Loads a bitmap from the given filename and location into the provided OpenGl texture and generates mipmaps for it.

Description

Demo Code

/*//from   w  w w . j a va 2 s.  c  o m
 * Created by Zahari Pastarmadjiev.
 * Copyright (c) 2013 Wacom. All rights reserved.
 */
import java.io.IOException;
import java.io.InputStream;
import javax.microedition.khronos.egl.EGL10;
import javax.microedition.khronos.egl.EGLContext;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.opengl.GLES20;
import android.opengl.GLUtils;

public class Main{
    public static Logger logger = new Logger(OpenGLUtils.class);
    /**
     * Loads a bitmap from the given filename and location into the provided OpenGl texture and generates mipmaps for it.
     * This method searches for additional image files in the provided location folder for the different mipmap levels.
     * For example: if the filename is image.png, the method will look for a image_i.png file for the i-th mipmap level.
     * @param context An Android context.
     * @param filename The image filename.
     * @param location The folder, where the image is located. If location is null, the method expects the file to be located in the assets folder of the application.
     * @param textureId A value to be used as {@link GLES20#GL_TEXTURE_MIN_FILTER} and {@link GLES20#GL_TEXTURE_MAG_FILTER} texture parameter.
     * @param sampleMode A value to be used as {@link GLES20#GL_TEXTURE_MIN_FILTER} and {@link GLES20#GL_TEXTURE_MAG_FILTER} texture parameter.
     * @param wrapMode A value to be used as {@link GLES20#GL_TEXTURE_WRAP_S} and {@link GLES20#GL_TEXTURE_WRAP_T} texture parameter.
     * @return OpengGl texture id.
     */
    public static boolean generateMipmaps(Context context, String filename,
            String location, int textureId, int sampleMode, int wrapMode) {
        InputStream is = null;
        String res[] = Utils.splitFilenameAndExt(filename);
        int errCode;

        if (res == null) {
            //can't split filename, that's odd
            return false;
        }

        String fn = res[0];
        String ext = res[1];

        if (Logger.LOG_ENABLED)
            logger.i("generateMipmaps / bind texture " + textureId);

        GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textureId);

        GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D,
                GLES20.GL_TEXTURE_WRAP_S, wrapMode);
        GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D,
                GLES20.GL_TEXTURE_WRAP_T, wrapMode);
        GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D,
                GLES20.GL_TEXTURE_MAG_FILTER, sampleMode);
        GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D,
                GLES20.GL_TEXTURE_MIN_FILTER,
                GLES20.GL_LINEAR_MIPMAP_LINEAR);

        Bitmap bitmap = null;
        Bitmap baseBitmap = null;
        boolean bMipmapping = true;
        int level = 0;
        int size = 0;
        while (bMipmapping) {
            String f = null;
            try {
                if (level == 0) {
                    f = filename;
                } else {
                    f = fn + "_" + level + "." + ext;
                }
                //            is = context.getAssets().open(f);
                is = Utils.openFile(context, f, location);
                bitmap = BitmapFactory.decodeStream(is);
                if (bitmap != null) {
                    baseBitmap = bitmap;
                    size = baseBitmap.getWidth();
                }
            } catch (IOException e) {
                if (Logger.LOG_ENABLED)
                    logger.i("generateMipmaps /  error opening asset " + f);
                bitmap = null;
            } finally {
                try {
                    is.close();
                } catch (Exception e) {
                }
            }
            if (bitmap == null) {
                size = size / 2;
                if (Logger.LOG_ENABLED)
                    logger.i("generateMipmaps / no bitmap allocated for "
                            + filename + ", level=" + level
                            + "; downscaling initial bitmap to " + size
                            + "x" + size);
                bitmap = Bitmap.createScaledBitmap(baseBitmap, size, size,
                        true);
                if (bitmap == baseBitmap) {
                    //if this ever happens, it seems like android sdk bug (1); maybe we should throw an exception here
                    if (Logger.LOG_ENABLED)
                        logger.i("generateMipmaps / if this ever happens, it seems like android sdk bug (1); maybe we should throw an exception here");
                    return false;
                }
                if (bitmap == null) {
                    //if this ever happens, it seems like android sdk bug (2); maybe we should throw an exception here
                    if (Logger.LOG_ENABLED)
                        logger.i("generateMipmaps / if this ever happens, it seems like android sdk bug (2); maybe we should throw an exception here");
                    return false;
                }
            }
            if (Logger.LOG_ENABLED)
                logger.i("generateMipmaps / texImage2D => fn=" + filename
                        + " level=" + level + " / size="
                        + bitmap.getWidth() + "x" + bitmap.getHeight());

            GLUtils.texImage2D(GLES20.GL_TEXTURE_2D, level, bitmap, 0);
            errCode = GLES20.glGetError();
            if (errCode != GLES20.GL_NO_ERROR) {
                if (Logger.LOG_ENABLED)
                    logger.e("generateMipmaps / ERROR " + errCode
                            + " with texImage2D => fn=" + filename
                            + " level=" + level);
            }
            if (level > 0) {
                bitmap = Utils.recycleBitmap(bitmap);
            }
            level++;
            bMipmapping = size > 1;
        }

        Utils.recycleBitmap(baseBitmap);

        return true;
    }
}
Loads a bitmap from the given filename and location into the provided OpenGl texture and generates mipmaps for it. - Android android.opengl

Description

Demo Code

Related Tutorials
