commonMain.earth.worldwind.shape.Ellipse.kt Maven / Gradle / Ivy
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The WorldWind Kotlin SDK (WWK) includes the library, examples and tutorials for building multiplatform 3D virtual globe applications for Android, Web and Java.
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package earth.worldwind.shape
import earth.worldwind.draw.DrawShapeState
import earth.worldwind.draw.Drawable
import earth.worldwind.draw.DrawableShape
import earth.worldwind.draw.DrawableSurfaceShape
import earth.worldwind.geom.*
import earth.worldwind.geom.Angle.Companion.ZERO
import earth.worldwind.geom.Angle.Companion.toDegrees
import earth.worldwind.render.*
import earth.worldwind.render.buffer.FloatBufferObject
import earth.worldwind.render.buffer.IntBufferObject
import earth.worldwind.render.buffer.ShortBufferObject
import earth.worldwind.render.image.ImageOptions
import earth.worldwind.render.image.ResamplingMode
import earth.worldwind.render.image.WrapMode
import earth.worldwind.render.program.TriangleShaderProgram
import earth.worldwind.util.Logger.ERROR
import earth.worldwind.util.Logger.logMessage
import earth.worldwind.util.kgl.*
import kotlin.jvm.JvmOverloads
import kotlin.math.*
/**
* Ellipse shape defined by a geographic center position and radii for the semi-major and semi-minor axes.
*
* Axes and Heading
*
* Ellipse axes, by default, are oriented such that the semi-major axis points East and the semi-minor axis points
* North. Ellipse provides an optional heading, which when set to anything other than 0.0 rotates the semi-major and
* semi-minor axes about the center position, while retaining the axes relative relationship to one another. Heading is
* defined clockwise from North. Configuring ellipse with a heading of 45.0 results in the semi-major axis
* pointing Southeast and the semi-minor axis pointing Northeast.
*
* Altitude Mode and Terrain Following
*
* Ellipse geometry displays at a constant altitude determined by the geographic center position and altitude mode. For
* example, an ellipse with a center position altitude of 1km and altitude mode of ABSOLUTE displays at 1km above mean
* sea level. The same ellipse with an altitude mode of RELATIVE_TO_GROUND displays at 1km above ground level, relative
* to the ellipse's center location.
*
* Surface ellipse geometry, where an ellipse appears draped across the terrain, may be achieved by enabling ellipse's
* terrain following state and setting its altitude mode to CLAMP_TO_GROUND. See [isFollowTerrain] and
* [altitudeMode].
*
* Display Granularity
*
* Ellipse's appearance on screen is composed of discrete segments which approximate the ellipse's geometry. This
* approximation is chosen such that the display appears to be a continuous smooth ellipse. Applications can control the
* maximum number of angular intervals used in this representation with [maximumIntervals].
*/
open class Ellipse @JvmOverloads constructor(
center: Position, majorRadius: Double, minorRadius: Double, attributes: ShapeAttributes = ShapeAttributes()
): AbstractShape(attributes) {
/**
* The ellipse's geographic center position.
*/
var center = Position(center)
set(value) {
field.copy(value)
reset()
}
/**
* The ellipse's radius perpendicular to it's heading, in meters.
* When the ellipse's heading is 0.0, the semi-major axis points East.
*
* @throws IllegalArgumentException If the radius is negative
*/
var majorRadius = majorRadius
set(value) {
require(value >= 0) {
logMessage(ERROR, "Ellipse", "setMajorRadius", "invalidRadius")
}
field = value
reset()
}
/**
* The ellipse's radius parallel to it's heading, in meters.
* When the ellipse's heading is 0.0, the semi-minor axis points North.
*
* @throws IllegalArgumentException If the radius is negative
*/
var minorRadius = minorRadius
set(value) {
require(value >= 0) {
logMessage(ERROR, "Ellipse", "setMinorRadius", "invalidRadius")
}
field = value
reset()
}
/**
* The ellipse's heading clockwise from North. When ellipse's heading is 0.0,
* the semi-major axis points East and the semi-minor axis points North.
