Cursor.java

/*
 * The MIT License (MIT)
 *
 * Copyright (c) 2014-2017 Sri Harsha Chilakapati
 *
 * 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 com.shc.silenceengine.backend.lwjgl.glfw;

import com.shc.silenceengine.core.SilenceException;
import com.shc.silenceengine.graphics.Color;
import com.shc.silenceengine.graphics.Image;
import org.lwjgl.BufferUtils;
import org.lwjgl.glfw.GLFWImage;

import java.nio.ByteBuffer;

import static org.lwjgl.glfw.GLFW.*;
import static org.lwjgl.system.MemoryUtil.*;

/**
 * A cursor is the visual representation of the mouse pointer. You can create a cursor using an image, OpenGL texture,
 * or also choose one from the ones provided by the operating system.
 *
 * @author Sri Harsha Chilakapati
 */
public class Cursor
{
    private long handle;

    /**
     * Constructs a cursor object using the pixels from an Image object and also the location of the pointer hot point
     * in the image pixels retrieved from the OpenGL Texture.
     *
     * @param image The Image object to retrieve the image data from.
     * @param xHot  The x-coordinate of the cursor hotspot in pixels.
     * @param yHot  The y-coordinate of the cursor hotspot in pixels.
     */
    public Cursor(Image image, int xHot, int yHot)
    {
        int width = image.getWidth();
        int height = image.getHeight();

        GLFWImage glfwImage = GLFWImage.calloc();
        glfwImage.width(width);
        glfwImage.height(height);

        ByteBuffer data = BufferUtils.createByteBuffer(width * height * 4);

        Color color = Color.REUSABLE_STACK.pop();

        for (int y = 0; y < height; y++)
        {
            for (int x = 0; x < width; x++)
            {
                image.getPixel(x, y, color);

                float r = (color.r * 255f);
                float g = (color.g * 255f);
                float b = (color.b * 255f);
                float a = ((1 - color.a) * 255f);

                data.put((byte) r)
                        .put((byte) g)
                        .put((byte) b)
                        .put((byte) a);
            }
        }

        Color.REUSABLE_STACK.push(color);

        data.flip();
        glfwImage.pixels(data);

        handle = glfwCreateCursor(glfwImage, xHot, yHot);

        if (handle == NULL)
            throw new SilenceException("Unable to load cursor from texture");

        glfwImage.free();
    }

    /**
     * Constructs a cursor object using the pixels from an Image object.
     *
     * @param image The Image object to retrieve the image data from.
     */
    public Cursor(Image image)
    {
        this(image, 0, 0);
    }

    /**
     * Constructs a cursor object that uses a predefined cursor defined by the operating system.
     *
     * @param standardType The type of the default cursor that this cursor object should look like.
     */
    public Cursor(Type standardType)
    {
        handle = glfwCreateStandardCursor(standardType.getType());

        if (handle == NULL)
            throw new SilenceException("Unable to load cursor from texture");
    }

    /**
     * Destroys this cursor object.
     */
    public void destroy()
    {
        glfwDestroyCursor(handle);
    }

    /**
     * @return The native handle of this cursor object.
     */
    public long getHandle()
    {
        return handle;
    }

    /**
     * The type of the OS defined cursors.
     */
    public enum Type
    {
        /**
         * The regular arrow cursor shape.
         */
        ARROW(GLFW_ARROW_CURSOR),

        /**
         * The text-input I-Beam cursor shape.
         */
        IBEAM(GLFW_IBEAM_CURSOR),

        /**
         * The crosshair cursor shape.
         */
        CROSSHAIR(GLFW_CROSSHAIR_CURSOR),

        /**
         * The hand cursor shape.
         */
        HAND(GLFW_HAND_CURSOR),

        /**
         * The horizontal resize arrow cursor shape.
         */
        HRESIZE(GLFW_HRESIZE_CURSOR),

        /**
         * The vertical resize arrow cursor shape.
         */
        VRESIZE(GLFW_VRESIZE_CURSOR);

        private int type;

        Type(int type)
        {
            this.type = type;
        }

        /**
         * @return The native value of the enum field.
         */
        public int getType()
        {
            return type;
        }
    }
}