[orx-quadtree] add quadtree module (#174)

orx-quadtree/README.md

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+# orx-quadtree
+
+An extension for creating a [Quadtree](https://en.wikipedia.org/wiki/Quadtree) for points. A quadtree is a spatial
+partioning tree structure meant to provide fast spatial queries such as nearest points within a range.
+
+## Example
+
+```kotlin
+val box = Rectangle.fromCenter(Vector2(400.0), 750.0)
+
+val quadTree = Quadtree<Vector2>(box) { it }
+
+for (point in points) {
+    quadTree.insert(point)
+}
+
+val nearestQuery = quadTree.nearest(points[4], 20.0)
+```
+
+### Author
+
+Ricardo Matias / [@ricardomatias](https://github.com/ricardomatias)

orx-quadtree/build.gradle

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+sourceSets {
+    demo {
+        java {
+            srcDirs = ["src/demo/kotlin"]
+            compileClasspath += main.getCompileClasspath()
+            runtimeClasspath += main.getRuntimeClasspath()
+        }
+    }
+}
+
+dependencies {
+    demoImplementation("org.openrndr:openrndr-core:$openrndrVersion")
+    demoImplementation("org.openrndr:openrndr-extensions:$openrndrVersion")
+    demoImplementation(project(":orx-noise"))
+    demoRuntimeOnly("org.openrndr:openrndr-gl3:$openrndrVersion")
+    demoRuntimeOnly("org.openrndr:openrndr-gl3-natives-$openrndrOS:$openrndrVersion")
+
+    demoImplementation(sourceSets.getByName("main").output)
+}

orx-quadtree/src/demo/kotlin/DemoQuadTree01.kt

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+import org.openrndr.application
+import org.openrndr.color.ColorRGBa
+import org.openrndr.draw.rectangleBatch
+import org.openrndr.extensions.SingleScreenshot
+import org.openrndr.extra.noise.Random
+import org.openrndr.extra.noise.gaussian
+import org.openrndr.math.Vector2
+import org.openrndr.shape.Rectangle
+import quadtree.Quadtree
+
+fun main() {
+    application {
+        configure {
+            width = 800
+            height = 800
+            title = "QuadTree"
+        }
+        program {
+            if (System.getProperty("takeScreenshot") == "true") {
+                extend(SingleScreenshot()) {
+                    this.outputFile = System.getProperty("screenshotPath")
+                }
+            }
+
+            val box = Rectangle.fromCenter(Vector2(400.0), 750.0)
+
+            val points = (0 until 1_000).map {
+                Vector2.gaussian(box.center, Vector2(95.0), Random.rnd)
+            }
+
+            val quadTree = Quadtree<Vector2>(box) { it }
+
+            for (point in points) {
+                quadTree.insert(point)
+            }
+
+            val batch = drawer.rectangleBatch {
+                this.fill = null
+                this.stroke = ColorRGBa.GRAY
+                this.strokeWeight = 0.5
+                quadTree.batch(this)
+            }
+
+            extend {
+                drawer.clear(ColorRGBa.BLACK)
+
+                drawer.rectangles(batch)
+
+                drawer.fill = ColorRGBa.PINK.opacify(0.7)
+                drawer.stroke = null
+                drawer.circles(points, 5.0)
+            }
+        }
+    }
+}

orx-quadtree/src/demo/kotlin/DemoQuadTree02.kt

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+import org.openrndr.application
+import org.openrndr.color.ColorRGBa
+import org.openrndr.draw.rectangleBatch
+import org.openrndr.extensions.SingleScreenshot
+import org.openrndr.extra.noise.Random
+import org.openrndr.extra.noise.gaussian
+import org.openrndr.math.Vector2
+import org.openrndr.shape.Rectangle
+import quadtree.Quadtree
+
+fun main() {
+    application {
+        configure {
+            width = 800
+            height = 800
+            title = "QuadTree"
+        }
+        program {
+            if (System.getProperty("takeScreenshot") == "true") {
+                extend(SingleScreenshot()) {
+                    this.outputFile = System.getProperty("screenshotPath")
+                }
+            }
+
+            val box = Rectangle.fromCenter(Vector2(400.0), 750.0)
+
+            val points = (0 until 100).map {
+                Vector2.gaussian(box.center, Vector2(95.0), Random.rnd)
+            }
+
+            val quadTree = Quadtree<Vector2>(box) { it }
+
+            for (point in points) {
+                quadTree.insert(point)
+            }
+
+            val selected = points[3]
+            val radius = 40.0
+
+            val nearestQuery = quadTree.nearest(selected, radius)
+
+            val batch = drawer.rectangleBatch {
+                this.fill = null
+                this.stroke = ColorRGBa.GRAY
+                this.strokeWeight = 0.5
+                quadTree.batch(this)
+            }
+
+            extend {
+                drawer.clear(ColorRGBa.BLACK)
+
+                drawer.rectangles(batch)
+
+                drawer.fill = ColorRGBa.PINK.opacify(0.7)
+                drawer.stroke = null
+                drawer.circles(points, 5.0)
+
+                nearestQuery?.let { (nearest, neighbours, nodes) ->
+                    drawer.stroke = null
+                    drawer.fill = ColorRGBa.YELLOW.opacify(0.2)
+
+                    for (node in nodes) {
+                        node.draw(drawer)
+                    }
+
+                    drawer.fill = ColorRGBa.GREEN.opacify(0.7)
+                    drawer.circles(neighbours, 5.0)
+
+                    drawer.fill = ColorRGBa.RED.opacify(0.9)
+                    drawer.circle(nearest, 5.0)
+
+                    drawer.fill = ColorRGBa.PINK
+                    drawer.circle(selected, 5.0)
+
+                    drawer.stroke = ColorRGBa.PINK
+                    drawer.fill = null
+                    drawer.circle(selected, radius)
+                }
+            }
+        }
+    }
+}