* Headings other than 0.0 rotate the axes about the ellipse's center position,
* while retaining the axes relative relationship to one another.
*/
var heading = ZERO
set(value) {
field = value
reset()
}
/**
* The maximum pixels a single edge interval will span before the number of intervals is increased. Increasing this
* value will make ellipses appear coarser.
*/
var maximumPixelsPerInterval = 50.0
set(value) {
require(value >= 0) {
logMessage(ERROR, "Ellipse", "maximumPixelsPerInterval", "invalidPixelsPerInterval")
}
field = value
reset()
}
/**
* Sets the maximum number of angular intervals that may be used to approximate this ellipse's on screen.
*
* Ellipse may use a minimum number of intervals to ensure that its appearance on screen at least roughly
* approximates the ellipse's shape. When the specified number of intervals is too small, it is clamped to an
* implementation-defined minimum number of intervals.
*
* Ellipse may require that the number of intervals is an even multiple of some integer. When the specified number
* of intervals does not meet this criteria, the next smallest integer that meets ellipse's criteria is used
* instead.
*
* @throws IllegalArgumentException If the number of intervals is negative
*/
var maximumIntervals = 256
set(value) {
require(value >= 0) {
logMessage(ERROR, "Ellipse", "setMaximumIntervals", "invalidNumIntervals")
}
field = value
reset()
}
/**
* The number of intervals used for generating geometry. Clamped between MIN_INTERVALS and maximumIntervals.
* Will always be even.
*/
protected var activeIntervals = 0
protected var vertexArray = FloatArray(0)
protected var vertexIndex = 0
protected var vertexBufferKey = Any()
protected var lineVertexArray = FloatArray(0)
protected var lineVertexIndex = 0
protected var lineVertexBufferKey = Any()
protected var lineElementBufferKey = Any()
protected var verticalVertexIndex = 0
protected val verticalElements = mutableListOf()
protected val outlineElements = mutableListOf()
protected val vertexOrigin = Vec3()
protected var texCoord1d = 0.0
protected val texCoord2d = Vec3()
protected val texCoordMatrix = Matrix3()
protected val modelToTexCoord = Matrix4()
protected var cameraDistance = 0.0
protected val prevPoint = Vec3()
init {
require(majorRadius >= 0 && minorRadius >= 0) {
logMessage(ERROR, "Ellipse", "constructor", "invalidRadius")
}
}
companion object {
protected const val VERTEX_STRIDE = 5
protected const val LINE_VERTEX_STRIDE = 10
/**
* The minimum number of intervals that will be used for geometry generation.
*/
protected const val MIN_INTERVALS = 32
/**
* Key for Range object in the element buffer describing the top of the Ellipse.
*/
protected const val TOP_RANGE = 0
/**
* Key for Range object in the element buffer describing the extruded sides of the Ellipse.
*/
protected const val SIDE_RANGE = 1
protected val defaultInteriorImageOptions = ImageOptions().apply { wrapMode = WrapMode.REPEAT }
protected val defaultOutlineImageOptions = ImageOptions().apply {
wrapMode = WrapMode.REPEAT
resamplingMode = ResamplingMode.NEAREST_NEIGHBOR
}
/**
* Simple interval count based cache of the keys for element buffers. Element buffers are dependent only on the
* number of intervals so the keys are cached here. The element buffer object itself is in the
* RenderResourceCache and subject to the restrictions and behavior of that cache.
