纯kotlin实现voxel解析器
可以看到文件分为几块：header，size，xyzi，rgba
创建VoxelChunk类来储存
class VoxelChunk(
var palette: List<Long>,
val size: Int3
) {
lateinit var data: ByteArray
}
// 辅助类，获取指定坐标的索引
class Int3(
var x: Int,
var y: Int,
var z: Int
) {
val dot: Int
get() = x * y * z
operator fun get(i: Int, j: Int, k: Int) = i * y * z + j * z + k
override fun toString(): String {
return "[$x, $y, $z]"
}
}
因为要从字节流中按高位或低位读取32位int，并且kotlin中类型判断过于严格，所以需要一个辅助类
class BufferReader(val buff: ByteArray) {
// 将1位byte转为非负int
fun i8(offset: Int): Int {
return this[offset].toInt() and 0xFF
}
// 将1位byte转为uint
fun u8(offset: Int): UInt {
return this[offset].toUInt()
}
// 按高位或低位读取32位int
fun i32(offset: Int, littleEndian: Boolean = false): Int {
return if(littleEndian) {
((this[offset+3].toInt() and 0xFF) shl 24) or
((this[offset+2].toInt() and 0xFF) shl 16) or
((this[offset+1].toInt() and 0xFF) shl 8) or
(this[offset].toInt() and 0xFF)
}else{
((this[offset].toInt() and 0xFF) shl 24) or
((this[offset+1].toInt() and 0xFF) shl 16) or
((this[offset+2].toInt() and 0xFF) shl 8) or
(this[offset+3].toInt() and 0xFF)
}
}
// 按高位或低位读取32位uint
fun u32(offset: Int, littleEndian: Boolean = false): UInt {
return if(littleEndian) {
((this[offset+3].toUInt() and 0xFFu) shl 24) or
((this[offset+2].toUInt() and 0xFFu) shl 16) or
((this[offset+1].toUInt() and 0xFFu) shl 8) or
(this[offset].toUInt() and 0xFFu)
}else{
((this[offset].toUInt() and 0xFFu) shl 24) or
((this[offset+1].toUInt() and 0xFFu) shl 16) or
((this[offset+2].toUInt() and 0xFFu) shl 8) or
(this[offset+3].toUInt() and 0xFFu)
}
}
// 按高位或低位读取Long
fun l(offset: Int, littleEndian: Boolean = false): Long = u32(offset, littleEndian).toLong()
// 读取char
fun char(offset: Int): Char {
return i8(offset).toChar()
}
operator fun get(o: Int) = buff[o]
fun copy(offset: Int, length: Int): ByteArray {
return buff.copyOfRange(offset, offset+length)
}
val size: Int
get() = buff.size
}
// int转byte
fun to4ByteArray(value: Int): ByteArray {
return byteArrayOf(
value.toByte(),
(value shr 8).toByte(),
(value shr 16).toByte(),
(value shr 24).toByte(),
)
}
// float转byte
fun to4ByteArray(value: Float): ByteArray {
val bitRep = value.toRawBits()
return byteArrayOf(
bitRep.toByte(),
(bitRep shr 8).toByte(),
(bitRep shr 16).toByte(),
(bitRep shr 24).toByte(),
)
}
fun intFrom4ByteArray(value: ByteArray): Int {
if(value.size != 4) return 0
return (value[3].toInt() and 0xff shl 24) or
(value[2].toInt() and 0xff shl 16) or
(value[1].toInt() and 0xff shl 8) or
(value[0].toInt() and 0xff)
}
fun floatFrom4ByteArray(value: ByteArray): Float {
if(value.size != 4) return 0.0f
return Float.fromBits(
(value[3].toInt() and 0xff shl 24) or
(value[2].toInt() and 0xff shl 16) or
(value[1].toInt() and 0xff shl 8) or
(value[0].toInt() and 0xff)
)
}
operator fun ByteArray.set(i: Int, v: Float) {
to4ByteArray(v).let {
this[i] = it[0]
this[i+1] = it[1]
this[i+2] = it[2]
this[i+3] = it[3]
}
}
operator fun ByteArray.set(i: Int, v: Int) {
to4ByteArray(v).let {
this[i] = it[0]
this[i+1] = it[1]
this[i+2] = it[2]
this[i+3] = it[3]
}
}
解析vox
object VoxelLoader {
fun load(buffer: ByteArray): List<VoxelChunk> {
val reader = BufferReader(buffer)
val vid = reader.u32(0, true)
val version = reader.u32(4, true)
if( vid != 542658390u) {
throw IllegalStateException("VOXLoader: Invalid VOX file.")
