move 3D entity in a direction defined by an angle

CesiumJS
1

Hello,

I'm new using Cesium and what I want to do is to draw a cone pointing in a certain direction and shift the cone so that one of the edges connect to a pole.

I have managed to draw the cone in the desired location, but I can't find a way to offset the cone to make the tip connect to a pole on the original coordinate.

What I need to do is to offset an object by half his size in a specific angle.

Here is the code I have so far. This function puts the cone pointing in the direction I want but it doesn't move where I want it:

          create3DNetwork = function (networkItem) {

            var solidLength = 2.0;
            var position = networkItem._position._value;
            var azimuthRadians = Cesium.Math.toRadians(networkItem.properties.AZIMUTH);
            var shift_x = -Math.sin(Cesium.Math.PI - azimuthRadians) * solidLength;
            var shift_y = -Math.cos(Cesium.Math.PI - azimuthRadians) * solidLength;

            //Transform a point
            var transformationMatrix = Cesium.Transforms.eastNorthUpToFixedFrame(position);
            var offset = new Cesium.Cartesian3(shift_x, shift_y, 0);
            var finalPos = Cesium.Matrix4.multiplyByPoint(transformationMatrix, offset, new Cesium.Cartesian3());

            var heading = azimuthRadians;
            var pitch = 0.0;
            var roll = Cesium.Math.PI_OVER_TWO - Cesium.Math.toRadians(networkItem.properties.TILT);
            orientation = Cesium.Transforms.headingPitchRollQuaternion(finalPos, heading, pitch, roll);
            $scope.viewer.entities.add({
              position: finalPos,
              orientation: orientation,
              cylinder: {
                length: solidLength * 2,
                topRadius: 0.0,
                bottomRadius: solidLength,
                //slices: 4, //Add this parameter if you want to change the shape of the cilinder (e.g. to a pyramid)
                material: Cesium.Color.fromCssColorString("#7A0304").withAlpha(0.5) //RBG: 122,3,4
              }
            });
          }

Thank you so much
Migue Dias

2

I found a solution. I'm not sure it is the best one using Cesium functionalities, but it works.

I created this function to shift the point of insertion of the cone:

      // shift a coordinate from a point to a certain distance and direction
          $scope.shiftPoint = function (startPoint, bearing, distance, earthRadius) {

            var verticalAngle = distance / earthRadius;
            var endLatitude = Math.asin(Math.sin(startPoint.latitude) * Math.cos(verticalAngle) +
                  Math.cos(startPoint.latitude) * Math.sin(verticalAngle) * Math.cos(bearing));
            var endLongitude = startPoint.longitude + Math.atan2(Math.sin(bearing) * Math.sin(verticalAngle) * Math.cos(startPoint.latitude),
                     Math.cos(verticalAngle) - Math.sin(startPoint.latitude) * Math.sin(endLatitude));
            return Cesium.Cartesian3.fromRadians(endLongitude, endLatitude, startPoint.height);
          }

quarta-feira, 4 de Novembro de 2015 às 10:49:57 UTC, mdi...@gmail.com escreveu: