FieldHoverSampler

The hover's sampler (field-presentation §FVS-4, matrix FVW-54).

In the namespace construct::rendering. Declared in src/libs/libconstruct/construct/rendering/FieldHoverSampler.hpp.

Detailed description

It holds one request in flight and one waiting. A new request replaces the waiting one, so the work never falls behind the pointer. The work runs on a pool thread of its own: the sampler is read-only, and a locator build of a large volume takes a few hundred milliseconds.

The first hover on an item builds its locator, and the answer says "locating" at once. A hover on a deformed part refits the locator to the moved nodes when the scale or the phase changed since the last refit, so the element and the weights are those of the material point (§FVS-2). The moved nodes come from the `deformed_offset` kernel, the formula of the vertex shader.

Answers come back on the thread of this object, as answered().