TEXTURE_UNITS

Texture units used for imagery compositing: unit 0 plus 5..7, within the ES2 minimum of 8 units. Units 1..4 hold the frame-wide shadow cascade binds shared by every receiver program and are never touched (see earth.worldwind.layer.shadow.applyShadowReceiverUniforms); unit 5's cube-map binding target is used by the sightline pipeline, which does not conflict with a 2D binding on the same unit. A wider table was measured on Mali-G72 and changed nothing: composite cost is proportional to overlapping-texture count, not pass count.