SceneObjectCircle
Extends: SceneObjectBillboard
Draws a DrawableCircle. The fill is inherited, unmodified SceneObjectBillboard machinery (pinned-corners texture warp, tinting, temp-bitmap caching) blitting the renderer's shared circle resource (Renderer.getCircleResource(), built lazily on first use) - exactly like SceneObjectImage, just with a fixed texture instead of one supplied by the drawable. Only the outline differs from a plain Image: it's stroked as an N-gon inscribed in this object's own already-transformed canvasPoints quad (via the generic getOutlineCanvasPoints() hook), which is far cheaper than rasterizing the fill itself as a many-sided polygon and needs no new Renderer draw method.
Properties
drawable(DrawableCircle)
Constructor
new SceneObjectCircle(
name: string,
drawableObj: DrawableCircle,
): SceneObjectCircleParameters
name(string)drawableObj(DrawableCircle)
Instance Methods
getBoundingPoints(cameraObj: Camera): dynamic
A circle always has a real width/height, unlike SceneObjectPolygon/SceneObjectModel (see the comment on SceneObjectBillboard.computeBillboardWorldCorners()) - so this overrides the base SceneObject.getBoundingPoints() wrapper to always return the object's 4 world-space corners rather than the frustum check's single-point shortcut in screen-aligned draw modes.
Parameters
cameraObj(Camera)
Returns
dynamic— the object's 4 world-space corners
getRegionWithIdToDraw(
rendererObj: BGE.Renderer,
): BGE.RendererHelpers.RegionWithId
Every DrawableCircle/DrawableSphere instance shares the exact same region, so this fetches the renderer's own cached one (built once, on first use) rather than allocating a fresh roRegion here every single frame.
Parameters
rendererObj(BGE.Renderer)
Returns
BGE.RendererHelpers.RegionWithId
usesTempBitmap(drawMode: SceneObjectDrawMode): boolean
The base class only caches a temp bitmap for the oriented modes by default, because its own solid-mode fill (a flat drawPolygon, no texture) is cheap enough not to need it - see SceneObjectRectangle.usesTempBitmap, which overrides this same hook for its own reason (skipping the cache for an unfilled rectangle). A circle's solid fill is the same expensive pinned-corners texture warp the oriented modes use, so it needs the same reuse-across-frames caching too, or drawToCanvas's inherited solid branch (see below) would re-run that warp from scratch on every single frame with no caching at all.
Parameters
drawMode(SceneObjectDrawMode)
Returns
boolean
drawToCanvas(
rendererObj: BGE.Renderer,
drawMode: SceneObjectDrawMode,
): boolean
The base class's own wireFrame branch draws the plain 4-corner quad directly (a square) - correct for DrawableRectangle, whose fill genuinely is its own quad, but wrong for a circle. Routed through drawOutlineToCanvas()/getOutlineCanvasPoints() below instead (same pattern SceneObjectRectangle uses). solid mode needs no override here at all now that usesTempBitmap() opts it in above - drawToCanvas is only ever called for draw modes that don't use a temp bitmap, so the base class's solid branch is simply never reached for a circle; the inherited drawToTempBitmap already draws the right thing (getRegionWithIdToDraw's circular region, via drawPinnedCornersTo) and caches it exactly like oriented mode does.
Parameters
rendererObj(BGE.Renderer)drawMode(SceneObjectDrawMode)
Returns
boolean
getOutlineCanvasPoints(): dynamic
N points around the ellipse inscribed in this object's own transformed canvasPoints quad, computed from the quad's own corner vectors as the ellipse's basis rather than a fresh world-to-canvas transform pass - so this automatically gets the same foreshortening the quad itself has in oriented 3D draw modes.
No hasOutline() check here, matching the base class's own default implementation - that gating already happens at the "stroke on top of the fill" call site (performDraw), and a wireFrame draw mode (see drawToCanvas above) needs these points regardless of whether an outline color was ever set, the same way SceneObjectRectangle's wireFrame mode still strokes with the fill color when no outlineRGBA is set (see Drawable.getOutlineColorRGBA's fallback).
Returns
dynamic