jmonkeyengine/sdk/jme3-navmesh-gen/src/com/jme3/gde/nmgen/NavMeshGenerator.java

package com.jme3.gde.nmgen;

import com.jme3.export.InputCapsule;
import com.jme3.export.JmeExporter;
import com.jme3.export.JmeImporter;
import com.jme3.export.OutputCapsule;
import com.jme3.export.Savable;
import com.jme3.math.FastMath;
import com.jme3.math.Vector3f;
import com.jme3.scene.Mesh;
import com.jme3.scene.Node;
import com.jme3.scene.VertexBuffer.Type;
import com.jme3.scene.mesh.IndexBuffer;
import com.jme3.terrain.Terrain;
import java.io.IOException;
import java.nio.FloatBuffer;
import org.critterai.nmgen.IntermediateData;
import org.critterai.nmgen.NavmeshGenerator;
import org.critterai.nmgen.TriangleMesh;
import org.openide.DialogDisplayer;
import org.openide.NotifyDescriptor;

/**
 * Generates the navigation mesh using the org.critterai.nmgen.NavmeshGenerator class.
 * 
 */ 
public class NavMeshGenerator implements Savable {

    private org.critterai.nmgen.NavmeshGenerator nmgen;
    private float cellSize = 1f;
    private float cellHeight = 1.5f;
    private float minTraversableHeight = 7.5f;
    private float maxTraversableStep = 1f;
    private float maxTraversableSlope = 48.0f;
    private boolean clipLedges = false;
    private float traversableAreaBorderSize = 1.2f;
    private int smoothingThreshold = 2;
    private boolean useConservativeExpansion = true;
    private int minUnconnectedRegionSize = 3;
    private int mergeRegionSize = 10;
    private float maxEdgeLength = 0;
    private float edgeMaxDeviation = 2.4f;
    private int maxVertsPerPoly = 6;
    private float contourSampleDistance = 25;
    private float contourMaxDeviation = 25;
    private IntermediateData intermediateData;
    private int timeout = 10000;

    public NavMeshGenerator() {
    }

    public void printParams() {
        System.out.println("Cell Size: " + cellSize);
        System.out.println("Cell Height: " + cellHeight);
        System.out.println("Min Trav. Height: " + minTraversableHeight);
        System.out.println("Max Trav. Step: " + maxTraversableStep);
        System.out.println("Max Trav. Slope: " + maxTraversableSlope);
        System.out.println("Clip Ledges: " + clipLedges);
        System.out.println("Trav. Area Border Size: " + traversableAreaBorderSize);
        System.out.println("Smooth Thresh.: " + smoothingThreshold);
        System.out.println("Use Cons. Expansion: " + useConservativeExpansion);
        System.out.println("Min Unconn. Region Size: " + minUnconnectedRegionSize);
        System.out.println("Merge Region Size: " + mergeRegionSize);
        System.out.println("Max Edge Length: " + maxEdgeLength);
        System.out.println("Edge Max Dev.: " + edgeMaxDeviation);
        System.out.println("Max Verts/Poly: " + maxVertsPerPoly);
        System.out.println("Contour Sample Dist: " + contourSampleDistance);
        System.out.println("Contour Max Dev.: " + contourMaxDeviation);
    }

    public void setIntermediateData(IntermediateData data) {
        this.intermediateData = data;
    }

    public Mesh optimize(Mesh mesh) {
        nmgen = new NavmeshGenerator(cellSize, cellHeight, minTraversableHeight,
                maxTraversableStep, maxTraversableSlope,
                clipLedges, traversableAreaBorderSize,
                smoothingThreshold, useConservativeExpansion,
                minUnconnectedRegionSize, mergeRegionSize,
                maxEdgeLength, edgeMaxDeviation, maxVertsPerPoly,
                contourSampleDistance, contourMaxDeviation);

        FloatBuffer pb = mesh.getFloatBuffer(Type.Position);
        IndexBuffer ib = mesh.getIndexBuffer();

        // copy positions to float array
        float[] positions = new float[pb.capacity()];
        pb.clear();
        pb.get(positions);