*/
protected val elementBufferKeys = mutableMapOf()
private val scratchPosition = Position()
private val scratchPoint = Vec3()
private val scratchVertPoint = Vec3()
protected fun assembleElements(intervals: Int): ShortBufferObject {
// Create temporary storage for elements
// TODO Use ShortArray instead of mutableListOf to avoid unnecessary memory re-allocations
val elements = mutableListOf()
// Generate the top element buffer with spine
var idx = intervals.toShort()
val offset = computeIndexOffset(intervals)
// Add the anchor leg
elements.add(0.toShort())
elements.add(1.toShort())
// Tessellate the interior
for (i in 2 until intervals) {
// Add the corresponding interior spine point if this isn't the vertex following the last vertex for the
// negative major axis
if (i != intervals / 2 + 1) if (i > intervals / 2) elements.add(--idx) else elements.add(idx++)
// Add the degenerate triangle at the negative major axis in order to flip the triangle strip back towards
// the positive axis
if (i == intervals / 2) elements.add(i.toShort())
// Add the exterior vertex
elements.add(i.toShort())
}
// Complete the strip
elements.add(--idx)
elements.add(0.toShort())
val topRange = Range(0, elements.size)
// Generate the side element buffer
for (i in 0 until intervals) {
elements.add(i.toShort())
elements.add(i.plus(offset).toShort())
}
elements.add(0.toShort())
elements.add(offset.toShort())
val sideRange = Range(topRange.upper, elements.size)
// Generate a buffer for the element
val elementBuffer = ShortBufferObject(GL_ELEMENT_ARRAY_BUFFER, elements.toShortArray())
elementBuffer.ranges[TOP_RANGE] = topRange
elementBuffer.ranges[SIDE_RANGE] = sideRange
return elementBuffer
}
protected fun computeNumberSpinePoints(intervals: Int) = intervals / 2 - 1 // intervals should be even
protected fun computeIndexOffset(intervals: Int) = intervals + computeNumberSpinePoints(intervals)
}
override fun makeDrawable(rc: RenderContext) {
if (majorRadius == 0.0 && minorRadius == 0.0) return // nothing to draw
if (mustAssembleGeometry(rc)) {
assembleGeometry(rc)
vertexBufferKey = Any()
lineVertexBufferKey = Any()
lineElementBufferKey = Any()
}
// Obtain a drawable form the render context pool.
val drawable: Drawable
val drawState: DrawShapeState
val drawableLines: Drawable
val drawStateLines: DrawShapeState
if (isSurfaceShape) {
val pool = rc.getDrawablePool()
drawable = DrawableSurfaceShape.obtain(pool)
drawState = drawable.drawState
drawable.offset = rc.globe.offset
drawable.sector.copy(boundingSector)
drawableLines = DrawableSurfaceShape.obtain(pool)
drawStateLines = drawableLines.drawState
// Use the basic GLSL program for texture projection.
drawableLines.offset = rc.globe.offset
drawableLines.sector.copy(boundingSector)
cameraDistance = cameraDistanceGeographic(rc, boundingSector)
} else {
val pool = rc.getDrawablePool()
drawable = DrawableShape.obtain(pool)
drawState = drawable.drawState
drawableLines = DrawableShape.obtain(pool)
drawStateLines = drawableLines.drawState
cameraDistance = boundingBox.distanceTo(rc.cameraPoint)
}
// Use the basic GLSL program to draw the shape.
drawState.program = rc.getShaderProgram { TriangleShaderProgram() }
// Assemble the drawable's OpenGL vertex buffer object.
drawState.vertexBuffer = rc.getBufferObject(vertexBufferKey) { FloatBufferObject(GL_ARRAY_BUFFER, vertexArray) }
// Get the attributes of the element buffer
val elementBufferKey = elementBufferKeys[activeIntervals] ?: Any().also { elementBufferKeys[activeIntervals] = it }
drawState.elementBuffer = rc.getBufferObject(elementBufferKey) { assembleElements(activeIntervals) }
drawStateLines.isLine = true
// Use the basic GLSL program to draw the shape.
drawStateLines.program = rc.getShaderProgram { TriangleShaderProgram() }
// Assemble the drawable's OpenGL vertex buffer object.
drawStateLines.vertexBuffer = rc.getBufferObject(lineVertexBufferKey) { FloatBufferObject(GL_ARRAY_BUFFER, lineVertexArray) }
// Assemble the drawable's OpenGL element buffer object.
drawStateLines.elementBuffer = rc.getBufferObject(lineElementBufferKey) {
val array = IntArray(outlineElements.size + verticalElements.size)
var index = 0
for (element in outlineElements) array[index++] = element
for (element in verticalElements) array[index++] = element
IntBufferObject(GL_ELEMENT_ARRAY_BUFFER, array)
}
drawInterior(rc, drawState)
drawOutline(rc, drawStateLines)
// Configure the drawable according to the shape's attributes.
