de.ikosa.mars.viewer.glviewer.engine.GLTexture.java Source code

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Here is the source code for de.ikosa.mars.viewer.glviewer.engine.GLTexture.java

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/*
 * Copyright (C) 2013 Clemens-Alexander Brust IT-Dienstleistungen
 *
 *     This program is free software: you can redistribute it and/or modify
 *     it under the terms of the GNU General Public License as published by
 *     the Free Software Foundation, either version 3 of the License, or
 *     (at your option) any later version.
 *
 *     This program 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 General Public License for more details.
 *
 *     You should have received a copy of the GNU General Public License
 *     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package de.ikosa.mars.viewer.glviewer.engine;

import de.ikosa.mars.ruleset.TerrainType;
import de.ikosa.mars.util.ML;
import org.lwjgl.BufferUtils;
import org.lwjgl.opengl.GL11;
import org.lwjgl.opengl.GL13;

import java.nio.ByteBuffer;
import java.nio.ShortBuffer;

public class GLTexture {
    private String name;
    private int textureId;

    public GLTexture(String name, int textureId) {
        this.name = name;
        this.textureId = textureId;
    }

    public int getTextureId() {
        return textureId;
    }

    public String getName() {
        return name;
    }

    public void use(int textureUnit) {
        if (textureUnit >= 0) {
            GL13.glActiveTexture(GL13.GL_TEXTURE0 + textureUnit);
            GL11.glBindTexture(GL11.GL_TEXTURE_2D, getTextureId());
        }
    }

    public int getSizeX() {
        use(0);
        return GL11.glGetTexLevelParameteri(GL11.GL_TEXTURE_2D, 0, GL11.GL_TEXTURE_WIDTH);
    }

    public int getSizeY() {
        use(0);
        return GL11.glGetTexLevelParameteri(GL11.GL_TEXTURE_2D, 0, GL11.GL_TEXTURE_HEIGHT);
    }

    public float[][] toHeightMap(int samplesX, int samplesY) {
        float[][] height = new float[samplesX][samplesY];

        ML.d(String.format("Loading texture for height map \"%s\"...", getName()));

        // check size
        int texSizeX = getSizeX();
        int texSizeY = getSizeY();
        if (texSizeX != samplesX | texSizeY != samplesY)
            ML.f(String.format("Texture size doesn't match height map size! (%d x %d) vs. (%d x %d)", texSizeX,
                    texSizeY, samplesX, samplesY));

        // create buffer
        ShortBuffer byteBuffer = BufferUtils.createShortBuffer(texSizeX * texSizeY);

        // and go
        GL11.glGetTexImage(GL11.GL_TEXTURE_2D, 0, GL11.GL_RED, GL11.GL_UNSIGNED_SHORT, byteBuffer);

        int error = GL11.glGetError();
        if (error != GL11.GL_NO_ERROR)
            ML.f(String.format("Cannot load height map from texture (GL error %x)", error));

        // read samples
        for (int x = 0; x < texSizeX; x++)
            for (int y = 0; y < texSizeY; y++) {
                short sValue = byteBuffer.get((samplesX * y + x));

                int value = fromShort(sValue);
                height[x][y] = value / 65535.0f;
            }

        return height;
    }

    public TerrainType[][] toTerrainMap(int samplesX, int samplesY) {
        TerrainType[][] height = new TerrainType[samplesX][samplesY];

        ML.d(String.format("Loading texture for terrain map \"%s\"...", getName()));

        // check size
        int texSizeX = getSizeX();
        int texSizeY = getSizeY();
        if (texSizeX != samplesX | texSizeY != samplesY)
            ML.f(String.format("Texture size doesn't match terrain map size! (%d x %d) vs. (%d x %d)", texSizeX,
                    texSizeY, samplesX, samplesY));

        // create buffer
        ByteBuffer byteBuffer = BufferUtils.createByteBuffer(texSizeX * texSizeY * 4);

        // and go
        GL11.glGetTexImage(GL11.GL_TEXTURE_2D, 0, GL11.GL_RGBA, GL11.GL_UNSIGNED_BYTE, byteBuffer);

        int error = GL11.glGetError();
        if (error != GL11.GL_NO_ERROR)
            ML.f(String.format("Cannot load terrain map from texture (GL error %x)", error));

        // read samples
        for (int x = 0; x < texSizeX; x++)
            for (int y = 0; y < texSizeY; y++) {
                float r = fromByte(byteBuffer.get(4 * (samplesX * y + x))) / 255.0f;
                float g = fromByte(byteBuffer.get(4 * (samplesX * y + x) + 1)) / 255.0f;
                float b = fromByte(byteBuffer.get(4 * (samplesX * y + x) + 2)) / 255.0f;
                height[x][y] = TerrainType.fromColor(r, g, b);
            }

        return height;
    }

    private int fromByte(byte b) {
        return (b >= 0) ? b : ((int) b) + 256;
    }

    private int fromShort(short s) {
        return (s >= 0) ? s : ((int) s) + 65536;
    }
}