        // generate int array of indices
        int[] indices = new int[ib.size()];
        for (int i = 0; i < indices.length; i++) {
            indices[i] = ib.get(i);
        }


        TriangleMesh triMesh = buildNavMesh(positions, indices, intermediateData);
        if (triMesh == null) {
            return null;
        }

        int[] indices2 = triMesh.indices;
        float[] positions2 = triMesh.vertices;

        Mesh mesh2 = new Mesh();
        mesh2.setBuffer(Type.Position, 3, positions2);
        mesh2.setBuffer(Type.Index, 3, indices2);
        mesh2.updateBound();
        mesh2.updateCounts();

        return mesh2;
    }

    private TriangleMesh buildNavMesh(float[] positions, int[] indices, IntermediateData intermediateData) {
        MeshBuildRunnable runnable = new MeshBuildRunnable(positions, indices, intermediateData);
        try {
            execute(runnable, timeout);
        } catch (TimeoutException ex) {
            DialogDisplayer.getDefault().notifyLater(new NotifyDescriptor.Message("NavMesh Generation timed out."));
        }
        return runnable.getTriMesh();
    }

    private static void execute(Thread task, long timeout) throws TimeoutException {
        task.start();
        try {
            task.join(timeout);
        } catch (InterruptedException e) {
        }
        if (task.isAlive()) {
//            task.interrupt();
            task.stop();
            throw new TimeoutException();
        }
    }

    private static void execute(Runnable task, long timeout) throws TimeoutException {
        Thread t = new Thread(task, "Timeout guard");
        t.setDaemon(true);
        execute(t, timeout);
    }

    public Mesh terrain2mesh(Terrain terr) {
        float[] heights = terr.getHeightMap();
        int length = heights.length;
        int side = (int) FastMath.sqrt(heights.length);
        float[] vertices = new float[length * 3];
        int[] indices = new int[(side - 1) * (side - 1) * 6];

        //Vector3f trans = ((Node) terr).getWorldTranslation().clone();
        Vector3f trans = new Vector3f(0,0,0);
        trans.x -= terr.getTerrainSize() / 2f;
        trans.z -= terr.getTerrainSize() / 2f;
        float offsetX = trans.x;
        float offsetZ = trans.z;

        // do vertices
        int i = 0;
        for (int z = 0; z < side; z++) {
            for (int x = 0; x < side; x++) {
                vertices[i++] = x + offsetX;
                vertices[i++] = heights[z * side + x];
                vertices[i++] = z + offsetZ;
            }
        }

        // do indexes
        i = 0;
        for (int z = 0; z < side - 1; z++) {
            for (int x = 0; x < side - 1; x++) {
                // triangle 1
                indices[i++] = z * side + x;
                indices[i++] = (z + 1) * side + x;
                indices[i++] = (z + 1) * side + x + 1;
                // triangle 2
                indices[i++] = z * side + x;
                indices[i++] = (z + 1) * side + x + 1;
                indices[i++] = z * side + x + 1;
            }
        }

        Mesh mesh2 = new Mesh();
        mesh2.setBuffer(Type.Position, 3, vertices);
        mesh2.setBuffer(Type.Index, 3, indices);
        mesh2.updateBound();
        mesh2.updateCounts();

        return mesh2;
    }

   
    /**
     * @return The height resolution used when sampling the source mesh. Value must be > 0.
     */
    public float getCellHeight() {
        return cellHeight;
    }

    /**
     * @param cellHeight - The height resolution used when sampling the source mesh. Value must be > 0.
     * Constraints: > 0
     */
    public void setCellHeight(float cellHeight) {
        this.cellHeight = cellHeight;
        if (this.cellHeight <= 0)
            this.cellHeight = 0.001f;
    }

    /**
     * @return The width and depth resolution used when sampling the the source mesh.
     */
    public float getCellSize() {
        return cellSize;
    }

