JavaFX material's bump and spec maps

问题

When JavaFX8 code loads the color, bump and spec maps, the color and spec work as expected, but bump map is causing strange effects. All three are Mercator maps of Earth. Generally, there is no 3d effect added by the bump map. Bump map only causes Himalaya and Andes appear on the lit side of the globe as black areas with shiny border and on the shaded side as they appear on the color map. What am I doing wrong?

Image diffMap = null;
Image bumpMap = null;
Image specMap = null;
diffMap = new Image(MoleculeSampleApp.class.getResource("Color Map1.jpg").toExternalForm());
bumpMap = new Image(MoleculeSampleApp.class.getResource("Bump1.jpg").toExternalForm());
specMap = new Image(MoleculeSampleApp.class.getResource("Spec Mask1.png").toExternalForm());
final PhongMaterial earthMaterial = new PhongMaterial(Color.WHITE, diffMap, specMap, bumpMap, null);
earthMaterial.setDiffuseColor(Color.WHITE);
earthMaterial.setSpecularColor(Color.WHITE);

Being new to 3d my first thought is that there should be some kind of scaling pixel color values of the bump map into elevation, which I am missing.

回答1:

Bump map for JavaFX is a normal map, not a height map, for more info see: normal map and height map info.

Here is a sample you can try.

The images for the maps are pretty large, so it might take a little while to download them before your scene shows.

Source I used for images was => Bored? Then Create a Planet

import javafx.animation.*;
import javafx.application.Application;
import javafx.scene.*;
import javafx.scene.image.Image;
import javafx.scene.layout.StackPane;
import javafx.scene.paint.*;
import javafx.scene.shape.Sphere;
import javafx.scene.transform.Rotate;
import javafx.stage.Stage;
import javafx.util.Duration;

public class EarthViewer extends Application {

  private static final double EARTH_RADIUS  = 400;
  private static final double VIEWPORT_SIZE = 800;
  private static final double ROTATE_SECS   = 30;

  private static final double MAP_WIDTH  = 8192 / 2d;
  private static final double MAP_HEIGHT = 4092 / 2d;

  private static final String DIFFUSE_MAP =
      "http://planetmaker.wthr.us/img/earth_gebco8_texture_8192x4096.jpg";
  private static final String NORMAL_MAP =
      "http://planetmaker.wthr.us/img/earth_normalmap_flat_8192x4096.jpg";
  private static final String SPECULAR_MAP =
      "http://planetmaker.wthr.us/img/earth_specularmap_flat_8192x4096.jpg";

  private Group buildScene() {
    Sphere earth = new Sphere(EARTH_RADIUS);
    earth.setTranslateX(VIEWPORT_SIZE / 2d);
    earth.setTranslateY(VIEWPORT_SIZE / 2d);

    PhongMaterial earthMaterial = new PhongMaterial();
    earthMaterial.setDiffuseMap(
      new Image(
        DIFFUSE_MAP,
        MAP_WIDTH,
        MAP_HEIGHT,
        true,
        true
      )
    );
    earthMaterial.setBumpMap(
      new Image(
        NORMAL_MAP,
        MAP_WIDTH,
        MAP_HEIGHT,
        true,
        true
      )
    );
    earthMaterial.setSpecularMap(
      new Image(
        SPECULAR_MAP,
        MAP_WIDTH,
        MAP_HEIGHT,
        true,
        true
      )
    );

    earth.setMaterial(
        earthMaterial
    );

    return new Group(earth);
  }

  @Override
  public void start(Stage stage) {
    Group group = buildScene();

    Scene scene = new Scene(
      new StackPane(group),
      VIEWPORT_SIZE, VIEWPORT_SIZE,
      true,
      SceneAntialiasing.BALANCED
    );

    scene.setFill(Color.rgb(10, 10, 40));

    scene.setCamera(new PerspectiveCamera());

    stage.setScene(scene);
    stage.show();

    stage.setFullScreen(true);

    rotateAroundYAxis(group).play();
  }

  private RotateTransition rotateAroundYAxis(Node node) {
    RotateTransition rotate = new RotateTransition(
      Duration.seconds(ROTATE_SECS), 
      node
    );
    rotate.setAxis(Rotate.Y_AXIS);
    rotate.setFromAngle(360);
    rotate.setToAngle(0);
    rotate.setInterpolator(Interpolator.LINEAR);
    rotate.setCycleCount(RotateTransition.INDEFINITE);

    return rotate;
  }

  public static void main(String[] args) {
    launch(args);
  }
}

Normal? Why????

The JavaDoc states for the PhongMaterial bumpMapProperty states:

The bump map of this PhongMaterial, which is a normal map stored as a RGB Image.

A normal map is used rather than a height map because:

[normal maps] are much more accurate, as rather than only simulating the pixel being away from the face along a line, they can simulate that pixel being moved at any direction, in an arbitrary way.

A brief description of both normal mapping and height mapping is provided in the wikipedia bump mapping article.

来源：https://stackoverflow.com/questions/19621423/javafx-materials-bump-and-spec-maps