Package eu.svjatoslav.sixth.e3d.renderer.raster.shapes.composite

Class BspCompositeShape

java.lang.Object

eu.svjatoslav.sixth.e3d.renderer.raster.shapes.AbstractShape

eu.svjatoslav.sixth.e3d.renderer.raster.shapes.composite.base.AbstractCompositeShape

eu.svjatoslav.sixth.e3d.renderer.raster.shapes.composite.BspCompositeShape

public class BspCompositeShape
extends AbstractCompositeShape

Composite shape whose polygons are ordered by a Binary Space Partitioning tree instead of the global average-Z sort.

Why: the painter's algorithm sorts shapes by a single average-Z key. When two polygons' depth ranges overlap — a floor tile extending under a piece of furniture, a wall seen through a doorway — no single key can order them correctly and the farther polygon visibly overdraws the nearer one. A BSP tree decides order by plane tests against the viewer position, which is exact for any geometry that does not interpenetrate, and becomes exact for interpenetrating geometry too because the build splits every polygon that straddles a partition plane.

Compile model: the polygons you add (directly or inside nested composites) remain the editable source of truth. When the render list is (re)built — after every structural edit — they are fan-triangulated and compiled into BSP fragments. The fragments are what actually renders. Rebuild is automatic via the normal cache-invalidation path.

How ordering works: every frame the tree is traversed back-to-front from the camera position and each fragment receives a per-slot rank (setBspRank). The aggregator's sort comparator orders two ranked shapes by rank; pairs where either shape has no rank fall back to average Z. Consequence: put ALL interpenetrating static geometry into the same BSP composite; shapes outside it (markers, lines, overlays) still sort by Z exactly as before.

Limitations:

• Nested composites are flattened at build time assuming identity transforms (vertices are used in the composite's local space).
• Split fragments lose the backface-culling flag; the correct painter order makes this cosmetically irrelevant, at a small overdraw cost.
• Frustum culling applies to this composite as a whole; nested composites are no longer culled individually.

See Also:

• the underlying tree (shared with CSG)
• the base composite

Field Summary

Fields inherited from class eu.svjatoslav.sixth.e3d.renderer.raster.shapes.AbstractShape

cachedBoundingBox, mouseInteractionController

Constructor Summary

Constructors

Constructor	Description
BspCompositeShape()

Method Summary

Modifier and Type	Method	Description
boolean	isLightmappingEnabled()	Returns whether lightmapping is enabled.
protected List<AbstractShape>	postprocessRenderList(List<AbstractShape> renderList)	Compiles the render list into BSP fragments: triangulates every solid polygon, flattens nested composites, builds the splitting BSP tree, and returns the resulting fragments plus all non-polygon shapes (which render through the normal Z-sorted path).
void	setLightmappingEnabled(boolean enabled)	Enables or disables lightmapping.
void	setLightmapUnitsPerTexel(double unitsPerTexel)	Sets the lightmap resolution.
void	transform(TransformStack transformPipe, RenderAggregator aggregator, RenderingContext context)	Assigns per-slot painter ranks by traversing the BSP tree back-to-front from the viewer position.

Methods inherited from class eu.svjatoslav.sixth.e3d.renderer.raster.shapes.composite.base.AbstractCompositeShape

addShape, addShape, beforeTransformHook, collectRenderTriangles, extractSolidPolygons, getBoundingBox, getGlobalRenderListVersion, getGroup, getLocation, getSubShapesRegistry, getTransform, getTransformWeight, getViewSpaceTracker, hideGroup, intersect, removeGroup, setBackfaceCulling, setCacheNeedsRebuild, setColor, setGroupForUngrouped, setMouseInteractionController, setRootComposite, setShadingEnabled, setTransform, showGroup, subtract, union

Methods inherited from class eu.svjatoslav.sixth.e3d.renderer.raster.shapes.AbstractShape

invalidateBounds

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

BspCompositeShape

public BspCompositeShape()

Method Details

postprocessRenderList

protected List<AbstractShape> postprocessRenderList(List<AbstractShape> renderList)

Compiles the render list into BSP fragments: triangulates every solid polygon, flattens nested composites, builds the splitting BSP tree, and returns the resulting fragments plus all non-polygon shapes (which render through the normal Z-sorted path).

Overrides:

postprocessRenderList in class AbstractCompositeShape

Parameters:

renderList - the render list built from the shape registry

Returns:

BSP fragments + non-polygon passthrough shapes

setLightmappingEnabled

public void setLightmappingEnabled(boolean enabled)

Enables or disables lightmapping. When enabled, BSP fragments render as LightmappedTriangles with per-fragment lightmap textures filled by the global illumination system. Rebuilds the render list (and BSP) on the next frame.

Parameters:

enabled - true to render fragments lightmapped

isLightmappingEnabled

public boolean isLightmappingEnabled()

Returns whether lightmapping is enabled.

Returns:

true when fragments render as lightmapped triangles

setLightmapUnitsPerTexel

public void setLightmapUnitsPerTexel(double unitsPerTexel)

Sets the lightmap resolution. Default 12 world units per texel: a 100-unit wall cell gets an 8x8 lightmap. Halving the units quadruples the GI tracing work; finer texels are the ONLY way to smoother shadow edges (there is no upsampling). Takes effect on the next render list rebuild.

Parameters:

unitsPerTexel - world units per lightmap texel

transform

public void transform(TransformStack transformPipe,
 RenderAggregator aggregator,
 RenderingContext context)

Assigns per-slot painter ranks by traversing the BSP tree back-to-front from the viewer position. Runs after the normal transform; ranks are pure functions of viewpoint and tree, so this is safe while parallel transform chunk tasks are still running.

Overrides:

transform in class AbstractCompositeShape

Parameters:

transformPipe - the current stack of transforms (world-to-camera transformations)

aggregator - collects transformed shapes for depth-sorted rendering

context - provides frame dimensions, graphics context, and frame metadata