Add fieldWarp and radialWarp

Author: micycle1

CHANGELOG.md

@@ -9,6 +9,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 - `polygonizeLines()` to `PGS_Processing`. Computes the polygonal faces formed by a set of intersecting line segments.
 - Additional method signature for `PGS_Processing.generateRandomGridPoints()` that accepts a random seed.
+- `fieldWarp()` to `PGS_Morphology`. Warps a shape by displacing vertices according to a 2D noise vector field.
+- `radialWarp()` to `PGS_Morphology`. Warps a shape by displacing vertices along a line between each vertex and the shape centroid.
 - Expand PGS_Conversion to support conversion between:
  - `TRIANGLES` PShape➜JTS `MultiPolygon`
  - `QUADS` PShape➜JTS `MultiPolygon`

README.md

@@ -244,6 +244,17 @@ Much of the functionality (but by no means all) is demonstrated below:
  <td valign="top" ><img src="resources/morphology/round2.gif"></td>
   </tr>
 
+  <tr>
+ <td align="center" valign="center" colspan="2"><b>Radial Warp</td>
+ <td align="center" valign="center" colspan="2"><b>Field Warp</td>
+  </tr>
+  <tr>
+ <td valign="top" width="25%"><img src="resources/morphology/radialWarp1.gif"></td>
+ <td valign="top" width="25%"><img src="resources/morphology/radialWarp2.gif"></td>
+ <td valign="top" width="25%"><img src="resources/morphology/fieldWarp.gif"></td>
+ <td valign="top" width="25%"><img src="resources/morphology/fieldWarp2.gif"></td>
+  </tr>
+
   <tr>
  <td align="center" valign="center"><b>Simplification</td>
  <td align="center" valign="center" colspan="2"><b>Chaikin Cutting</td>

pom.xml

@@ -136,9 +136,9 @@
 			<version>24.4</version>
 		</dependency>
 		<dependency>
-			<groupId>org.locationtech.jts</groupId>
-			<artifactId>jts-core</artifactId>
-			<version>1.18.1</version>
+			<groupId>com.github.locationtech</groupId>
+			<artifactId>jts</artifactId>
+			<version>6cf20ff392</version>
 		</dependency>
 		<dependency>
 			<groupId>com.github.twak</groupId>
@@ -153,7 +153,7 @@
 		<dependency>
 			<groupId>org.tinfour</groupId>
 			<artifactId>TinfourCore</artifactId>
-			<version>2.1.6</version>
+			<version>2.1.7</version>
 		</dependency>
 		<dependency>
 			<groupId>io.github.earcut4j</groupId>
@@ -197,6 +197,11 @@
 			<artifactId>balaban-intersection</artifactId>
 			<version>1.0.0</version>
 		</dependency>
+		<dependency>
+			<groupId>com.github.micycle1</groupId>
+			<artifactId>UniformNoise</artifactId>
+			<version>1.1</version>
+		</dependency>
 	</dependencies>
 
 </project>

resources/morphology/fieldWarp.gif

@@ -3,10 +3,15 @@
 import static micycle.pgs.PGS_Conversion.fromPShape;
 import static micycle.pgs.PGS_Conversion.toPShape;
 
+import java.util.List;
+
 import org.geotools.geometry.jts.JTS;
+import org.locationtech.jts.densify.Densifier;
 import org.locationtech.jts.geom.Geometry;
 import org.locationtech.jts.geom.LineString;
+import org.locationtech.jts.geom.Point;
 import org.locationtech.jts.geom.Polygon;
+import org.locationtech.jts.geom.util.GeometryFixer;
 import org.locationtech.jts.simplify.DouglasPeuckerSimplifier;
 import org.locationtech.jts.simplify.TopologyPreservingSimplifier;
 import org.locationtech.jts.simplify.VWSimplifier;
@@ -17,7 +22,9 @@
 import micycle.pgs.utility.GaussianLineSmoothing;
 import processing.core.PConstants;
 import processing.core.PShape;
+import processing.core.PVector;
 import uk.osgb.algorithm.minkowski_sum.Minkowski_Sum;
+import micycle.uniformnoise.UniformNoise;
 
 /**
  * Methods that affect the geometry or topology of shapes.
@@ -214,4 +221,133 @@ public static PShape chaikinCut(PShape shape, double ratio, int iterations) {
  return cut;
 	}
 
