ES2: Texture.update() calculates source rect incorrectly

I have a Prism image and want to flush part of that image to a texture. I use one of the Texture.update() methods, the one that allows to specify source rectangle. When srcx==srcy==0, I get the expected result. If however srcy>0, wrong part of the image is flushed.

Below is the test, mostly boilerplate code, the essential method is renderImagePart(). It uses a 237x1256 image (http://static.groupon.ru/images/layout-s57f8f82d95.png , you may want to open it in a browser to see what happens). The part I'm interested in is the green-roofed house close to the bottom. What I get instead is some part of the image about one-third from the top.

This bug occurs with ES2 pipeline both on Windows and Mac, D3D works fine.


import com.sun.javafx.geom.BaseBounds;
import com.sun.javafx.geom.transform.BaseTransform;
import com.sun.javafx.iio.ImageFrame;
import com.sun.javafx.iio.ImageStorage;
import com.sun.javafx.iio.common.ImageTools;
import com.sun.javafx.jmx.MXNodeAlgorithm;
import com.sun.javafx.jmx.MXNodeAlgorithmContext;
import com.sun.javafx.sg.PGNode;
import com.sun.javafx.sg.prism.NGGroup;
import com.sun.prism.Graphics;
import com.sun.prism.GraphicsPipeline;
import com.sun.prism.Image;
import com.sun.prism.ImageFormatTool;
import com.sun.prism.ResourceFactory;
import com.sun.prism.Texture;
import java.io.InputStream;
import java.nio.Buffer;
import javafx.application.Application;
import javafx.scene.Group;
import javafx.scene.Node;
import javafx.scene.Scene;
import javafx.stage.Stage;


public class PrismImagePart extends Application {
    final int X = 0;
    final int Y = 776;
    final int WIDTH = 100;
    final int HEIGHT = 100;
        
    class CustomNode extends Node {
    
        @Override public Object impl_processMXNode(MXNodeAlgorithm alg, MXNodeAlgorithmContext ctx) {
            return null;
        }

        @Override protected PGNode impl_createPGNode() {
            return new NGCustomNode();
        }

        @Override public BaseBounds impl_computeGeomBounds(BaseBounds bounds, BaseTransform tx) {
            bounds.deriveWithNewBounds(0, 0, 0, WIDTH, HEIGHT, 0);
            tx.transform(bounds, bounds);
            return bounds;
        }

        @Override protected boolean impl_computeContains(double localX, double localY) {
            return true;
        }
    }
    
    class NGCustomNode extends NGGroup {

        @Override public boolean hasOverlappingContents() {
            return false;
        }
        
        @Override protected void renderContent(Graphics g) {
            renderImagePart(g);
        }

        void renderImagePart(Graphics g) {
            try {
                // create an instance of com.sun.prism.Image
                InputStream in = ImageTools.createInputStream("http://static.groupon.ru/images/layout-s57f8f82d95.png");
                ImageFrame[] frames = ImageStorage.loadAll(in, null, 0, 0, true, false);
                Image img = ImageFormatTool.convertImageFrame(frames[0]);
                
                // dump part of the image into a texture
                ResourceFactory f = GraphicsPipeline.getDefaultResourceFactory();
                Texture txt = f.createTexture(img.getPixelFormat(),
                        Texture.Usage.DEFAULT, WIDTH, HEIGHT);
                Buffer buffer = img.getPixelBuffer();
                buffer.rewind();
                txt.update(buffer, img.getPixelFormat(), 0, 0, X, Y, WIDTH, HEIGHT,
                        img.getScanlineStride(), false);

                // render the texture
                g.drawTexture(txt,
                        0, 0, WIDTH, HEIGHT,
                        0, 0, WIDTH, HEIGHT);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        
    }
    
    @Override public void start(Stage stage) {
        stage.setScene(new Scene(new Group(new CustomNode())));
        stage.sizeToScene();
        stage.show();
    }
    
    public static void main(String[] args) {
        launch();
    }
}