Culling (visibility helpers)

Mibo.Elmish.Culling is a tiny helper module that keeps visibility math separate from your renderer and your spatial partitioning.

It operates on MonoGame primitives:

• BoundingFrustum
• BoundingSphere
• BoundingBox
• Rectangle

3D: frustum culling

Culling works with any BoundingFrustum - from either camera:

Elmish Camera3D:

let frustum = Camera3D.boundingFrustum camera

Rendering3D Camera:

let frustum = Camera.boundingFrustum camera

Both return same BoundingFrustum type, so culling works the same:

if Culling.isVisible frustum entitySphere then
  // submit draw commands
  ()

Or for AABBs:

if Culling.isGenericVisible frustum nodeBounds then
  ()

2D: rectangle overlap

Uses Camera2D.viewportBounds with generic rectangle overlap test:

let viewBounds = Camera2D.viewportBounds camera viewport

if Culling.isVisible2D viewBounds spriteBounds then
  ()

What this is not

This module doesn’t try to be your spatial index.

• If you have many objects: use a grid / quadtree / BVH / octree.
• Use these helpers at the edge: “is this node/object worth considering for rendering?”