Message HrzProtocol.ImpostorParams

Defined in hrz/protocol/3d_model/impostor_params.proto.

use_impostor: bool

When this is true the representation of 3D models for vector data will alternate between 3D models and impostors based on the viewing distance to the tile the feature is in. Using impostors can improve performance at the cost of small visual quality loss.

atlas_size: HrzProtocol.Vec2ui

This parameter determines the number of shots taken of the model.

This parameter plays a role on the impostor smoothness. A small atlas_size leads to a very rough impostor with abrupt transitions between different points of view. At the opposite, large atlas_size values will result in smooth transitions.

image_size: HrzProtocol.Vec2ui

Size of a single impostor shot in the atlas (in pixels).

This parameter plays a direct role on the impostor visual quality. A small image_size leads to a poorly resoluted impostor with low memory usage. At the opposite, big image_size values will give detailed impostors at the cost of more memory.

max_screen_size_pixels: double

Size in pixels on screen below which impostors start to get rendered. It can be visualised as the size of the side of a square. If the model fits inside the square, it is rendered as an impostor, otherwise it is rendered as a full 3D model. This size is in logical pixels.

The larger this size is, the closer to the camera the impostors will be rendered. In this scenario, less realistic 3D models will be rendered, thus the performance will be better at the cost of a small degradation of quality. The opposite applies, meaning smaller values will force impostors to render further from the camera, keeping high visual quality in the camera surrounding with a bigger impact on performance.

Note that this threshold is applied per tile using the average scale of the 3D model instances. This means that in tiles where there is a wide range of model scales, the threshold won’t be ideal for all of them.