Files
orx/orx-obj-loader/src/commonMain/kotlin/ObjReader.kt

137 lines
6.2 KiB
Kotlin

package org.openrndr.extra.objloader
import org.openrndr.color.ColorRGBa
import org.openrndr.draw.VertexBuffer
import org.openrndr.extra.mesh.*
import org.openrndr.math.Vector2
import org.openrndr.math.Vector3
/**
* Reads and processes mesh data from a list of lines in OBJ format.
*
* @param lines An iterable collection of strings representing the lines of an OBJ file.
* Each line contains information about vertices, normals, texture coordinates,
* face definitions, or group definitions.
* @return A `CompoundMeshData` object containing processed vertex data and meshes.
* The resulting data includes vertices, texture coordinates, colors, normals, tangents, and bitangents,
* alongside their associated face indices, grouped into meshes.
*/
fun readObjMeshData(lines: Iterable<String>): CompoundMeshData {
val meshes = mutableMapOf<String, List<IndexedPolygon>>()
val positions = mutableListOf<Vector3>()
val normals = mutableListOf<Vector3>()
val tangents = mutableListOf<Vector3>()
val bitangents = mutableListOf<Vector3>()
val textureCoords = mutableListOf<Vector2>()
val colors = mutableListOf<ColorRGBa>()
var activeMesh = mutableListOf<IndexedPolygon>()
lines.forEach { line ->
if (line.isNotEmpty()) {
val tokens = line.split(Regex("[ |\t]+")).map { it.trim() }.filter { it.isNotEmpty() }
if (tokens.isNotEmpty()) {
when (tokens[0]) {
"v" -> {
when (tokens.size) {
3, 4 -> {
positions += Vector3(tokens[1].toDouble(), tokens[2].toDouble(), tokens[3].toDouble())
}
6 -> {
positions += Vector3(tokens[1].toDouble(), tokens[2].toDouble(), tokens[3].toDouble())
colors += ColorRGBa(tokens[4].toDouble(), tokens[5].toDouble(), tokens[6].toDouble())
}
7 -> {
positions += Vector3(tokens[1].toDouble(), tokens[2].toDouble(), tokens[3].toDouble())
colors += ColorRGBa(
tokens[4].toDouble(),
tokens[5].toDouble(),
tokens[6].toDouble(),
tokens[7].toDouble()
)
}
else -> error("vertex has ${tokens.size - 1} components, loader only supports 3/4/6/7 components")
}
}
"vn" -> {
when (tokens.size) {
3, 4 -> normals += Vector3(tokens[1].toDouble(), tokens[2].toDouble(), tokens[3].toDouble())
9 -> {
normals += Vector3(tokens[1].toDouble(), tokens[2].toDouble(), tokens[3].toDouble())
tangents += Vector3(tokens[4].toDouble(), tokens[5].toDouble(), tokens[6].toDouble())
bitangents += Vector3(tokens[7].toDouble(), tokens[8].toDouble(), tokens[9].toDouble())
}
}
}
"vt" -> textureCoords += Vector2(tokens[1].toDouble(), tokens[2].toDouble())
"g" -> {
activeMesh = mutableListOf()
meshes[tokens.getOrNull(1) ?: "no-name-${meshes.size}"] = activeMesh
}
"f" -> {
val indices = tokens.subList(1, tokens.size).map { it.split("/") }.map {
it.map { it.toIntOrNull() ?: 0 }
}
val hasPosition = (indices[0].getOrNull(0) ?: 0) != 0
val hasUV = (indices[0].getOrNull(1) ?: 0) != 0
val hasNormal = (indices[0].getOrNull(2) ?: 0) != 0
val hasColor = colors.isNotEmpty()
val hasTangents = tangents.isNotEmpty()
val hasBitangents = bitangents.isNotEmpty()
activeMesh.add(
IndexedPolygon(
if (hasPosition) indices.map { it[0] - 1 } else listOf(),
if (hasUV) indices.map { it[1] - 1 } else listOf(),
if (hasColor) indices.map { it[0] - 1 } else listOf(),
if (hasNormal) indices.map { it[2] - 1 } else listOf(),
if (hasTangents) indices.map { it[2] - 1 } else listOf(),
if (hasBitangents) indices.map { it[2] - 1 } else listOf()
)
)
if (meshes.isEmpty()) {
meshes["no-name"] = activeMesh
}
}
}
}
}
}
val vertexData = VertexData(positions, textureCoords, colors, normals)
return CompoundMeshData(
vertexData,
meshes.mapValues {
MeshData(vertexData, it.value)
}
)
}
/**
* Loads a Wavefront OBJ file representation provided as a list of strings and parses it into a VertexBuffer.
*
* @param lines The list of strings representing the content of the Wavefront OBJ file. Each string corresponds to a line in the file.
* @return A VertexBuffer containing the vertex information parsed from the OBJ data.
*/
fun loadOBJasVertexBuffer(lines: List<String>): VertexBuffer {
return readObjMeshData(lines).toVertexBuffer()
}
/**
* Parses a list of strings representing the content of a Wavefront OBJ file and converts it into
* a map of polygon groups, where each key corresponds to a mesh name and the value is a list of polygons.
*
* @param lines the lines of the OBJ file as a list of strings, with each string representing a line in the file.
* @return a map where keys are mesh names and values are lists of polygons ([IPolygon]) corresponding to those meshes.
*/
fun loadOBJ(lines: List<String>): Map<String, List<IPolygon>> = readObjMeshData(lines).triangulate().toPolygons()