    /**
     * @param cellSize - The width and depth resolution used when sampling the the source mesh.
     * Constraints: > 0
     */
    public void setCellSize(float cellSize) {
        this.cellSize = cellSize;
        if (this.cellSize <= 0)
            this.cellSize = 0.001f;
    }

    public boolean isClipLedges() {
        return clipLedges;
    }

    /**
     * Indicates whether ledges should be marked as unwalkable.
     * A ledge is a normally walkable voxel that has one or more accessible neighbors with a an un-steppable drop from voxel top to voxel top.
     * E.g. If an agent using the navmesh were to travel down from the ledge voxel to its neighbor voxel, it would result in the maximum traversable step distance being violated. The agent cannot legally "step down" from a ledge to its neighbor.
     */
    public void setClipLedges(boolean clipLedges) {
        this.clipLedges = clipLedges;
    }

    public float getContourMaxDeviation() {
        return contourMaxDeviation;
    }

    /**
     * The maximum distance the surface of the navmesh may deviate from the surface of the original geometry.
     * The accuracy of the algorithm which uses this value is impacted by the value of the contour sample distance argument.
     * The value of this argument has no meaning if the contour sample distance argument is set to zero.
     * Setting the value to zero is not recommended since it can result in a large increase in the number of triangles in the 
     * final navmesh at a high processing cost.
     * Constraints: >= 0
     */
    public void setContourMaxDeviation(float contourMaxDeviation) {
        this.contourMaxDeviation = contourMaxDeviation;
        if (this.contourMaxDeviation < 0)
            this.contourMaxDeviation = 0.0f;
    }

    public float getContourSampleDistance() {
        return contourSampleDistance;
    }

    /**
     * Sets the sampling distance to use when matching the navmesh to the surface of the original geometry.
     * Impacts how well the final mesh conforms to the original geometry's surface contour. Higher values result in 
     * a navmesh which conforms more closely to the original geometry's surface at the cost of a higher final triangle 
     * count and higher processing cost.
     * Setting this argument to zero will disable this functionality.
     * Constraints: >= 0
     */
    public void setContourSampleDistance(float contourSampleDistance) {
        this.contourSampleDistance = contourSampleDistance;
        if (this.contourSampleDistance < 0)
            this.contourSampleDistance = 0;
    }

    public float getEdgeMaxDeviation() {
        return edgeMaxDeviation;
    }

    /**
     * The maximum distance the edge of the navmesh may deviate from the source geometry.
     * Setting this lower will result in the navmesh edges following the geometry contour more 
     * accurately at the expense of an increased triangle count.
     * Setting the value to zero is not recommended since it can result in a large increase in 
     * the number of triangles in the final navmesh at a high processing cost.
     * Constraints: >= 0
     */
    public void setEdgeMaxDeviation(float edgeMaxDeviation) {
        this.edgeMaxDeviation = edgeMaxDeviation;
        if (this.edgeMaxDeviation < 0)
            this.edgeMaxDeviation= 0;
    }

    public float getMaxEdgeLength() {
        return maxEdgeLength;
    }

    /**
     * The maximum length of polygon edges that represent the border of the navmesh.
     * More vertices will be added to navmesh border edges if this value is exceeded for a 
     * particular edge. In certain cases this will reduce the number of thin, long triangles in the navmesh.
     * A value of zero will disable this feature.
     * Constraints: >= 0
     */
    public void setMaxEdgeLength(float maxEdgeLength) {
        this.maxEdgeLength = maxEdgeLength;
        if (this.maxEdgeLength < 0)
            this.maxEdgeLength= 0;
    }

    public float getMaxTraversableSlope() {
        return maxTraversableSlope;
    }

    /**
     * The maximum slope that is considered walkable. (Degrees)
     * Constraints: 0 <= value <= 85
     */
    public void setMaxTraversableSlope(float maxTraversableSlope) {
        this.maxTraversableSlope = maxTraversableSlope;
        if (this.maxTraversableSlope < 0)
            this.maxTraversableSlope = 0;
        if (this.maxTraversableSlope > 85)
            this.maxTraversableSlope = 85;
    }