drawState.vertexOrigin.copy(vertexOrigin)
drawState.vertexStride = VERTEX_STRIDE * 4 // stride in bytes
drawState.enableCullFace = isExtrude
drawState.enableDepthTest = activeAttributes.isDepthTest
drawState.enableDepthWrite = activeAttributes.isDepthWrite
// Configure the drawable according to the shape's attributes.
drawStateLines.vertexOrigin.copy(vertexOrigin)
drawStateLines.enableCullFace = false
drawStateLines.enableDepthTest = activeAttributes.isDepthTest
drawStateLines.enableDepthWrite = activeAttributes.isDepthWrite
// Enqueue the drawable for processing on the OpenGL thread.
if (isSurfaceShape) {
rc.offerSurfaceDrawable(drawable, 0.0 /*zOrder*/)
rc.offerSurfaceDrawable(drawableLines, 0.0 /*zOrder*/)
} else {
rc.offerShapeDrawable(drawableLines, cameraDistance)
rc.offerShapeDrawable(drawable, cameraDistance)
}
}
protected open fun drawInterior(rc: RenderContext, drawState: DrawShapeState) {
if (!activeAttributes.isDrawInterior) return
// Configure the drawable to use the interior texture when drawing the interior.
activeAttributes.interiorImageSource?.let { interiorImageSource ->
rc.getTexture(interiorImageSource, defaultInteriorImageOptions)?.let { texture ->
val metersPerPixel = rc.pixelSizeAtDistance(cameraDistance)
computeRepeatingTexCoordTransform(texture, metersPerPixel, texCoordMatrix)
drawState.texture(texture)
drawState.texCoordMatrix(texCoordMatrix)
}
} ?: drawState.texture(null)
// Configure the drawable to display the shape's interior.
drawState.color(if (rc.isPickMode) pickColor else activeAttributes.interiorColor)
drawState.opacity(if (rc.isPickMode) 1f else rc.currentLayer.opacity)
drawState.texCoordAttrib(2 /*size*/, 12 /*offset in bytes*/)
val top = drawState.elementBuffer!!.ranges[TOP_RANGE]!!
drawState.drawElements(GL_TRIANGLE_STRIP, top.length, GL_UNSIGNED_SHORT, top.lower * 2 /*offset*/)
if (isExtrude) {
val side = drawState.elementBuffer!!.ranges[SIDE_RANGE]!!
drawState.texture(null)
drawState.drawElements(GL_TRIANGLE_STRIP, side.length, GL_UNSIGNED_SHORT, side.lower * 2)
}
}
protected open fun drawOutline(rc: RenderContext, drawState: DrawShapeState) {
if (!activeAttributes.isDrawOutline) return
// Configure the drawable to use the outline texture when drawing the outline.
activeAttributes.outlineImageSource?.let { outlineImageSource ->
rc.getTexture(outlineImageSource, defaultOutlineImageOptions)?.let { texture ->
val metersPerPixel = rc.pixelSizeAtDistance(cameraDistance)
computeRepeatingTexCoordTransform(texture, metersPerPixel, texCoordMatrix)
drawState.texture(texture)
drawState.texCoordMatrix(texCoordMatrix)
}
} ?: drawState.texture(null)
// Configure the drawable to display the shape's outline.
drawState.color(if (rc.isPickMode) pickColor else activeAttributes.outlineColor)
drawState.opacity(if (rc.isPickMode) 1f else rc.currentLayer.opacity)
drawState.lineWidth(activeAttributes.outlineWidth)
drawState.drawElements(
GL_TRIANGLE_STRIP, outlineElements.size,
GL_UNSIGNED_INT, 0 * Int.SIZE_BYTES
)
if (activeAttributes.isDrawVerticals && isExtrude && !isSurfaceShape) {
drawState.color(if (rc.isPickMode) pickColor else activeAttributes.outlineColor)
drawState.opacity(if (rc.isPickMode) 1f else rc.currentLayer.opacity)
drawState.lineWidth(activeAttributes.outlineWidth)
drawState.texture(null)
drawState.drawElements(
GL_TRIANGLES, verticalElements.size,
GL_UNSIGNED_INT, (outlineElements.size) * Int.SIZE_BYTES
)
}
}
protected open fun mustAssembleGeometry(rc: RenderContext): Boolean {
val calculatedIntervals = computeIntervals(rc)
val sanitizedIntervals = sanitizeIntervals(calculatedIntervals)
if (vertexArray.isEmpty() || isExtrude && !isSurfaceShape && lineVertexArray.isEmpty() || sanitizedIntervals != activeIntervals) {
activeIntervals = sanitizedIntervals
return true
}
return false
}
protected open fun assembleGeometry(rc: RenderContext) {
// Compute a matrix that transforms from Cartesian coordinates to shape texture coordinates.
determineModelToTexCoord(rc)
// Use the ellipse's center position as the local origin for vertex positions.
if (isSurfaceShape) {
vertexOrigin.set(center.longitude.inDegrees, center.latitude.inDegrees, center.altitude)
} else {
rc.geographicToCartesian(center, altitudeMode, scratchPoint)
vertexOrigin.set(scratchPoint.x, scratchPoint.y, scratchPoint.z)
}
// Determine the number of spine points
val spineCount = computeNumberSpinePoints(activeIntervals) // activeIntervals must be even
// Clear the shape's vertex array. The array will accumulate values as the shapes's geometry is assembled.
vertexIndex = 0
vertexArray = if (isExtrude && !isSurfaceShape) FloatArray((activeIntervals * 2 + spineCount) * VERTEX_STRIDE)
else FloatArray((activeIntervals + spineCount) * VERTEX_STRIDE)
lineVertexIndex = 0
lineVertexArray = if (isExtrude && !isSurfaceShape) FloatArray((activeIntervals + 3 + (activeIntervals + 1) * 4) * LINE_VERTEX_STRIDE)
else FloatArray((activeIntervals + 3) * LINE_VERTEX_STRIDE)
verticalVertexIndex = (activeIntervals + 3) * LINE_VERTEX_STRIDE
verticalElements.clear()
outlineElements.clear()
// Check if minor radius is less than major in which case we need to flip the definitions and change the phase
val isStandardAxisOrientation = majorRadius > minorRadius
val headingAdjustment = if (isStandardAxisOrientation) 90.0 else 0.0
// Vertex generation begins on the positive major axis and works ccs around the ellipse. The spine points are
// then appended from positive major axis to negative major axis.
val deltaRadians = 2 * PI / activeIntervals
val majorArcRadians: Double
val minorArcRadians: Double
val globeRadius = max(rc.globe.equatorialRadius, rc.globe.polarRadius)
if (isStandardAxisOrientation) {
majorArcRadians = majorRadius / globeRadius
minorArcRadians = minorRadius / globeRadius
} else {
majorArcRadians = minorRadius / globeRadius
minorArcRadians = majorRadius / globeRadius
}
// Determine the offset from the top and extruded vertices
val arrayOffset = computeIndexOffset(activeIntervals) * VERTEX_STRIDE
// Setup spine radius values
var spineIdx = 0
val spineRadius = DoubleArray(spineCount)
var firstLoc = Position()
// Iterate around the ellipse to add vertices
for (i in 0 until activeIntervals) {
val radians = deltaRadians * i
val x = cos(radians) * majorArcRadians
val y = sin(radians) * minorArcRadians
val azimuthDegrees = toDegrees(-atan2(y, x))
val arcRadius = sqrt(x * x + y * y)
// Calculate the great circle location given this activeIntervals step (azimuthDegrees) a correction value to
// start from an east-west aligned major axis (90.0) and the user specified user heading value
val azimuth = heading.plusDegrees(azimuthDegrees + headingAdjustment)
val loc = center.greatCircleLocation(azimuth, arcRadius, scratchPosition)
addVertex(rc, loc.latitude, loc.longitude, center.altitude, arrayOffset, isExtrude)
// Add the major arc radius for the spine points. Spine points are vertically coincident with exterior
// points. The first and middle most point do not have corresponding spine points.