}
// if( version != 150u ) {
// throw IllegalStateException("VOXLoader: Invalid VOX file. Unsupported version: $version")
// }
var chunk: VoxelChunk? = null
val chunks = mutableListOf<VoxelChunk>()
var i = 8
while(i < reader.size) {
var id = ""
for(j in 0 .. 3) {
id += reader.char(i++)
}
val chunkSize = reader.i32(i, true)
i += 8
when(id) {
"SIZE" -> {
val x = reader.i32(i, true)
i += 4
val y = reader.i32(i, true)
i += 4
val z = reader.i32(i, true)
i += 4
chunk = VoxelChunk(
DEFAULT_PALETTE,
size = Int3(x,y,z)
)
chunks.add(chunk)
i += chunkSize - ( 3 * 4 )
}
"XYZI" -> {
val numVoxels = reader.i32(i, true)
i += 4
chunk?.data = reader.copy(i, numVoxels * 4)
i += numVoxels * 4
}
"RGBA" -> {
val palette = List(257) {
if(it==0) 0L
else {
i += 4
reader.l(i-4, true)
}
}
chunk?.palette = palette
}
else -> {
i += chunkSize
}
}
}
return chunks
}
val DEFAULT_PALETTE = listOf(0x00000000, 0xffffffff, 0xffccffff, 0xff99ffff, 0xff66ffff, 0xff33ffff, 0xff00ffff, 0xffffccff,
0xffccccff, 0xff99ccff, 0xff66ccff, 0xff33ccff, 0xff00ccff, 0xffff99ff, 0xffcc99ff, 0xff9999ff,
0xff6699ff, 0xff3399ff, 0xff0099ff, 0xffff66ff, 0xffcc66ff, 0xff9966ff, 0xff6666ff, 0xff3366ff,
0xff0066ff, 0xffff33ff, 0xffcc33ff, 0xff9933ff, 0xff6633ff, 0xff3333ff, 0xff0033ff, 0xffff00ff,
0xffcc00ff, 0xff9900ff, 0xff6600ff, 0xff3300ff, 0xff0000ff, 0xffffffcc, 0xffccffcc, 0xff99ffcc,
0xff66ffcc, 0xff33ffcc, 0xff00ffcc, 0xffffcccc, 0xffcccccc, 0xff99cccc, 0xff66cccc, 0xff33cccc,
0xff00cccc, 0xffff99cc, 0xffcc99cc, 0xff9999cc, 0xff6699cc, 0xff3399cc, 0xff0099cc, 0xffff66cc,
0xffcc66cc, 0xff9966cc, 0xff6666cc, 0xff3366cc, 0xff0066cc, 0xffff33cc, 0xffcc33cc, 0xff9933cc,
0xff6633cc, 0xff3333cc, 0xff0033cc, 0xffff00cc, 0xffcc00cc, 0xff9900cc, 0xff6600cc, 0xff3300cc,
0xff0000cc, 0xffffff99, 0xffccff99, 0xff99ff99, 0xff66ff99, 0xff33ff99, 0xff00ff99, 0xffffcc99,
0xffcccc99, 0xff99cc99, 0xff66cc99, 0xff33cc99, 0xff00cc99, 0xffff9999, 0xffcc9999, 0xff999999,
0xff669999, 0xff339999, 0xff009999, 0xffff6699, 0xffcc6699, 0xff996699, 0xff666699, 0xff336699,
0xff006699, 0xffff3399, 0xffcc3399, 0xff993399, 0xff663399, 0xff333399, 0xff003399, 0xffff0099,
0xffcc0099, 0xff990099, 0xff660099, 0xff330099, 0xff000099, 0xffffff66, 0xffccff66, 0xff99ff66,
0xff66ff66, 0xff33ff66, 0xff00ff66, 0xffffcc66, 0xffcccc66, 0xff99cc66, 0xff66cc66, 0xff33cc66,
0xff00cc66, 0xffff9966, 0xffcc9966, 0xff999966, 0xff669966, 0xff339966, 0xff009966, 0xffff6666,
0xffcc6666, 0xff996666, 0xff666666, 0xff336666, 0xff006666, 0xffff3366, 0xffcc3366, 0xff993366,
0xff663366, 0xff333366, 0xff003366, 0xffff0066, 0xffcc0066, 0xff990066, 0xff660066, 0xff330066,
0xff000066, 0xffffff33, 0xffccff33, 0xff99ff33, 0xff66ff33, 0xff33ff33, 0xff00ff33, 0xffffcc33,
0xffcccc33, 0xff99cc33, 0xff66cc33, 0xff33cc33, 0xff00cc33, 0xffff9933, 0xffcc9933, 0xff999933,
0xff669933, 0xff339933, 0xff009933, 0xffff6633, 0xffcc6633, 0xff996633, 0xff666633, 0xff336633,
0xff006633, 0xffff3333, 0xffcc3333, 0xff993333, 0xff663333, 0xff333333, 0xff003333, 0xffff0033,
0xffcc0033, 0xff990033, 0xff660033, 0xff330033, 0xff000033, 0xffffff00, 0xffccff00, 0xff99ff00,
0xff66ff00, 0xff33ff00, 0xff00ff00, 0xffffcc00, 0xffcccc00, 0xff99cc00, 0xff66cc00, 0xff33cc00,
0xff00cc00, 0xffff9900, 0xffcc9900, 0xff999900, 0xff669900, 0xff339900, 0xff009900, 0xffff6600,
0xffcc6600, 0xff996600, 0xff666600, 0xff336600, 0xff006600, 0xffff3300, 0xffcc3300, 0xff993300,
0xff663300, 0xff333300, 0xff003300, 0xffff0000, 0xffcc0000, 0xff990000, 0xff660000, 0xff330000,
0xff0000ee, 0xff0000dd, 0xff0000bb, 0xff0000aa, 0xff000088, 0xff000077, 0xff000055, 0xff000044,
0xff000022, 0xff000011, 0xff00ee00, 0xff00dd00, 0xff00bb00, 0xff00aa00, 0xff008800, 0xff007700,
0xff005500, 0xff004400, 0xff002200, 0xff001100, 0xffee0000, 0xffdd0000, 0xffbb0000, 0xffaa0000,
0xff880000, 0xff770000, 0xff550000, 0xff440000, 0xff220000, 0xff110000, 0xffeeeeee, 0xffdddddd,
0xffbbbbbb, 0xffaaaaaa, 0xff888888, 0xff777777, 0xff555555, 0xff444444, 0xff222222, 0xff111111)
}
完整代码在github中