使用PySide2加载.obj模型文件

要使用PySide2加载.obj模型文件，可以使用Qt 3D Studio Viewer，以下是示例代码：

from PySide2.Qt3DExtras import Qt3DWindow
from PySide2.Qt3DCore import QEntity
from PySide2.Qt3DRender import (QCamera, QCameraLens, QMesh, QPointLight,
                                QRenderAspect, QTechnique, QMaterial,
                                QParameter, QShaderProgram)

app = QApplication([])
window = Qt3DWindow()

scene_root_entity = QEntity()

camera_entity = window.camera()
camera_entity.lens().setPerspectiveProjection(45.0, 16.0 / 9.0, 0.1, 1000.0)
camera_entity.setPosition(QVector3D(0, 0, 20))
camera_entity.setUpVector(QVector3D(0, 1, 0))
camera_entity.setViewCenter(QVector3D(0, 0, 0))

light_entity = QEntity(scene_root_entity)
light = QPointLight(light_entity)
light.setColor(Qt.white)
light.setIntensity(1)
light_entity.addComponent(light)
light_entity.setPosition(QVector3D(0, 0, 20))

mesh_entity = QEntity(scene_root_entity)
mesh = QMesh(mesh_entity)
mesh.setSource(QUrl.fromLocalFile('your_file.obj'))

material = QMaterial(mesh_entity)
technique = QTechnique(material)
render_pass = technique.renderPasses()[0]
shader_program = QShaderProgram(render_pass)
shader_program.setVertexShaderCode(QShaderProgram.Vertex,
                                   QUrl.fromLocalFile('your_vertex_shader.vert'))
shader_program.setFragmentShaderCode(QShaderProgram.Fragment,
                                     QUrl.fromLocalFile('your_fragment_shader.frag'))
render_pass.setShaderProgram(shader_program)

texture_parameter = QParameter(material)
texture_parameter.setName('diffuseTexture')
texture_parameter.setValue(QUrl.fromLocalFile('your_texture.png'))
render_pass.addParameter(texture_parameter)

mesh_entity.addComponent(mesh)
mesh_entity.addComponent(material)

aspect = QRenderAspect()
aspect.setCamera(camera_entity)
aspect.setRenderPolicy(QRenderAspect.Synchronous)
aspect.setClearBuffers(QRenderAspect.AllBuffers)
window.setActiveFrameGraph(aspect)
window.setRootEntity(scene_root_entity)

window.show()
app.exec_()

其中，`your_file.obj`是要加载的.obj模型文件，`your_vertex_shader.vert`和`your_fragment_shader.frag`是顶点和片元着色器代码，`your_texture.png`是贴图文件。你需要将这些文件放在合适的位置，并将路径指定到代码中。