+ /**
+	 * Warps/perturbs a shape by displacing vertices along a line between each
+	 * vertex and the shape centroid.
+	 * 
+	 * <p>
+	 * Inputs may be densified before warping.
+	 * 
+	 * @param shape      a polygonal shape
+	 * @param magnitude  magnitude of the displacement. The value defines the
+	 *                   maximum euclidean displacement of a vertex compared to the
+	 *                   shape centroid
+	 * @param warpOffset offset angle that determines at which angle to begin the
+	 *                   displacement.
+	 * @param densify    whether to densify the shape (using distance=1) before
+	 *                   warping. When true, shapes with long edges will undergo
+	 *                   warping along the whole edge (rather than only at the
+	 *                   original vertices).
+	 * @return
+	 */
+ public static PShape radialWarp(PShape shape, double magnitude, double warpOffset, boolean densify) {
+ Geometry g = fromPShape(shape);
+ if (!g.getGeometryType().equals(Geometry.TYPENAME_POLYGON)) {
+ System.err.println("radialWarp() expects (single) polygon input. The geometry resolved to a " + g.getGeometryType());
+ return shape;
+		}
+
+ final Point point = g.getCentroid();
+ final PVector c = new PVector((float) point.getX(), (float) point.getY());
+
+ final List<PVector> coords;
+
+ if (densify) {
+ final Densifier d = new Densifier(fromPShape(shape));
+ d.setDistanceTolerance(1);
+ d.setValidate(false);
+ coords = PGS_Conversion.toPVector(toPShape(d.getResultGeometry()));
+		} else {
+ coords = PGS_Conversion.toPVector(shape);
+		}
+
+ final UniformNoise noise = new UniformNoise(1337);
+ coords.forEach(coord -> {
+ PVector heading = PVector.sub(coord, c); // vector from center to each vertex
+ final double angle = heading.heading() + warpOffset;
+ float perturbation = noise.uniformNoise(Math.cos(angle), Math.sin(angle));
+ perturbation -= 0.5f; // [0...1] -> [-0.5...0.5]
+ perturbation *= magnitude * 2;
+ coord.add(heading.normalize().mult(perturbation)); // add perturbation to vertex
+		});
+ return PGS_Conversion.fromPVector(coords);
+	}
+
+ /**
+	 * Warps/perturbs a shape by displacing vertices according to a 2D noise vector
+	 * field.
+	 * 
+	 * <p>
+	 * Inputs may be densified before warping.
+	 * 
+	 * @param shape      a polygonal shape
+	 * @param magnitude  magnitude of the displacement (acting as noise value
+	 *                   multiplier). The value defines the maximum displacement of
+	 *                   a vertex in the both x and y axes.
+	 * @param noiseScale the scale of the 2D noise vector field. This affects how of
+	 *                   the coarseness of warping. Smaller values (~0.2) lead to
+	 *                   more fine warping (at edges), whereas larger values (~2)
+	 *                   affect the shape geometry at a larger scale.
+	 * @param densify    whether to densify the shape (using distance=1) before
+	 *                   warping. When true, shapes with long edges will undergo
+	 *                   warping along the whole edge (rather than only at the
+	 *                   original vertices).
+	 * @return
+	 * @see #fieldWarp(PShape, double, double, double, boolean, int)
+	 */
+ public static PShape fieldWarp(PShape shape, double magnitude, double noiseScale, boolean densify) {
+ return fieldWarp(shape, magnitude, noiseScale, 0, densify, 1337);
+	}
+
+ /**
+	 * Warps/perturbs a shape by displacing vertices according to a 2D noise vector
+	 * field.
+	 * 
+	 * <p>
+	 * Inputs may be densified before warping.
+	 * 
+	 * @param shape      a polygonal shape
+	 * @param magnitude  magnitude of the displacement (acting as noise value
+	 *                   multiplier). The value defines the maximum displacement of
+	 *                   a vertex in the both x and y axes.
+	 * @param noiseScale the scale of the 2D noise vector field. This affects how of
+	 *                   the coarseness of warping. Smaller values (~0.2) lead to
+	 *                   more fine warping (at edges), whereas larger values (~2)
+	 *                   affect the shape geometry at a larger scale.
+	 * @param time       used to offset the underlying noise field and hence animate
+	 *                   the warping over time
+	 * @param densify    whether to densify the shape (using distance=1) before
+	 *                   warping. When true, shapes with long edges will undergo
+	 *                   warping along the whole edge (rather than only at the
+	 *                   original vertices).
+	 * @param noiseSeed  a seed to pass to the underlying noise generator
+	 * 
+	 * @see #fieldWarp(PShape, double, double, boolean)
+	 * @return
+	 */
+ public static PShape fieldWarp(PShape shape, double magnitude, double noiseScale, double time, boolean densify, int noiseSeed) {
+ float scale = (float) noiseScale * 500f;
+ final List<PVector> coords;
+
+ if (densify) {
+ final Densifier d = new Densifier(fromPShape(shape));
+ d.setDistanceTolerance(1);
+ d.setValidate(false);
+ coords = PGS_Conversion.toPVector(toPShape(d.getResultGeometry()));
+		} else {
+ coords = PGS_Conversion.toPVector(shape);
+		}
+
+ final UniformNoise noise = new UniformNoise(noiseSeed);
+
+ coords.forEach(coord -> {
+//			float dx = noise.uniformNoise(coord.x / scale, coord.y / scale, time) - 0.5f;
+ float dx = noise.uniformNoise(coord.x / scale, coord.y / scale + time) - 0.5f;
+//			float dy = noise.uniformNoise(coord.x / scale, coord.y / scale, 100 + time) - 0.5f;
+ float dy = noise.uniformNoise(coord.x / scale + (101 + time), coord.y / scale + (101 + time)) - 0.5f;
+ coord.add(dx * (float) magnitude * 2, dy * (float) magnitude * 2);
+		});
+ return toPShape(GeometryFixer.fix(fromPShape(PGS_Conversion.fromPVector(coords))));
+	}
+
 }