camera heading = roll?

CesiumJS
1

Hello,
I am not sure if this is a bug or a feature.
I try to manipulate the camera's heading, pitch and roll. And it seems that the heading does the same rotation as the roll.

So using this:
viewer.camera.setView({
    orientation : {
        heading : h + 0.5,
        pitch : p,
        roll : r
    }
});

has the same results like this:

viewer.camera.setView({
    orientation : {
        heading : h,
        pitch : p,
        roll : r + 0.5
    }
});

Below code to reproduce this in the Sandcastle. You will first see the rotation using heading, then it will reset the camera's position and do the same rotation using roll. I think it should look different. Could you help me understand this? Thanks :slight_smile:

var viewer = new Cesium.Viewer('cesiumContainer');
var h = viewer.camera.heading;
var p = viewer.camera.pitch;
var r = viewer.camera.roll;

var value = 0.5;

console.log(h);
console.log(p);
console.log(r);

var b = function() {
    viewer.camera.setView({
        destination : Cesium.Cartesian3.fromDegrees(13.305, 52.528, 3000000),
        orientation : {
            heading : h,
            pitch : p,
            roll : r
        }
    });

    viewer.camera.flyTo({
        destination : Cesium.Cartesian3.fromDegrees(13.305, 52.528, 3000000),
        orientation : {
            heading : h,
            pitch : p,
            roll : r + value
        },
    });
};

viewer.camera.setView({
    destination : Cesium.Cartesian3.fromDegrees(13.305, 52.528, 3000000),
    orientation : {
        heading : h,
        pitch : p,
        roll : r
    }
});

viewer.camera.flyTo({
    destination : Cesium.Cartesian3.fromDegrees(13.305, 52.528, 3000000),
    orientation : {
        heading : h + value,
        pitch : p,
        roll : r
    },
    complete : b
});

2

Hello,

I believe this is expected. This looks like the result of gimbal lock. Because the camera is pointed straight down, the heading and roll rotations are the same.

Best,

Hannah

3

Hallo Hannah,
thanks for your response.

You are right. I figured out that setting pitch to 0 solves this problem. But obviously changes the rotation I wanted.
I will try to use direction vector and up vector instead.