info.laht.threekt.geometries.PolyhedronBufferGeometry.kt Maven / Gradle / Ivy
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Port of the three.js 3D javascript library for Kotlin/JVM
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package info.laht.threekt.geometries
import info.laht.threekt.core.BufferGeometry
import info.laht.threekt.core.FloatBufferAttribute
import info.laht.threekt.math.Vector2
import info.laht.threekt.math.Vector3
import info.laht.threekt.push
import kotlin.math.*
@Suppress("NAME_SHADOWING")
open class PolyhedronBufferGeometry(
private val vertices: FloatArray,
private val indices: IntArray,
radius: Float? = null,
detail: Int? = null
) : BufferGeometry() {
private val vertexBuffer = mutableListOf()
private val uvBuffer = mutableListOf()
init {
val radius = radius ?: 1f
val detail = detail ?: 0
subdivide(detail)
applyRadius(radius)
generateUVs()
addAttribute("position", FloatBufferAttribute(vertexBuffer.toFloatArray(), 3))
addAttribute("normal", FloatBufferAttribute(vertexBuffer.toFloatArray(), 3))
addAttribute("uv", FloatBufferAttribute(uvBuffer.toFloatArray(), 2))
if (detail == 0) {
computeVertexNormals()
} else {
normalizeNormals()
}
}
private fun subdivide(detail: Int) {
val a = Vector3()
val b = Vector3()
val c = Vector3()
// iterate over all faces and apply a subdivison with the given detail value
var i = 0
while (i < indices.size) {
// get the vertices of the face
getVertexByIndex(indices[i + 0], a)
getVertexByIndex(indices[i + 1], b)
getVertexByIndex(indices[i + 2], c)
// perform subdivision
subdivideFace(a, b, c, detail)
i += 3
}
}
private fun subdivideFace(a: Vector3, b: Vector3, c: Vector3, detail: Int) {
val cols = 2f.pow(detail).toInt()
// we use this multidimensional array as a data structure for creating the subdivision
val v = mutableListOf>()
// construct all of the vertices for this subdivision
for (i in 0..cols) {
v.add(mutableListOf())
val aj = a.clone().lerp(c, i.toFloat() / cols)
val bj = b.clone().lerp(c, i.toFloat() / cols)
val rows = cols - i
for (j in 0..rows) {
if (j == 0 && i == cols) {
v[i].push(aj)
} else {
v[i].push(aj.clone().lerp(bj, j.toFloat() / rows))
}
}
}
// construct all of the faces
for (i in 0 until cols) {
for (j in 0 until 2 * (cols - i) - 1) {
val k = floor(j.toFloat() / 2).toInt()
if (j % 2 == 0) {
pushVertex(v[i][k + 1])
pushVertex(v[i + 1][k])
pushVertex(v[i][k])
} else {
pushVertex(v[i][k + 1]);
pushVertex(v[i + 1][k + 1]);
pushVertex(v[i + 1][k]);
}
}
}
}
private fun applyRadius(radius: Float) {
val vertex = Vector3()
// iterate over the entire buffer and apply the radius to each vertex
var i = 0
while (i < vertexBuffer.size) {
vertex.x = vertexBuffer[i + 0]
vertex.y = vertexBuffer[i + 1]
vertex.z = vertexBuffer[i + 2]
vertex.normalize().multiplyScalar(radius)
vertexBuffer[i + 0] = vertex.x
vertexBuffer[i + 1] = vertex.y
vertexBuffer[i + 2] = vertex.z
i += 3
}
}
private fun generateUVs() {
val vertex = Vector3()
var i = 0
while (i < vertexBuffer.size) {
vertex.x = vertexBuffer[i + 0]
vertex.y = vertexBuffer[i + 1]
vertex.z = vertexBuffer[i + 2]
val u = azimuth(vertex) / 2 / PI.toFloat() + 0.5f
val v = inclination(vertex) / PI.toFloat() + 0.5f
uvBuffer.push(u, 1 - v);
i += 3
}
correctUVs();
correctSeam();
}
private fun correctSeam() {
// handle case when face straddles the seam, see #3269
var i = 0
while (i < uvBuffer.size) {
// uv data of a single face
val x0 = uvBuffer[i + 0]
val x1 = uvBuffer[i + 2]
val x2 = uvBuffer[i + 4]
val max = max(x0, max(x1, x2))
val min = min(x0, min(x1, x2))
// 0.9 is somewhat arbitrary
if (max > 0.9 && min < 0.1) {
if (x0 < 0.2) uvBuffer[i + 0] = uvBuffer[i + 0] + 1
if (x1 < 0.2) uvBuffer[i + 2] = uvBuffer[i + 2] + 1
if (x2 < 0.2) uvBuffer[i + 4] = uvBuffer[i + 4] + 1
}
i += 6
}
}
private fun pushVertex(vertex: Vector3) {
vertexBuffer.push(vertex.x, vertex.y, vertex.z)
}
private fun getVertexByIndex(index: Int, vertex: Vector3) {
val stride = index * 3
vertex.x = vertices[stride + 0]
vertex.y = vertices[stride + 1]
vertex.z = vertices[stride + 2]
}
private fun correctUVs() {
val a = Vector3()
val b = Vector3()
val c = Vector3();
val centroid = Vector3()
val uvA = Vector2()
val uvB = Vector2()
val uvC = Vector2()
var i = 0
var j = 0
while (i < vertexBuffer.size) {
a.set(vertexBuffer[i + 0], vertexBuffer[i + 1], vertexBuffer[i + 2])
b.set(vertexBuffer[i + 3], vertexBuffer[i + 4], vertexBuffer[i + 5])
c.set(vertexBuffer[i + 6], vertexBuffer[i + 7], vertexBuffer[i + 8])
uvA.set(uvBuffer[j + 0], uvBuffer[j + 1])
uvB.set(uvBuffer[j + 2], uvBuffer[j + 3])
uvC.set(uvBuffer[j + 4], uvBuffer[j + 5])
centroid.copy(a).add(b).add(c).divideScalar(3f)
val azi = azimuth(centroid)
correctUV(uvA, j + 0, a, azi)
correctUV(uvB, j + 2, b, azi)
correctUV(uvC, j + 4, c, azi)
i += 9
j += 6
}
}
private fun correctUV(uv: Vector2, stride: Int, vector: Vector3, azimuth: Float) {
if ((azimuth < 0) && (uv.x == 1f)) {
uvBuffer[stride] = uv.x - 1
}
if ((vector.x == 0f) && (vector.z == 0f)) {
uvBuffer[stride] = azimuth / 2f / PI.toFloat() + 0.5f
}
}
private fun azimuth(vector: Vector3): Float {
return atan2(vector.z, -vector.x)
}
// Angle above the XZ plane.
private fun inclination(vector: Vector3): Float {
return atan2(-vector.y, sqrt((vector.x * vector.x) + (vector.z * vector.z)));
}
}
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