BlueMap/BlueMapCore/src/main/java/de/bluecolored/bluemap/core/threejs/BufferAttribute.java

/*
 * This file is part of BlueMap, licensed under the MIT License (MIT).
 *
 * Copyright (c) Blue (Lukas Rieger) <https://bluecolored.de>
 * Copyright (c) contributors
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package de.bluecolored.bluemap.core.threejs;

import com.google.gson.stream.JsonReader;
import com.google.gson.stream.JsonWriter;
import de.bluecolored.bluemap.core.util.Preconditions;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

/**
 * Represents a ThreeJS BufferAttribute
 */
public class BufferAttribute {

    private int itemSize;
    private boolean normalized;
    private float[] values;

    /**
     * Creates a new {@link BufferAttribute} with the defined item-size
     */
    public BufferAttribute(float[] values, int itemSize) {
        Preconditions.checkArgument(values.length % itemSize == 0, "The length of the values-array is not a multiple of the item-size!");

        this.values = values;
        this.itemSize = itemSize;
        this.normalized = false;
    }

    /**
     * Creates a new {@link BufferAttribute} with the defined item-size and the
     * defined threejs "normalized" attribute
     */
    public BufferAttribute(float[] values, int itemSize, boolean normalized) {
        Preconditions.checkArgument(values.length % itemSize == 0, "The length of the values-array is not a multiple of the item-size!");

        this.values = values;
        this.itemSize = itemSize;
        this.normalized = normalized;
    }

    public void writeJson(JsonWriter json) throws IOException {
        json.beginObject();

        json.name("type").value("Float32Array");
        json.name("itemSize").value(itemSize);
        json.name("normalized").value(normalized);

        json.name("array").beginArray();
        for (int i = 0; i < values.length; i++) {
            // rounding and remove ".0" to save string space
            double d = Math.round(values[i] * 10000d) / 10000d;
            if (d == (long) d) json.value((long) d);
            else json.value(d);
        }
        json.endArray();

        json.endObject();
    }

    public int getItemSize() {
        return this.itemSize;
    }

    public boolean isNormalized() {
        return this.normalized;
    }

    public int getValueCount() {
        return this.values.length;
    }

    public int getItemCount() {
        return Math.floorDiv(getValueCount(), getItemSize());
    }

    public float[] values() {
        return values;
    }

    public static BufferAttribute readJson(JsonReader json) throws IOException {
        List<Float> list = new ArrayList<>(1000);
        int itemSize = 1;
        boolean normalized = false;

        json.beginObject(); //root
        while (json.hasNext()){
            String name = json.nextName();

            if(name.equals("array")){
                json.beginArray(); //array
                while (json.hasNext()){
                    list.add((float) json.nextDouble());
                }
                json.endArray(); //array
            }

            else if (name.equals("itemSize")) {
                itemSize = json.nextInt();
            }

            else if (name.equals("normalized")) {
                normalized = json.nextBoolean();
            }

            else json.skipValue();
        }
        json.endObject(); //root

        //collect values in array
        float[] values = new float[list.size()];
        for (int i = 0; i < values.length; i++) {
            values[i] = list.get(i);
        }

        return new BufferAttribute(values, itemSize, normalized);
    }

}