Expose GDAL resampling methods to Geodot

demo/World.gd

@@ -1,9 +1,7 @@
 extends Spatial
 
 
-# Declare member variables here. Examples:
-# var a = 2
-# var b = "text"
+var instanced_image_count = 0
 
 
 # Called when the node enters the scene tree for the first time.
@@ -13,11 +11,11 @@ func _ready():
 
 	var img = Geodot.save_tile_from_heightmap(
 		"/home/retour/LandscapeLab/testdata/webm.tif",
-		"/home/retour/LandscapeLab/testdata/tile.tif",
 		1546670.0,
 		5918250.0,
 		500.0,
-		256
+		256,
+		1
 	)
 
 	get_node("MeshInstance").mesh.surface_get_material(0).set_shader_param("heightmap", img)
@@ -26,13 +24,15 @@ func _ready():
 func _process(delta):
 	var img = Geodot.save_tile_from_heightmap(
 		"/home/retour/LandscapeLab/testdata/webm.tif",
-		"/home/retour/LandscapeLab/testdata/tile.tif",
-		1546670.0 + Geodot.get_time_passed() * 1000,
+		1546670.0,
 		5918250.0,
 		500.0,
-		256
+		256,
+		1
 	)
 
+	instanced_image_count += 1
+
 	get_node("MeshInstance").mesh.surface_get_material(0).set_shader_param("heightmap", img)
 
-	print(Geodot.get_time_passed())
+	print(instanced_image_count / Geodot.get_time_passed())

src/geodot.cpp

@@ -42,14 +42,14 @@ union {
     int8_t bval[4];
 } floatAsBytes;
 
-Ref<ImageTexture> Geodot::save_tile_from_heightmap(String infile, String outfile, float new_top_left_x, float new_top_left_y, float new_size, int img_size) {
+Ref<ImageTexture> Geodot::save_tile_from_heightmap(String infile, float new_top_left_x, float new_top_left_y, float new_size, int img_size, int interpolation) {
     // We need to lock a mutex because the RasterTileExtractor seems not to be thread-safe (due to gdal?)
     load_mutex->lock();
 
     RasterTileExtractor rte;
 
     float *data = new float[sizeof(float) * img_size * img_size];
-    rte.clip(infile.utf8().get_data(), outfile.utf8().get_data(), new_top_left_x, new_top_left_y, new_size, img_size, data);
+    rte.clip(infile.utf8().get_data(), new_top_left_x, new_top_left_y, new_size, img_size, interpolation, data);
 
     PoolByteArray pba;
 
@@ -85,7 +85,17 @@ Ref<ImageTexture> Geodot::save_tile_from_heightmap(String infile, String outfile
     // Create an ImageTexture wrapping the Image
     ImageTexture *imgTex = ImageTexture::_new();
     imgTex->set_storage(ImageTexture::STORAGE_RAW);
-    imgTex->create_from_image(Ref<Image>(img), ImageTexture::FLAG_FILTER);
+
+    // By default, the returned texture has the FILTER flag. Only if the interpolation method
+    //  is nearest neighbor or one of the modal types, it is disabled, since we most likely
+    //  want crisp textures then.
+    int flag = ImageTexture::FLAG_FILTER;
+    if (interpolation == INTERPOLATION::NEAREST
+        || interpolation > 5) {
+        flag = 0;
+    }
+
+    imgTex->create_from_image(Ref<Image>(img), flag);
 
     return Ref<ImageTexture>(imgTex);
 }

src/geodot.h

@@ -18,6 +18,22 @@ class Geodot : public Node {
     Ref<Mutex> load_mutex;
 
 public:
+    // TODO: Not exportable? https://github.com/godotengine/godot/issues/15922
+    enum INTERPOLATION {
+        NEAREST,
+        BILINEAR,
+        CUBIC,
+        CUBICSPLINE,
+        LANCZOS,
+        AVG,
+        MODE,
+        MAX,
+        MIN,
+        MED,
+        Q1,
+        Q2,
+    };
+
     static void _register_methods();
 