    public float getMaxTraversableStep() {
        return maxTraversableStep;
    }

    /**
     * Represents the maximum ledge height that is considered to still be walkable.
     * Prevents minor deviations in height from improperly showing as obstructions. Permits detection of stair-like structures, curbs, etc.
     * Constraints: >= 0
     */
    public void setMaxTraversableStep(float maxTraversableStep) {
        this.maxTraversableStep = maxTraversableStep;
        if (this.maxTraversableStep < 0)
            this.maxTraversableStep = 0;
    }

    public int getMaxVertsPerPoly() {
        return maxVertsPerPoly;
    }

    /**
     * The maximum number of vertices per polygon for polygons generated during the voxel to polygon conversion stage.
     * Higher values reduce performance, but can also result in better formed triangles in the navmesh. A value of 
     * around 6 is generally adequate with diminishing returns for values higher than 6.
     * Contraints: >= 3
     */
    public void setMaxVertsPerPoly(int maxVertsPerPoly) {
        this.maxVertsPerPoly = maxVertsPerPoly;
        if (this.maxVertsPerPoly < 3)
            this.maxVertsPerPoly = 3;
    }

    public int getMergeRegionSize() {
        return mergeRegionSize;
    }

    /**
     * Any regions smaller than this size will, if possible, be merged with larger regions. (Voxels)
     * Helps reduce the number of unnecessarily small regions that can be formed. This is especially an issue in 
     * diagonal path regions where inherent faults in the region generation algorithm can result in unnecessarily 
     * small regions.
     * If a region cannot be legally merged with a neighbor region, then it will be left alone.
     * Constraints: >= 0
     */
    public void setMergeRegionSize(int mergeRegionSize) {
        this.mergeRegionSize = mergeRegionSize;
        if (this.mergeRegionSize < 0)
            this.mergeRegionSize = 0;
    }

    public float getMinTraversableHeight() {
        return minTraversableHeight;
    }

    /**
     * Represents the minimum floor to ceiling height that will still allow the floor area to be considered walkable.
     * Permits detection of overhangs in the geometry which make the geometry below become unwalkable.
     * Constraints: > 0
     */
    public void setMinTraversableHeight(float minTraversableHeight) {
        this.minTraversableHeight = minTraversableHeight;
        if (this.minTraversableHeight <= 0)
            this.minTraversableHeight = 0.001f;
    }

    public int getMinUnconnectedRegionSize() {
        return minUnconnectedRegionSize;
    }

    /**
     * The minimum region size for unconnected (island) regions. (Voxels)
     * Any generated regions that are not connected to any other region and are smaller than this size will be 
     * culled before final navmesh generation. I.e. No longer considered walkable.
     * Constraints: > 0
     */
    public void setMinUnconnectedRegionSize(int minUnconnectedRegionSize) {
        this.minUnconnectedRegionSize = minUnconnectedRegionSize;
        if (this.minUnconnectedRegionSize <= 0)
            this.minUnconnectedRegionSize = 1;
    }

    public NavmeshGenerator getNmgen() {
        return nmgen;
    }

    public void setNmgen(NavmeshGenerator nmgen) {
        this.nmgen = nmgen;
    }

    public int getSmoothingThreshold() {
        return smoothingThreshold;
    }

    /**
     * The amount of smoothing to be performed when generating the distance field.
     * This value impacts region formation and border detection. A higher value results in generally 
     * larger regions and larger border sizes. A value of zero will disable smoothing.
     * Constraints: 0 <= value <= 4
     */
    public void setSmoothingThreshold(int smoothingThreshold) {
        this.smoothingThreshold = smoothingThreshold;
        if (this.smoothingThreshold < 0)
            this.smoothingThreshold = 0;
        if (this.smoothingThreshold > 4)
            this.smoothingThreshold = 4;
    }

    public float getTraversableAreaBorderSize() {
        return traversableAreaBorderSize;
    }

    /**
     * Represents the closest any part of the navmesh can get to an obstruction in the source mesh.
     * Usually set to the maximum bounding radius of entities utilizing the navmesh for navigation decisions.
     * Constraints: >= 0
     */
    public void setTraversableAreaBorderSize(float traversableAreaBorderSize) {
        this.traversableAreaBorderSize = traversableAreaBorderSize;
        if (this.traversableAreaBorderSize < 0)
            this.traversableAreaBorderSize = 0;
    }

    public boolean isUseConservativeExpansion() {
        return useConservativeExpansion;
    }