if (i > 0 && i < activeIntervals / 2) spineRadius[spineIdx++] = x
if (i < 1) {
firstLoc = Position(loc.latitude, loc.longitude, center.altitude)
addLineVertex(rc, loc.latitude, loc.longitude, center.altitude, verticalVertexIndex, true)
}
addLineVertex(rc, loc.latitude, loc.longitude, center.altitude, verticalVertexIndex, false)
}
addLineVertex(rc, firstLoc.latitude, firstLoc.longitude, firstLoc.altitude, verticalVertexIndex, false)
addLineVertex(rc, firstLoc.latitude, firstLoc.longitude, firstLoc.altitude, verticalVertexIndex, true)
// Add the interior spine point vertices
for (i in 0 until spineCount) {
center.greatCircleLocation(heading.plusDegrees(headingAdjustment), spineRadius[i], scratchPosition)
addVertex(rc, scratchPosition.latitude, scratchPosition.longitude, center.altitude, arrayOffset, false)
}
// Compute the shape's bounding sector from its assembled coordinates.
if (isSurfaceShape) {
boundingSector.setEmpty()
boundingSector.union(vertexArray, vertexArray.size, VERTEX_STRIDE)
boundingSector.translate(vertexOrigin.y /*lat*/, vertexOrigin.x /*lon*/)
boundingBox.setToUnitBox() // Surface/geographic shape bounding box is unused
} else {
boundingBox.setToPoints(vertexArray, vertexArray.size, VERTEX_STRIDE)
boundingBox.translate(vertexOrigin.x, vertexOrigin.y, vertexOrigin.z)
boundingSector.setEmpty()
}
}
protected open fun addLineVertex(
rc: RenderContext, latitude: Angle, longitude: Angle, altitude: Double, offset : Int, firstOrLast : Boolean
) {
val vertex = (lineVertexIndex / LINE_VERTEX_STRIDE - 1) * 2
val point = rc.geographicToCartesian(latitude, longitude, altitude, altitudeMode, scratchPoint)
if (lineVertexIndex == 0) texCoord1d = 0.0
else texCoord1d += point.distanceTo(prevPoint)
prevPoint.copy(point)
if (isSurfaceShape) {
lineVertexArray[lineVertexIndex++] = (longitude.inDegrees - vertexOrigin.x).toFloat()
lineVertexArray[lineVertexIndex++] = (latitude.inDegrees - vertexOrigin.y).toFloat()
lineVertexArray[lineVertexIndex++] = (altitude - vertexOrigin.z).toFloat()
lineVertexArray[lineVertexIndex++] = 1.0f
lineVertexArray[lineVertexIndex++] = texCoord1d.toFloat()
lineVertexArray[lineVertexIndex++] = (longitude.inDegrees - vertexOrigin.x).toFloat()
lineVertexArray[lineVertexIndex++] = (latitude.inDegrees - vertexOrigin.y).toFloat()
lineVertexArray[lineVertexIndex++] = (altitude - vertexOrigin.z).toFloat()
lineVertexArray[lineVertexIndex++] = -1.0f
lineVertexArray[lineVertexIndex++] = texCoord1d.toFloat()
if (!firstOrLast) {
outlineElements.add(vertex)
outlineElements.add(vertex.inc())
}
} else {
lineVertexArray[lineVertexIndex++] = (point.x - vertexOrigin.x).toFloat()
lineVertexArray[lineVertexIndex++] = (point.y - vertexOrigin.y).toFloat()
lineVertexArray[lineVertexIndex++] = (point.z - vertexOrigin.z).toFloat()
lineVertexArray[lineVertexIndex++] = 1.0f
lineVertexArray[lineVertexIndex++] = texCoord1d.toFloat()
lineVertexArray[lineVertexIndex++] = (point.x - vertexOrigin.x).toFloat()
lineVertexArray[lineVertexIndex++] = (point.y - vertexOrigin.y).toFloat()
lineVertexArray[lineVertexIndex++] = (point.z - vertexOrigin.z).toFloat()
lineVertexArray[lineVertexIndex++] = -1.0f
lineVertexArray[lineVertexIndex++] = texCoord1d.toFloat()
if (!firstOrLast) {
outlineElements.add(vertex)