     Geodot();
@@ -31,7 +47,7 @@ class Geodot : public Node {
 
     void reproject_to_webmercator(String infile, String outfile);
 
-    Ref<ImageTexture> save_tile_from_heightmap(String infile, String outfile, float new_top_left_x, float new_top_left_y, float new_size, int img_size);
+    Ref<ImageTexture> save_tile_from_heightmap(String infile, float new_top_left_x, float new_top_left_y, float new_size, int img_size, int interpolation);
 };
 
 }

src/raster-tile-extractor/RasterTileExtractor.cpp

@@ -107,8 +107,8 @@ void RasterTileExtractor::reproject_to_webmercator(const char *infile, const cha
 }
 
 void
-RasterTileExtractor::clip(const char *infile, const char *outfile, double top_left_x, double top_left_y,
-                          double size_meters, int img_size, float *result_target) {
+RasterTileExtractor::clip(const char *infile, double top_left_x, double top_left_y, double size_meters, int img_size,
+                          int interpolation_type, float *result_target) {
     GDALDatasetH source, dest;
     GDALDriverH pDriver;
 
@@ -120,6 +120,9 @@ RasterTileExtractor::clip(const char *infile, const char *outfile, double top_le
 
     source = GDALOpen(infile, GA_ReadOnly);
 
+    // TODO: Use this datatype instead of Float32 only! (Requires changes in Geodot itself as well)
+    GDALDataType datatype = GDALGetRasterDataType(GDALGetRasterBand(source, 1));
+
     // Get the current Transform of the source image
     double transform[6];
     GDALGetGeoTransform(source, transform);
@@ -137,7 +140,8 @@ RasterTileExtractor::clip(const char *infile, const char *outfile, double top_le
     transform[5] = -new_pixel_size;
 
     // Create a new geoimage at the given path with our img_size
-    dest = GDALCreate(pDriver, outfile, img_size, img_size,
+    // The outfile path is empty since it's only in RAM
+    dest = GDALCreate(pDriver, "", img_size, img_size,
                       GDALGetRasterCount(source), GDT_Float32, nullptr);
 
     // Get Source coordinate system.
@@ -174,7 +178,7 @@ RasterTileExtractor::clip(const char *infile, const char *outfile, double top_le
 
     // If we are going beyond the available resolution, use bilinear scaling
     if (new_pixel_size < previous_pixel_size) {
-        psWarpOptions->eResampleAlg = GRA_Bilinear;
+        psWarpOptions->eResampleAlg = static_cast<GDALResampleAlg>(interpolation_type);
     } else {
         psWarpOptions->eResampleAlg = GRA_NearestNeighbour;
     }

src/raster-tile-extractor/RasterTileExtractor.h

@@ -15,8 +15,8 @@ class RasterTileExtractor {
 
     /// Clip the infile to an image starting at top_left_x, top_left_y with a given size (in meters).
     /// The resulting image has the resolution img_size x img_size (pixels).
-    void clip(const char *infile, const char *outfile, double top_left_x, double top_left_y,
-                     double size_meters, int img_size, float *result_target);
+    void clip(const char *infile, double top_left_x, double top_left_y, double size_meters, int img_size,
+              int interpolation_type, float *result_target);
 };
 
 

src/raster-tile-extractor/test.cpp

@@ -18,7 +18,7 @@ int main() {
     int img_size = 256;
 
     auto *result = new float[sizeof(float) * img_size * img_size];
-    rte.clip("/home/retour/LandscapeLab/testdata/DGM_K_5m.tif", "/home/retour/LandscapeLab/testdata/tile.tif", new_top_left_x, new_top_left_y, new_size, img_size, result);
+    rte.clip("/home/retour/LandscapeLab/testdata/DGM_K_5m.tif", new_top_left_x, new_top_left_y, new_size, img_size, 0, result);
 
     std::cout << result[0] << std::endl;