fr.guillaume.prive.viper.core.model.texture.PNGTextureLoader.java Source code

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Here is the source code for fr.guillaume.prive.viper.core.model.texture.PNGTextureLoader.java

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package fr.guillaume.prive.viper.core.model.texture;

import de.matthiasmann.twl.utils.PNGDecoder;
import de.matthiasmann.twl.utils.PNGDecoder.Format;
import fr.guillaume.prive.viper.core.graphic.GraphicMotor;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import org.lwjgl.opengl.GL11;
import org.lwjgl.opengl.GL13;
import org.lwjgl.opengl.GL30;

/**
 *
 * @author guillaume
 */
public class PNGTextureLoader {

    public static int loadTexture(String filename, int textureUnit) {
        ByteBuffer buf = null;
        int tWidth = 0;
        int tHeight = 0;

        try (InputStream in = new FileInputStream(filename)) {
            PNGDecoder decoder = new PNGDecoder(in);

            tWidth = decoder.getWidth();
            tHeight = decoder.getHeight();

            buf = ByteBuffer.allocateDirect(4 * decoder.getWidth() * decoder.getHeight());
            decoder.decode(buf, decoder.getWidth() * 4, Format.RGBA);
            buf.flip();
            in.close();
        } catch (IOException e) {
            throw new IllegalStateException("PNG file i/o error", e);
        }

        // Create a new texture object in memory and bind it
        int texId = GL11.glGenTextures();
        GL13.glActiveTexture(textureUnit);
        GL11.glBindTexture(GL11.GL_TEXTURE_2D, texId);

        // All RGB bytes are aligned to each other and each component is 1 byte
        GL11.glPixelStorei(GL11.GL_UNPACK_ALIGNMENT, 1);

        // Upload the texture data and generate mip maps (for scaling)
        GL11.glTexImage2D(GL11.GL_TEXTURE_2D, 0, GL11.GL_RGBA16, tWidth, tHeight, 0, GL11.GL_RGBA,
                GL11.GL_UNSIGNED_BYTE, buf);
        GL30.glGenerateMipmap(GL11.GL_TEXTURE_2D);

        // Setup the ST coordinate system
        GL11.glTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_WRAP_S, GL11.GL_REPEAT);
        GL11.glTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_WRAP_T, GL11.GL_REPEAT);

        // Setup what to do when the texture has to be scaled
        GL11.glTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_MAG_FILTER, GL11.GL_NEAREST);
        GL11.glTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_MIN_FILTER, GL11.GL_LINEAR_MIPMAP_LINEAR);

        GraphicMotor.exitOnGLError("loadPNGTexture");

        return texId;
    }

    private PNGTextureLoader() {
        super();
    }

}