mwisbest.openbase.opengl.UtilsGL.java Source code

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Here is the source code for mwisbest.openbase.opengl.UtilsGL.java

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/*
 * This file is part of OpenBASE.
 *
 * Copyright  2012, Kyle Repinski
 * OpenBASE is licensed under the GNU Lesser General Public License.
 *
 * OpenBASE is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * OpenBASE is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
package mwisbest.openbase.opengl;

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;

import javax.imageio.ImageIO;

import mwisbest.openbase.Common;

import org.lwjgl.BufferUtils;
import org.lwjgl.opengl.Display;
import org.lwjgl.opengl.GL11;
import org.newdawn.slick.opengl.PNGDecoder;
import org.newdawn.slick.util.ResourceLoader;

public class UtilsGL {
    public static ByteBuffer loadIcon(String path) throws IOException {
        try (InputStream is = ResourceLoader.getResourceAsStream(path)) {
            PNGDecoder decoder = new PNGDecoder(is);
            ByteBuffer bb = ByteBuffer.allocateDirect(decoder.getWidth() * decoder.getHeight() * 4);
            decoder.decode(bb, decoder.getWidth() * 4, PNGDecoder.Format.RGBA);
            bb.flip();
            return bb;
        }
    }

    public static void takeScreenshot(String filename) {
        GL11.glReadBuffer(GL11.GL_FRONT);
        int width = Display.getDisplayMode().getWidth();
        int height = Display.getDisplayMode().getHeight();
        int bpp = 4;
        ByteBuffer buffer = BufferUtils.createByteBuffer(width * height * bpp);
        GL11.glReadPixels(0, 0, width, height, GL11.GL_RGBA, GL11.GL_UNSIGNED_BYTE, buffer);
        File file = new File(filename);
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);

        for (int x = 0; x < width; x++) {
            for (int y = 0; y < height; y++) {
                int i = (x + width * y) * bpp;
                int r = buffer.get(i) & 0xFF;
                int g = buffer.get(i + 1) & 0xFF;
                int b = buffer.get(i + 2) & 0xFF;
                image.setRGB(x, height - (y + 1), 0xFF << 24 | r << 16 | g << 8 | b);
            }
        }

        try {
            ImageIO.write(image, "PNG", file);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * Draws the specified texture to positions x and y on the screen and scaled with the specified width and height
     * 
     * @param texture
     * @param x
     * @param y
     * @param width
     * @param height
     */
    public static void drawTexture(Texture texture, int x, int y, int width, int height) {
        GL11.glPushMatrix();
        GL11.glEnable(GL11.GL_BLEND);
        GL11.glBlendFunc(GL11.GL_SRC_ALPHA, GL11.GL_ONE_MINUS_SRC_ALPHA);
        GL11.glDepthMask(false);
        GL11.glColor4f(1.0F, 1.0F, 1.0F, 1.0F);
        if (Common.currentTextureID != texture.getTextureID()) {
            int texID = texture.getTextureID();
            GL11.glBindTexture(GL11.GL_TEXTURE_2D, texID);
            Common.currentTextureID = texID;
        }
        GL11.glTranslatef(x, y, 0);
        GL11.glBegin(GL11.GL_QUADS);
        GL11.glTexCoord2f(0, 0);
        GL11.glVertex2f(0, 0);
        GL11.glTexCoord2f(0, texture.getHeight());
        GL11.glVertex2f(0, height);
        GL11.glTexCoord2f(texture.getWidth(), texture.getHeight());
        GL11.glVertex2f(width, height);
        GL11.glTexCoord2f(texture.getWidth(), 0);
        GL11.glVertex2f(width, 0);
        GL11.glEnd();
        GL11.glPopMatrix();
    }
}