    /**
     * Applies extra algorithms to regions to help prevent poorly formed regions from forming.
     * If the navigation mesh is missing sections that should be present, then enabling this feature will likely 
     * fix the problem.
     * Enabling this feature significantly increased processing cost.
     */
    public void setUseConservativeExpansion(boolean useConservativeExpansion) {
        this.useConservativeExpansion = useConservativeExpansion;
    }

    public int getTimeout() {
        return timeout;
    }

    public void setTimeout(int timeout) {
        this.timeout = timeout;
    }
    
    public void write(JmeExporter ex) throws IOException {
        OutputCapsule oc = ex.getCapsule(this);
        oc.write(cellSize, "cellSize", 1f);
        oc.write(cellHeight, "cellHeight", 1.5f);
        oc.write(minTraversableHeight, "minTraversableHeight", 7.5f);
        oc.write(maxTraversableStep, "maxTraversableStep", 1f);
        oc.write(maxTraversableSlope, "maxTraversableSlope", 48f);
        oc.write(clipLedges, "clipLedges", false);
        oc.write(traversableAreaBorderSize, "traversableAreaBorderSize", 1.2f);
        oc.write(smoothingThreshold, "smoothingThreshold", 2);
        oc.write(useConservativeExpansion, "useConservativeExpansion", true);
        oc.write(minUnconnectedRegionSize, "minUnconnectedRegionSize", 3);
        oc.write(mergeRegionSize, "mergeRegionSize", 10);
        oc.write(maxEdgeLength, "maxEdgeLength", 0);
        oc.write(edgeMaxDeviation, "edgeMaxDeviation", 2.4f);
        oc.write(maxVertsPerPoly, "maxVertsPerPoly", 6);
        oc.write(contourSampleDistance, "contourSampleDistance", 25);
        oc.write(contourMaxDeviation, "contourMaxDeviation", 25);
    }

    public void read(JmeImporter im) throws IOException {
        InputCapsule ic = im.getCapsule(this);
        cellSize = ic.readFloat("cellSize", 1f);
        cellHeight = ic.readFloat("cellHeight", 1.5f);
        minTraversableHeight = ic.readFloat("minTraversableHeight", 7.5f);
        maxTraversableStep = ic.readFloat("maxTraversableStep", 1f);
        maxTraversableSlope = ic.readFloat("maxTraversableSlope", 48f);
        clipLedges = ic.readBoolean("clipLedges", false);
        traversableAreaBorderSize = ic.readFloat("traversableAreaBorderSize", 1.2f);
        smoothingThreshold = (int) ic.readFloat("smoothingThreshold", 2);
        useConservativeExpansion = ic.readBoolean("useConservativeExpansion", true);
        minUnconnectedRegionSize = (int) ic.readFloat("minUnconnectedRegionSize", 3);
        mergeRegionSize = (int) ic.readFloat("mergeRegionSize", 10);
        maxEdgeLength = ic.readFloat("maxEdgeLength", 0);
        edgeMaxDeviation = ic.readFloat("edgeMaxDeviation", 2.4f);
        maxVertsPerPoly = (int) ic.readFloat("maxVertsPerPoly", 6);
        contourSampleDistance = ic.readFloat("contourSampleDistance", 25);
        contourMaxDeviation = ic.readFloat("contourMaxDeviation", 25);
    }

    private class MeshBuildRunnable implements Runnable {

        private float[] positions;
        private int[] indices;
        private IntermediateData intermediateData;
        private TriangleMesh triMesh;

        public MeshBuildRunnable(float[] positions, int[] indices, IntermediateData intermediateData) {
            this.positions = positions;
            this.indices = indices;
            this.intermediateData = intermediateData;
        }

        @Override
        public void run() {
            triMesh = nmgen.build(positions, indices, intermediateData);
        }

        public TriangleMesh getTriMesh() {
            return triMesh;
        }
    }

    public static class TimeoutException extends Exception {

        /** Create an instance */
        public TimeoutException() {
        }
    }
}