + 1];
+
+        uv[index    ] = uv[index + 2    ];
+        uv[index + 1] = uv[index + 2 + 1];
+
+        uv[index + 2    ] = x;
+        uv[index + 2 + 1] = y;
+
+        return this;
+    }
+
     @Override
     public ArrayTileModel rotate(
             int start, int count,

core/src/main/java/de/bluecolored/bluemap/core/map/hires/TileModel.java

@@ -63,6 +63,8 @@ TileModel setColor(
 
     TileModel setMaterialIndex(int face, int m);
 
+    TileModel invertOrientation(int face);
+
     TileModel rotate(
             int start, int count,
             float angle, float axisX, float axisY, float axisZ
@@ -107,6 +109,14 @@ TileModel transform(
             float m30, float m31, float m32, float m33
     );
 
+    default TileModel invertOrientation(int start, int count) {
+        int end = start + count;
+        for (int face = start; face < end; face++) {
+            invertOrientation(face);
+        }
+        return this;
+    }
+
     TileModel reset(int size);
 
     TileModel clear();

core/src/main/java/de/bluecolored/bluemap/core/map/hires/TileModelView.java

@@ -138,6 +138,11 @@ public TileModelView transform(
         return this;
     }
 
+    public TileModelView invertOrientation() {
+        tileModel.invertOrientation(start, size);
+        return this;
+    }
+
     public TileModel getTileModel() {
         return tileModel;
     }

core/src/main/java/de/bluecolored/bluemap/core/map/hires/VoidTileModel.java

@@ -95,6 +95,11 @@ public TileModel setMaterialIndex(int face, int m) {
         return this;
     }
 
+    @Override
+    public TileModel invertOrientation(int face) {
+        return this;
+    }
+
     @Override
     public TileModel rotate(
             int start, int count,
@@ -167,6 +172,11 @@ public TileModel transform(
         return this;
     }
 
+    @Override
+    public TileModel invertOrientation(int start, int count) {
+        return this;
+    }
+
     @Override
     public TileModel reset(int size) {
         return this;