THREE.JS / FOUNDATIONS 219

Cut the view at the threshold.

A portal camera can be perfectly framed and still see geometry on the wrong side of the doorway. Compare material clipping, renderer-global clipping, and an oblique near plane while bounded recursion keeps the capture cost visible.

Initializing Preparing WebGL2

Preparing paired targets, clipping policy, and the portal camera...

renderer: -
targets: -
captures: -
depth: -
clip policy: -
projection: -
calls: -
frame ms: -

Portal visibility policylive

clip policy clip bias capture layers target size

capture every frame show portal effect show threshold plane animate scene objects

Each capture layer renders both portals. The leak beacon sits beyond the destination plane so the clipping policy is visible.

Visibility contractWebGL2 portal pass

material.clippingPlanesobject-local policy

renderer.clippingPlanesglobal capture policy

projectionMatrix[2,6,10,14]oblique near plane

Plane.distanceToPoint()signed-side probe

captureDepth × 2bounded portal work

The portal texture is still a render target. This lab adds the missing visibility decision: only the intended side of the destination surface should reach that target.

Capture readoutready

portal camera-

plane normal-

camera signed distance-

state restore-

GPU resourcesowned

The threshold plane is shown only in the main view; capture temporarily hides it and restores renderer state afterward.

Derived from the official portal example, clipping example, Reflector oblique clip, and the current Material / WebGLRenderer docs.

THREE.JS FOUNDATIONS LAB