如何从 GLSurfaceView 获取输出位图？

Question

我面前有 android Hello Effect 示例。我可以看到它如何对 android.opengl.GLSurfaceView 应用不同的效果。一切顺利完成。我想知道如何从 GLSurfaceView 获取输出位图？这是代码：

   private GLSurfaceView glSurfaceView;
    private int[] mTextures = new int[2];
    private EffectContext mEffectContext;
    private Effect mEffect;
    private TextureRenderer mTexRenderer = new TextureRenderer();
    private int mImageWidth;
    private int mImageHeight;
    private boolean mInitialized = false;
    int mCurrentEffect;

    public void setCurrentEffect(int effect) {
        mCurrentEffect = effect;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        /**
         * Initialize the renderer and tell it to only render when
         * explicity requested with the RENDERMODE_WHEN_DIRTY option
         */
        glSurfaceView = (GLSurfaceView) findViewById(R.id.effectsview);
        glSurfaceView.setEGLContextClientVersion(2);
        glSurfaceView.setRenderer(this);
        glSurfaceView.setRenderMode(GLSurfaceView.RENDERMODE_WHEN_DIRTY);
        mCurrentEffect = R.id.none;

    }



    private void loadTextures() {
        // Generate textures
        GLES20.glGenTextures(2, mTextures, 0);

        // Load input bitmap
        Bitmap bitmap = BitmapFactory.decodeResource(getResources(),
                R.drawable.puppy);
        mImageWidth = bitmap.getWidth();
        mImageHeight = bitmap.getHeight();
        mTexRenderer.updateTextureSize(mImageWidth, mImageHeight);

        // Upload to texture
        GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, mTextures[0]);
        GLUtils.texImage2D(GLES20.GL_TEXTURE_2D, 0, bitmap, 0);
        // Set texture parameters
        GLToolbox.initTexParams();
    }

    private void initEffect() {
        EffectFactory effectFactory = mEffectContext.getFactory();
        if (mEffect != null) {
            mEffect.release();
        }
        /**
         * Initialize the correct effect based on the selected menu/action item
         */
        switch (mCurrentEffect) {

            case R.id.none:
                break;

            case R.id.autofix:
                mEffect = effectFactory.createEffect(
                        EffectFactory.EFFECT_AUTOFIX);
                mEffect.setParameter("scale", 0.5f);
                break;

            case R.id.bw:
                mEffect = effectFactory.createEffect(
                        EffectFactory.EFFECT_BLACKWHITE);
                mEffect.setParameter("black", .1f);
                mEffect.setParameter("white", .7f);
                break;

            case R.id.brightness:
                mEffect = effectFactory.createEffect(
                        EffectFactory.EFFECT_BRIGHTNESS);
                mEffect.setParameter("brightness", 2.0f);
                break;

            case R.id.contrast:
                mEffect = effectFactory.createEffect(
                        EffectFactory.EFFECT_CONTRAST);
                mEffect.setParameter("contrast", 1.4f);
                break;

            case R.id.crossprocess:
                mEffect = effectFactory.createEffect(
                        EffectFactory.EFFECT_CROSSPROCESS);
                break;

            case R.id.documentary:
                mEffect = effectFactory.createEffect(
                        EffectFactory.EFFECT_DOCUMENTARY);
                break;

            case R.id.duotone:
                mEffect = effectFactory.createEffect(
                        EffectFactory.EFFECT_DUOTONE);
                mEffect.setParameter("first_color", Color.YELLOW);
                mEffect.setParameter("second_color", Color.DKGRAY);
                break;

            case R.id.filllight:
                mEffect = effectFactory.createEffect(
                        EffectFactory.EFFECT_FILLLIGHT);
                mEffect.setParameter("strength", .8f);
                break;

            case R.id.fisheye:
                mEffect = effectFactory.createEffect(
                        EffectFactory.EFFECT_FISHEYE);
                mEffect.setParameter("scale", .5f);
                break;

            case R.id.flipvert:
                mEffect = effectFactory.createEffect(
                        EffectFactory.EFFECT_FLIP);
                mEffect.setParameter("vertical", true);
                break;

            case R.id.fliphor:
                mEffect = effectFactory.createEffect(
                        EffectFactory.EFFECT_FLIP);
                mEffect.setParameter("horizontal", true);
                break;

            case R.id.grain:
                mEffect = effectFactory.createEffect(
                        EffectFactory.EFFECT_GRAIN);
                mEffect.setParameter("strength", 1.0f);
                break;

            case R.id.grayscale:
                mEffect = effectFactory.createEffect(
                        EffectFactory.EFFECT_GRAYSCALE);
                break;

            case R.id.lomoish:
                mEffect = effectFactory.createEffect(
                        EffectFactory.EFFECT_LOMOISH);
                break;

            case R.id.negative:
                mEffect = effectFactory.createEffect(
                        EffectFactory.EFFECT_NEGATIVE);
                break;

