com.xrbpowered.gl.scene.ActorPicker.java Source code

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Here is the source code for com.xrbpowered.gl.scene.ActorPicker.java

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/*******************************************************************************
 * MIT License
 *
 * Copyright (c) 2016 Ashur Rafiev
 *
 * 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.xrbpowered.gl.scene;

import java.nio.ByteBuffer;

import org.lwjgl.opengl.GL11;

import com.xrbpowered.gl.res.buffers.RenderTarget;

public class ActorPicker {

    private static final int[] ATTRIB_MASK = { 0 };

    private int x, y;
    private ByteBuffer pixels = ByteBuffer.allocateDirect(4);

    public void startPicking(int x, int y, RenderTarget pickTarget) {
        this.x = x;
        this.y = y;
        pickTarget.use();
        GL11.glScissor(x, y, 1, 1);
        GL11.glEnable(GL11.GL_SCISSOR_TEST);
        GL11.glClearColor(0f, 0f, 0f, 0f);
        GL11.glClear(GL11.GL_COLOR_BUFFER_BIT | GL11.GL_DEPTH_BUFFER_BIT);
        ActorPickerShader.getInstance().use();
    }

    public void drawActor(StaticMeshActor actor, int objId) {
        ActorPickerShader.getInstance().updateUniforms(actor, objId);
        actor.getMesh().draw(ATTRIB_MASK);
    }

    public int finishPicking(RenderTarget nextTarget) {
        GL11.glReadPixels(x, y, 1, 1, GL11.GL_RGB, GL11.GL_UNSIGNED_BYTE, pixels);
        GL11.glDisable(GL11.GL_SCISSOR_TEST);
        nextTarget.use();
        return pixels.asIntBuffer().get(0) >> 8;
    }

    public static final ActorPicker instance = new ActorPicker();
}