[orx-force-2d] Add DemoGraphLayout01.kt

Author: edwinRNDR

orx-force-2d/build.gradle.kts

@@ -23,6 +23,7 @@ kotlin {
                 implementation(project(":orx-shapes"))
                 implementation(project(":orx-color"))
                 implementation(project(":orx-noise"))
+                implementation(project(":orx-kdtree"))
             }
         }
     }

orx-force-2d/src/jvmDemo/kotlin/DemoGraphLayout01.kt

@@ -0,0 +1,71 @@
+import kotlinx.coroutines.runBlocking
+import org.openrndr.application
+import org.openrndr.color.ColorRGBa
+import org.openrndr.extra.force2d.Body
+import org.openrndr.extra.force2d.ForceSimulation
+import org.openrndr.extra.force2d.Link
+import org.openrndr.extra.force2d.Node
+import org.openrndr.extra.force2d.linkLengthConstraint
+import org.openrndr.extra.force2d.nodeRepulseForce
+import org.openrndr.extra.force2d.rectangularBoundsConstraint
+import org.openrndr.extra.kdtree.kdTree
+import org.openrndr.extra.noise.scatter
+import org.openrndr.math.Vector2
+import org.openrndr.shape.LineSegment
+
+/**
+ * Demonstrates a simple force graph layout
+ */
+fun main() {
+    application {
+        configure {
+            width = 720
+            height = 720
+        }
+        program {
+            val pts = drawer.bounds.scatter(20.0)
+            val index = pts.mapIndexed { index, vector2 -> vector2 to index }.toMap()
+            val kd = pts.kdTree()
+
+            val nodes = pts.map {
+                Node(it, it, Vector2.ZERO, radius = 4.0)
+            }
+
+            val links = pts.flatMapIndexed { source, it ->
+                kd.findKNearest(it, 2).map {
+                    val idx = index.getValue(it)
+                    Link(source, idx)
+                }
+            }
+
+            val body = Body(nodes, links = links).apply {
+                linkLengthConstraint {
+                    compliance = 1E-1
+
+                }
+                nodeRepulseForce {
+                    searchRadius = 100.0
+                    strength = 10.0
+                }
+                rectangularBoundsConstraint {
+                    bounds = drawer.bounds.offsetEdges(-10.0)
+                }
+            }
+
+            val sim = ForceSimulation(mutableListOf(body))
+
+            extend {
+                runBlocking {
+                    sim.simulate(1.0 / 60.0, 10)
+                }
+
+                drawer.stroke = ColorRGBa.PINK
+                drawer.lineSegments(body.links.map {
+                    LineSegment(body.nodes[it.source].position, body.nodes[it.target].position)
+                })
+
+                drawer.circles(body.nodes.map { it.position }, 4.0)
+            }
+        }
+    }
+}