            case R.id.posterize:
                mEffect = effectFactory.createEffect(
                        EffectFactory.EFFECT_POSTERIZE);
                break;

            case R.id.rotate:
                mEffect = effectFactory.createEffect(
                        EffectFactory.EFFECT_ROTATE);
                mEffect.setParameter("angle", 180);
                break;

            case R.id.saturate:
                mEffect = effectFactory.createEffect(
                        EffectFactory.EFFECT_SATURATE);
                mEffect.setParameter("scale", .5f);
                break;

            case R.id.sepia:
                mEffect = effectFactory.createEffect(
                        EffectFactory.EFFECT_SEPIA);
                break;

            case R.id.sharpen:
                mEffect = effectFactory.createEffect(
                        EffectFactory.EFFECT_SHARPEN);
                break;

            case R.id.temperature:
                mEffect = effectFactory.createEffect(
                        EffectFactory.EFFECT_TEMPERATURE);
                mEffect.setParameter("scale", .9f);
                break;

            case R.id.tint:
                mEffect = effectFactory.createEffect(
                        EffectFactory.EFFECT_TINT);
                mEffect.setParameter("tint", Color.MAGENTA);
                break;

            case R.id.vignette:
                mEffect = effectFactory.createEffect(
                        EffectFactory.EFFECT_VIGNETTE);
                mEffect.setParameter("scale", .5f);
                break;

            default:
                break;

        }

    }

    private void applyEffect() {
        mEffect.apply(mTextures[0], mImageWidth, mImageHeight, mTextures[1]);
    }

    private void renderResult() {
        if (mCurrentEffect != R.id.none) {
            // if no effect is chosen, just render the original bitmap
            mTexRenderer.renderTexture(mTextures[1]);
        } else {
            // render the result of applyEffect()
            mTexRenderer.renderTexture(mTextures[0]);
        }
    }

    @Override
    public void onDrawFrame(GL10 gl) {
        if (!mInitialized) {
            //Only need to do this once
            mEffectContext = EffectContext.createWithCurrentGlContext();
            mTexRenderer.init();
            loadTextures();
            mInitialized = true;
        }
        if (mCurrentEffect != R.id.none) {
            //if an effect is chosen initialize it and apply it to the texture
            initEffect();
            applyEffect();
        }
        renderResult();
    }

    @Override
    public void onSurfaceChanged(GL10 gl, int width, int height) {
        if (mTexRenderer != null) {
            mTexRenderer.updateViewSize(width, height);

        }
    }

    @Override
    public void onSurfaceCreated(GL10 gl, EGLConfig config) {
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        setCurrentEffect(item.getItemId());
        glSurfaceView.requestRender();
        return true;
    }
}

Answer 1

您可以在完成渲染后但在调用 eglSwapBuffers() 之前使用 glReadPixels() 读取像素。您正在使用 GLSurfaceView，它会在 onDrawFrame() returns 时为您进行缓冲区交换，因此您需要在 onDrawFrame().[=15= 结束时立即进行捕获]

您可以在Grafika. See the EglSurfaceBase#saveFrame() 方法中找到将当前 GLES 帧缓冲区保存到 PNG 的示例（您可以忽略顶部的 mEglCore 测试）。

Answer 2

要从 glSurfaceView 获取输出位图，您需要使用 glReadPixes()。使用 glReadPixels() 时，请确保从渲染器线程调用它。如果您从主线程调用，它不会工作。这是获取输出位图的代码。

   public Bitmap createBitmapFromGLSurface(int w, int h) {
    w = screenWidth;
    h = screenHeight;


    int bitmapBuffer[] = new int[w * h];
    int bitmapSource[] = new int[w * h];
    IntBuffer intBuffer = IntBuffer.wrap(bitmapBuffer);
    intBuffer.position(0);
    try {


        GLES20.glReadPixels(x, y, w, h, GLES20.GL_RGBA, GLES20.GL_UNSIGNED_BYTE, intBuffer);
        int offset1, offset2;
        for (int i = 0; i < h; i++) {
            offset1 = i * w;
            offset2 = (h - i - 1) * w;
            for (int j = 0; j < w; j++) {
                int texturePixel = bitmapBuffer[offset1 + j];
                int blue = (texturePixel >> 16) & 0xff;
                int red = (texturePixel << 16) & 0x00ff0000;
                int pixel = (texturePixel & 0xff00ff00) | red | blue;
                bitmapSource[offset2 + j] = pixel;
            }
        }
    } catch (GLException e) {
        e.printStackTrace();
        return null;
    }
    return Bitmap.createBitmap(bitmapSource, w, h, Bitmap.Config.ARGB_8888);
    }

如何从 GLSurfaceView 获取输出位图？

how to get output bitmap from GLSurfaceView?

android

bitmap

glsurfaceview