feat: render programmable 3d scenes cameras and picking

src/runtime/api/guide.rs

@@ -142,9 +142,11 @@ ScrollBlock.axis is a managed visual attribute: "both" (default), "vertical" or
 
 ContainerBlock.mainAlign accepts "start" (default), "center", "end" or "space-between". Native arrangement uses allocated Bounds after padding/minimum gap, distributes positive remaining main-axis space and keeps child sizes unchanged. Overflow keeps start placement. Explicit source arrange placements remain authoritative; this is alignment, not flex sizing.
 
-Finite box layout: Overlay(padding, gap, children...) stacks children (gap is unused); mainAlign aligns horizontally and crossAlign vertically. Row/Column crossAlign accepts "start", "center", "end" or "stretch". Block.alignSelf defaults to "auto" and can override crossAlign per occurrence. marginTop/Right/Bottom/Left participate in measurement, alignment and flex allocation, without collapsing. paddingTop/Right/Bottom/Left override a side of the container padding; "auto" restores its fallback. borderTop/Right/Bottom/Left reserve inner border space; borderColor controls native border paint. Source paint overrides remain authoritative. boxWidth/boxHeight accept "auto", a nonnegative border-box dimension, or "fill" (finite parent required). Main-axis fill shares remaining space with weight 1 unless flex is set; minWidth/minHeight/maxWidth/maxHeight bound each dimension. Stretch changes only auto cross-axis dimensions. overflow is "visible" or "clip"; clipping affects descendant paint and hits. ScrollBlock handles scrolling independently of its content layout. See examples/box-layout.endor and docs/scene-architecture.md. Independent 2D scenes are described below; Scene3D/Viewport3D are still pending. Page.mode remains a compatibility API.
+Finite box layout: Overlay(padding, gap, children...) stacks children (gap is unused); mainAlign aligns horizontally and crossAlign vertically. Row/Column crossAlign accepts "start", "center", "end" or "stretch". Block.alignSelf defaults to "auto" and can override crossAlign per occurrence. marginTop/Right/Bottom/Left participate in measurement, alignment and flex allocation, without collapsing. paddingTop/Right/Bottom/Left override a side of the container padding; "auto" restores its fallback. borderTop/Right/Bottom/Left reserve inner border space; borderColor controls native border paint. Source paint overrides remain authoritative. boxWidth/boxHeight accept "auto", a nonnegative border-box dimension, or "fill" (finite parent required). Main-axis fill shares remaining space with weight 1 unless flex is set; minWidth/minHeight/maxWidth/maxHeight bound each dimension. Stretch changes only auto cross-axis dimensions. overflow is "visible" or "clip"; clipping affects descendant paint and hits. ScrollBlock handles scrolling independently of its content layout. See examples/box-layout.endor and docs/scene-architecture.md. Independent 2D scenes are described below; 3D support is described below. Page.mode remains a compatibility API.
 
-Independent 2D scenes are now implemented: Scene2D(children...) stores world content at child x/y; CanvasViewport(width,height,scene) is a finite layout box with its own Camera2D(). Camera2D(x=0,y=0,zoom=1) fields are ordinary managed attributes; zoom is 0.01–100. Sharing a scene does not share its camera; assigning second.camera=first.camera does. Scene content may contain layout containers and nested finite viewports; Overlay siblings stay fixed. Mount.fitView() fits finite direct scene-child bounds using that occurrence's allocation. Native wheel/pinch/space or middle drag targets the innermost viewport; drag retains its initial target. viewport-pan/viewport-zoom carry the viewport Mount and current frame identities, with signed logical page coordinates. Pan delta is measured before the viewport projection; zoom delta is [factor,0] with an in-content pointer anchor. Worker validation rejects stale/invalid input before invoking the VM. Draw and hit transforms compose consistently while layout geometry and measurement caches remain in world coordinates. ScrollView is a nominal ScrollBlock subtype. The default page uses these APIs; old Page.mode/panX/panY/zoom remain for compatibility. Scene3D/Viewport3D are still pending. See examples/scene-viewports.endor.
+Independent 2D scenes are now implemented: Scene2D(children...) stores world content at child x/y; CanvasViewport(width,height,scene) is a finite layout box with its own Camera2D(). Camera2D(x=0,y=0,zoom=1) fields are ordinary managed attributes; zoom is 0.01–100. Sharing a scene does not share its camera; assigning second.camera=first.camera does. Scene content may contain layout containers and nested finite viewports; Overlay siblings stay fixed. Mount.fitView() fits finite direct scene-child bounds using that occurrence's allocation. Native wheel/pinch/space or middle drag targets the innermost viewport; drag retains its initial target. viewport-pan/viewport-zoom carry the viewport Mount and current frame identities, with signed logical page coordinates. Pan delta is measured before the viewport projection; zoom delta is [factor,0] with an in-content pointer anchor. Worker validation rejects stale/invalid input before invoking the VM. Draw and hit transforms compose consistently while layout geometry and measurement caches remain in world coordinates. ScrollView is a nominal ScrollBlock subtype. The default page uses these APIs; old Page.mode/panX/panY/zoom remain for compatibility. 3D support is described below. See examples/scene-viewports.endor.
+
+3D basics are now implemented: Scene3D/Group3D, Box3D, immutable Geometry3D made from Vec3/Triangle3D ObjectLists, Mesh3D, DirectionalLight, and finite Viewport3D. PerspectiveCamera and OrthographicCamera expose x/y/z, targetX/Y/Z, upX/Y/Z, near/far, fov or height; viewport aspect is derived separately. New viewports have independent cameras and OrbitController; explicit camera assignment shares a camera. A controller can be replaced with an Endor object defining update(camera,gesture), or disabled by assigning "none". Native scene-orbit/scene-pan/scene-zoom events carry viewport Mount/frame identities. Mesh/group translate and rotate use native arithmetic; camera.translate moves position and target. This avoids the fixed Aster version's unsupported numeric arithmetic expressions. Mount.pick3D(x,y) returns nullable RayHit3D with managed mesh and world intersection data; pointer click Event.hit carries the same result. Rendering uses frustum clipping and a depth buffer in a bounded cached surface. World-space interactive UI panels and complete nesting budgets remain pending. See examples/scene3d.endor and docs/scene-architecture.md.
 
 Block.flex is a nonnegative weight (default 0). Native containers reserve fixed measured children, padding and gaps, then share remaining allocated main-axis space between positive weights with zero basis. Actual child allocation feeds remeasurement. It does not request parent expansion. Further controls are described below.