outlineElements.add(vertex.inc())
}
if (isExtrude && !firstOrLast) {
val vertPoint = rc.geographicToCartesian(latitude, longitude, 0.0, altitudeMode, scratchVertPoint)
val index = verticalVertexIndex / LINE_VERTEX_STRIDE * 2
lineVertexArray[verticalVertexIndex++] = (point.x - vertexOrigin.x).toFloat()
lineVertexArray[verticalVertexIndex++] = (point.y - vertexOrigin.y).toFloat()
lineVertexArray[verticalVertexIndex++] = (point.z - vertexOrigin.z).toFloat()
lineVertexArray[verticalVertexIndex++] = 1f
lineVertexArray[verticalVertexIndex++] = 0f
lineVertexArray[verticalVertexIndex++] = (point.x - vertexOrigin.x).toFloat()
lineVertexArray[verticalVertexIndex++] = (point.y - vertexOrigin.y).toFloat()
lineVertexArray[verticalVertexIndex++] = (point.z - vertexOrigin.z).toFloat()
lineVertexArray[verticalVertexIndex++] = -1f
lineVertexArray[verticalVertexIndex++] = 0f
lineVertexArray[verticalVertexIndex++] = (point.x - vertexOrigin.x).toFloat()
lineVertexArray[verticalVertexIndex++] = (point.y - vertexOrigin.y).toFloat()
lineVertexArray[verticalVertexIndex++] = (point.z - vertexOrigin.z).toFloat()
lineVertexArray[verticalVertexIndex++] = 1f
lineVertexArray[verticalVertexIndex++] = 0f
lineVertexArray[verticalVertexIndex++] = (point.x - vertexOrigin.x).toFloat()
lineVertexArray[verticalVertexIndex++] = (point.y - vertexOrigin.y).toFloat()
lineVertexArray[verticalVertexIndex++] = (point.z - vertexOrigin.z).toFloat()
lineVertexArray[verticalVertexIndex++] = -1f
lineVertexArray[verticalVertexIndex++] = 0f
lineVertexArray[verticalVertexIndex++] = (vertPoint.x - vertexOrigin.x).toFloat()
lineVertexArray[verticalVertexIndex++] = (vertPoint.y - vertexOrigin.y).toFloat()
lineVertexArray[verticalVertexIndex++] = (vertPoint.z - vertexOrigin.z).toFloat()
lineVertexArray[verticalVertexIndex++] = 1f
lineVertexArray[verticalVertexIndex++] = 0f
lineVertexArray[verticalVertexIndex++] = (vertPoint.x - vertexOrigin.x).toFloat()
lineVertexArray[verticalVertexIndex++] = (vertPoint.y - vertexOrigin.y).toFloat()
lineVertexArray[verticalVertexIndex++] = (vertPoint.z - vertexOrigin.z).toFloat()
lineVertexArray[verticalVertexIndex++] = -1f
lineVertexArray[verticalVertexIndex++] = 0f
lineVertexArray[verticalVertexIndex++] = (vertPoint.x - vertexOrigin.x).toFloat()
lineVertexArray[verticalVertexIndex++] = (vertPoint.y - vertexOrigin.y).toFloat()
lineVertexArray[verticalVertexIndex++] = (vertPoint.z - vertexOrigin.z).toFloat()
lineVertexArray[verticalVertexIndex++] = 1f
lineVertexArray[verticalVertexIndex++] = 0f
lineVertexArray[verticalVertexIndex++] = (vertPoint.x - vertexOrigin.x).toFloat()
lineVertexArray[verticalVertexIndex++] = (vertPoint.y - vertexOrigin.y).toFloat()
lineVertexArray[verticalVertexIndex++] = (vertPoint.z - vertexOrigin.z).toFloat()
lineVertexArray[verticalVertexIndex++] = -1f
lineVertexArray[verticalVertexIndex++] = 0f
verticalElements.add(index)
verticalElements.add(index + 1)
verticalElements.add(index + 2)
verticalElements.add(index + 2)
verticalElements.add(index + 1)
verticalElements.add(index + 3)
}
}
}
protected open fun addVertex(
rc: RenderContext, latitude: Angle, longitude: Angle, altitude: Double, offset: Int, isExtrudedSkirt: Boolean
) {
var offsetVertexIndex = vertexIndex + offset
