Renderer/src/main/java/electrosphere/server/pathfinding/NavMeshConstructor.java

package electrosphere.server.pathfinding;

import org.recast4j.detour.MeshData;
import org.recast4j.detour.NavMeshBuilder;
import org.recast4j.detour.NavMeshDataCreateParams;
import org.recast4j.recast.AreaModification;
import org.recast4j.recast.PolyMesh;
import org.recast4j.recast.PolyMeshDetail;
import org.recast4j.recast.RecastBuilder;
import org.recast4j.recast.RecastBuilder.RecastBuilderResult;
import org.recast4j.recast.RecastConstants.PartitionType;
import org.recast4j.recast.RecastBuilderConfig;
import org.recast4j.recast.RecastConfig;
import org.recast4j.recast.geom.SingleTrimeshInputGeomProvider;

import electrosphere.client.terrain.data.TerrainChunkData;

/**
 * Constructor methods for nav meshes
 */
public class NavMeshConstructor {

    /**
     * Size of a recast cell
     */
    static final float RECAST_CELL_SIZE = 1.0f;

    /**
     * Height of a recast cell
     */
    static final float RECAST_CELL_HEIGHT = 1.0f;

    /**
     * Size of a recast agent
     */
    static final float RECAST_AGENT_SIZE = 1.0f;

    /**
     * Height of a recast agent
     */
    static final float RECAST_AGENT_HEIGHT = 1.0f;

    /**
     * Maximum height a recast agent can climb
     */
    static final float RECAST_AGENT_MAX_CLIMB = 0.1f;

    /**
     * Maximum slope a recast agent can handle
     */
    static final float RECAST_AGENT_MAX_SLOPE = 0.4f;

    /**
     * Minimum size of a recast region
     */
    static final int RECAST_MIN_REGION_SIZE = 1;

    /**
     * Merge size of a recast region
     */
    static final int RECAST_REGION_MERGE_SIZE = 1;

    static final float RECAST_REGION_EDGE_MAX_LEN = 1.0f;

    static final float RECAST_REGION_EDGE_MAX_ERROR = 1.0f;

    static final int RECAST_VERTS_PER_POLY = 3;

    static final float RECAST_DETAIL_SAMPLE_DIST = 0.1f;

    static final float RECAST_DETAIL_SAMPLE_MAX_ERROR = 0.1f;
    
    /**
     * Constructs a navmesh
     * @param terrainChunk The terrain chunk
     * @return the MeshData
     */
    public static MeshData constructNavmesh(TerrainChunkData terrainChunkData){
        MeshData rVal = null;

        try {
            RecastConfig recastConfig = new RecastConfig(
                PartitionType.WATERSHED,
                RECAST_CELL_SIZE,
                RECAST_CELL_HEIGHT,
                RECAST_AGENT_HEIGHT,
                RECAST_AGENT_SIZE,
                RECAST_AGENT_MAX_CLIMB,
                RECAST_AGENT_MAX_SLOPE,
                RECAST_MIN_REGION_SIZE,
                RECAST_REGION_MERGE_SIZE,
                RECAST_REGION_EDGE_MAX_LEN,
                RECAST_REGION_EDGE_MAX_ERROR,
                RECAST_VERTS_PER_POLY,
                RECAST_DETAIL_SAMPLE_DIST,
                RECAST_DETAIL_SAMPLE_MAX_ERROR,
                new AreaModification(0)
            );
            SingleTrimeshInputGeomProvider geomProvider = new SingleTrimeshInputGeomProvider(terrainChunkData.getVertices(), terrainChunkData.getFaceElements());
            RecastBuilderConfig recastBuilderConfig = new RecastBuilderConfig(recastConfig, geomProvider.getMeshBoundsMin(), geomProvider.getMeshBoundsMax());
            RecastBuilder recastBuilder = new RecastBuilder();
            RecastBuilderResult recastBuilderResult = recastBuilder.build(geomProvider, recastBuilderConfig);
            PolyMesh polyMesh = recastBuilderResult.getMesh();
            for(int i = 0; i < polyMesh.npolys; i++){
                polyMesh.flags[i] = 1;
            }


            //set params
            NavMeshDataCreateParams params = new NavMeshDataCreateParams();
            params.verts = polyMesh.verts;
            params.vertCount = polyMesh.nverts;
            params.polys = polyMesh.polys;
            params.polyAreas = polyMesh.areas;
            params.polyFlags = polyMesh.flags;
            params.polyCount = polyMesh.npolys;
            params.nvp = polyMesh.nvp;
            params.walkableHeight = RECAST_AGENT_HEIGHT;
            params.walkableRadius = RECAST_AGENT_SIZE;
            params.walkableClimb = RECAST_AGENT_MAX_CLIMB;
            params.bmin = polyMesh.bmin;
            params.bmax = polyMesh.bmax;
            params.cs = RECAST_CELL_SIZE;
            params.ch = RECAST_CELL_HEIGHT;
            params.buildBvTree = true;

            PolyMeshDetail polyMeshDetail = recastBuilderResult.getMeshDetail();
            if(polyMeshDetail != null){
                params.detailMeshes = polyMeshDetail.meshes;
                params.detailVerts = polyMeshDetail.verts;
                params.detailVertsCount = polyMeshDetail.nverts;
                params.detailTris = polyMeshDetail.tris;
                params.detailTriCount = polyMeshDetail.ntris;
            }

            // params.offMeshConVerts = new float[6];
            // params.offMeshConVerts[0] = 0.1f;
            // params.offMeshConVerts[1] = 0.2f;
            // params.offMeshConVerts[2] = 0.3f;
            // params.offMeshConVerts[3] = 0.4f;
            // params.offMeshConVerts[4] = 0.5f;
            // params.offMeshConVerts[5] = 0.6f;
            // params.offMeshConRad = new float[1];
            // params.offMeshConRad[0] = 0.1f;
            // params.offMeshConDir = new int[1];
            // params.offMeshConDir[0] = 1;
            // params.offMeshConAreas = new int[1];
            // params.offMeshConAreas[0] = 2;
            // params.offMeshConFlags = new int[1];
            // params.offMeshConFlags[0] = 12;
            // params.offMeshConUserID = new int[1];
            // params.offMeshConUserID[0] = 0x4567;
            // params.offMeshConCount = 1;

            //actually build
            rVal = NavMeshBuilder.createNavMeshData(params);


        } catch (Exception e){
            e.printStackTrace();
        }

        return rVal;
    }

}