WorldWind Point地标标题 [英] WorldWind PointPlacemark Heading
问题描述
在NASA WorldWind Java中，我使用PointPlacemark表示图像，因为无论缩放级别如何，它都保持相同的大小.问题是，即使相机倾斜，我也要在Point Placemark上设置航向并将其停留在指南针航向上.当查看倾斜的地球仪时，它的工作方式完全符合我的要求，但是当我倾斜时，地标将继续面对屏幕，而不是与地球仪一起倾斜，这会使它变得奇怪.
In NASA WorldWind Java, I'm using PointPlacemark to represent an image because it stays the same size regardless of zoom level. The problem is that I want to set the heading on the Point Placemark and have it stay on that compass heading even when the camera is tilted. It works exactly as I want when viewing an untilted globe, but when I tilt, the placemark continues to face the screen instead of tilting with the globe, which causes it to act strange.
以下是显示我所看到内容的GIF: https://giphy.com/embed/3o7WIqZUceR8xh6BOg
Here is a GIF illustrating what I'm seeing: https://giphy.com/embed/3o7WIqZUceR8xh6BOg
我希望点地标图像即使在倾斜时也要相对于地球保持在标题上-因此，随着视图的倾斜，图像实质上是变平的"，而无论缩放级别如何，其尺寸都保持不变.
I would like the Point Placemark Image to stay on a heading relative to the globe, even when tilted -- so the image essentially is "flattened" as the view is tilted, while still remaining the same size regardless of zoom level.
这是我正在使用的代码段.我正在设置attrs.setHeadingReference(AVKey.RELATIVE_TO_GLOBE);在关联的PointPlacemarkAttributes上.在此示例中，我将航向设置为135度.
Here is a code snippet that I'm using. I am setting attrs.setHeadingReference(AVKey.RELATIVE_TO_GLOBE); on the associated PointPlacemarkAttributes. In this example, I am setting the heading to 135 degrees.
import gov.nasa.worldwind.WorldWind;
import gov.nasa.worldwind.avlist.AVKey;
import gov.nasa.worldwind.geom.Position;
import gov.nasa.worldwind.layers.RenderableLayer;
import gov.nasa.worldwind.render.Offset;
import gov.nasa.worldwind.render.PointPlacemark;
import gov.nasa.worldwind.render.PointPlacemarkAttributes;
public class Placemarks extends ApplicationTemplate {
public static class AppFrame extends ApplicationTemplate.AppFrame {
public AppFrame() {
super(true, true, false);
final RenderableLayer layer = new RenderableLayer();
PointPlacemark pp = new PointPlacemark(Position.fromDegrees(28, -102, 30000));
pp.setLabelText("Airplane");
pp.setLineEnabled(false);
pp.setAltitudeMode(WorldWind.ABSOLUTE);
PointPlacemarkAttributes attrs = new PointPlacemarkAttributes();
attrs.setImageAddress("images/airplane.png");
attrs.setScale(0.05);
attrs.setImageOffset(Offset.CENTER);
//Point to 135.0
attrs.setHeading(135.0);
attrs.setHeadingReference(AVKey.RELATIVE_TO_GLOBE);
pp.setAttributes(attrs);
layer.addRenderable(pp);
// Add the layer to the model.
insertBeforeCompass(getWwd(), layer);
}
}
public static void main(String[] args) {
ApplicationTemplate.start("WorldWind Placemarks", AppFrame.class);
}
}
我还玩了一个使用了贴图的多边形的游戏.定位的方式是我要寻找的-除了我希望图标保持相同的大小而不考虑缩放级别(例如PointPlacemark所做的事情).
I've also played with using a Polygon with a Texture applied to it. The way it is oriented is what I'm looking for -- except I want the icon to remain the same size regardless of zoom level (like what the PointPlacemark does).
