new3d/src/com/android/gallery3d/ui/BasicTexture.java

/*
 * Copyright (C) 2010 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.gallery3d.ui;

import java.lang.ref.WeakReference;

// BasicTexture is a Texture corresponds to a real GL texture.
// The state of a BasicTexture indicates whether its data is loaded to GL memory.
// If a BasicTexture is loaded into GL memory, it has a GL texture id.
abstract class BasicTexture implements Texture {

    protected static final int UNSPECIFIED = -1;

    protected static final int STATE_UNLOADED = 0;
    protected static final int STATE_LOADED = 1;
    protected static final int STATE_ERROR = -1;

    protected int mId;
    protected int mState;

    protected int mWidth = UNSPECIFIED;
    protected int mHeight = UNSPECIFIED;

    private int mTextureWidth;
    private int mTextureHeight;

    protected WeakReference<GLCanvas> mCanvasRef = null;

    protected BasicTexture(GLCanvas canvas, int id, int state) {
        setAssociatedCanvas(canvas);
        mId = id;
        mState = state;
    }

    protected BasicTexture() {
        this(null, 0, STATE_UNLOADED);
    }

    protected void setAssociatedCanvas(GLCanvas canvas) {
        mCanvasRef = canvas == null
                ? null
                : new WeakReference<GLCanvas>(canvas);
    }

    /**
     * Sets the content size of this texture. In OpenGL, the actual texture
     * size must be of power of 2, the size of the content may be smaller.
     */
    protected void setSize(int width, int height) {
        mWidth = width;
        mHeight = height;
        mTextureWidth = Util.nextPowerOf2(width);
        mTextureHeight = Util.nextPowerOf2(height);
    }

    public int getId() {
        return mId;
    }

    public int getWidth() {
        return mWidth;
    }

    public int getHeight() {
        return mHeight;
    }

    // Returns the width rounded to the next power of 2.
    public int getTextureWidth() {
        return mTextureWidth;
    }

    // Returns the height rounded to the next power of 2.
    public int getTextureHeight() {
        return mTextureHeight;
    }

    public void draw(GLCanvas canvas, int x, int y) {
        canvas.drawTexture(this, x, y, getWidth(), getHeight());
    }

    public void draw(GLCanvas canvas, int x, int y, int w, int h) {
        canvas.drawTexture(this, x, y, w, h);
    }

    // onBind is called before GLCanvas binds this texture.
    // It should make sure the data is uploaded to GL memory.
    abstract protected void onBind(GLCanvas canvas);

    public boolean isLoaded(GLCanvas canvas) {
        return mState == STATE_LOADED && mCanvasRef.get() == canvas;
    }

    public void recycle() {
        GLCanvas canvas = mCanvasRef == null ? null : mCanvasRef.get();
        if (canvas != null) {
            canvas.unloadTexture(this);
            setAssociatedCanvas(null);
            mState = BasicTexture.STATE_UNLOADED;
        }
    }
}