Package-level declarations

Drawable group provides a standard set of group IDs for organizing WorldWindow drawing into four phases: background, surface, shape, and screen. Accepted values are BACKGROUND, SURFACE, SHAPE and SCREEN.

Surface drawable for the 3D camera-frustum projection path of earth.worldwind.shape.ProjectedMediaSurface. Bypasses the surface-skin stage that DrawableSurfaceQuad uses for the homography path: there's no intermediate skin texture and no per-tile rasterise-then-resample, just a per-tile direct render of the source texture against the terrain triangulation with a per-fragment image projection. Trade-off: per-shape, per-tile draw call (no batching like DrawableSurfaceQuad's scratch list does), but correct projection on relief.

Runs the cascaded shadow map depth pass for the directional sun-shadow pipeline. Enqueued each frame by earth.worldwind.layer.shadow.ShadowLayer in the BACKGROUND drawable group, so its draw runs before any receiver shape / terrain draw and the cascade depth textures are populated by the time receivers sample them (DrawContext.shadowCascadeFramebuffer).

Renders the active sightline: a depth pass that rasterises the scene into the shared depth-only cube map (DrawContext.sightlineDepthCubeTexture) from the sightline's point of view, and an overlay pass that tints terrain visible/occluded by PCF-comparing each fragment against that cube (see earth.worldwind.layer.sightline.SightlineReceiverGlsl).

Single-pass GPU dispatch for earth.worldwind.shape.ViewshedSightline's visibility kernel. Uploads the elevation grid as R32F, runs the per-fragment Amanatides–Woo walk via ViewshedKernelShaderProgram into an externally-owned RGBA8 outputTexture, and signals completion via callback. The texture lives on the GPU and is sampled directly by SurfaceImage on its own draw — no CPU readback, no PBO, no fence.

Ground surface that can receive draped surface-shape textures (e.g. a 3D-Tile mesh). After a surface-shape drawable composites its per-terrain-tile texture onto the terrain, it re-draws registered overlay surfaces through SurfaceOverlayProgram, which projects the same texture with per-fragment sector-local UVs — the raster-overlay draping pattern.

Marker for a Drawable that wishes to participate as an occluder in DrawableSightline's depth pass.

A composited surface-shape RTT texture plus the shape-set content hash it was rendered for, so a terrain tile can keep reusing its last complete texture until its shapes change AND finish uploading.

Bit 7 of the stencil byte = "covered by a ground-group drawable" (e.g. 3D-Tile mesh). Written by ground-group draws that participate in terrain composition, tested by BasicDrawableTerrain.drawTriangles so terrain skips pixels claimed by mesh content. Bits 0..6 stay free for subsystem-specific use (e.g. Cesium skip-LoD subtree ids).