QgsChunkedEntity::SceneState _sceneState( QgsCameraController *cameraController )
{
Qt3DRender::QCamera *camera = cameraController->camera();
QgsChunkedEntity::SceneState state;
state.cameraFov = camera->fieldOfView();
state.cameraPos = camera->position();
QRect rect = cameraController->viewport();
state.screenSizePx = std::max( rect.width(), rect.height() ); // TODO: is this correct?
state.viewProjectionMatrix = camera->projectionMatrix() * camera->viewMatrix();
return state;
}
float Qgs3DMapScene::worldSpaceError( float epsilon, float distance )
{
Qt3DRender::QCamera *camera = mCameraController->camera();
float fov = camera->fieldOfView();
QRect rect = mCameraController->viewport();
float screenSizePx = std::max( rect.width(), rect.height() ); // TODO: is this correct?
// in qgschunkedentity_p.cpp there is inverse calculation (world space error to screen space error)
// with explanation of the math.
float frustumWidthAtDistance = 2 * distance * tan( fov / 2 );
float err = frustumWidthAtDistance * epsilon / screenSizePx;
return err;
}