这是一个GIF，说明我在使用Polygon时看到的内容.请注意地球倾斜时的行为: https://giphy.com/embed/xThta4USlDzd8Ii5ZS
Here is a GIF illustrating what I'm seeing when using a Polygon. Note how it acts when the globe is tilted: https://giphy.com/embed/xThta4USlDzd8Ii5ZS
以下是我用于多边形"的来源:
Here is the source I'm using for the Polygon:
import java.awt.geom.AffineTransform;
import java.util.Arrays;
import java.util.List;
import gov.nasa.worldwind.WorldWind;
import gov.nasa.worldwind.geom.Position;
import gov.nasa.worldwind.layers.RenderableLayer;
import gov.nasa.worldwind.render.BasicShapeAttributes;
import gov.nasa.worldwind.render.Polygon;
public class TexturedPolygon extends ApplicationTemplate {
public static Polygon createPolygonTexturedImage(String filePath, Position pos, double heading, double scale) {
double offsetDist = 1.0D * scale;
Position p1 = Position.fromDegrees(pos.getLatitude().addDegrees(-offsetDist).getDegrees(),
pos.getLongitude().addDegrees(-offsetDist).getDegrees(), pos.getAltitude());
Position p2 = Position.fromDegrees(pos.getLatitude().addDegrees(offsetDist).getDegrees(),
pos.getLongitude().addDegrees(-offsetDist).getDegrees());
Position p3 = Position.fromDegrees(pos.getLatitude().addDegrees(offsetDist).getDegrees(),
pos.getLongitude().addDegrees(offsetDist).getDegrees());
Position p4 = Position.fromDegrees(pos.getLatitude().addDegrees(-offsetDist).getDegrees(),
pos.getLongitude().addDegrees(offsetDist).getDegrees());
double[] points = new double[] { p1.getLatitude().getDegrees(), p1.getLongitude().getDegrees(),
p2.getLatitude().getDegrees(), p2.getLongitude().getDegrees(), p3.getLatitude().getDegrees(),
p3.getLongitude().getDegrees(), p4.getLatitude().getDegrees(), p4.getLongitude().getDegrees() };
double[] transformedPoints = new double[8];
AffineTransform rotation = new AffineTransform();
rotation.rotate(Math.toRadians(heading), pos.getLatitude().getDegrees(), pos.getLongitude().getDegrees());
rotation.transform(points, 0, transformedPoints, 0, 4);
double altitude = pos.getAltitude();
p1 = Position.fromDegrees(transformedPoints[0], transformedPoints[1], altitude);
p2 = Position.fromDegrees(transformedPoints[2], transformedPoints[3], altitude);
p3 = Position.fromDegrees(transformedPoints[4], transformedPoints[5], altitude);
p4 = Position.fromDegrees(transformedPoints[6], transformedPoints[7], altitude);
List<Position> positions = Arrays.asList(p1, p2, p3, p4);
Polygon polygon = new Polygon(positions);
polygon.setAltitudeMode(WorldWind.ABSOLUTE);
BasicShapeAttributes mattr = new BasicShapeAttributes();
mattr.setDrawOutline(false);
mattr.setDrawInterior(true);
polygon.setAttributes(mattr);
polygon.setTextureImageSource(filePath, new float[] { 0.0F, 0.0F, 1.0F, 0.0F, 1.0F, 1.0F, 0.0F, 1.0F }, 4);
return polygon;
}
public static class AppFrame extends ApplicationTemplate.AppFrame {
public AppFrame() {
super(true, true, false);
final RenderableLayer layer = new RenderableLayer();
Position pos = Position.fromDegrees(28, -102, 30000);
String url = "images/airplane.png";
layer.addRenderable(createPolygonTexturedImage(url, pos, 135.0, 1.05));
// Add the layer to the model.
insertBeforeCompass(getWwd(), layer);
}
}
public static void main(String[] args) {
ApplicationTemplate.start("WorldWind Placemarks", AppFrame.class);
}
}
为了完整性起见，这是我正在使用的图片作为我的planet.png:
For completeness sake -- here is the image I'm using as my airplane.png:
总而言之，我正在寻找什么:
So to sum it up, what I'm looking for:
- 以图标图像表示的可渲染对象
- 无论缩放级别如何，图标都保持不变
- 即使相机视角倾斜，图标仍会以地球罗盘方向为准
推荐答案
通过将解决方案结合到此问题以及将屏幕倾斜度与间距相关联的CompassLayer逻辑.
By combining the solution to this question and the CompassLayer logic that ties the screen tilt to the pitch.
将此方法添加到PointPlacemark.java(来自CompassLayer):
Add this method to PointPlacemark.java (Taken from CompassLayer):
protected double computePitch(View view)
{
if (view == null)
return 0.0;
if (!(view instanceof OrbitView))
return 0.0;
OrbitView orbitView = (OrbitView) view;
return orbitView.getPitch().getDegrees();
}
然后在doDrawOrderedRenderable(DrawContext dc，PickSupport pickCandidates，OrderedPlacemark opm)方法中，使用以下逻辑:
And then in the doDrawOrderedRenderable(DrawContext dc, PickSupport pickCandidates, OrderedPlacemark opm) method, use this logic:
protected void doDrawOrderedRenderable(DrawContext dc, PickSupport pickCandidates, OrderedPlacemark opm)
{
if (this.isDrawLine(dc, opm))
this.drawLine(dc, pickCandidates, opm);
if (this.activeTexture == null)
{
if (this.isDrawPoint(dc))
this.drawPoint(dc, pickCandidates, opm);
return;
}
GL2 gl = dc.getGL().getGL2(); // GL initialization checks for GL2 compatibility.
OGLStackHandler osh = new OGLStackHandler();
try
{
if (dc.isPickingMode())
{
// Set up to replace the non-transparent texture colors with the single pick color.
gl.glEnable(GL.GL_TEXTURE_2D);
gl.glTexEnvf(GL2.GL_TEXTURE_ENV, GL2.GL_TEXTURE_ENV_MODE, GL2.GL_COMBINE);
gl.glTexEnvf(GL2.GL_TEXTURE_ENV, GL2.GL_SRC0_RGB, GL2.GL_PREVIOUS);
gl.glTexEnvf(GL2.GL_TEXTURE_ENV, GL2.GL_COMBINE_RGB, GL2.GL_REPLACE);
Color pickColor = dc.getUniquePickColor();
pickCandidates.addPickableObject(this.createPickedObject(dc, pickColor));
gl.glColor3ub((byte) pickColor.getRed(), (byte) pickColor.getGreen(), (byte) pickColor.getBlue());
}
else
{
gl.glEnable(GL.GL_TEXTURE_2D);
Color color = this.getActiveAttributes().getImageColor();
if (color == null)
color = PointPlacemarkAttributes.DEFAULT_IMAGE_COLOR;
gl.glColor4ub((byte) color.getRed(), (byte) color.getGreen(), (byte) color.getBlue(),
(byte) color.getAlpha());
}
// This was relocated from the check in version.
// Compute the scale
double xscale;
Double scale = this.getActiveAttributes().getScale();
if (scale != null)
xscale = scale * this.activeTexture.getWidth(dc);
else
xscale = this.activeTexture.getWidth(dc);
double yscale;
if (scale != null)
yscale = scale * this.activeTexture.getHeight(dc);
else
yscale = this.activeTexture.getHeight(dc);
double maxwh = Math.max(xscale, yscale);
// The image is drawn using a parallel projection.
// This came from the fix in https://stackoverflow.com/questions/49637844/worldwind-pointplacemark-pitch
osh.pushProjectionIdentity(gl);
gl.glOrtho(0d, dc.getView().getViewport().width, 0d, dc.getView().getViewport().height, -0.6 * maxwh, 0.6 * maxwh);
// Apply the depth buffer but don't change it (for screen-space shapes).
if ((!dc.isDeepPickingEnabled()))
gl.glEnable(GL.GL_DEPTH_TEST);
gl.glDepthMask(false);
// Suppress any fully transparent image pixels.
gl.glEnable(GL2.GL_ALPHA_TEST);
gl.glAlphaFunc(GL2.GL_GREATER, 0.001f);
// Adjust depth of image to bring it slightly forward
double depth = opm.screenPoint.z - (8d * 0.00048875809d);
depth = depth < 0d ? 0d : (depth > 1d ? 1d : depth);
gl.glDepthFunc(GL.GL_LESS);
gl.glDepthRange(depth, depth);
// The image is drawn using a translated and scaled unit quad.
// Translate to screen point and adjust to align hot spot.
osh.pushModelviewIdentity(gl);
gl.glTranslated(opm.screenPoint.x + this.dx, opm.screenPoint.y + this.dy, 0);
Double heading = getActiveAttributes().getHeading();
Double pitch = this.computePitch(dc.getView());
// Adjust heading to be relative to globe or screen
if (heading != null)
{
if (AVKey.RELATIVE_TO_GLOBE.equals(this.getActiveAttributes().getHeadingReference()))
heading = dc.getView().getHeading().degrees - heading;
else
heading = -heading;
}
// Apply the heading and pitch if specified.
if (heading != null || pitch != null)
{
gl.glTranslated(xscale / 2, yscale / 2, 0);
if (pitch != null)
gl.glRotated(pitch, 1, 0, 0);
if (heading != null)
gl.glRotated(heading, 0, 0, 1);
gl.glTranslated(-xscale / 2, -yscale / 2, 0);
}
// Scale the unit quad
gl.glScaled(xscale, yscale, 1);
if (this.activeTexture.bind(dc))
dc.drawUnitQuad(activeTexture.getTexCoords());
gl.glDepthRange(0, 1); // reset depth range to the OGL default
if (this.mustDrawLabel())
{
if (!dc.isPickingMode() || this.isEnableLabelPicking())
this.drawLabel(dc, pickCandidates, opm);
}
}
finally
{
if (dc.isPickingMode())
{
gl.glTexEnvf(GL2.GL_TEXTURE_ENV, GL2.GL_TEXTURE_ENV_MODE, OGLUtil.DEFAULT_TEX_ENV_MODE);
gl.glTexEnvf(GL2.GL_TEXTURE_ENV, GL2.GL_SRC0_RGB, OGLUtil.DEFAULT_SRC0_RGB);
gl.glTexEnvf(GL2.GL_TEXTURE_ENV, GL2.GL_COMBINE_RGB, OGLUtil.DEFAULT_COMBINE_RGB);
}
gl.glDisable(GL.GL_TEXTURE_2D);
osh.pop(gl);
}
}
它看起来像这样:
这篇关于WorldWind Point地标标题的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