var point = rc.geographicToCartesian(latitude, longitude, altitude, altitudeMode, scratchPoint)
val texCoord2d = texCoord2d.copy(point).multiplyByMatrix(modelToTexCoord)
prevPoint.copy(point)
if (isSurfaceShape) {
vertexArray[vertexIndex++] = (longitude.inDegrees - vertexOrigin.x).toFloat()
vertexArray[vertexIndex++] = (latitude.inDegrees - vertexOrigin.y).toFloat()
vertexArray[vertexIndex++] = (altitude - vertexOrigin.z).toFloat()
// reserved for future texture coordinate use
vertexArray[vertexIndex++] = texCoord2d.x.toFloat()
vertexArray[vertexIndex++] = texCoord2d.y.toFloat()
} else {
vertexArray[vertexIndex++] = (point.x - vertexOrigin.x).toFloat()
vertexArray[vertexIndex++] = (point.y - vertexOrigin.y).toFloat()
vertexArray[vertexIndex++] = (point.z - vertexOrigin.z).toFloat()
vertexArray[vertexIndex++] = texCoord2d.x.toFloat()
vertexArray[vertexIndex++] = texCoord2d.y.toFloat()
if (isExtrudedSkirt) {
point = rc.geographicToCartesian(latitude, longitude, 0.0, AltitudeMode.CLAMP_TO_GROUND, scratchPoint)
vertexArray[offsetVertexIndex++] = (point.x - vertexOrigin.x).toFloat()
vertexArray[offsetVertexIndex++] = (point.y - vertexOrigin.y).toFloat()
vertexArray[offsetVertexIndex++] = (point.z - vertexOrigin.z).toFloat()
vertexArray[offsetVertexIndex++] = 0f //unused
vertexArray[offsetVertexIndex] = 0f //unused
}
}
}
protected open fun determineModelToTexCoord(rc: RenderContext) {
val point = rc.geographicToCartesian(center, altitudeMode, scratchPoint)
rc.globe.cartesianToLocalTransform(point.x, point.y, point.z, modelToTexCoord)
modelToTexCoord.invertOrthonormal()
}
/**
* Calculate the number of times to split the edges of the shape for geometry assembly.
*
* @param rc current RenderContext
*
* @return an even number of intervals
*/
protected open fun computeIntervals(rc: RenderContext): Int {
var intervals = MIN_INTERVALS
if (intervals >= maximumIntervals) return intervals // use at least the minimum number of intervals
val centerPoint = rc.geographicToCartesian(center, altitudeMode, scratchPoint)
val maxRadius = max(majorRadius, minorRadius)
val cameraDistance = centerPoint.distanceTo(rc.cameraPoint) - maxRadius
if (cameraDistance <= 0) return maximumIntervals // use the maximum number of intervals when the camera is very close
val metersPerPixel = rc.pixelSizeAtDistance(cameraDistance)
val circumferencePixels = computeCircumference() / metersPerPixel
val circumferenceIntervals = circumferencePixels / maximumPixelsPerInterval
val subdivisions = ln(circumferenceIntervals / intervals) / ln(2.0)
val subdivisionCount = ceil(subdivisions).toInt().coerceAtLeast(0)
intervals = intervals shl subdivisionCount // subdivide the base intervals to achieve the desired number of intervals
return intervals.coerceAtMost(maximumIntervals) // don't exceed the maximum number of intervals
}
protected open fun sanitizeIntervals(intervals: Int) = if (intervals % 2 == 0) intervals else intervals - 1
open fun computeCircumference(): Double {
val a = majorRadius
val b = minorRadius
return PI * (3 * (a + b) - sqrt((3 * a + b) * (a + 3 * b)))
}
override fun reset() {
super.reset()
vertexArray = FloatArray(0)
lineVertexArray = FloatArray(0)
}
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