Add flag to toggle using the quadtree for object culling

redhorizon-engine/source/nz/net/ultraq/redhorizon/engine/graphics/pipeline/RenderPipeline.groovy

@@ -171,6 +171,7 @@ class RenderPipeline implements AutoCloseable {
 	private class SceneRenderPass implements RenderPass<Void> {
 
 		final Framebuffer framebuffer
+		private final boolean traverseScene = true
 		private final FrustumIntersection frustumIntersection = new FrustumIntersection()
 
 		Scene scene
@@ -201,17 +202,29 @@ class RenderPipeline implements AutoCloseable {
 					// Cull the list of renderable items to those just visible in the scene
 					average('objectCulling', 1f, logger) { ->
 						visibleElements.clear()
-						frustumIntersection.set(camera.viewProjection, false)
-						scene.traverse { Node element ->
-							if (element.isVisible(frustumIntersection)) {
+
+						if (traverseScene) {
+							frustumIntersection.set(camera.viewProjection, false)
+							scene.traverse { Node element ->
+								if (element.isVisible(frustumIntersection)) {
+									if (element instanceof GraphicsElement) {
+										element.update()
+										element.script?.update()
+										visibleElements << element
+									}
+									return true
+								}
+								return false
+							}
+						}
+						else {
+							scene.quadTree.query(camera.viewBox).each { Node element ->
 								if (element instanceof GraphicsElement) {
 									element.update()
 									element.script?.update()
 									visibleElements << element
 								}
-								return true
 							}
-							return false
 						}
 					}
 

redhorizon-engine/source/nz/net/ultraq/redhorizon/engine/scenegraph/nodes/Camera.groovy

@@ -24,6 +24,7 @@ import nz.net.ultraq.redhorizon.engine.scenegraph.Scene
 
 import org.joml.Matrix4f
 import org.joml.Vector3f
+import org.joml.primitives.Rectanglef
 import org.slf4j.Logger
 import org.slf4j.LoggerFactory
 import static org.lwjgl.system.MemoryStack.stackPush
@@ -39,21 +40,21 @@ class Camera extends Node<Camera> {
 
 	private static final Logger logger = LoggerFactory.getLogger(Camera)
 
+	private final Rectanglef box
 	private final Matrix4f projection
 	private final Matrix4f view
 	private final Matrix4f viewTransform = new Matrix4f()
 	private final Matrix4f viewProjection = new Matrix4f()
 	private UniformBuffer viewProjectionBuffer
+	private final Rectanglef boxTransform = new Rectanglef()
 
 	/**
 	 * Constructor, build a camera to work with the given dimensions.
 	 */
 	Camera(Dimension size) {
 
-		projection = new Matrix4f().setOrtho2D(
-			-size.width() / 2, size.width() / 2,
-			-size.height() / 2, size.height() / 2
-		)
+		box = new Rectanglef(-size.width() / 2, -size.height() / 2, size.width() / 2, size.height() / 2)
+		projection = new Matrix4f().setOrtho2D(box.minX, box.maxX, box.minY, box.maxY)
 		logger.debug('Establishing an orthographic projection of {}x{}', size.width(), size.height())
 
 		view = new Matrix4f().setLookAt(
@@ -81,6 +82,16 @@ class Camera extends Node<Camera> {
 		return view.mulAffine(transform, viewTransform)
 	}
 
+	/**
+	 * Return a rectangle that represents the 2D area being viewed by this
+	 * orthographic projection camera.
+	 */
+	Rectanglef getViewBox() {
+
+		var position = getPosition()
+		return box.translate(position.x, position.y, boxTransform)
+	}
+
 	/**
 	 * Return a matrix that is the projection * view * local transform of this
 	 * camera.  Note that the returned matrix is a live value, so be sure to wrap

redhorizon-engine/source/nz/net/ultraq/redhorizon/engine/scenegraph/partioning/QuadTree.groovy

@@ -132,6 +132,22 @@ class QuadTree {
 		return quadrants.any { quadrant -> quadrant.add(node) }
 	}
 
+	/**
+	 * Return all nodes that are within the bounding box of {@code range}.
+	 */
+	List<Node> query(Rectanglef range, List<Node> results = new ArrayList<>()) {
+
+		if (area.intersectsRectangle(range)) {
+			if (children) {
+				results.addAll(children)
+			}
+			else if (quadrants) {
+				quadrants*.query(range, results)
+			}
+		}
+		return results
+	}
+
 	/**
 	 * Removes a node from this quadtree.  Nodes will attempt to rebalance
 	 * themselves if quadrants can also be removed.
@@ -148,7 +164,7 @@ class QuadTree {
 				children.remove(node)
 
 				// If all children removed, rebalance the parent node
-				if (!children && !parent.size()) {
+				if (!children && !parent?.size()) {
 					// TODO: There are probably some smarts we can do here, but for now
 					//       the only rebalancing we're doing is to collapse a node with
 					//       4 empty quadrants