Switch cameras

[valleymouth]

Hi guys,
What is the correct/best way to switch cameras? Let's say I have multiple cameras in the scene, and I want to switch between them to select which one is rendering.
Cheers,
Denis

[robertosfield]

On Fri, 18 Nov 2022 at 15:07, valleymouth ***@***.***> wrote: What is the correct/best way to switch cameras? Let's say I have multiple cameras in the scene, and I want to switch between them to select which one is rendering. Message ID: ***@***.***>

In the VSG the vsg::Camera is best thought of as just the camera settings used by a RenderGraph/View to control the viewing direction and projection (lens) used when traversing a subgraph. So it's the RenderGraph/View that is really responsible for the rendering. If you have various viewpoints in your scene graph that you wish to become the the view you want to render then you update the View's Camera's viewMatrix to a new value. The vsg::Trackball <https://github.com/vsg-dev/VulkanSceneGraph/blob/master/include/vsg/app/Trackball.h>has a support for mapping key presses to different look at settings that do this job: /// add Key to Viewpoint binding using a LookAt to define the viewpoint void addKeyViewpoint(KeySymbol key, ref_ptr<LookAt> lookAt, double duration = 1.0); /// add Key to Viewpoint binding using a latitude, longitude and altitude to define the viewpoint. Requires an EllipsoidModel to be assigned when constructing the Trackball void addKeyViewpoint(KeySymbol key, double latitude, double longitude, double altitude, double duration = 1.0); This essentially copies the selected LookAt values to the Camrea->viewMatrix to update the view, handling animation between the current and the new viewpoint. Another approach is the vsg::TrackingViewMatrix <https://github.com/vsg-dev/VulkanSceneGraph/blob/master/include/vsg/app/ViewMatrix.h#L117> subclass from vsg::ViewMatrix that you can set up to follow objects in the scene graph, so as they move - such as a MatrixTransform moving them, then the ViewMatrix value will be updated and then Camera will then take it's view matrix for this on each new frame. Cheers, Robert.

[robertosfield]

As well as updating what the Camera looks at by modifying the Camera's viewMatrix, you can also change the Camera that is being rendered by a View is to simply change the camera assigned to the View i.e.

view->camera = new_camera;

[valleymouth]

Thanks once again!