no-wrap option; pivoted exponential zoom

client/world/renderer.go

@@ -21,6 +21,10 @@ type RenderOptions struct {
 	Style  *RenderStyle
 	// Incremental controls incremental pan behavior. If nil, defaults are used.
 	Incremental *IncrementalPolicy
+	// DisableWrapScroll controls whether the world is treated as a torus (false)
+	// or as a bounded plane without wrap (true).
+	// Default is false.
+	DisableWrapScroll bool
 }
 
 var (
@@ -66,7 +70,7 @@ func (p RenderParams) CanvasHeightPx() int { return p.ViewportHeightPx + 2*p.Mar
 
 // CameraZoomFp converts the UI-facing zoom value into the package fixed-point form.
 func (p RenderParams) CameraZoomFp() (int, error) {
-	return cameraZoomToWorldFixed(p.CameraZoom)
+	return CameraZoomToWorldFixed(p.CameraZoom)
 }
 
 // ExpandedCanvasWorldRect returns the world-space half-open rectangle covered by
@@ -210,6 +214,8 @@ func (w *World) Render(drawer PrimitiveDrawer, params RenderParams) error {
 		layers = params.Options.Layers
 	}
 
+	allowWrap := params.Options == nil || !params.Options.DisableWrapScroll
+
 	// --- Try incremental path first when state is initialized and geometry matches ---
 	dxPx, dyPx, derr := w.ComputePanShiftPx(params)
 	if derr == nil {
@@ -246,13 +252,13 @@ func (w *World) Render(drawer PrimitiveDrawer, params RenderParams) error {
 						switch layer {
 						case RenderLayerPoints:
 							applyPointStyle(drawer, style)
-							drawPointsFromPlanWithRadius(drawer, catchUpPlan, w.W, w.H, style.PointRadiusPx)
+							drawPointsFromPlanWithRadius(drawer, catchUpPlan, w.W, w.H, style.PointRadiusPx, allowWrap)
 						case RenderLayerCircles:
 							applyCircleStyle(drawer, style)
-							drawCirclesFromPlan(drawer, catchUpPlan, w.W, w.H)
+							drawCirclesFromPlan(drawer, catchUpPlan, w.W, w.H, allowWrap)
 						case RenderLayerLines:
 							applyLineStyle(drawer, style)
-							drawLinesFromPlan(drawer, catchUpPlan, w.W, w.H)
+							drawLinesFromPlan(drawer, catchUpPlan, w.W, w.H, allowWrap)
 						default:
 							panic("render: unknown layer")
 						}
@@ -319,13 +325,13 @@ func (w *World) Render(drawer PrimitiveDrawer, params RenderParams) error {
 				switch layer {
 				case RenderLayerPoints:
 					applyPointStyle(drawer, style)
-					drawPointsFromPlanWithRadius(drawer, dirtyPlan, w.W, w.H, style.PointRadiusPx)
+					drawPointsFromPlanWithRadius(drawer, dirtyPlan, w.W, w.H, style.PointRadiusPx, allowWrap)
 				case RenderLayerCircles:
 					applyCircleStyle(drawer, style)
-					drawCirclesFromPlan(drawer, dirtyPlan, w.W, w.H)
+					drawCirclesFromPlan(drawer, dirtyPlan, w.W, w.H, allowWrap)
 				case RenderLayerLines:
 					applyLineStyle(drawer, style)
-					drawLinesFromPlan(drawer, dirtyPlan, w.W, w.H)
+					drawLinesFromPlan(drawer, dirtyPlan, w.W, w.H, allowWrap)
 				default:
 					panic("render: unknown layer")
 				}
@@ -352,13 +358,13 @@ func (w *World) Render(drawer PrimitiveDrawer, params RenderParams) error {
 		switch layer {
 		case RenderLayerPoints:
 			applyPointStyle(drawer, style)
-			drawPointsFromPlanWithRadius(drawer, plan, w.W, w.H, style.PointRadiusPx)
+			drawPointsFromPlanWithRadius(drawer, plan, w.W, w.H, style.PointRadiusPx, allowWrap)
 		case RenderLayerCircles:
 			applyCircleStyle(drawer, style)
-			drawCirclesFromPlan(drawer, plan, w.W, w.H)
+			drawCirclesFromPlan(drawer, plan, w.W, w.H, allowWrap)
 		case RenderLayerLines:
 			applyLineStyle(drawer, style)
-			drawLinesFromPlan(drawer, plan, w.W, w.H)
+			drawLinesFromPlan(drawer, plan, w.W, w.H, allowWrap)
 		default:
 			panic("render: unknown layer")
 		}
@@ -448,6 +454,27 @@ func tileWorldRect(rect Rect, worldWidthFp, worldHeightFp int) []WorldTile {
 	return out
 }
 
+// tileWorldRectNoWrap returns 0..1 tiles for a bounded world (no wrap).
+// It intersects the expanded unwrapped rect with the canonical world [0..W)x[0..H).
+func tileWorldRectNoWrap(worldRect Rect, W, H int) []WorldTile {
+	ix0 := max(worldRect.minX, 0)
+	iy0 := max(worldRect.minY, 0)
+	ix1 := min(worldRect.maxX, W)
+	iy1 := min(worldRect.maxY, H)
+
+	if ix0 >= ix1 || iy0 >= iy1 {
+		return nil
+	}
+
+	return []WorldTile{
+		{
+			Rect:    Rect{minX: ix0, maxX: ix1, minY: iy0, maxY: iy1},
+			OffsetX: 0,
+			OffsetY: 0,
+		},
+	}
+}
+
 func isEmptyRectPx(r RectPx) bool {
 	return r.W <= 0 || r.H <= 0
 }