Qt 5.9 | Qt 3D | Qt 3D: Planets QML Example | Ring.qml Example File

Qt 5.9.3 Reference Documentation

# Ring.qml Example File

planets-qml/Ring.qml

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      import Qt3D.Render 2.0

      // TODO: Once support for meshes from arrays is implemented, replace ring.obj with that
      Mesh {
          property real innerRadius
          property real outerRadius
          /*
          property real ringSegments

          property var vertices: []
          property var faces: []
          property var faceVertexUvs: []
          */

          source: "qrc:/meshes/ring.obj"

          // Converted from the _RingGeometry() method in the threex.planets.js extension.
          /*
          function makeRing() {
              innerRadius = innerRadius || 0
              outerRadius = outerRadius || 50
              var thetaSegments = ringSegments || 8
              console.log(innerRadius + "," + outerRadius + "," + thetaSegments)

              var normal = Qt.vector3d(0, 0, 1)

              for (var i = 0; i < thetaSegments; i++) {
                  var angleLo = (i / thetaSegments) * Math.PI * 2
                  var angleHi = ((i + 1) / thetaSegments) * Math.PI * 2

                  var vertex1 = Qt.vector3d(innerRadius * Math.cos(angleLo),
                                            innerRadius * Math.sin(angleLo),
                                            0)
                  var vertex2 = Qt.vector3d(outerRadius * Math.cos(angleLo),
                                            outerRadius * Math.sin(angleLo),
                                            0)
                  var vertex3 = Qt.vector3d(innerRadius * Math.cos(angleHi),
                                            innerRadius * Math.sin(angleHi),
                                            0)
                  var vertex4 = Qt.vector3d(outerRadius * Math.cos(angleHi),
                                            outerRadius * Math.sin(angleHi),
                                            0)

                  vertices.push(vertex1)
                  vertices.push(vertex2)
                  vertices.push(vertex3)
                  vertices.push(vertex4)

                  var vertexIdx = i * 4

                  // Create the first triangle
                  var face = Qt.vector4d(vertexIdx + 0, vertexIdx + 1, vertexIdx + 2, normal)
                  var uvs = []

                  var uv = Qt.vector2d(0, 0)
                  uvs.push(uv)
                  uv = Qt.vector2d(1, 0)
                  uvs.push(uv)
                  uv = Qt.vector2d(0, 1)
                  uvs.push(uv)

                  faces.push(face)
                  //faceVertexUvs[0].push(uvs)
                  faceVertexUvs.push(uvs)

                  // Create the second triangle
                  face = Qt.vector4d(vertexIdx + 2, vertexIdx + 1, vertexIdx + 3, normal)
                  uvs = []

                  uv = Qt.vector2d(0, 1)
                  uvs.push(uv)
                  uv = Qt.vector2d(1, 0)
                  uvs.push(uv)
                  uv = Qt.vector2d(1, 1)
                  uvs.push(uv)

                  faces.push(face)
                  //faceVertexUvs[0].push(uvs)
                  faceVertexUvs.push(uvs)
              }

              computeFaceNormals()
          }

          // Converted from the computeFaceNormals() method in the three.js extension.
          function computeFaceNormals() {
              var cb = Qt.vector3d(0, 0, 0)
              var ab = Qt.vector3d(0, 0, 0)

              for (var f = 0, fl = faces.length; f < fl; f ++) {
                  var face = faces[f]

                  var vA = vertices[face.x]
                  var vB = vertices[face.y]
                  var vC = vertices[face.z]

                  cb = vC.minus(vB)
                  ab = vA.minus(vB)
                  cb = cb.crossProduct(ab)

                  cb = cb.normalized()

                  face.w = cb
              }
          }
          */
      }